Fuel cell system and control method for it

Abstract

Fuel cell system (10), comprising: a fuel cell (50); a plurality of tanks (TK1, TK2) that store a fuel gas which is used for electricity generation in the fuel cell (50); a feed channel (200) with first channels (Fa1, Fa2), each connected to the tanks; and a second channel (Fb) that merges with each of the first channels and is connected to the fuel cell; first on / off valves (Va1, Va2) arranged in each of the first channels (Fa1, Fa2), wherein the first on / off valves (Va1, Va2) are configured to switch between opening and closing the first channels (Fa1, Fa2), wherein the first on / off valves (Va1, Va2) each comprise a valve body, wherein the first on / off valves (Va1, Va2) are configured to seal the first channels (Fa1, Fa2) with a differential pressure between a first side and a second side of the valve body; a second on / off valve (Vb) which is arranged in the second channel (Fb), wherein the second on / off valve (Vb) is configured to switch back and forth between opening and closing the second channel (Fb); a controller (300) configured to control a current supplied to the first on / off valves (Va1, Va2) and the second on / off valve (Vb) to control the opening and closing of the first on / off valves (Va1, Va2) and the opening and closing of the second on / off valve (Vb), first pressure sensors (Se1, Se2) which are set up to obtain tank internal pressure values ​​in each of the tanks (Va1, Va2); and a second pressure sensor (215) which is configured to obtain a pressure value in the supply channel (200), wherein In a state where the second on / off valve (Vb) is closed, the controller, responding to a start command to start the fuel cell system, supplies a first current to at least one of the first on / off valves (Va1, Va2), the first current being used to open the first on / off valve against a first differential pressure, and supplies a second current, smaller than the first current, to the other on / off valves besides the at least one first on / off valve, the second current being used to open the first on / off valves against a second differential pressure, which is smaller than the first differential pressure. While the fuel cell system (10) is stopped, the controller (300) obtains the tank internal pressure values ​​in each of the tanks (Va1, Va2) and the pressure value in the supply channel (200), and, if a high differential pressure condition exists in which a differential pressure value between the tank internal pressure values ​​in at least one of the tanks (Va1, Va2) and the pressure value in the supply channel (200) is greater than or equal to a set value, the controller (300) performs a valve opening process, wherein the valve opening process is configured to supply the first flow to at least one first on / off valve and to supply the second flow to the other first on / off valves besides the at least one first on / off valve.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present invention relates to a fuel cell system and a control method for the fuel cell system. 2. Description of the state of the art

[0002] A fuel cell system is known which includes a fuel cell, a plurality of tanks that store a fuel gas which is used for generating electricity in the fuel cell, and an on / off valve formed in each of the tanks to switch between opening and closing the tank (see JP 2009-018803 A).

[0003] Furthermore, DE 10 2006 031 875 A1 discloses a method for opening tank shut-off valves in a fuel cell system comprising several pressure tanks. A flow control device is positioned in a supply line downstream of the tank shut-off valves. When the system is started, only one of the tank shut-off valves is opened to allow the pressure in the supply line between the tank shut-off valves and the flow control device to rise before the other tank shut-off valves are opened. Therefore, only one of the tank shut-off valves is exposed to the high pressure differential, which causes significant valve wear and tear. The valve opening sequence is controlled such that each of the tank shut-off valves is selected by a switching process as the one that is opened at system start-up.

[0004] Furthermore, JP 2017-157283A discloses a fuel cell system comprising: a fuel cell; a number n of fuel tanks; a manifold connected to the fuel cell; a number n of branch channels branching off from the manifold and connected to the respective fuel tanks; a number n of shut-off valves that shut off the supply of fuel from a corresponding fuel tank to the fuel cell; and a control device that controls the opening / closing of the number n tank shut-off valves. In the fuel cell system, each tank shut-off valve can open the valve with a force corresponding to a current that decreases as the difference between the upstream and downstream pressures decreases.When fuel supply to the fuel cell is initiated, the control device opens a first tank shut-off valve by supplying an initial current sufficient to open the first tank shut-off valve from a state in which all n tank shut-off valves are closed. After the first tank shut-off valve has opened, the control device opens an nth tank shut-off valve, starting from the second tank shut-off valve, by supplying a current smaller than the first current. SUMMARY OF THE INVENTION

[0005] The on / off valve in the fuel cell system, as described in JP 2009-018803 A, is of the type where a valve body presses against a valve seat with gas pressure on one side of the tank to ensure a seal. Opening such an on / off valve against a differential pressure requires a relatively high electrical power or current. Consequently, the fuel cell system, as described in JP 2009-018803 A, has the problem that a significant amount of current is used to open on / off valves when all valves are open during power generation in the fuel cell. To solve this problem, a technique is desired for the fuel cell system, which includes multiple tanks, that allows for a reduction in the current required to open on / off valves when all valves are open during power generation in a single fuel cell.

