Fuel cell system

Abstract

To reduce probability of operation of a fuel cell system being restricted when a mechanism of a path for supplying hydrogen has no abnormality.SOLUTION: A fuel cell system comprises: a fuel cell; a fuel gas tank; a gas passage connecting the fuel cell and the fuel gas tank; a pressure reduction valve capable of blocking or circulating fuel gas by reducing pressure of the fuel gas in the gas passage; a pressure sensor for acquiring pressure of gas on the side of the fuel cell with respect to the pressure reduction valve; an operation storage unit for storing a length of a dormant period of the fuel cell system; and a controlling unit. The controlling unit performs start control for starting operation of the fuel cell when a first start condition including the pressure acquired by the pressure sensor being lower than a first pressure threshold value is satisfied, and performs the start control when a second start condition including the pressure acquired by the pressure sensor being higher than the first pressure threshold value and the length of the dormant period stored in the operation storage unit being larger than a dormant threshold value is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to fuel cell systems. [Background technology]

[0002] Conventionally, there exists a fuel cell system that includes a hydrogen tank, a shutoff valve, a pressure reducing valve, and a pressure regulating valve in the path that supplies hydrogen to the fuel cell stack. High-pressure hydrogen gas supplied from the hydrogen tank passes through the pressure reducing valve and pressure regulating valve, where it is adjusted to an appropriate pressure and amount before being supplied to the fuel cell stack. When the fuel cell system is not in operation, the pressure reducing valve and pressure regulating valve are both closed. In such a fuel cell system, there is a technology that determines an abnormality when a command to start operation is received and the pressure in the flow path between the pressure reducing valve and the pressure regulating valve is higher than a threshold value. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-1113366 Summary of the Invention [Problem to be solved by the invention]

[0004] If the fuel cell system has not been operated for a long period of time, hydrogen gas may have permeated the seal of the pressure reducing valve during that time, causing the pressure in the flow path between the pressure reducing valve and the pressure regulating valve to exceed the threshold. In such a case, even if there is no abnormality in the pressure reducing valve installed in the hydrogen supply path, an abnormality is detected and the operation of the fuel cell system is restricted. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a fuel cell system including: a fuel cell; a fuel gas tank holding fuel gas; a gas flow path connecting the fuel cell and the fuel gas tank for distributing the fuel gas; a pressure reducing valve provided in the gas flow path, the pressure reducing valve capable of reducing the pressure of the fuel gas supplied from the fuel gas tank and allowing it to flow and blocking the fuel gas supplied from the fuel gas tank; a pressure sensor capable of measuring the pressure in the gas flow path on the fuel cell side relative to the pressure reducing valve; an operation memory unit storing the length of an idle period of the fuel cell system; and a control unit controlling the fuel cell system. The control unit performs start control to start operation of the fuel cell when a command to start operation of the fuel cell is received and a first start condition is satisfied, the first start condition including the pressure measured by the pressure sensor being lower than a predetermined first pressure threshold; and performs the start control when a second start condition is satisfied, the second start condition including the pressure measured by the pressure sensor being higher than the first pressure threshold and the length of the idle period stored in the operation memory unit being higher than a predetermined idle threshold. In this embodiment, even if there is no abnormality in the function of the pressure reducing valve, if the pause period during which the fuel cell was not in operation is longer than the pause threshold, and the pressure in the gas flow path on the fuel cell side relative to the pressure reducing valve becomes higher than the first pressure threshold, it is possible to avoid a situation in which start control is not performed. In other words, start control for starting operation of the fuel cell can be performed in the same way as when the pressure in the gas flow path on the fuel cell side relative to the pressure reducing valve is lower than the first pressure threshold. (2) A fuel cell system of the above form may also be configured, further comprising: an adjustment unit that is provided in the gas flow path on the fuel cell side of the pressure reducing valve and receives fuel gas and supplies the fuel gas to the fuel cell at a specified opening; and a power supply memory unit that stores the cutoff of the power supply to the operation memory unit, wherein the pressure sensor acquires the pressure in the gas flow path between the pressure reducing valve and the adjustment unit, and the control unit performs the start control when it receives an instruction to start operation of the fuel cell and a third start condition is satisfied, including: (i) the pressure acquired by the pressure sensor is greater than the first pressure threshold, (ii) the cutoff of the power supply to the operation memory unit is stored, and (iii) after the adjustment unit has supplied fuel gas to the fuel cell, the pressure acquired by the pressure sensor has become smaller than a predetermined second pressure threshold. By adopting this aspect, it is possible to avoid a situation in which start control is not performed even though there is no abnormality in the function of the pressure reducing valve when the pressure in the gas flow path on the fuel cell side relative to the pressure reducing valve becomes greater than the first pressure threshold because the length of the pause period during which the fuel cell was not operating is greater than the pause threshold, and the length of the pause period is not stored in the operation memory unit because the supply of power to the operation memory unit is cut off.In this case, the condition is that the pressure acquired by the pressure sensor becomes smaller than the second pressure threshold after the adjustment unit has supplied fuel gas to the fuel cell, so it is possible to avoid a situation in which start control is not performed even though there is an abnormality in the function of the pressure reducing valve. (3) In the fuel cell system of the above form, the gas flow path is provided with a main stop valve that is located on the fuel gas tank side of the pressure reducing valve and that allows or blocks the flow of fuel gas, and the pressure acquired by the pressure sensor after the adjustment unit has supplied fuel gas toward the fuel cell becoming smaller than the second pressure threshold value means that the pressure acquired by the pressure sensor becomes smaller than the second pressure threshold value within a predetermined time threshold value after the main stop valve is closed and the adjustment unit has supplied fuel gas toward the fuel cell. In this configuration, the main stop valve is closed to check for a drop in pressure downstream of the pressure reducing valve, which reduces the possibility that, in the event of a malfunction of the pressure reducing valve, the adjusting unit will be exposed to high-pressure fuel gas and destroyed, or that the relief mechanism of the adjusting unit will be opened, causing fuel gas to spray out. (4) According to another aspect of the present disclosure, there is provided a fuel cell system including: a fuel cell, a fuel gas tank that holds fuel gas, a gas flow path that connects the fuel cell and the fuel gas tank and allows the fuel gas to flow, a pressure reducing valve that is provided in the gas flow path and is capable of reducing the pressure of the fuel gas supplied from the fuel gas tank to allow the fuel gas to flow and of blocking the fuel gas supplied from the fuel gas tank, an adjustment unit that is provided in the gas flow path on the fuel cell side of the pressure reducing valve and is configured to receive the fuel gas and supply the fuel gas to the fuel cell at a specified opening, a pressure sensor that is capable of obtaining pressure in the gas flow path between the pressure reducing valve and the adjustment unit, and a control unit that controls the fuel cell system. When the control unit receives an instruction to start operation of the fuel cell and a start condition is satisfied, including the pressure acquired by the pressure sensor being smaller than a predetermined first pressure threshold, the control unit performs start control to start operation of the fuel cell, and when additional start conditions are satisfied, including (i) the pressure acquired by the pressure sensor being larger than the first pressure threshold, and (ii) after the adjustment unit has supplied fuel gas toward the fuel cell, the pressure acquired by the pressure sensor being smaller than a predetermined second pressure threshold. By adopting this aspect, it is possible to avoid a situation in which start-up control is not performed even if there is no abnormality in the function of the pressure reducing valve when the pressure in the gas flow path on the fuel cell side relative to the pressure reducing valve becomes higher than the first pressure threshold due to a long pause period in which the fuel cell was not operating.In this case, the condition is that the pressure acquired by the pressure sensor becomes lower than the second pressure threshold after the adjustment unit has supplied fuel gas to the fuel cell, so it is possible to avoid a situation in which start-up control is performed even if there is an abnormality in the function of the pressure reducing valve. The present disclosure can also be realized in various forms other than a fuel cell system, such as a method for manufacturing a fuel cell system, a method for controlling a fuel cell system, a computer program for implementing the control method, or a non-transitory recording medium on which the computer program is recorded. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing the general configuration of a fuel cell system 100 according to the present embodiment. [Figure 2] 10 is a flowchart showing the process executed when an instruction Is to start operation of the fuel cell 20 is received. [Figure 3] 10 is a flowchart showing the processing in the second embodiment that is executed when an instruction Is to start the operation of the fuel cell 20 is received. [Figure 4] 10 is a flowchart showing a process in a third embodiment that is executed when an instruction Is to start the operation of the fuel cell 20 is received. [Figure 5] 10 is a flowchart showing a process in a third embodiment that is executed when an instruction Is to start the operation of the fuel cell 20 is received. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: 1 is a schematic diagram showing the general configuration of a fuel cell system 100 according to this embodiment. The fuel cell system 100 is mounted on a vehicle. The fuel cell system 100 supplies electric power to a load 300 mounted on the vehicle.

