Fuel cell system and industrial vehicle

Abstract

To provide a fuel cell system equipped with a shut-off valve having a solenoid in which power generation of a fuel cell is prevented from stopping even when there occurs an abnormality in which current temporarily stops flowing into the solenoid during power generation control of the fuel cell.SOLUTION: A fuel cell system FCS is configured to include a shut-off valve SV and a control unit Cnt, the shut-off valve SV maintaining a valve-open state when a second current flows through a solenoid L1 after a first current flows through the solenoid L1 to switch a valve-closed state to the valve-open state, and switching the valve-open state to the valve-closed state when the current stops flowing through the solenoid L1. When the control unit Cnt determines that the shut-off valve SV is in the closed state in spite of the current flowing through the solenoid L1 during power generation control of a fuel cell FC, the control unit Cnt causes the first current to flow through the solenoid L1 again, and then causes the second current to flow through the solenoid L1.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] As a fuel cell system, there is one that detects an abnormality of a shut-off valve provided between a hydrogen tank and a fuel cell based on the state of hydrogen gas supplied from the hydrogen tank to the fuel cell. As a related technique, for example, there is Patent Document 1.

[0003] By the way, when the shut-off valve is composed of a solenoid-operated valve, a relatively large current flows through the solenoid, and the shut-off valve switches from the closed state to the open state. Then, while a relatively small current is flowing through the solenoid, the shut-off valve is maintained in the open state. When the current stops flowing through the solenoid, the shut-off valve switches from the open state to the closed state. In the shut-off valve configured in this way, after switching from the open state to the closed state due to an abnormality such that the current stops flowing through the solenoid, such as a disconnection of the electric circuit including the solenoid, even if the disconnection is restored immediately and the current starts flowing through the solenoid again, if the current of a magnitude necessary to switch the shut-off valve from the closed state to the open state does not flow through the solenoid, the shut-off valve remains in the closed state.

[0004] Therefore, in the above fuel cell system, when the shut-off valve is composed of a solenoid-operated valve and an abnormality occurs in which a momentary disconnection occurs during the power generation control of the fuel cell and the current stops flowing through the solenoid temporarily, there is a concern that the shut-off valve remains in the closed state, hydrogen gas is not supplied to the fuel cell, and the power generation of the fuel cell stops.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] An object according to one aspect of the present invention is to suppress the power generation of a fuel cell from stopping even if an abnormality occurs in which current temporarily stops flowing through a solenoid during power generation control of the fuel cell in a fuel cell system including a shut-off valve having a solenoid.

Means for Solving the Problems

[0007] A fuel cell system according to one embodiment of the present invention is a fuel cell system including a hydrogen tank for storing hydrogen gas supplied to a fuel cell, provided between the hydrogen tank and the fuel cell, and after switching from a closed valve state to an open valve state when a first current flows through a first solenoid, maintaining the open valve state when a second current smaller than the first current flows through the first solenoid, and a shut-off valve that switches from the open valve state to the closed valve state when current stops flowing through the first solenoid, and a control unit.

[0008] When starting the fuel cell system, the control unit flows the first current through the first solenoid, then flows the second current through the first solenoid, and after starting the fuel cell system, if it is determined that the shut-off valve is in the closed valve state even though current is flowing through the first solenoid, the first current is again flowed through the first solenoid, and then the second current is flowed through the first solenoid.

[0009] Thereby, even if an abnormality occurs in which current temporarily stops flowing through the first solenoid during power generation control of the fuel cell, the shut-off valve can be returned to the open valve state, so that the supply of hydrogen gas from the hydrogen tank to the fuel cell can be restored, and the power generation of the fuel cell can be suppressed from stopping.