[0006] The foregoing problem is solved by the subject matter of dependent claims 1 and 5. Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0007] The present invention can be implemented as the following aspects.

[0008] A first aspect of the present invention relates to a fuel cell system. The fuel cell system comprises: a fuel cell; a plurality of tanks storing a fuel gas used for power generation in the fuel cell; a supply channel with first channels each connected to the tanks and a second channel joining each of the first channels and connecting to the fuel cell; first on / off valves arranged in each of the first channels, the first on / off valves being configured to switch between opening and closing the first channels, the first on / off valves each comprising a valve body, the first on / off valves being configured to seal the first channels with a differential pressure between a first side and a second side of the valve body; a second on / off valve arranged in the second channel,wherein the second on / off valve is configured to toggle between opening and closing the second channel; and a controller configured to control current supplied to the first on / off valves and the second on / off valve to control the opening and closing of the first on / off valves and the opening and closing of the second on / off valve. In a state where the second on / off valve is closed, the controller, in response to a start command to start the fuel cell system, supplies a first current to at least one first on / off valve of the first on / off valves, the first current being used to open the first on / off valve against a first differential pressure, and supplies a second current, smaller than the first current, to the other on / off valves besides the at least one first on / off valve, the second current being used toto open the first on / off valves against a second differential pressure that is lower than the first differential pressure. According to this principle, the first on / off valve receiving the first flow opens, and fuel gas flows into the supply channel. Consequently, the differential pressure between the internal tank pressure in the tanks equipped with the first on / off valves receiving the second flow and the pressure in the supply channel decreases. Therefore, the first on / off valves can be opened even with a supply of the second flow, which is lower than the first flow. Thus, the flow required to open all the first on / off valves can be reduced compared to when the first flow is supplied to all the first on / off valves.

[0009] In the first aspect, the fuel cell system may further include: a filling channel branching off from a filling port, which is a hydrogen gas filling connection, and connected to each of the tanks; a first pressure sensor configured to obtain a pressure value in the filling channel; and a second pressure sensor configured to obtain a pressure value in the supply channel.While the fuel cell system is stopped, the controller can obtain the pressure value in the filling channel and the pressure value in the supply channel, and if it is in a high differential pressure state where the differential pressure value between the pressure value in the filling channel and the pressure value in the supply channel is greater than or equal to a set value, the controller can execute a valve opening process, wherein the valve opening process is configured to supply the first flow to at least one first on / off valve and to supply the second flow to the other first on / off valves besides the at least one first on / off valve.

[0010] In the first aspect, the fuel cell system further comprises: first pressure sensors configured to obtain tank internal pressure values ​​in each of the tanks; and a second pressure sensor configured to obtain a pressure value in the supply channel. While the fuel cell system is stopped, the controller obtains the tank internal pressure values ​​in the tanks and the pressure value in the supply channel. When it is in a high differential pressure state, where the differential pressure value between the tank internal pressure value in at least one of the tanks and the pressure value in the supply channel is greater than or equal to a set value, the controller executes a valve opening process. This process is configured to supply the first flow to at least one first on / off valve and to supply the second flow to the other first on / off valves besides the at least one first on / off valve.According to this approach, the pressure in the supply channel can be increased in advance while the fuel cell system is stationary. This makes it possible to shorten the time it takes for the first on / off valves to open, which receive the supply of the second flow after the fuel cell system has been switched on.

[0011] In the first aspect, the controller can be configured to execute the valve opening process at regular intervals while the fuel cell system is stationary.

[0012] In the first aspect, the controller can be configured to supply the second current to the first on / off valves, except for the at least one first on / off valve, and, once all of the first on / off valves are open, the controller can be configured to supply the second current to the at least one first on / off valve that has received a supply of the first current.

[0013] In the first aspect, the first on / off valves receiving the second flow can have a lower upper differential pressure than the first on / off valve receiving the first flow. The upper differential pressure is the upper limit of the differential pressure between the first and second sides of the on / off valves, within a range that allows the on / off valves to open. According to this aspect, the cost of the fuel cell system can be reduced, as on / off valves with a small upper differential pressure are generally less expensive than those with a large upper differential pressure.