[0009] The vehicle includes a fuel cell system 100, a secondary battery 200, and a load 300. The load 300 functions by receiving power from the fuel cell system 100 and the secondary battery 200. The load 300 includes a drive motor for moving the vehicle, an air conditioning system for adjusting the temperature inside the vehicle, and the like.

[0010] The fuel cell system 100 includes a fuel cell 20, a cathode gas supply / discharge system 30, an anode gas supply / discharge system 50, a DC / DC converter 70, and a control device 90.

[0011] The fuel cell 20 generates electricity by receiving air as a cathode gas from a cathode gas supply / discharge system 30 and hydrogen gas as an anode gas from an anode gas supply / discharge system 50 (see the lower center of Figure 1). The fuel cell 20 is a solid polymer fuel cell. The fuel cell 20 has a stack structure made up of a plurality of stacked unit cells 21. Each unit cell 21 has an anode 22 and a cathode 23. The unit cell 21 generates electricity by receiving hydrogen gas supplied to the anode 22 and air supplied to the cathode 23. The unit cell 21 constitutes the smallest unit for power generation. In Figure 1, the anode 22 and cathode 23 of each unit cell 21 are shown together to facilitate understanding of the technology.

[0012] The cathode gas supply / discharge system 30 supplies cathode gas to the fuel cell 20 and discharges cathode off-gas discharged from the fuel cell 20 to the outside of the fuel cell system 100 (see the middle left part of FIG. 1). The cathode gas supply / discharge system 30 includes a cathode gas supply flow path 31, an air flow meter 32, a compressor 33, a cathode pressure sensor 34, a flow adjustment valve 36, a bypass flow path 41, a flow dividing valve 42, and a cathode off-gas discharge flow path 45.

[0013] The cathode gas supply passage 31 is a passage that supplies air taken in from outside the fuel cell system 100 as cathode gas to the fuel cell 20 (see the middle left part of FIG. 1). The cathode gas supply passage 31 is provided with an air flow meter 32, a compressor 33, a cathode pressure sensor 34, and a flow adjustment valve 36i, in that order.

[0014] The air flow meter 32 detects the flow rate of the cathode gas taken into the cathode gas supply passage 31. The compressor 33 compresses the cathode gas supplied by the cathode gas supply passage 31 and supplies it downstream. The cathode pressure sensor 34 detects the pressure inside the cathode gas supply passage 31 on the fuel cell 20 side with respect to the compressor 33. The flow regulating valve 36i adjusts the flow rate of the cathode gas flowing through the cathode gas supply passage 31.

[0015] The cathode offgas discharge flow path 45 is a flow path that discharges the cathode offgas discharged from the fuel cell 20 to the outside of the fuel cell system 100 (see the lower left part of FIG. 1). The cathode offgas discharge flow path 45 is provided with a flow regulating valve 36o. The flow regulating valve 36o adjusts the flow rate of the cathode offgas flowing through the cathode offgas discharge flow path 45. In this specification, the flow regulating valves 36i and 36o are collectively referred to as the "flow regulating valve 36."