[0010] Further, when a third current is flowing through the second solenoid, the fuel cell system permits current to flow through the first solenoid, and when the third current is not flowing through the second solenoid, the fuel cell system includes a contact that prohibits current from flowing through the first solenoid. When starting up the fuel cell system, the control unit first causes the third current to flow through the second solenoid and the first current to flow through the first solenoid, and then causes the third current to flow through the second solenoid and the second current to flow through the first solenoid. During power generation control of the fuel cell, if it is determined that the shutoff valve is in a closed state even though current is flowing through the first solenoid, the control unit may be configured to first cause the third current to flow through the second solenoid and the first current to flow through the first solenoid again, and then cause the third current to flow through the second solenoid and the second current to flow through the first solenoid again.

[0011] Accordingly, even if an abnormality occurs in which current temporarily stops flowing through at least one of the first solenoid and the second solenoid during power generation control of the fuel cell, the shutoff valve can be returned to the open state, so that the supply of hydrogen gas from the hydrogen tank to the fuel cell can be resumed, and the stoppage of power generation of the fuel cell can be suppressed.

[0012] Further, during power generation control of the fuel cell, the control unit may be configured to determine that the shutoff valve is in a closed state even though current is flowing through the first solenoid when current flows again through at least one of the first circuit including the first solenoid and the second circuit including the second solenoid after a predetermined time has elapsed since current stopped flowing through at least one of the first and second circuits.

[0013] Further, during power generation control of the fuel cell, the control unit may be configured to determine that the shutoff valve is in a closed state even though current is flowing through the first solenoid when current flows again through at least one of the first and second circuits after a predetermined time has elapsed since current stopped flowing through at least one of the first and second circuits, and a value indicating the state of hydrogen gas between the shutoff valve and the fuel cell becomes equal to or less than a threshold value.

[0014] This can improve the accuracy of the state determination of the shut-off valve.

[0015] Further, the second circuit may be provided with an emergency stop button that prohibits current from flowing through the second solenoid when operated by the user.

[0016] Further, the industrial vehicle may be equipped with the above fuel cell system.

Advantages of the Invention

[0017] According to the present invention, in a fuel cell system including a shut-off valve having a solenoid, even if an abnormality occurs in which current temporarily stops flowing through the solenoid during power generation control of the fuel cell, it is possible to suppress the stop of power generation of the fuel cell.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0019] Hereinafter, embodiments will be described in detail with reference to the drawings.

[0020] FIG. 1 is a diagram showing an example of a fuel cell system according to an embodiment.

[0021] In the fuel cell system FCS shown in FIG. 1, for example, it is mounted on an industrial vehicle Ve such as a forklift, a towing tractor, or an automatic guided vehicle (AGV), and supplies power to a load Lo mounted on the industrial vehicle Ve. For example, the load Lo is an inverter circuit that drives a loading and unloading device or a traveling motor.

[0022] Further, the industrial vehicle Ve includes an emergency stop button PB that stops the power generation of the fuel cell FC when operated by a user (such as a driver of the industrial vehicle Ve). The emergency stop button PB is defined by the High-Pressure Gas Safety Act, IEC (International Electrotechnical Commission) standards, etc., and is installed on the dashboard DB of the industrial vehicle Ve as shown in FIG. 2, for example.

[0023] The fuel cell system FCS shown in FIG. 1 includes a main fuel cell FC and a plurality of auxiliary machines for generating power in the fuel cell FC.

[0024] That is, the fuel cell system FCS includes, as fuel gas system auxiliary machines, a hydrogen tank HT, a shut-off valve SV, a contactor CNT, and an injector INJ.

[0025] The fuel cell system FCS also includes, as oxidant gas system auxiliary machines, an air compressor ACP and an air pressure regulating valve ARV.

[0026] The fuel cell system FCS also includes, as electric system auxiliary machines, a DCDC converter CNV and a power storage device B.

[0027] The fuel cell system FCS also includes a control unit Cnt that controls the power generation of the fuel cell FC.

[0028] The fuel cell FC is composed of a plurality of fuel cells connected in series with each other, and generates electricity through an electrochemical reaction between hydrogen contained in hydrogen gas (fuel gas) and oxygen contained in air (oxidant gas).