[0014] A second aspect of the present invention relates to a control method for the fuel cell system. The fuel cell system comprises: a fuel cell; a plurality of tanks storing a fuel gas used for power generation in the fuel cell; a supply channel with first channels each connected to the tanks, and a second channel joining each of the first channels and connected to the fuel cell; first on / off valves arranged in each of the first channels, the first on / off valves being configured to switch between opening and closing the first channels, the first on / off valves each comprising a valve body, and the first on / off valves being configured to seal the first channels with a differential pressure between a first side and a second side of the valve body.and a second on / off valve arranged in the second channel, the second on / off valve being configured to switch the second channel between opening and closing. The control method of the fuel cell system comprises: supplying, in a state where the second on / off valve is closed, in response to a start command to start the fuel cell system, a first current to at least one first on / off valve of the first on / off valves, the first current being used to open the first on / off valve against a first differential pressure; and supplying, in that state, a second current, smaller than the first current, to the other first on / off valves besides the at least one first on / off valve, the second current being used to open the first on / off valves against the second differential pressure, which is smaller than the first differential pressure.

[0015] The present invention can also be implemented in the form of various aspects other than the fuel cell system. For example, the present invention can also be implemented in aspects such as a method for supplying a fuel gas to a fuel cell in a fuel cell system installed in a vehicle, a controller that executes the supply method, a computer program that implements the supply method, a recording medium that stores the computer program, and a mobile object containing a fuel cell system. BRIEF DESCRIPTION OF THE DRAWING

[0016] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying drawing, where the same reference numerals denote the same elements and where: Fig. 1 is an explanatory view that shows the configuration of a fuel cell system according to a first embodiment; Fig. 2 is a process that represents a valve opening process at start time, executed by a controller; Fig. 3 is a process that represents a valve opening process at stop time, which is executed by the controller; Fig. Figure 4 is an explanatory view showing a pressure fluctuation in a supply channel during the valve opening process at the stop time; and Fig. 5 is an explanatory view that shows the configuration of a fuel cell system according to a third embodiment. DETAILED DESCRIPTION OF EXECUTIVE FORMS A. First embodiment: A1. Configuration of the device:

[0017] Fig. Figure 1 is an illustrative view showing the configuration of a fuel cell system 10 according to a first embodiment of the present invention. The fuel cell system 10 is mounted in a vehicle powered by an electric motor, which serves as the vehicle's power source. Examples of the vehicle include passenger cars, buses, and the like. The fuel cell system 10 comprises a fuel cell stack 50, a filling port 100, a filling channel 110, tanks TK1 to TK10, a feed channel 200, and a controller 300. The fuel cell system 10 comprises a total of ten tanks, from tank TK1 to tank TK10. Fig. In Figure 1, tanks TK1, TK2, and TK10 are shown, while tanks TK3 to TK9 are omitted. In the following description, the ten tanks can be collectively referred to by the reference symbol "TK".

[0018] The fuel cell stack 50 has a stacked structure formed by stacking multiple individual cells on top of each other. Each individual cell consists of a membrane electrode array arranged between separators. The membrane electrode array is formed by connecting an anode and a cathode at the two surfaces of a proton-conducting electrolyte membrane. Upon receiving a supply of hydrogen gas and air, the fuel cell stack 50 generates electricity through an electrochemical reaction of hydrogen and oxygen.

[0019] Container 100 is a filling port for hydrogen gas, which is a fuel gas. During filling, a hydrogen filling station nozzle is attached to filling port 100. Filling port 100 has a shut-off valve 105. The shut-off valve 105 prevents backflow of the filled fuel gas.

[0020] Filling channel 110 is used to convey the fuel gas from filling opening 100 to tanks TK1 to TK10. Filling channel 110 branches off from filling opening 100 to tanks TK1 and is connected to these tanks. A section of channel 110 branching off to tank TK1 is equipped with a shut-off valve Cv1. The shut-off valve Cv1 prevents the fuel gas filled into tank TK1 from flowing back towards filling opening 100. Shut-off valves Cv2 to Cv10 have the same configuration as shut-off valve Cv1. The shut-off valves Cv2 and Cv10 are located in channel sections of filling channel 110, each branching off to tanks TK2 to TK10.

[0021] The filling channel 110 is equipped with a pressure sensor 115. The pressure sensor 115 measures a pressure P0 in the filling channel 110. Since the filling channel 110 and the tanks TK are connected, it can be assumed that the pressure P0 measured by the pressure sensor 115 is equal to the pressures in the tanks TK1 to TK10.

[0022] Tank TK1 stores hydrogen gas as fuel, which is used for power generation in the fuel cell stack 50. Tanks TK2 to TK10 have the same configuration as tank TK1.

[0023] The supply channel 200 connects the tanks TK to the fuel cell stack 50 and directs the fuel gas supplied from the tanks TK to the fuel cell stack 50. The supply channel 200 has first channels Fa1 to Fa10, each connected to the tanks TK1 to TK10, and a second channel Fb, which joins the first channels Fa1 to Fa10 and is connected to the fuel cell stack 50.