[0016] The bypass flow path 41 is a flow path that connects the cathode gas supply flow path 31 and the cathode off-gas discharge flow path 45 (see the middle left part of FIG. 1 ). The bypass flow path 41 is provided with a flow diverter valve 42. The flow diverter valve 42 can adjust the flow rate of the cathode gas flowing through the bypass flow path 41, and can also block the flow of the cathode gas in the bypass flow path 41. The flow diverter valve 42 divides the flow of the cathode gas supplied from the cathode gas supply flow path 31 into a flow toward the fuel cell 20 and a flow toward the bypass flow path 41.

[0017] The anode gas supply / discharge system 50 supplies anode gas to the fuel cell 20 and discharges anode off-gas discharged from the fuel cell 20 to the outside of the fuel cell system 100 (see the lower right part of FIG. 1). The anode gas supply / discharge system 50 includes an anode gas tank 51, an anode gas supply path 52, a main stop valve 54, a pressure reducing valve 55, an adjustment unit 56, and pressure sensors 53, 57, and 58. The anode gas supply / discharge system 50 further includes an anode gas discharge path 61, a gas-liquid separator 62, a circulation path 63, an anode gas pump 64, and an exhaust / drain valve 65.

[0018] The anode gas tank 51 holds the anode gas (see the middle right part of FIG. 1). More specifically, the anode gas tank 51 stores hydrogen gas at a pressure higher than that of the hydrogen gas supplied to the fuel cell 20.

[0019] The anode gas supply path 52 is a flow path that connects the fuel cell 20 and the anode gas tank 51 and allows the anode gas to flow (see the middle right part of FIG. 1). The anode gas supply path 52 is provided with a pressure sensor 53, a main stop valve 54, a pressure reducing valve 55, a pressure sensor 57, an adjustment unit 56, and a pressure sensor 58, in that order.

[0020] The main stop valve 54 is provided in the anode gas supply passage 52 at a position closer to the anode gas tank 51 than the pressure reducing valve 55. The main stop valve 54 allows or blocks the flow of the anode gas.

[0021] The pressure reducing valve 55 can reduce the pressure of the anode gas supplied from the anode gas tank 51 to allow it to flow, and can also block the anode gas supplied from the anode gas tank 51.

[0022] The adjustment unit 56 is provided on the anode gas supply path 52 on the fuel cell 20 side relative to the pressure reducing valve 55. The adjustment unit 56 can have various opening degrees. The larger the opening degree, the greater the flow rate of the anode gas flowing downstream from the adjustment unit 56. The adjustment unit 56 receives the anode gas and supplies it to the fuel cell 20 at a specified opening degree. Specifically, the adjustment unit 56 is a linear solenoid valve.

[0023] The pressure sensors 53, 57, and 58 acquire the pressure in the anode gas supply channel 52. The pressure sensor 53 acquires the pressure of the anode gas supplied by the anode gas tank 51. Specifically, the pressure sensor 53 acquires the pressure in the anode gas supply channel 52 on the anode gas tank 51 side relative to the main stop valve 54. The pressure sensor 57 can acquire the pressure in the anode gas supply channel 52 on the fuel cell 20 side relative to the pressure reducing valve 55. More specifically, the pressure sensor 57 acquires the pressure in the anode gas supply channel 52 between the pressure reducing valve 55 and the adjustment unit 56. The pressure sensor 58 acquires the pressure in the anode gas supply channel 52 on the fuel cell 20 side relative to the connection portion with the circulation flow channel 63.

[0024] The anode gas discharge path 61 connects the fuel cell 20 and the gas-liquid separator 62, and is a flow path that supplies the anode off-gas discharged from the fuel cell 20 to the gas-liquid separator 62 (see the lower center part of FIG. 1). The anode off-gas discharged from the fuel cell 20 contains anode gas that was not used in the electrochemical reaction in the fuel cell 20, liquid water, and impurity gases.

[0025] The gas-liquid separator 62 separates liquid water from the anode off-gas containing liquid water (see the lower center part of FIG. 1). An exhaust drain valve 65 is connected to the gas-liquid separator 62.

[0026] The exhaust / drain valve 65 allows or blocks the discharge of liquid water and impurity gases from the gas-liquid separator 62. The exhaust / drain valve 65 is normally closed and opens in response to a command from the control device 90. As a result, the liquid water and impurity gases separated from the anode off-gas by the gas-liquid separator 62 are discharged to the outside of the fuel cell system 100 via the cathode off-gas discharge flow path 45.

[0027] The circulation flow path 63 connects the portion of the anode gas supply path 52 that is on the fuel cell 20 side relative to the adjustment unit 56 with the gas-liquid separator 62 (see the center portion of the middle section in FIG. 1 ). The circulation flow path 63 is a flow path that supplies the anode off-gas, from which liquid water and impurity gases have been removed, supplied from the gas-liquid separator 62 to the anode gas supply path 52. An anode gas pump 64 is provided in the circulation flow path 63.

[0028] The anode gas pump 64 supplies the anode off-gas supplied from the gas-liquid separator 62 to the anode gas supply path 52. As a result, the anode off-gas supplied via the gas-liquid separator 62 and the anode gas supplied from the anode gas tank 51 are supplied to the fuel cell 20 via the anode gas supply path 52.

[0029] The DC / DC converter 70 is disposed between the electrically connected load 300 and fuel cell 20 (see the center of the middle row in FIG. 1). The DC / DC converter 70 receives power from the fuel cell 20 and converts the voltage to a desired voltage. The power output by the DC / DC converter 70 is supplied to the load 300 via an inverter.

[0030] 1, in order to facilitate understanding of the technology, the fuel cell system 100 and the load 300 are shown as separate structures. However, the load 300 includes auxiliary equipment such as the compressor 33 and anode gas pump 64 of the fuel cell system 100 in addition to the vehicle's drive motor and air conditioning equipment.