[0029] The hydrogen tank HT is a storage container for hydrogen gas. The hydrogen gas stored in the hydrogen tank HT is supplied to the fuel cell FC via the shut-off valve SV and the injector INJ.

[0030] The shut-off valve SV is a solenoid valve having a solenoid L1 (first solenoid), and is provided between the hydrogen tank HT and the fuel cell FC (injector INJ). Further, when a relatively large first current (inrush current (for example, 1 to 4 [A])) flows through the solenoid L1, the shut-off valve SV switches from the closed state to the open state. After switching from the closed state to the open state, when a second current (holding current) smaller than the first current flows through the solenoid L1, the open state is maintained, and when the current stops flowing through the solenoid L1, it switches from the open state to the closed state. For example, the first current is the current that flows through the solenoid L1 when the valve provided in the hydrogen gas flow path in the shut-off valve SV switches from the closed state to the open state due to the magnetic force generated by the solenoid L1. The second current is the current that flows through the solenoid L1 when the valve provided in the hydrogen gas flow path in the shut-off valve SV is maintained in the open state due to the magnetic force generated by the solenoid L1.

[0031] The contactor CNT is an electromagnetic relay having a solenoid L2 (second solenoid) and a switch SWc that operates by the magnetic force generated in the solenoid L2, and is provided in an electric circuit H1 (first electric circuit) including the solenoid L1. Further, when a third current is flowing in the solenoid L2, the contactor CNT permits current to flow in the solenoid L1, and when the third current is not flowing in the solenoid L2, prohibits current from flowing in the solenoid L1. For example, the third current is a current that flows in the solenoid L2 when the switch SWc is maintained in a conductive state by the magnetic force generated by the solenoid L2. That is, when the third current is not flowing in the solenoid L2, the switch SWc is in an open state, and current cannot flow in the solenoid L1. On the other hand, when the third current is flowing in the solenoid L2, the switch SWc is in a conductive state, and current can flow in the solenoid L1.

[0032] For example, one terminal of switch SWc is connected to the power supply P in the control unit Cnt via the solenoid L1 and the switch SW1 in the control unit Cnt, and the other terminal of the switch SWc is connected to the ground GND in the control unit Cnt. Also, one terminal of the solenoid L2 is connected to the power supply P via the switch SW2 in the control unit Cnt, and the other terminal of the solenoid L2 is connected to the emergency stop button PB via the ground GND. When this configuration is formed, when the emergency stop button PB is not operated by the user and the emergency stop button PB is in a conductive state, and when a third current is flowing through the solenoid L2, the switch SWc is in a conductive state, and current can flow from the power supply P to the ground GND via the switch SW1, the solenoid L1, and the switch SWc. At this time, when a first current flows through the solenoid L1, the shut-off valve SV switches from the closed valve state to the open valve state, and when a second current flows through the solenoid L1, the shut-off valve SV is maintained in the open valve state. Also, when the emergency stop button PB is in a conductive state, but when the switch SW2 switches from the conductive state to the cut-off state, no current flows through the solenoid L1, the shut-off valve SV switches from the open valve state to the closed valve state, the supply of hydrogen gas to the fuel cell FC stops, and the power generation of the fuel cell FC stops. Also, when an abnormality such as an abnormal noise is heard from the industrial vehicle Ve and the user operates the emergency stop button PB and the emergency stop button PB switches from the conductive state to the cut-off state, no current flows through the solenoid L2, the switch SWc switches from the conductive state to the cut-off state, no current flows through the solenoid L1, the shut-off valve SV switches from the open valve state to the closed valve state, the supply of hydrogen gas to the fuel cell FC stops, and the power generation of the fuel cell FC stops. Note that when the emergency stop button PB is not operated by the user, the emergency stop button PB shall always be in a conductive state. Also, it is assumed that power is supplied from the DCDC converter CNV to the power supply P. Also, the power supply P, the switch SW1, and the switch SW2 may be provided outside the control unit Cnt. Also, if arbitrary currents can flow through the solenoids L1 and L2 respectively, it is not limited to the circuit configuration consisting of the power supply P, the switch SW1, and the switch SW2 shown in FIG. 1.