[0024] The first channel Fa1 is equipped with a first on / off valve Va1, which switches between opening and closing the first channel Fa1. The first on / off valve Va1 is a solenoid valve that seals the first channel Fa1 with a differential pressure between upstream and downstream of the valve body of the first on / off valve Va1. The first on / off valve Va1 is also a solenoid valve that can be opened against the differential pressure using the force corresponding to the applied current. In the present embodiment, the first on / off valve Va1 is a pilot valve. In other embodiments, the first on / off valve Va1 can be a valve of any shape, as long as it is a solenoid valve that seals the first channel Fa1 with the differential pressure between upstream and downstream of the valve body and is also a solenoid valve that can be opened against the differential pressure using the force corresponding to the applied current.Like the first on / off valve Va1 of the first channel Fa1, the first channels Fa2 to Fa10 are equipped with corresponding first on / off valves Va2 to Va10. The first on / off valves Va2 to Va10 are solenoid valves that have the same configuration as the first on / off valve Va1. In the following description, the first ten on / off valves can be collectively referred to by the reference symbol "Va".

[0025] The second channel Fb is equipped with a second on / off valve Vb, which switches between opening and closing the second channel Fb. The second channel Fb is equipped with a pressure sensor 215. The pressure sensor 215 measures a pressure P1 in the supply channel 200.

[0026] The controller 300 receives signals output by various sensors (not shown) included in the fuel cell system 10 and controls the actuation of each unit of the fuel cell system 10. The controller 300 controls the current supplied to the first on / off valves Va and the second on / off valves Vb to control the opening and closing of the first on / off valves Va and the second on / off valve Vb. In the present embodiment, the current required to open the first on / off valves Va and the second on / off valve Vb is supplied by a battery (not shown). The controller 300 may consist of an electronic control unit (ECU).

[0027] In the fuel cell system 10, the first on / off valves Va are all opened when power generation is performed by the fuel cell stack 50. At this time, the pressure in each of the tanks TK is identical. However, the positions in which the tanks TK are located in the vehicle are different. Accordingly, when the fuel cell system 10 is operating, the tanks TK differ in their ambient temperature due to a difference in the amount of radiant heat emitted by devices located around each tank TK. Therefore, the pressures in the tanks TK may develop differently when the temperature difference between the tanks TK disappears after the fuel cell system 10 shuts down.

[0028] Under such circumstances, if only the first on / off valve Va in some of the tanks TK is open, and the open tank TK stores a high-pressure gas that has a higher pressure than the gas in other, closed tanks TK, the high-pressure fuel gas released from the open tank TK can damage the first on / off valves Va of the closed tanks TK. To prevent such damage, the fuel cell system 10, when power generation starts in the fuel cell stack 50, performs a valve opening process at start-up time, described later, to open all of the first on / off valves Va. A2. Valve opening process at start time:

[0029] Fig. 2 is a sequence representing the valve opening process at start-up time, which is executed by the controller 300. When the fuel cell system 10 is stopped, the controller 300, upon receiving a start command to start the fuel cell system 10, executes the valve opening process at start-up time. The controller 300 receives a notification as a start command that an ignition switch, located in the vehicle in which the fuel cell system 10 is installed, is being turned on. The valve opening process at start-up time is a process performed to open the first on / off valves Va1 to Va10 when power is generated by the fuel cell stack 50.

[0030] A description is given of the state in which the fuel cell system 10 stops before the valve opening process is executed at start time. In the state in which the fuel cell system 10 stops, the first on / off valves Va and the second on / off valve Vb are closed. In the state in which the fuel cell system 10 stops, the pressure in the supply channel 200 is relatively lower than the pressures in each of the tanks TK, which are located at their respective positions in the vehicle. This is because, when the fuel cell system 10 stops, electricity is required during the process of stopping the devices that make up the fuel cell system 10, and therefore the fuel cell stack 50 consumes the fuel gas in the supply channel 200 to generate the required electricity.

[0031] As in Fig. As shown in Figure 2, when the valve opening process is started at start time, the controller 300 supplies a first current to the first on / off valve Va1, which is used to open the first on / off valve, while a second current, which is smaller than the first current, is supplied to the other first on / off valves Va (Va2 to Va10) (step S110).

[0032] The first current is the current used to open the first on / off valve Va against the first differential pressure. In the present embodiment, the first differential pressure is an upper limit differential pressure. The upper limit differential pressure used here refers to an upper limit of the differential pressure between one side and the other of the on / off valves, the differential pressure being within a range that allows the on / off valves to open. In the present embodiment, the upper limit differential pressure of the first on / off valve Va1 is 90 MPa. Therefore, the first current is the current that allows the first on / off valves Va to open against a differential pressure of 90 MPa. In other embodiments, the first differential pressure may be lower than the upper limit differential pressure.

