JP2008277215A - Fuel cell system, and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce interpolar differential pressure at the time of starting or shutdown of a fuel cell system regardless of a pressure environment. <P>SOLUTION: When a starting demand to a fuel cell system 100 is detected, a control part 40 starts an air compressor 30 and starts supply of an oxidizer gas to a cathode 10c. The control part 40 obtains a cathode pressure Pc from an oxidizer gas pressure sensor 41 and, when the cathode pressure Pc is higher than a target pressure Pref1, opens a fuel gas inlet valve 51 and starts supply of the fuel gas to an anode 10a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system and a control method for the fuel cell system.

  In the fuel cell system, when the difference between the pressure on the anode side and the pressure on the cathode side of the fuel cell increases, mechanical stress applied to the membrane electrode assembly (MEA) increases, and deterioration of the membrane electrode assembly is promoted. It is known. In order to solve this problem, for example, a technique for controlling supply of anode gas and cathode gas so as to reduce the differential pressure between the electrodes is known (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2004-253208

  However, when a high-pressure supply source having a pressure higher than atmospheric pressure is used as the anode gas supply source, the pressure increase rate at the cathode is lower than the pressure increase rate at the anode. There is a problem that the differential pressure control is not easy.

  Further, the pressure difference between the electrodes becomes more prominent in a pressure environment lower than atmospheric pressure, for example, at high altitudes, but in the conventional technology, the pressure difference between the electrodes at the time of starting or stopping the fuel cell system at high altitudes is There is a problem that it is not considered.

  The present invention has been made to solve at least a part of the conventional problems described above, and aims to reduce the differential pressure between the electrodes at the time of starting or stopping the fuel cell system regardless of the pressure environment. And

  The present invention for solving at least a part of the above problems adopts the following aspects.

  A first aspect of the present invention provides a fuel cell system. A fuel cell system according to a first aspect of the present invention includes a fuel cell including an anode and a cathode, a high-pressure fuel gas source storing fuel gas to be supplied to the anode, and supplying an oxidizing gas to the cathode. When the fuel cell is started and the fuel cell is started, it is determined whether the pressure on the cathode side has reached a predetermined pressure, and when the pressure on the cathode side has reached the predetermined pressure, A fuel gas supply control unit for starting supply of fuel gas from the high-pressure fuel gas source to the anode.

  According to the fuel cell system of the first aspect of the present invention, when the pressure on the cathode side reaches a predetermined pressure, the supply of fuel gas from the high-pressure fuel gas source to the anode is started. Regardless, the pressure difference between the electrodes at the start of the fuel cell system can be reduced.

  The fuel cell system according to the first aspect of the present invention further includes a cathode pressure detector for detecting the pressure on the cathode side of the fuel cell, and the fuel gas supply control unit is detected by the cathode pressure detector. The cathode side pressure may be used to determine whether or not the cathode side pressure has reached a predetermined pressure. In this case, the pressure on the cathode side can be determined based on the actually measured value.

  The fuel cell system according to the first aspect of the present invention further includes an atmospheric pressure detector for detecting an atmospheric pressure, and the fuel gas supply control unit uses the atmospheric pressure detected by the atmospheric pressure detector as a standard. When the pressure is lower than the atmospheric pressure, the predetermined pressure is set to the standard atmospheric pressure, and when the pressure on the cathode side detected by the cathode pressure detector reaches the predetermined pressure, the fuel gas to the anode May be started. In this case, regardless of the pressure environment, it is possible to reduce the pressure difference between the electrodes when starting the fuel cell system, and it is possible to start the fuel cell system quickly.

In the fuel cell system according to the first aspect of the present invention, the high-pressure fuel gas source is connected to the anode of the fuel cell via a fuel gas supply pipe,
The fuel gas supply control unit is disposed in the fuel gas supply pipe and switches the fuel gas supply pipe to a communication state or a non-communication state, and switches the switch to a non-communication state when the fuel cell is started. And a switch controller that switches the switch from a non-communication state to a communication state after the cathode-side pressure reaches a predetermined pressure. In this case, the fuel gas can be supplied to and stopped from the anode by the switch.