[0031] The control device 90 controls the fuel cell system 100 (see the upper part of FIG. 1). The control device 90 is a so-called ECU (Electronic Control Unit). The control device 90 includes a control unit 92, which is a CPU (Central Processing Unit), an operation memory unit 94, a power source memory unit 96, an input unit 97, and an output unit 98.

[0032] The control unit 92 controls the fuel cell system 100. Specifically, the control unit 92 controls the fuel cell system 100 by executing a program stored in the operation memory unit 94. The control unit 92 receives detection signals from sensors included in the fuel cell system 100, such as the cathode pressure sensor 34, pressure sensor 53, and pressure sensor 57, as well as from a group of sensors such as an accelerator position sensor and a vehicle speed sensor. The control unit 92 controls each unit involved in power generation by the fuel cell 20, including the main stop valve 54, pressure reducing valve 55, adjustment unit 56, anode gas pump 64, and exhaust drain valve 65, by outputting drive signals to the units. For example, the control unit 92 instructs the adjustment unit 56 about the opening degree.

[0033] The control unit 92 records the length Tia of the pause period of the fuel cell system 100 in the operation memory unit 94. The pause period is a period during which anode gas and cathode gas are not supplied to the fuel cell 20 and power generation is not performed in the fuel cell 20. Specifically, the control unit 92 records the length of the period from the input of an instruction to end the operation of the fuel cell system 100 via the input unit 97 to the input of the next instruction to start the operation of the fuel cell system 100 via the input unit 97 as the length Tia of the pause period in the operation memory unit 94. In other words, when the instruction to end the operation of the fuel cell system 100 is input, the control unit 92 records the time at that time in the operation memory unit 94, stops the supply of anode gas and cathode gas to the fuel cell 20, and stops power generation by the fuel cell 20. When an instruction to start operation of the fuel cell system 100 is input for the first time thereafter, the control unit 92 records the time in the operation memory unit 94, resumes the supply of anode gas and cathode gas to the fuel cell 20, and resumes power generation by the fuel cell 20. The control unit 92 then records in the operation memory unit 94 the length of the period from the time when the instruction to end operation of the fuel cell system 100 was input to the time when an instruction to start operation of the fuel cell system 100 was input for the first time thereafter as the length of the pause period Tia.

[0034] The control unit 92 records the interruption of the power supply to the driving memory unit 94 in the power source memory unit 96. The interruption of the power supply to the driving memory unit 94 occurs, for example, when the secondary battery 200 is removed from the vehicle and replaced. The functions of the control unit 92 may be realized by software or by a hardware circuit.

[0035] The operation memory unit 94 stores a program for controlling the fuel cell system 100 and data used to control the fuel cell system 100. The operation memory unit 94 stores, for example, the length Tia of the last outage period of the fuel cell system 100. Specifically, the operation memory unit 94 is composed of a RAM (Random Access Memory) and a ROM (Read Only Memory). The length Tia of the outage period of the fuel cell system 100 is stored in the RAM.

[0036] The power supply storage unit 96 stores a program for controlling the fuel cell system 100 and data used to control the fuel cell system 100. The power supply storage unit 96 stores, for example, information about the interruption of power supply to the operation storage unit 94. Specifically, the power supply storage unit 96 is configured with a rewritable non-volatile memory. Therefore, the history of power supply interruptions to the operation storage unit 94 stored in the power supply storage unit 96 is not lost even if the power supply to the fuel cell system 100 is interrupted.

[0037] The input unit 97 receives instructions from the vehicle driver regarding the operation of the fuel cell system 100 and inputs them to the control unit 92. Specifically, the input unit 97 is a switch that receives instructions to start or stop the operation of the fuel cell 20, and a touch panel that instructs the operation mode of the fuel cell 20.

[0038] The output unit 98 is controlled by the control unit 92 to output to the driver of the vehicle information relating to the operation of the fuel cell system 100. Specifically, the output unit 98 is a liquid crystal display.

[0039] 2 is a flowchart showing the process executed when an instruction Is to start the operation of the fuel cell 20 is received (see the upper part of FIG. 1). The process shown in FIG.

[0040] In step 110, the control unit 92 acquires the pressure in the anode gas supply passage 52 between the pressure reducing valve 55 and the adjustment unit 56 from the pressure sensor 57 (see the middle right part of FIG. 1). At this time, the main stop valve 54 and the pressure reducing valve 55 are closed.

[0041] In step 115, the control unit 92 determines whether the pressure Pm acquired by the pressure sensor 57 is smaller than a predetermined first pressure threshold Pth1. If the pressure Pm is smaller than the first pressure threshold Pth1, the process proceeds to step 140. If the pressure Pm is equal to or greater than the first pressure threshold Pth1, the process proceeds to step 120.

[0042] In step 120, the control unit 92 acquires the length Tia of the pause period stored in the operation memory unit 94 (see the upper part of FIG. 1).

[0043] In step 125, the control unit 92 determines whether the length Tia of the pause period stored in the operation memory unit 94 is greater than a predetermined pause threshold Tthia. If the length Tia of the pause period is greater than the pause threshold Tthia, the process proceeds to step 130. If the length Tia of the pause period is equal to or less than the pause threshold Tthia, the process proceeds to step 150.

[0044] In step 130, the pressure abnormality detection process is masked. That is, the process of step 150 is not executed, and the process proceeds directly to step 140.

[0045] In step 140, the control unit 92 starts normal startup control. Specifically, valves such as the main stop valve 54 and the pressure reducing valve 55 are opened, and startup control is performed to start the operation of the fuel cell 20 (see the middle right part of FIG. 1).

[0046] 2, the process of step 140 is performed when a Yes determination is made in step 115 and when a Yes determination is made in step 125. A Yes determination is made in step 115 when a first start condition is satisfied, that is, the pressure Pm acquired by the pressure sensor 57 is smaller than a predetermined first pressure threshold Pth1.