[0033] The second current is smaller than the first and is used to open the first on / off valves Va against a second differential pressure that is also lower than the first differential pressure. In the present embodiment, the second differential pressure is 20 MPa. Therefore, the second current enables the first on / off valves Va to open against a differential pressure of 20 MPa. In other embodiments, the second differential pressure can be any differential pressure lower than the first differential pressure.

[0034] When the first on / off valve Va1, which receives the first stream, opens, the fuel gas is fed from tank TK1 into supply channel 200. As the fuel gas is fed in, the pressure in supply channel 200 approaches the internal pressures in tanks TK2 to TK10. The first on / off valves Va2 to Va10 open when the differential pressure between the pressure on the supply channel 200 side and the pressure on the side of tanks TK2 to TK10 reaches the second differential pressure, which is within the range that allows the first on / off valves Va2 to Va10, which receive the second stream, to open. After the first on / off valves Va2 to Va10 have been opened, the second current is supplied to the first on / off valve Va1, which received the first current, in order to keep the first on / off valve Va1 in an open state.

[0035] After the first and second currents have been applied to the first on / off valves Va (step S110), the controller 300 determines whether a preset time has elapsed or not (step S120). The preset time used here is a sufficient time, set as the time required to open all the first on / off valves Va after the first and second currents have been applied.

[0036] After the controller 300 has determined that the preset time has elapsed (step S120: YES), it opens the second on / off valve Vb (step S130). The controller 300 then completes the valve opening process at the start time. When the second on / off valve Vb is open, the fuel cell stack 50 starts generating electricity.

[0037] According to the first embodiment described above, the first on / off valve Va1, which receives a supply of the first stream, is opened, and the fuel gas flows into the supply channel 200. This reduces the differential pressure between the internal tank pressure in tanks TK2 to TK10, which are equipped with the first on / off valves Va2 to Va10, which receive a supply of the second stream, and the pressure in the supply channel 200. Consequently, the first on / off valves Va2 to Va10 can be opened with a supply of the second stream. Therefore, the power consumption required to open all first on / off valves Va can be reduced compared to when the first stream is supplied to all first on / off valves Va. B. Second embodiment:

[0038] A second embodiment of the fuel cell system is now described. The configuration of the second embodiment's fuel cell system is the same as the configuration of the first embodiment's fuel cell system 10. The second embodiment's fuel cell system differs with respect to the details of the process executed by the controller 300.

[0039] Fig. Figure 3 is a sequence representing a valve opening process at standstill time, which is executed by the controller of the second embodiment. The controller 300 in the fuel cell system of the second embodiment performs the valve opening process at standstill time in addition to the valve opening process at start-up time described in the first embodiment. The controller 300 of the second embodiment performs the valve opening process at standstill time at regular intervals while the fuel cell system is stopped. The valve opening process at standstill time is a process for increasing the pressure in the feed channel 200 in advance while the fuel cell system is stopped.

[0040] If the valve opening process is started at the stop time, the controller 300 of the second embodiment refers to the following as in Fig. Figure 3 shows a pressure P0 in the filling channel 110, which is measured by the pressure sensor 115, and a pressure P1 in the supply channel 200, which is measured by the pressure sensor 215 (step S210).

[0041] After the pressure P0 and the pressure P1 have been obtained (step S210), the controller 300 of the second embodiment determines whether it is in a high differential pressure state or not, in which a differential pressure between the pressure P0 and the pressure P1 is greater than or equal to the set value (step S220).

[0042] If it is determined that it is not in the high differential pressure state (step S220: NO), the controller 300 of the second embodiment terminates the valve opening process at the stop time.

[0043] If it is determined that it is in the high differential pressure state (step S220: YES), the controller 300 of the second embodiment starts the fuel cell system (step S230).

[0044] After the fuel cell system has been started (step S230), the controller 300 of the second embodiment supplies the first current to the first on / off valve Va1, while the second current is supplied to the other first on / off valves Va (Va2 to Va10) (step S240). At that time, as in step S110 during the valve opening process at start-up time, the Fig. As shown in Figure 2, the first on / off valve Va1 opens, receiving a supply of the first stream, and the fuel gas is fed into the supply channel 200. Accordingly, the pressure in the supply channel 200 approaches the internal tank pressures in tanks TK2 to TK10. Consequently, the first on / off valves Va2 to Va10 open when the differential pressure between the side of the supply channel 200 and the side of tanks TK2 to TK10 reaches the second differential pressure, which is a differential pressure within the range that allows the first on / off valves Va2 to Va10, receiving a supply of the second stream, to open.

[0045] After the first and second streams have been supplied to the first on / off valves Va (step S240), the controller 300 of the second embodiment determines whether a preset time has elapsed (step S250). The preset time used here is a sufficient time, set as the time required until the pressure in the tanks TK with the first on / off valves Va open becomes substantially equal to the pressure in the supply channel 200.