  A second aspect of the present invention provides a fuel cell system. A fuel cell system according to a second aspect of the present invention includes a fuel cell including an anode and a cathode, a high-pressure fuel gas source storing fuel gas to be supplied to the anode, and supplying an oxidizing gas to the cathode. And when the fuel cell is stopped, it is determined whether the pressure on the anode side has reached a predetermined pressure, and when the pressure on the anode side has reached the predetermined pressure, An oxidant gas supply control unit that stops supply of the oxidant gas to the cathode by the oxidant gas supply unit.

  According to the fuel cell system of the second aspect of the present invention, when the pressure on the anode side reaches the predetermined pressure, the supply of the oxidizing gas from the high-pressure fuel gas source to the cathode is stopped. It is possible to reduce the pressure difference between the electrodes when the fuel cell system is stopped.

  The fuel cell system according to the second aspect of the present invention further comprises an anode pressure detector for detecting the pressure on the anode side of the fuel cell, and the pressure on the anode side detected by the anode pressure detector is detected. It may be used to determine whether or not the pressure on the anode side has reached a predetermined pressure. In this case, the pressure on the anode side can be determined based on the actually measured value.

  The fuel cell system according to the second aspect of the present invention further includes an atmospheric pressure detector for detecting atmospheric pressure, and the oxidizing gas supply control unit uses the atmospheric pressure detected by the atmospheric pressure detector as a standard. When the pressure is lower than the atmospheric pressure, the predetermined pressure is set to the standard atmospheric pressure, and when the pressure on the anode side detected by the anode pressure detector reaches the predetermined pressure, the oxidizing gas to the cathode Supply may be stopped. In this case, regardless of the pressure environment, it is possible to reduce the differential pressure between the electrodes when the fuel cell system is stopped, and it is possible to stop the fuel cell system quickly.

  The fuel cell system according to a second aspect of the present invention further includes a fuel gas consumption control unit that executes a fuel gas consumption process for consuming fuel gas remaining in the anode when the fuel cell is stopped. The gas supply control unit may determine whether or not the pressure on the anode side has reached a predetermined pressure after the fuel gas consumption process is executed. In this case, the pressure on the anode side can be reduced by the fuel gas consumption process.

  In the fuel cell system according to the first or second aspect of the present invention, the oxidizing gas supplier may be an air compressor. In this case, an oxidizing gas having a predetermined pressure is supplied to the cathode.

  A third aspect of the present invention provides a startup control method in a fuel cell system. In the start-up control method according to the third aspect of the present invention, when the fuel cell is started, it is determined whether or not the detected cathode-side pressure has reached a predetermined pressure, and the cathode-side pressure is determined to be the predetermined pressure. Is reached, the fuel gas supply to the anode of the fuel cell is started from the high-pressure fuel gas source.

  According to the control method at the time of stop concerning the 3rd mode of the present invention, the same operation effect as the fuel cell system concerning the 1st mode of the present invention can be obtained. Further, the stop-time control method according to the third aspect of the present invention can be realized in various aspects similarly to the fuel cell system according to the first aspect of the present invention.

  A fourth aspect of the present invention provides a stop time control method in a fuel cell system. In the stop time control method according to the fourth aspect of the present invention, when the fuel cell is stopped, it is determined whether or not the detected anode side pressure has reached a predetermined pressure, and the anode side pressure is determined to be the predetermined pressure. If it has reached, the supply of the oxidizing gas to the cathode by the oxidizing gas supplier is stopped.

  According to the control method at the time of stop concerning the 4th mode of the present invention, the same operation effect as the fuel cell system concerning the 2nd mode of the present invention can be obtained. Further, the stop time control method according to the fourth aspect of the present invention can be realized in various aspects similarly to the fuel cell system according to the second aspect of the present invention.

  Furthermore, the start time control method according to the third aspect of the present invention or the stop time control method according to the fourth aspect can also be realized as a computer program executed by a computer and a recording medium storing the computer program.

  A fifth aspect of the present invention provides a fuel cell system. A fuel cell system according to a fifth aspect of the present invention includes a fuel cell including an anode and a cathode, a high-pressure fuel gas source that stores fuel gas to be supplied to the anode, and an oxidizing gas that is supplied to the cathode. And a control unit that suppresses an increase in the difference between the pressure of the anode and the pressure of the cathode according to the atmospheric pressure when the fuel cell is started or stopped.