[0033] The injector INJ adjusts the flow rate of the hydrogen gas supplied to the fuel cell FC.

[0034] The air compressor ACP compresses air and supplies it to the fuel cell FC.

[0035] The air pressure regulating valve ARV adjusts the pressure of the air supplied to the fuel cell FC.

[0036] The DCDC converter CNV is connected to the downstream of the fuel cell FC and converts the voltage output from the fuel cell FC into a predetermined voltage (for example, 48 [V]). The power output from the DCDC converter CNV is supplied to each auxiliary machine such as the shut-off valve SV and the air compressor ACP, the load Lo, and the power storage device B.

[0037] The power storage device B is composed of a lithium-ion capacitor or the like and is connected between the DCDC converter CNV and the load Lo. When the supply power corresponding to the difference between the power output from the DCDC converter CNV and the total power supplied to each auxiliary machine is greater than the required power requested from the outside of the fuel cell system FCS (for example, an industrial vehicle side control unit that controls the operation of the load Lo), among the supply power, the power corresponding to the required power is supplied to the load Lo, and the remaining power is supplied to the power storage device B. When power is supplied from the DCDC converter CNV to the power storage device B, the power storage device B is charged and the charge rate of the power storage device B (the ratio [%] of the remaining capacity to the full charge capacity of the power storage device B) increases. Also, when the regenerative power supplied from the load Lo to the fuel cell system FCS is supplied to the power storage device B, the power storage device B is charged and the charge rate of the power storage device B increases. Further, when the supply power corresponding to the difference between the power output from the DCDC converter CNV and the total power supplied to each auxiliary machine is less than the required power requested from the outside of the fuel cell system FCS, the supply power is supplied to the load Lo, and the insufficient power is supplied from the power storage device B to the load Lo. When power is supplied from the power storage device B to the load Lo, the power storage device B is discharged and the charge rate of the power storage device B decreases.

[0038] The control unit Cnt is composed of a microcomputer or the like, and controls the power generation of the fuel cell FC by controlling the operations of various auxiliary devices (such as the shut-off valve SV and the air compressor ACP).

[0039] For example, when an activation instruction for the fuel cell system FCS is input, the control unit Cnt reads out various setting values (such as the charge rate of the power storage device B) stored in the storage unit at the end of the previous power generation control from the storage unit, or switches the shut-off valve SV from the closed state to the open state, as preparations for starting the power generation control of the fuel cell FC.

[0040] That is, when starting the fuel cell system FCS, the control unit Cnt switches the shut-off valve SV from the closed state to the open state by flowing a third current through the solenoid L2 and a first current through the solenoid L1, and then maintains the shut-off valve SV in the open state by flowing a third current through the solenoid L2 and a second current through the solenoid L1. For example, when switching the shut-off valve SV from the closed state to the open state at the start of the fuel cell system FCS, the control unit Cnt repeatedly turns on and off the switch SW2 by PWM (Pulse Width Modulation) control to flow a third current through the solenoid L2, and repeatedly turns on and off the switch SW1 by PWM control to flow a first current through the solenoid L1. After that, the control unit Cnt repeatedly turns on and off the switch SW2 by PWM control to flow a third current through the solenoid L2, and repeatedly turns on and off the switch SW1 by PWM control to flow a second current through the solenoid L1.