[0046] After the controller 300 has determined that the preset time has elapsed (step S250: YES), it closes the first open / close valves Va (step S260). In the second embodiment, the first open / close valves Va1 to Va10 are closed in step S260. Then, in the second embodiment, the controller 300 terminates the valve opening process at the stop time.

[0047] Fig. Figure 4 is an explanatory view showing a pressure fluctuation in the supply channel 200 during the valve opening process at the stop time in the second embodiment. Fig. 4 denotes a horizontal axis for time and a vertical axis for pressure.

[0048] At control time t0, in step S240 the following occurs: Fig. The valve opening process described in section 3 is executed at the stop time, and the first on / off valves Va1 to Va10 are opened. A pressure Pp in the supply channel 200 at control time t0 represents the pressure caused by the fuel gas remaining in the supply channel 200 after the last stop of the fuel cell system. During a period from control time t0 to control time t1, the fuel gas is discharged from the tanks TK1 to TK10, with the first on / off valves Va1 to Va10 open. This increases the pressure in the supply channel 200.

[0049] At control time t1, the pressure in the supply channel 200 is a pressure Pt, which is essentially equal to the pressure in tanks TK1 to TK10. The expression "preset time" in step S250 of the valve opening process at the stop time, which is in Fig. The description in section 3 refers to a time span from control time t0 to control time t1. At control time t1, the first on / off valves Va1 to Va10 are closed.

[0050] At control time t2, the process for the fuel cell system's shutdown time is executed. Here, the fuel cell stack 50 consumes the fuel gas in the supply channel 200 to generate electricity, which is required during the process of shutting down each of the devices that make up the fuel cell system. Therefore, at control time t2, the pressure in the supply channel 200 drops from pressure Pt.

[0051] At control time t3, the in Fig. The valve opening process described in step 2 is started at the start time, and step S110 is executed. Consequently, the first on / off valve Va1 opens, receiving the first flow. During a period from control time t3 to control time t4, the fuel gas is discharged from tank TK1 while the first on / off valve Va1 remains open. This increases the pressure in the supply channel 200.

[0052] At control time t4, the pressure in supply channel 200 reaches pressure Pt. As the pressure in supply channel 200 increases during the period from control time t3 to control time t4, a differential pressure decreases between the pressure on the side of supply channel 200 and the pressure in tanks TK2 to TK10, which is equal to pressure Pt at control time t1. When the differential pressure reaches the second differential pressure, which is a differential pressure within a range that allows the first on / off valves Va2 to Va10, which receive a supply of the second stream, to open, the first on / off valves Va2 to Va10 are opened.

[0053] According to the second embodiment described above, the pressure in the supply channel 200 can be increased in advance while the fuel cell system is stopped. This makes it possible to shorten the time it takes for the first on / off valves Va, which receive the supply of the second current, to open after the fuel cell system has been switched on. Here, the time until the first on / off valves, which receive a supply of the second current, open refers to the time span from control time t3 to control time t4. Fig. 4.

[0054] The effects of the valve opening process described in the second embodiment at the standstill time become apparent when the fuel cell system is started for the first time, particularly after the tanks TK are filled with the fuel gas. When the fuel cell system is started for the first time after the tanks TK are filled with the fuel gas, there is highly likely to be a large difference between the pressure in the tanks TK and the pressure in the supply channel 200. Accordingly, in the fuel cell system that does not perform the valve opening process at the standstill time, the time required for the pressure in the supply channel 200 to approach the internal tank pressure in tanks TK2 to TK10 by opening the first on / off valve Va1 and supplying the fuel gas from tank TK1 tends to be longer in the start-up valve opening process.In contrast, in the fuel cell system that performs the valve opening process described in the second embodiment at the standstill time, the time required until the pressure in the supply channel 200 assumes the internal tank pressure in the tanks TK2 to TK10 can be shortened by performing the valve opening process at a standstill time in advance, before the fuel cell system is started for the first time after the tanks TK have been filled with the fuel gas. C. Third embodiment:

[0055] Fig. Figure 5 is an illustrative view showing the configuration of a fuel cell system 10a according to a third embodiment. The configuration of the fuel cell system 10a is similar to that of the fuel cell system in the second embodiment, except that the fuel cell system 10a includes pressure sensors Se1 to Se10 instead of the pressure sensor 115 and includes a controller 300a which differs from the controller 300 in the second embodiment with respect to the details of the process for its execution.

[0056] Pressure sensor Se1 is located in tank TK1. Pressure sensor Se1 measures a pressure PT1 in tank TK1. Pressure sensors Se2 to Se10 are located in their respective tanks TK2 to TK10, as is the case with pressure sensor Se1. Pressure sensors Se2 to Se10 measure pressures PT2 to PT10 in tanks TK2 to TK10.