[0047] In step 150, the control unit 92 executes a pressure abnormality detection process. Step 150 includes steps 152 and 154. In step 152, the control unit 92 executes a fail-safe process. Specifically, the control unit 92 sets the system so that even if an instruction Is to start operation of the fuel cell 20 is input via the input unit 97, the power is turned on once and then immediately turned off. This setting is stored in the non-volatile memory. In step 154, the control unit 92 executes start-up control in the event of an abnormality. Specifically, the control unit 92 closes the main stop valve 54 and stops the fuel cell system 100.

[0048] For example, if the pressure reducing valve 55 is unable to adequately block the anode gas due to deterioration of the sealing portion, the anode gas in the anode gas supply path 52 between the pressure reducing valve 55 and the main stop valve 54 will enter the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 via the pressure reducing valve 55 during an outage of the fuel cell system 100. As a result, even if the length of the outage period Tia is short and equal to or less than the outage threshold value Tthia, the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 will exceed the outage threshold value Tthia (see S115: No and S125: No in FIG. 2). In this embodiment, in such a case, the pressure abnormality detection process of step 150 is performed. Therefore, if there is an abnormality in the function of the pressure reducing valve 55, operation of the fuel cell system 100 can be avoided against an instruction from the driver.

[0049] On the other hand, even when the pressure reducing valve 55 is able to sufficiently block the anode gas, anode gas in the anode gas supply path 52 between the pressure reducing valve 55 and the main stop valve 54 gradually leaks from the pressure reducing valve 55 and enters the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56. For this reason, if the fuel cell system 100 is not in operation for a long period of time, the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 may become equal to or higher than the suspension threshold value Tthia. This state may also occur, for example, when the owner of the vehicle replaces the pressure reducing valve 55 after purchasing the vehicle.

[0050] In this embodiment, when a first start condition is satisfied, including that the pressure Pm acquired by the pressure sensor 57 is smaller than a predetermined first pressure threshold Pth1, start control is performed to start the operation of the fuel cell 20 (see S115: Yes and S140 in FIG. 2). Furthermore, when a second start condition is satisfied, including that the pressure Pm acquired by the pressure sensor 57 is larger than the first pressure threshold Pth1 and the length Tia of the pause period stored in the operation memory unit 94 is larger than a predetermined pause threshold Tthia, start control is also performed (see S115: No, S125: Yes, and S140 in FIG. 2).

[0051] Therefore, in this embodiment, even if there is no abnormality in the function of the pressure reducing valve 55, if the pause period during which the fuel cell 20 was not in operation is longer than the pause threshold value Tthia and the pressure in the anode gas supply path 52 on the fuel cell 20 side relative to the pressure reducing valve 55 becomes higher than the first pressure threshold value Pth1, it is possible to avoid a situation in which start control is not performed. In other words, start control for starting operation of the fuel cell 20 can be performed in the same way as when the pressure in the anode gas supply path 52 on the fuel cell 20 side relative to the pressure reducing valve 55 is lower than the first pressure threshold value Pth1.

[0052] The anode gas in this embodiment is also called "fuel gas." The anode gas tank 51 is also called "fuel gas tank." The anode gas supply path 52 is also called "gas path."

[0053] B. Second embodiment: Fig. 3 is a flowchart showing the processing in the second embodiment that is executed when an instruction Is to start operation of the fuel cell 20 is received (see the upper part of Fig. 1). In the processing in Fig. 3, the processing of steps 122 and 127 is executed instead of the processing of steps 120 and 125 in Fig. 2. The configuration and processing of the fuel cell system of the second embodiment are otherwise the same as those of the fuel cell system 100 of the first embodiment. In Fig. 3, steps that perform the same processing as the steps shown in Fig. 2 are indicated by the same reference numerals.

[0054] In step 122, the control unit 92 opens the main stop valve 54 and causes the adjustment unit 56 to supply the anode gas. At this time, the pressure reducing valve 55 is closed.

[0055] After a predetermined time has elapsed since the control unit 92 caused the adjustment unit 56 to supply fuel gas, the control unit 92 acquires the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 from the pressure sensor 57 (see the middle right part of Figure 1).

[0056] In step 127, the control unit 92 determines whether the pressure Pm acquired by the pressure sensor 57 has become smaller than a predetermined second pressure threshold Pth2.

[0057] In the anode gas supply path 52, if the pressure reducing valve 55 can sufficiently block the anode gas, causing the adjustment unit 56 to supply fuel gas causes the anode gas in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 to flow downstream, resulting in a significant drop in the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56. In this case, the determination in step 127 is Yes.

[0058] On the other hand, if the pressure reducing valve 55 is not able to sufficiently block the anode gas in the anode gas supply path 52, the anode gas between the pressure reducing valve 55 and the adjustment unit 56 flows downstream, while the anode gas in the anode gas tank 51 enters the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 via the main stop valve 54 and the pressure reducing valve 55. Therefore, even if the adjustment unit 56 is caused to supply fuel gas, the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 does not decrease. In this case, the determination in step 127 is No.

[0059] If the pressure Pm becomes smaller than the second pressure threshold Pth2 in step 127, the process proceeds to step 130. If the pressure Pm is equal to or greater than the second pressure threshold Pth2, the process proceeds to step 150.

[0060] In the second embodiment, when a start condition is satisfied, including that the pressure Pm acquired by the pressure sensor 57 is smaller than a predetermined first pressure threshold Pth1, start control is performed to start the operation of the fuel cell 20 (see S115: Yes and S140 in FIG. 3). (i) The pressure Pm acquired by the pressure sensor 57 is greater than the first pressure threshold Pth1 (see S115: No in FIG. 3), and (ii) After the adjustment unit 56 supplies the fuel gas to the fuel cell 20, the pressure Pm acquired by the pressure sensor 57 becomes smaller than the predetermined second pressure threshold Pth2 (see S122 and S127: Yes in FIG. 3 ). The start control is also performed when additional start conditions are met, including (see S140 in FIG. 3).