[0041] Further, during the power generation control of the fuel cell FC after the start-up of the fuel cell system FCS, the control unit Cnt gradually changes the target power generation power Pt according to the comparison result between the charge rate of the power storage device B and a plurality of charge rate thresholds, and controls the operations of each auxiliary machine so that the power generation power of the fuel cell FC follows the target power generation power Pt by means of PI (Proportional-Integral) control or the like. For example, the control unit Cnt controls the operation of the air compressor ACP so that the rotational speed of the motor M follows the target rotational speed corresponding to the target power generation power Pt, and controls the operation of the air pressure regulating valve ARV so that the pressure of the air supplied to the fuel cell FC does not exceed the upper limit value.

[0042] Also, during the power generation control of the fuel cell FC, when a stop instruction for the fuel cell system FCS is input, or when an abnormality such as the fuel cell FC becoming hot or an abnormality such as the current output from the DCDC converter CNV becoming overcurrent occurs, the control unit Cnt performs processes for stopping the power generation of the fuel cell FC (processes for stopping the air compressor ACP and processes for storing various set values (such as the charge rate of the power storage device B) in the storage unit), and switches the shut-off valve SV from the open valve state to the closed valve state. For example, when stopping the power generation of the fuel cell FC, the control unit Cnt turns off the switches SW1 and SW2 constantly to make the current flowing through the solenoid L1 and the solenoid L2 zero, and switches the shut-off valve SV from the open valve state to the closed valve state.

[0043] Further, during the power generation control of the fuel cell FC, when the control unit Cnt determines that a disconnection abnormality has occurred in at least one of the circuit H1 including the solenoid L1 and the circuit H2 (second circuit) including the solenoid L2, and if it continues for a predetermined time T (for example, 10 [ms] to 1 [s]) or more, the control unit Cnt determines that there is no expectation of the disconnection abnormality returning, and performs a process to stop the fuel cell FC. For example, the circuit H1 is a circuit from the switch SW1 to the ground GND through the solenoid L1 and the switch SWc. Also, the circuit H2 is a circuit from the switch SW2 to the ground GND through the solenoid L2 and the emergency stop button PB. Further, for example, when the current of the circuit H1 detected by a current sensor (not shown) or the voltage of the circuit H1 detected by a voltage sensor (not shown) is equal to or less than a predetermined value (for example, zero), the control unit Cnt determines that a disconnection abnormality has occurred in the circuit H1. When the current of the circuit H2 detected by a current sensor (not shown) or the voltage of the circuit H2 detected by a voltage sensor (not shown) is equal to or less than a predetermined value, the control unit Cnt determines that a disconnection abnormality has occurred in the circuit H2. Thereafter, for example, when the current of the circuit H1 detected by a current sensor (not shown) or the voltage of the circuit H1 detected by a voltage sensor (not shown) becomes greater than the predetermined value, the control unit Cnt determines that the disconnection abnormality of the circuit H1 has returned. When the current of the circuit H2 detected by a current sensor (not shown) or the voltage of the circuit H2 detected by a voltage sensor (not shown) becomes greater than the predetermined value, the control unit Cnt determines that the disconnection abnormality of the circuit H2 has returned.