[0057] The controller 300a performs a valve opening process at the time of a stop, which differs from the valve opening process at the stop time described in the second embodiment.

[0058] A description of the valve opening process at standstill time, executed by controller 300a, is now given. Controller 300a executes the valve opening process at standstill time using the same procedures as described in [reference to relevant section]. Fig. The process described in the second version is shown in Figure 3, with the exception of the following points. That is, the pressures PT1 to PT10 in tanks TK1 to TK10, measured by pressure sensors Se1 to Se10, and the pressure P1 in feed channel 200, measured by pressure sensor 215, are referenced in step S210, and the state of a high differential pressure is determined in step S220 based on the pressures PT1 to PT10 and the pressure P1.

[0059] In step S220, the controller 300a determines whether it is in a high differential pressure state, in which the differential pressure between each of the pressures PT1 to PT10 and the pressure P1 is greater than or equal to a set value. In other words, the controller 300a determines whether any of the pressures PT1 to PT10 has a high differential pressure relative to the pressure P1. If any of the pressures PT1 to PT10 has a high differential pressure relative to the pressure P1, the process after step S230 is carried out. With regard to the process from step S230 to step S250, the controller 300a performs the same process as the valve opening process at hold time described in the second embodiment. D. Fourth embodiment:

[0060] A fuel cell system of a fourth embodiment is now described. The configuration of the fuel cell system of the fourth embodiment is similar to that of the fuel cell system 10 of the first embodiment, except that the first on / off valve Va1 and the first on / off valves Va2 to Va10 are solenoid valves that differ in their structure.

[0061] In the fuel cell system of the fourth embodiment, the first on / off valve Va1 differs from the first on / off valves Va2 to Va10 with respect to its upper differential pressure limit. In the fourth embodiment, the first on / off valves Va2 to Va10 have a lower upper differential pressure limit than that of the first on / off valve Va1. The upper differential pressure limit of the first on / off valve Va1 is 90 MPa, while the upper differential pressure limit of the first on / off valves Va2 to Va10 is 20 MPa.

[0062] According to the fourth embodiment described above, the costs of the fuel cell system can be reduced because the on / off valves with a small upper differential pressure limit are generally cheaper than the on / off valves with a large upper differential pressure limit. E. Other embodiments:

[0063] In the first embodiment described above, etc., the fuel cell system is installed in a vehicle. However, the present invention is not limited thereto. For example, the fuel cell system can be installed on mobile objects, such as boats or aircraft that use electricity as a power source, and it can also be installed in various devices, systems, and the like, such as industrial machinery and power plants, without being limited to mobile objects.

[0064] In the embodiment described above, the fuel cell system 10 comprises a total of ten tanks, designated TK1 to TK10. However, the present invention is not limited thereto. For example, the fuel cell system 10 can exhibit the effects of the present invention as long as the fuel cell system 10 comprises a number of tanks TK greater than or equal to two.

[0065] Although the first on / off valve Va that receives a supply of the first current is the first on / off valve Va1 in the first embodiment described above, etc., the present invention is not limited thereto. For example, the first on / off valve Va that receives a supply of the first current can be any first on / off valve Va other than the first on / off valve Va1. Besides the first current being supplied to all first on / off valves Va included in the fuel cell system, any number of first on / off valves Va can receive the first current from the first on / off valves Va.

[0066] Although in the first embodiment described above, the controller 300 receives a notification as a start command that the ignition switch, which is included in the vehicle in which the fuel cell system 10 is installed, is switched on, the present invention is not limited thereto. For example, the controller 300 can receive a notification as a start command that a fixed time period has elapsed, or it can receive a notification as a start command that a driver is sitting in the driver's seat.

[0067] Without being limited to the foregoing embodiments, the present invention can be implemented in various configurations without departing from its spirit. For example, technical features in embodiments corresponding to the technical features disclosed in each aspect under the SUMMARY OF THE INVENTION may be expediently substituted or combined to solve some or all of the problems mentioned above or to achieve some or all of the effects mentioned above. Technical features may expediently be omitted unless they are designated as essential elements in this specification.