[0061] By performing such processing, it is possible to avoid a situation in which start control is not performed even if there is no abnormality in the function of the pressure reducing valve 55 when the pressure in the anode gas supply path 52 on the fuel cell 20 side relative to the pressure reducing valve 55 becomes higher than the first pressure threshold Pth1 due to the length of the pause period Tia during which the fuel cell 20 was not in operation being long. In this case, the condition is that the pressure Pm acquired by the pressure sensor 57 becomes lower than the second pressure threshold Pth2 after the adjustment unit 56 has supplied fuel gas to the fuel cell 20, so it is possible to avoid a situation in which start control is performed even if there is an abnormality in the function of the pressure reducing valve 55 (see S127: Yes in FIG. 3).

[0062] In the second embodiment, (i) The pressure Pm acquired by the pressure sensor 57 is greater than the first pressure threshold Pth1 (see S115: No in FIG. 3), and (ii) After the adjustment unit 56 has supplied the fuel gas to the fuel cell 20, the pressure Pm acquired by the pressure sensor 57 has not become smaller than the first pressure threshold Pth1 within a predetermined period (see S127: No in FIG. 3 ). If the additional cancellation conditions, including the above, are satisfied, the start control is not performed and the pressure abnormality detection process is executed (see S150 in FIG. 3).

[0063] Therefore, if the pressure reducing valve 55 is not able to sufficiently shut off the anode gas supplied from the anode gas tank 51, it is possible to avoid operating the fuel cell system 100 against the instructions of the driver.

[0064] C. Third embodiment: 4 and 5 are flowcharts showing the processing in the third embodiment that is executed when an instruction Is to start operation of the fuel cell 20 is received (see the upper part of FIG. 1). In the processing in FIGS. 4 and 5, the processing of steps 116-119 is executed instead of the processing of step 122 in FIG. 3. Furthermore, the processing of steps 120, 125, and 132 is executed branching from step 117. The configuration and processing of the fuel cell system of the third embodiment are otherwise the same as those of the fuel cell system of the second embodiment. In FIGS. 4 and 5, steps that perform the same processing as the steps shown in FIGS. 2 and 3 are designated by the same reference numerals.

[0065] In step 116 , the control unit 92 refers to the history of power supply cutoffs to the operation memory unit 94 that is recorded in the power source memory unit 96 .

[0066] In step 117, the control unit 92 determines whether or not the interruption of the power supply to the operation memory unit 94 is stored in the power supply memory unit 96. If the interruption of the power supply to the operation memory unit 94 is stored in the power supply memory unit 96, the process proceeds to step 118. If the interruption of the power supply to the operation memory unit 94 is not stored in the power supply memory unit 96, the process proceeds to step 120 (see A in FIG. 4 and the upper part of FIG. 5).

[0067] The processing of steps 120 and 125 is the same as the processing of steps 120 and 125 in the first embodiment. If, in step 125, the length Tia of the pause period is equal to or less than the pause threshold Tthia, the processing proceeds to step 150 (see B of FIG. 5 and the lower right part of FIG. 4). If the length Tia of the pause period is greater than the pause threshold Tthia, the processing proceeds to step 130c. Step 130 is shown in FIG. 5 as "step 130c" to distinguish it from step 130 shown in FIG. 4. The processing of step 130c is the same as step 130 in the first embodiment. After step 130c, the processing proceeds to step 140 (see C of FIG. 5 and the lower right part of FIG. 4).

[0068] That is, in the third embodiment, start control is also performed when the second start condition is satisfied, which includes that the pressure Pm acquired by the pressure sensor 57 is greater than the first pressure threshold Pth1 and the length Tia of the pause period stored in the operation memory unit 94 is greater than the predetermined pause threshold Tthia (see S115: No, S117: NO in Figure 4, S125: Yes, and S140 in Figure 5).

[0069] In step 118, the control unit 92 switches the start-up control from the start-up control that is normally performed (see S140 in FIG. 4). Specifically, the processing from step 119 onwards is performed.

[0070] In step 119, the control unit 92 causes the adjustment unit 56 to supply fuel gas. At this time, the main stop valve 54 and the pressure reducing valve 55 are closed. The processing of step 119 differs from the processing of step 122 in FIG. 3 in that the main stop valve 54 is closed.

[0071] When a predetermined time threshold Tth has elapsed since the control unit 92 caused the adjustment unit 56 to supply fuel gas, the control unit 92 acquires the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 from the pressure sensor 57 (see the middle right part of Figure 1).

[0072] The processing in step 127 in FIG. 4 is the same as the processing in step 127 in the second embodiment.

[0073] In the anode gas supply path 52, if the pressure reducing valve 55 can sufficiently block the anode gas, causing the adjustment unit 56 to supply fuel gas causes the anode gas in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 to flow downstream, resulting in a significant drop in the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56. In this case, the determination in step 127 is Yes.

[0074] On the other hand, if the pressure reducing valve 55 is not able to sufficiently block the anode gas in the anode gas supply path 52, the anode gas between the pressure reducing valve 55 and the adjustment unit 56 flows downstream, while the high-pressure anode gas in the anode gas supply path 52 between the pressure reducing valve 55 and the main stop valve 54 enters the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 via the pressure reducing valve 55. For this reason, even if the adjustment unit 56 is caused to supply fuel gas, the pressure in the anode gas supply path 52 between the pressure reducing valve 55 and the adjustment unit 56 does not decrease significantly within the time threshold Tth. In this case, the determination in step 127 is No.

[0075] In the third embodiment, the main stop valve 54 is closed and a drop in pressure downstream of the pressure reducing valve 55 is confirmed (see S119 in FIG. 4). Therefore, when the pressure reducing valve 55 malfunctions and is unable to sufficiently shut off the gas flow, it is possible to reduce the possibility that the downstream adjustment unit 56 will be exposed to high-pressure fuel gas and destroyed, or that the relief mechanism of the adjustment unit 56 will be opened, causing the fuel gas to spray out. For example, when the valve element of the adjustment unit 56 is configured to be pressed from the upstream side to the downstream side when the valve is closed, there is a possibility that the relief mechanism will be opened as described above.