[0044] Also, during the power generation control of the fuel cell FC, after the cutoff valve SV switches from the open valve state to the closed valve state due to a disconnection abnormality occurring in at least one of the circuits H1 and H2, if the control unit Cnt determines that the disconnection has immediately returned and current has started flowing through the solenoid L1 again, that is, if it determines that the cutoff valve SV is in the closed valve state even though current is flowing through the solenoid L1, it will again pass a third current through the solenoid L2 and a first current through the solenoid L1 to switch the cutoff valve SV from the closed valve state to the open valve state, and then pass a third current through the solenoid L2 and a second current through the solenoid L1 to maintain the cutoff valve SV in the open valve state. For example, during the power generation control of the fuel cell FC, if the current or voltage in at least one of the circuits H1 and H2 becomes greater than a predetermined value within a predetermined time T after the current or voltage in at least one of the circuits H1 and H2 has fallen below a predetermined value, the control unit Cnt determines that the cutoff valve SV is in the closed valve state even though current is flowing through the solenoid L1. Or, during the power generation control of the fuel cell FC, if current starts flowing again through the circuits H1 and H2 within a predetermined time T after the current has stopped flowing through at least one of the circuits H1 and H2, and the state value indicating the state of the hydrogen gas (pressure, temperature, flow rate, etc.) between the cutoff valve SV and the fuel cell FC becomes below a threshold value, the control unit Cnt determines that the cutoff valve SV is in the closed valve state even though current is flowing through the solenoid L1. Note that when the cutoff valve SV is in the closed valve state, hydrogen gas is not supplied from the hydrogen tank HT to the fuel cell FC, but the hydrogen gas in the fuel cell FC is consumed, so it is assumed that the state value indicating the state of the hydrogen gas between the cutoff valve SV and the fuel cell FC gradually decreases. Thus, when determining the state of the cutoff valve SV using not only the current flowing through the circuits H1 and H2 but also the state value indicating the state of the hydrogen gas, the accuracy of determining the state of the cutoff valve SV can be improved compared to the case of determining the state of the cutoff valve SV using only the current flowing through the circuits H1 and H2. Note that as a cause for the disconnection immediately returning after an instantaneous disconnection occurs in at least one of the circuits H1 and H2, for example, it is assumed that the harness constituting the circuits H1 and H2 is on the verge of breaking or that the emergency stop button PB has been pressed by the user for a relatively short time.

[0045] FIG. 3 is a flowchart showing an example of the operation of the control unit Cnt.

[0046] First, when an activation instruction for the fuel cell system FCS is input to the control unit Cnt (step Stp1: Yes), the shutoff valve SV is switched from the closed state to the open state (step Stp2), and power generation control is performed (step Stp3).

[0047] Next, when a stop instruction for the fuel cell system FCS has not been input (step Stp4: No) and no disconnection abnormality has occurred in the electric circuits H1 and H2 (step Stp5: No), the control unit Cnt continues to perform power generation control (step Stp3).

[0048] Also, when a stop instruction for the fuel cell system FCS is input (step Stp4: Yes), the control unit Cnt performs a process to stop the power generation of the fuel cell FC (step Stp6) and switches the shutoff valve SV from the open state to the closed state (step Stp7).

[0049] Also, after a disconnection abnormality has occurred, when the state where the disconnection abnormality does not recover continues for a predetermined time T (step Stp5: Yes, step Stp8: No, step Stp9: Yes), the control unit Cnt performs a process to stop the power generation of the fuel cell FC (step Stp10) and ends the power generation control.

[0050] Also, when the disconnection abnormality recovers within the predetermined time T after the disconnection abnormality has occurred (step Stp5: Yes, step Stp8: Yes), the control unit Cnt determines that the shutoff valve SV is in the closed state despite the current flowing through the solenoid L1, switches the shutoff valve SV from the closed state to the open state again (step Stp11), returns to step Stp3, and continues to perform power generation control.

[0051] Figure 4 is a flowchart showing another example of the operation of the control unit Cnt. Since steps Stp1 to Stp11 shown in FIG. 4 are the same as steps Stp1 to Stp11 shown in FIG. 3, the description thereof is omitted.

[0052] If the disconnection abnormality is restored within a predetermined time T after the disconnection abnormality occurs (step Stp5: Yes, step Stp8: Yes), and the state value indicating the state of the hydrogen gas between the shut-off valve SV and the fuel cell FC becomes equal to or less than the threshold value (step Stp7': Yes), the control unit Cnt determines that the shut-off valve SV is in the closed state even though current is flowing through the solenoid L1, and switches the shut-off valve SV from the closed state to the open state again (step Stp11), returns to step Stp3, and continues the power generation control.

[0053] As described above, in the fuel cell system FCS of the embodiment, during the power generation control of the fuel cell FC, if it is determined that the shut-off valve SV is in the closed state even though current is flowing through the solenoid L1, a third current is passed through the solenoid L2 again and a first current is passed through the solenoid L1, and then a third current is passed through the solenoid L2 and a second current is passed through the solenoid L1.