  According to the fuel cell system of the fifth aspect of the present invention, when the fuel cell is started or stopped, an increase in the difference between the anode pressure and the cathode pressure is suppressed according to the atmospheric pressure. Regardless of this, it is possible to reduce the differential pressure between the electrodes when the fuel cell system is started or stopped.

  In the fuel cell system according to a fifth aspect of the present invention, the control unit supplies fuel gas from the high-pressure fuel gas source to the anode and oxidizes the cathode by the oxidizing gas supplier according to the atmospheric pressure. At least one of the gas supply may be controlled to suppress an increase in the difference between the anode pressure and the cathode pressure. In this case, the control unit controls at least one of the supply of the fuel gas from the high-pressure fuel gas source to the anode and the supply of the oxidizing gas to the cathode by the oxidizing gas supply device, and the pole at the time of starting or stopping the fuel cell system The differential pressure can be reduced.

  Hereinafter, a fuel cell system according to the present invention will be described based on examples with reference to the drawings.

First embodiment:
The configuration of the fuel cell system according to the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is an explanatory diagram schematically showing the configuration of the fuel cell system according to the first embodiment. FIG. 2 is an explanatory diagram schematically showing the internal configuration of the control unit provided in the fuel cell system according to the first embodiment.

  The fuel cell system 100 according to the first embodiment includes a fuel cell 10, a high-pressure hydrogen tank 20, an air compressor 30, and a control unit 40 as main components. The fuel cell 10 and the high-pressure hydrogen tank 20 are connected by a fuel gas supply pipe 21. The fuel cell 10 and the air compressor 30 are connected by an oxidizing gas supply pipe 31.

  The fuel cell 10 is a fuel cell including, for example, a solid electrolyte membrane electrode assembly between an anode 10a (anode separator) and a cathode 10c (cathode separator). In the high-pressure hydrogen tank 20, fuel gas, in this embodiment pure hydrogen, is stored at a high pressure. As the fuel gas, for example, hydrogen rich gas (hydrogen containing gas) can be used in addition to pure hydrogen gas. The air compressor 30 is a pump that compresses the air and discharges it at a predetermined discharge pressure. For example, a compressor such as a scroll method or a rotary method is used.

  The fuel cell 10 includes an oxidizing gas supply unit 11 for supplying an oxidizing gas to the cathode 10c, an oxidizing gas discharge unit 12 for discharging the oxidizing gas from the cathode 10c, and a fuel gas supply for supplying the fuel gas to the anode 10a. And a fuel off-gas discharge part 14 for discharging fuel off-gas which is residual fuel gas from the anode 10a. In the present embodiment, the anode means not only an electrode that causes an electrochemical reaction, but also the entire flow path and space to which fuel gas is supplied. Similarly, the cathode means not only an electrode that causes an electrochemical reaction but also a general flow path and space to which an oxidizing gas is supplied.

  An oxidizing gas supply pipe 31 is connected to the oxidizing gas supply unit 11. An oxidizing gas discharge pipe 32 is connected to the oxidizing gas discharge unit 12. The oxidizing gas discharge pipe 32 is provided with an oxidizing gas pressure sensor 41 and an oxidizing gas pressure regulating valve 53 from upstream to downstream, that is, in a direction from the oxidizing gas discharge unit 12 toward the outside of the fuel cell 10.

  The oxidizing gas pressure sensor 41 detects the cathode outlet pressure of the fuel cell 10 as the cathode pressure Pc. The oxidizing gas pressure regulating valve 53 adjusts the cathode pressure to a desired pressure value by changing the valve opening.

  Between the oxidizing gas pressure sensor 41 and the oxidizing gas pressure regulating valve 53 in the oxidizing gas supply pipe 31 and the oxidizing gas discharge pipe 32, a humidifying module 35 for humidifying the oxidizing supply gas is disposed. The humidification module 35 is generated along with the electromotive reaction, and humidifies the oxidation supply gas by using water vapor contained in the oxidation exhaust gas.