[0076] 4, if the pressure Pm becomes smaller than the second pressure threshold Pth2, the process proceeds to step 130. If the pressure Pm is equal to or greater than the second pressure threshold Pth2, the process proceeds to step 150.

[0077] In the third embodiment, (i) The pressure Pm acquired by the pressure sensor 57 is greater than the first pressure threshold Pth1 (see S115: No in FIG. 4), (ii) The interruption of the power supply to the operation memory unit 94 is stored (see S117: Yes in FIG. 4), and (iii) After the adjustment unit 56 supplies the fuel gas to the fuel cell 20, the pressure Pm acquired by the pressure sensor 57 becomes smaller than the predetermined second pressure threshold Pth2 (see S119 and S127: Yes in FIG. 4 ). If a third start condition is satisfied, the start control is performed (S140).

[0078] By performing such processing, it is possible to avoid a situation in which start control is not performed even though there is no abnormality in the function of the pressure reducing valve 55 in the following cases: That is, it is possible to avoid a situation in which start control is not performed when the length Tia of the pause period during which the fuel cell 20 was not operating is greater than the pause threshold Tthia (see S125: Yes in FIG. 5), the pressure in the anode gas supply path 52 on the fuel cell 20 side with respect to the pressure reducing valve 55 is greater than the first pressure threshold Pth1 (see S115: Yes in FIG. 4), and the length Tia of the pause period is not stored in the operation memory unit 94 because the supply of power to the operation memory unit 94 has been cut off (see S117: Yes in FIG. 4). In this case, it is required that the pressure Pm acquired by the pressure sensor 57 becomes smaller than the second pressure threshold Pth2 after the adjustment unit 56 has supplied fuel gas to the fuel cell 20 (see S127: Yes in FIG. 4), and therefore it is possible to avoid a situation in which start control is not performed even though there is an abnormality in the function of the pressure reducing valve 55.

[0079] D. Other Embodiments: D1. Alternative Embodiment 1: (1) In the above embodiment, the adjusting unit 56 is a linear solenoid valve (see the center of the middle row in FIG. 1). However, the adjusting unit 56 may have other configurations, such as an injector.

[0080] (2) In the first embodiment, the pressure sensor 57 acquires the pressure in the anode gas supply passage 52 between the pressure reducing valve 55 and the adjusting unit 56 (see the middle right part of FIG. 1). However, the pressure sensor 57 may acquire the pressure in the anode gas supply passage 52 between the adjusting unit 56 and the fuel cell 20 (see the middle right part of FIG. 1). The processes of steps 110, 115, 119, and 127 may be performed based on the measurement value of the pressure sensor 58.

[0081] (3) In the first embodiment, the first start condition is that the pressure Pm acquired by the pressure sensor 57 is smaller than a predetermined first pressure threshold Pth1 (see S115: Yes in FIG. 2). However, the first start condition may include other weighted conditions, such as the operation mode of the fuel cell system 100 being set to a predetermined mode. The same applies to the second and third start conditions.

[0082] (4) In the second and third embodiments, the second pressure threshold Pth2 may be higher than, lower than, or equal to the first pressure threshold Pth1. The second pressure threshold Pth2 can be determined based on the hardware configurations of the anode gas supply channel 52, the pressure reducing valve 55, and the adjustment unit 56, as well as the time from when the adjustment unit 56 is caused to supply fuel gas to when the pressure sensor 57 is caused to measure the pressure. When the second pressure threshold is set high, a decrease in pressure is detected a short time after the adjustment unit 56 is caused to supply fuel gas. When the second pressure threshold is set lower, a decrease in pressure is detected a long time after the adjustment unit 56 is caused to supply fuel gas.

[0083] (5) The second pressure threshold Pth2 in the third embodiment has been described as being the same as the second pressure threshold Pth2 in the second embodiment. However, when a pressure drop is detected with the main stop valve 54 closed, the second pressure threshold Pth2 may be set lower than when a pressure drop is detected with the main stop valve 54 open.

[0084] (6) In the above embodiment, in step 154, the control unit 92 performs startup control in the event of an abnormality. Specifically, the control unit 92 sets the system so that even if an instruction Is to start operation of the fuel cell 20 is input via the input unit 97 thereafter, the power is turned on once and then immediately turned off (see S150 in FIG. 2). However, in step 150, the control unit 92 may not perform such processing, but may simply perform processing to close the main stop valve 54 and stop the fuel cell system 100 in response to the current instruction Is to start operation of the fuel cell 20.

[0085] (7) In the above embodiment, the fuel cell system 100 is mounted on a vehicle. However, the fuel cell system 100 may be mounted on other moving bodies such as a ship or an airplane, or may be installed in a building or the like.

[0086] D2. Alternative Embodiment 2: In the third embodiment, (i) The pressure Pm acquired by the pressure sensor 57 is greater than the first pressure threshold Pth1 (see S115: No in FIG. 4), (ii) The interruption of the power supply to the operation memory unit 94 is stored (see S117: Yes in FIG. 4), and (iii) After the adjustment unit 56 supplies the fuel gas to the fuel cell 20, the pressure Pm acquired by the pressure sensor 57 becomes smaller than the predetermined second pressure threshold Pth2 (see S119 and S127: Yes in FIG. 4 ). If a third start condition is satisfied, the start control is performed (S140).

[0087] However, as shown in the first embodiment, it is also possible to have an aspect in which start control is performed when a second start condition is satisfied, which includes that the pressure Pm acquired by the pressure sensor 57 is greater than the first pressure threshold Pth1 and the length Tia of the pause period stored in the operation memory unit 94 is greater than a predetermined pause threshold Tthia (see S115: No, S125: Yes, and S140 in Figure 2), rather than the third start condition.