[0054] Thereby, even if an abnormality occurs in which current temporarily stops flowing through at least one of the solenoid L1 and the solenoid L2 during the power generation control of the fuel cell FC, the shut-off valve SV can be returned to the open state, so that the supply of hydrogen gas from the hydrogen tank HT to the fuel cell FC can be restored, and the power generation of the fuel cell FC can be suppressed from stopping.

[0055] Note that the present invention is not limited to the above-described embodiments, and various improvements and modifications can be made without departing from the gist of the present invention.

[0056] <Modification Example 1> FIG. 5 is a diagram showing Modification Example 1 of the fuel cell system FCS of the embodiment. In the fuel cell system FCS shown in FIG. 5, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0057] The fuel cell system FCS shown in FIG. 5 is provided in a stationary generator Pc such as an industrial stationary generator, a household stationary generator, or an emergency stationary generator. When configured in this way, the load Lo is, for example, industrial machinery, home appliances, etc.

[0058] Also in the fuel cell system FCS in Modification 1, during the power generation control of the fuel cell FC, if it is determined that the shut-off valve SV is in the closed state even though current is flowing through the solenoid L1, again, a third current is passed through the solenoid L2 and a first current is passed through the solenoid L1, and then a third current is passed through the solenoid L2 and a second current is passed through the solenoid L1.

[0059] Thereby, even if an abnormality occurs in which current temporarily stops flowing through at least one of the solenoid L1 and the solenoid L2 during the power generation control of the fuel cell FC, the shut-off valve SV can be returned to the open state, so that the supply of hydrogen gas from the hydrogen tank HT to the fuel cell FC can be restored, and the power generation of the fuel cell FC can be suppressed from stopping.

[0060] <Modification 2> FIG. 6 is a diagram showing Modification 2 of the fuel cell system FCS of the embodiment. In the fuel cell system FCS shown in FIG. 6, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0061] In the fuel cell system FCS shown in FIG. 6, the difference from the fuel cell system FCS shown in FIG. 1 is that the emergency stop button PB is omitted. The other terminal of the solenoid L2 is connected to the ground GND. That is, the fuel cell system FCS shown in FIG. 6 is applicable to devices and systems that do not require an emergency stop button PB.

[0062] Also in the fuel cell system FCS in Modification 2, during the power generation control of the fuel cell FC, if it is determined that the shut-off valve SV is in the closed state despite current flowing through the solenoid L1, then again, after flowing a third current through the solenoid L2 and a first current through the solenoid L1, a third current is flowed through the solenoid L2 and a second current is flowed through the solenoid L1.

[0063] Thereby, even if an abnormality occurs in which current temporarily stops flowing through at least one of the solenoid L1 and the solenoid L2 during the power generation control of the fuel cell FC, the shut-off valve SV can be returned to the open state, so that the supply of hydrogen gas from the hydrogen tank HT to the fuel cell FC can be restored, and the power generation of the fuel cell FC can be suppressed from stopping.

[0064] <Modification 3> FIG. 7 is a diagram showing Modification 3 of the fuel cell system FCS of the embodiment. In the fuel cell system FCS shown in FIG. 7, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0065] In the fuel cell system FCS shown in FIG. 7, the difference from the fuel cell system FCS shown in FIG. 1 is that the emergency stop button PB and the contactor CNT are omitted. The other terminal of the solenoid L1 is connected to the ground GND. That is, the fuel cell system FCS shown in FIG. 7 is applicable to devices and systems that do not require an emergency stop button PB.

[0066] The control unit Cnt shown in FIG. 7, when starting the fuel cell system FCS, after flowing a first current through the solenoid L1, flows a second current through the solenoid L1.