  A fuel gas supply pipe 21 is connected to the fuel gas supply unit 13. The fuel gas supply pipe 21 is provided with a fuel gas pressure regulating valve 50 and a fuel gas introduction valve 51 from upstream to downstream, that is, in a direction from the high-pressure hydrogen tank 20 toward the fuel cell 10.

  The fuel gas pressure regulating valve 50 adjusts the supply pressure of hydrogen supplied from the high-pressure hydrogen tank 20 to the fuel cell 10 to a desired pressure. Since the hydrogen pressure stored in the high-pressure hydrogen tank 20 is higher than the hydrogen supply pressure to be supplied to the fuel cell 10, the pressure is reduced to the hydrogen supply pressure by the fuel gas pressure regulating valve 50.

  The fuel gas introduction valve 51 is a valve device for allowing or stopping the supply (flow) of fuel gas from the high-pressure hydrogen tank 20 to the fuel cell 10 by switching the fuel gas supply pipe 21 to a communication state or a non-communication state. .

  A fuel off gas discharge pipe 22 is connected to the fuel off gas discharge portion 14. The fuel off-gas discharge pipe 22 is provided with a fuel gas pressure sensor 42 and a fuel gas purge valve 52 from upstream to downstream, that is, in a direction from the fuel off-gas discharge unit 14 toward the outside of the fuel cell 10 from the fuel gas high-pressure hydrogen tank 20. Yes.

  The fuel gas pressure sensor 42 detects the outlet pressure of the fuel cell 10 as the anode pressure Pa. The fuel gas purge valve 52 is normally closed and is opened when scavenging the fuel gas in the anode 10a.

  The control unit 40 is connected to the compressor 30, the oxidant gas pressure sensor 41, the fuel gas pressure sensor 42, the fuel gas introduction valve 51, and the oxidant gas pressure regulating valve 53 via a control line. The control unit 40 includes a central processing unit (CPU) 401, a memory 402, an input / output interface 403, and an internal bus 404 as shown in FIG. The memory 402 stores a control execution program at the time of start and stop of the fuel cell system executed by the CPU 401, and temporarily stores a calculation result by the CPU 401. The CPU 401 executes various programs and modules stored in the memory 402. The input / output interface 403 electrically connects the CPU 401 and the memory 402 to the compressor 30, the oxidizing gas pressure sensor 41, the fuel gas pressure sensor 42, the fuel gas introduction valve 51, and the oxidizing gas pressure adjustment valve 53. The CPU 401, the memory 402, and the input / output interface 403 are connected to each other via an internal bus 404.

  The memory 402 includes a fuel gas supply control module M1 that is executed by the CPU 401 and performs fuel gas supply control when the fuel cell system is started, and an oxidation gas that performs oxidation gas supply control when the fuel cell system is stopped. A gas supply control module M2 is stored.

-Start-up control of the fuel cell system The start-up control executed when the fuel cell system according to the first embodiment is started will be described with reference to Figs. FIG. 3 is a flowchart showing a processing routine executed when starting the fuel cell system according to the first embodiment. FIG. 4 is an explanatory diagram showing changes in the anode pressure obtained by the fuel cell system according to the first embodiment and changes in the anode pressure obtained by the conventional fuel cell system.

  When a start request for the fuel cell system 100 (fuel cell 10) is detected, the control unit 40 starts a start time control process. Specifically, the following steps are executed when the CPU 401 executes the fuel gas supply control module M1. This processing routine is a processing routine that is executed when the fuel cell system 100 is started, specifically, until fuel gas supply is started. After the fuel cell system 100 is started, another operation processing program is executed. Executed.

  The CPU 401 starts the air compressor 30 and starts supplying the oxidizing gas to the cathode 10c (step S110). The CPU 401 acquires the cathode pressure Pc from the oxidizing gas pressure sensor 41 (step S120), and determines whether the cathode pressure Pc is higher than the target pressure Pref1 (step S130).

  When the CPU 401 determines that the cathode pressure Pc> the target pressure Pref1 (step S130: Yes), the fuel gas introduction valve 51 is opened, the supply of the fuel gas to the anode 10a is started, and this processing routine is executed. finish.