[0088] D3. Alternative Embodiment 3: After the main stop valve 54 is closed and the adjustment unit 56 is caused to supply anode gas toward the fuel cell 20, start control is performed when a third start condition is satisfied, including the pressure Pm acquired by the pressure sensor 57 becoming smaller than the second pressure threshold Pth2 within a predetermined time threshold Tth (see S119, S127: Yes, and S140 in Figure 4).

[0089] However, as shown in the second embodiment, the main stop valve 54 may be closed, and it may be determined whether the pressure Pm acquired by the pressure sensor 57 has become smaller than the second pressure threshold Pth2 (see S122 and S127 in Figure 3).

[0090] D4. Alternative Embodiment 4: In the second and third embodiments described above, start control is performed (S140) when start conditions are met, including the pressure Pm acquired by the pressure sensor 57 becoming smaller than the predetermined second pressure threshold Pth2 after the adjustment unit 56 has supplied fuel gas to the fuel cell 20 (see S127: Yes and S127: Yes in Figure 3).

[0091] However, instead of such a condition, as shown in the first embodiment, the start control may be performed when a start condition is satisfied, including that the length Tia of the pause period stored in the operation memory unit 94 is greater than a predetermined pause threshold Tthia (see S115: No, S125: Yes, and S140 in Figure 2).

[0092] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0093] 20... fuel cell, 21... single cell, 22... anode, 23... cathode, 30... cathode gas supply / discharge system, 31... cathode gas supply flow path, 32... air flow meter, 33... compressor, 34... cathode pressure sensor, 36... flow adjustment valve, 36i... flow adjustment valve, 36o... flow adjustment valve, 41... bypass flow path, 42... flow division valve, 45... cathode off-gas discharge flow path, 50... anode gas supply / discharge system, 51... anode gas tank, 52... anode gas supply path, 53... pressure sensor, 54... main valve Valve, 55...pressure reducing valve, 56...adjustment unit, 57...pressure sensor, 58...pressure sensor, 61...anode gas discharge path, 62...gas-liquid separator, 63...circulation path, 64...anode gas pump, 65...exhaust drain valve, 70...DC / DC converter, 90...control device, 92...control unit, 94...operation memory unit, 96...power supply memory unit, 97...input unit, 98...output unit, 100...fuel cell system, 200...secondary battery, 300...load, Is...instruction to start fuel cell operation, Tia...length of pause period

Claims

1. 1. A fuel cell system, comprising: A fuel cell; a fuel gas tank holding fuel gas; a gas flow path that connects the fuel cell and the fuel gas tank and allows fuel gas to flow; a pressure reducing valve provided in the gas flow path, capable of reducing the pressure of the fuel gas supplied from the fuel gas tank and allowing the fuel gas to flow, and capable of blocking the fuel gas supplied from the fuel gas tank; a pressure sensor capable of acquiring a pressure in the gas flow path on the fuel cell side relative to the pressure reducing valve; an operation memory unit that stores the length of a shutdown period of the fuel cell system; a control unit that controls the fuel cell system, When the control unit receives an instruction to start operation of the fuel cell, performing start control to start operation of the fuel cell when a first start condition is satisfied, the start condition including the pressure acquired by the pressure sensor being lower than a predetermined first pressure threshold value; A fuel cell system that performs the start control when a second start condition is satisfied, including the pressure acquired by the pressure sensor being greater than the first pressure threshold and the length of the pause period stored in the operation memory unit being greater than a predetermined pause threshold.

2. 2. The fuel cell system according to claim 1, an adjusting unit that is provided in the gas flow path on the fuel cell side of the pressure reducing valve and receives the fuel gas and supplies the fuel gas to the fuel cell at a specified opening degree; a power supply memory unit that stores information about the interruption of power supply to the operation memory unit; the pressure sensor acquires a pressure in the gas flow path between the pressure reducing valve and the adjustment unit, When the control unit receives an instruction to start operation of the fuel cell, (i) the pressure acquired by the pressure sensor is greater than the first pressure threshold; (ii) the interruption of the supply of power to the operation memory unit is stored, and (iii) after the adjustment unit supplies fuel gas to the fuel cell, the pressure acquired by the pressure sensor becomes smaller than a predetermined second pressure threshold value; and performing the start control when a third start condition is satisfied.

3. 3. The fuel cell system according to claim 2, a main stop valve provided in the gas flow path on the fuel gas tank side with respect to the pressure reducing valve, the main stop valve allowing or blocking the flow of fuel gas; After the adjustment unit supplies the fuel gas to the fuel cell, the pressure acquired by the pressure sensor becomes smaller than the second pressure threshold value. A fuel cell system in which, after the main stop valve is closed and the adjustment unit is caused to supply fuel gas toward the fuel cell, the pressure acquired by the pressure sensor becomes smaller than the second pressure threshold within a predetermined time threshold.

4. 1. A fuel cell system, comprising: A fuel cell; a fuel gas tank holding fuel gas; a gas flow path that connects the fuel cell and the fuel gas tank and allows fuel gas to flow; a pressure reducing valve provided in the gas flow path, capable of reducing the pressure of the fuel gas supplied from the fuel gas tank and allowing the fuel gas to flow, and capable of blocking the fuel gas supplied from the fuel gas tank; an adjusting unit that is provided in the gas flow path on the fuel cell side of the pressure reducing valve and receives the fuel gas and supplies the fuel gas to the fuel cell at a specified opening degree; a pressure sensor capable of acquiring a pressure in the gas flow path between the pressure reducing valve and the adjusting unit; a control unit that controls the fuel cell system, When the control unit receives an instruction to start operation of the fuel cell, performing start control to start operation of the fuel cell when a start condition is satisfied, the start condition including the pressure acquired by the pressure sensor being lower than a predetermined first pressure threshold; (i) the pressure acquired by the pressure sensor is greater than the first pressure threshold; and (ii) after the adjustment unit supplies fuel gas to the fuel cell, the pressure acquired by the pressure sensor becomes smaller than a predetermined second pressure threshold value; and performing the start control when an additional start condition is satisfied, the additional start condition including:

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