[0067] Also, the control unit Cnt shown in FIG. 7, during the power generation control of the fuel cell FC, if it is determined that the shut-off valve SV is in the closed state despite current flowing through the solenoid L1, then again, after flowing a first current through the solenoid L1, flows a second current through the solenoid L1.

[0068] Thus, in the fuel cell system FCS according to Modification 3, during power generation control of the fuel cell FC, if it is determined that the shutoff valve SV is in the closed state even though current is flowing through the solenoid L1, the configuration is such that after flowing the first current through the solenoid L1 again, the second current is flowed through the solenoid L1.

[0069] As a result, even if an abnormality occurs in which current temporarily stops flowing through the solenoid L1 during power generation control of the fuel cell FC, the shutoff valve SV can be returned to the open state, so the supply of hydrogen gas from the hydrogen tank HT to the fuel cell FC can be restored, and it is possible to suppress the power generation of the fuel cell FC from stopping.

Explanation of Reference Numerals

[0070] FCS Fuel cell system Ve Industrial vehicle Lo Load PB Emergency stop button FC Fuel cell HT Hydrogen tank SV Shutoff valve L1, L2 Solenoid CNT Contact SW1, SW2, SWc Switch INJ Injector ACP Air compressor ARV Air pressure regulating valve CNV DCDC converter B Power storage device Cnt Control unit P Power source GND Ground

Claims

1. A fuel cell system comprising a hydrogen tank for storing hydrogen gas supplied to a fuel cell, a shut-off valve provided between the hydrogen tank and the fuel cell, which switches from a closed valve state to an open valve state when a first current flows through a first solenoid, maintains the open valve state when a second current smaller than the first current flows through the first solenoid, and switches from the open valve state to the closed valve state when the current stops flowing through the first solenoid, a control unit, and comprising, wherein the control unit, at the start-up of the fuel cell system, after flowing the first current through the first solenoid, flows the second current through the first solenoid, during power generation control of the fuel cell, if it is determined that the shut-off valve is in the closed valve state even though a current is flowing through the first solenoid, again, after flowing the first current through the first solenoid, flows the second current through the first solenoid Fuel cell system.

2. The fuel cell system according to claim 1, comprising a contact that permits current to flow through the first solenoid when a third current is flowing through a second solenoid and prohibits current from flowing through the first solenoid when the third current is not flowing through the second solenoid, wherein the control unit, at the start-up of the fuel cell system, while flowing the third current through the second solenoid and flowing the first current through the first solenoid, then while flowing the third current through the second solenoid and flowing the second current through the first solenoid, during power generation control of the fuel cell, if it is determined that the shut-off valve is in the closed valve state even though a current is flowing through the first solenoid, again, while flowing the third current through the second solenoid and flowing the first current through the first solenoid, then while flowing the third current through the second solenoid and flowing the second current through the first solenoid Fuel cell system.

3. The fuel cell system according to claim 2, wherein the control unit, during power generation control of the fuel cell, if current flows again through at least one of a first electric circuit including the first solenoid and a second electric circuit including the second solenoid after a predetermined time has elapsed since the current stopped flowing through at least one of the first and second electric circuits, determines that the shut-off valve is in the closed valve state even though a current is flowing through the first solenoid Fuel cell system.

4. The fuel cell system according to claim 3, During the power generation control of the fuel cell, if a current flows again through at least one of the first and second electric paths after the current stops flowing through at least one of the first and second electric paths and before the lapse of the predetermined time, and if a value indicating the state of the hydrogen gas between the shut-off valve and the fuel cell becomes equal to or less than a threshold value, it is determined that the shut-off valve is in a closed state even though a current is flowing through the first solenoid. Fuel cell system.

5. The fuel cell system according to claim 3, wherein the second electric path is provided with an emergency stop button that, when operated by a user, prohibits a current from flowing through the second solenoid. Fuel cell system.

6. An industrial vehicle comprising the fuel cell system according to any one of claims 1 to 5.

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