Claims

[1] Fuel cell system (10) comprising: a fuel cell (50); a plurality of tanks (TK1, TK2) that store a fuel gas which is used for electricity generation in the fuel cell (50); a feed channel (200) with first channels (Fa1, Fa2), each connected to the tanks; and a second channel (Fb) that merges with each of the first channels and is connected to the fuel cell; first on / off valves (Va1, Va2) arranged in each of the first channels (Fa1, Fa2), wherein the first on / off valves (Va1, Va2) are configured to switch between opening and closing the first channels (Fa1, Fa2), wherein the first on / off valves (Va1, Va2) each comprise a valve body, wherein the first on / off valves (Va1, Va2) are configured to seal the first channels (Fa1, Fa2) with a differential pressure between a first side and a second side of the valve body; a second on / off valve (Vb) which is arranged in the second channel (Fb), wherein the second on / off valve (Vb) is configured to switch back and forth between opening and closing the second channel (Fb); a controller (300) configured to control a current supplied to the first on / off valves (Va1, Va2) and the second on / off valve (Vb) to control the opening and closing of the first on / off valves (Va1, Va2) and the opening and closing of the second on / off valve (Vb), first pressure sensors (Se1, Se2) which are set up to obtain tank internal pressure values ​​in each of the tanks (Va1, Va2); and a second pressure sensor (215) which is configured to obtain a pressure value in the supply channel (200), wherein In a state where the second on / off valve (Vb) is closed, the controller, responding to a start command to start the fuel cell system, supplies a first current to at least one of the first on / off valves (Va1, Va2), the first current being used to open the first on / off valve against a first differential pressure, and supplies a second current, smaller than the first current, to the other on / off valves besides the at least one first on / off valve, the second current being used to open the first on / off valves against a second differential pressure, which is smaller than the first differential pressure. While the fuel cell system (10) is stopped, the controller (300) obtains the tank internal pressure values ​​in each of the tanks (Va1, Va2) and the pressure value in the supply channel (200), and, if a high differential pressure condition exists in which a differential pressure value between the tank internal pressure values ​​in at least one of the tanks (Va1, Va2) and the pressure value in the supply channel (200) is greater than or equal to a set value, the controller (300) performs a valve opening process, wherein the valve opening process is configured to supply the first flow to at least one first on / off valve and to supply the second flow to the other first on / off valves besides the at least one first on / off valve. [2] Fuel cell system (10) according to claim 1, wherein, while the fuel cell system (10) is stopped, the controller (300) is configured to perform the valve opening process at regular intervals. [3] Fuel cell system (10) according to claim 1, wherein the controller (300) is configured to supply the second current to the first on / off valves in addition to the at least one first on / off valve, and, once all of the first on / off valves are open, the controller (300) is configured to supply the second current to the at least one on / off valve which received a supply of the first current. [4] Fuel cell system (10) according to one of claims 1 to 3, wherein the first on / off valves receiving a supply of the second stream are smaller with respect to the upper limit differential pressure than the first on / off valve receiving a supply of the first stream, wherein the upper limit differential pressure is an upper limit of the differential pressure between the first side and the second side of the first on / off valves, wherein the differential pressure is in a range which makes it possible to open the on / off valves. [5] Control method of a fuel cell system (10), wherein the fuel cell system (10) comprises: a fuel cell (50); a plurality of tanks (TK1, TK2) storing a fuel gas which is used for electricity generation in the fuel cell (50); a supply channel (200) with first channels (Fa1, Fa2) each connected to the tanks and a second channel (Fb) which joins to each of the first channels and is connected to the fuel cell;First on / off valves (Va1, Va2) arranged in each of the first channels (Fa1, Fa2), wherein the first on / off valves (Va1, Va2) are configured to switch between opening and closing the first channels (Fa1, Fa2), wherein the first on / off valves (Va1, Va2) each comprise a valve body, wherein the first on / off valves (Va1, Va2) are configured to seal the first channels (Fa1, Fa2) with a differential pressure between a first side and a second side of the valve body; a second on / off valve (Vb) arranged in the second channel (Fb), wherein the second on / off valve (Vb) is configured to switch between opening and closing the second channel (Fb);first pressure sensors (Se1, Se2) configured to obtain tank internal pressure values ​​in each of the tanks (Va1, Va2), and a second pressure sensor (215) configured to obtain a pressure value in the supply channel (200), wherein the control method comprises:; Supplying, in a state in which the second on / off valve (Vb) is closed, responding to a start command to start the fuel cell system, a first current to at least one first on / off valve of the first on / off valves (Va1, Va2), wherein the first current is used to open the first on / off valve against a first differential pressure; Supplying, in the state of, a second stream which is smaller than the first stream, to the other first on / off valves than the at least one first on / off valve, wherein the second stream is used to open the first on / off valves against the second differential pressure which is smaller than the first differential pressure; and While the fuel cell system (10) is stopped, the internal tank pressure values ​​in each of the tanks (Va1, Va2) and the pressure value in the supply channel (200) are obtained, and, if a high differential pressure condition exists in which a differential pressure value between the internal tank pressure value in at least one of the tanks (Va1, Va2) and the pressure value in the supply channel (200) is greater than or equal to a set value, a valve opening process is carried out, wherein the valve opening process is configured to supply the first stream to at least one first on / off valve and to supply the second stream to the other first on / off valves besides the at least one first on / off valve.

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