  When the CPU 401 determines that the cathode pressure Pc> the target pressure Pref1, that is, the cathode pressure Pc is equal to or lower than the target pressure Pref1 (step S130: No), the CPU 401 stands by until the cathode pressure Pc> the target pressure Pref1.

  The effect of the starting fuel gas supply control in the first embodiment will be described with reference to FIG. In FIG. 4, a solid line L1 represents a change with time in the cathode pressure Pc, a one-dot chain line L2 represents a change with time in the conventional anode pressure, and a one-dot chain line L3 represents a change with time in the anode pressure in this embodiment. In this embodiment, since the supply of fuel gas is started after the cathode pressure Pc exceeds the target pressure Pref1, the cathode-anode differential pressure (electrode pressure difference) is reduced from the conventional differential pressure Pd1 to Pd2. The Therefore, it is possible to suppress or prevent the deterioration of the membrane electrode assembly due to the differential pressure between the electrodes. As the determination value Pbref, a value lower than the standard atmospheric pressure Pb, for example, 90 kPaabs is used. As the target pressure Pref1, a value between the anode target control pressure and the standard atmospheric pressure Pb, for example, 150 kPaabs is used. As Pref2, a value between the cathode target control pressure and the standard atmospheric pressure Pb, for example, 120 kPaabs can be used.

Control at Stop of Fuel Cell System The stop control executed when the fuel cell system according to the first embodiment is stopped will be described with reference to FIGS. 5 and 6. FIG. 5 is a flowchart showing a processing routine executed when the fuel cell system according to the first embodiment is stopped. FIG. 6 is an explanatory diagram showing a change in cathode pressure obtained by the fuel cell system according to the first embodiment and a change in cathode pressure obtained by the conventional fuel cell system.

  When a stop request for the fuel cell system 100 (fuel cell 10) is detected, the control unit 40 starts a stop time control process. Specifically, the following steps are executed when the CPU 401 executes the oxidizing gas supply control module M2. This processing routine is a processing routine that is executed when the fuel cell system 100 is stopped, specifically, after a stop request is generated. Before the fuel cell system 100 is stopped, another operation processing program is executed. The

  The CPU 401 disconnects a load, for example, an electric motor from the fuel cell 10 (step S200), and executes a fuel gas consumption process (step S202). The disconnection of the load is performed, for example, by turning off (cutting off) a switch provided in a wiring that electrically connects the fuel cell 10 and the load. The fuel gas consumption process is a process for removing the fuel gas from the anode 10a by performing an electromotive reaction using the fuel gas remaining in the anode 10a and storing the fuel gas in, for example, a secondary battery or a capacitor.

  The CPU 401 acquires the anode pressure Pa from the fuel gas pressure sensor 42 (step S204), and determines whether the anode pressure Pa is lower than the target pressure Pref2 (step S206).

  When the CPU 401 determines that the anode pressure Pa <the target pressure Pref2 (step S206: Yes), the CPU 401 stops the air compressor 30 and stops the supply of the oxidizing gas (step S208). Here, the target pressure Pref1 is a target value for increasing the pressure in the fuel cell 10 and is low as a target value for decreasing the pressure in the fuel cell 10, so that target pressure Pref2 = target pressure Pref1 + α. It is preferable. The CPU 401 opens the oxidizing gas pressure regulating valve 53, opens the cathode 10c to the atmosphere, and ends this processing routine. As a result, the cathode pressure Pc, which is the pressure of the cathode 10c, becomes atmospheric pressure.

  When the CPU 401 determines that the anode pressure Pa <the target pressure Pref2, that is, the anode pressure Pc is equal to or higher than the target pressure Pref2 (step S206: No), the CPU 401 stands by until the anode pressure Pa <the target pressure Pref2.

  The effect of the stop-time oxidizing gas supply control in the first embodiment will be described with reference to FIG. In FIG. 6, a solid line L1 indicates a change with time of the cathode pressure Pc in the conventional example, a solid line L2 indicates a change with time of the cathode pressure in this example, and a one-dot chain line L3 indicates a change with time of the anode pressure. In this embodiment, since the supply of the oxidizing gas is stopped after the anode pressure Pa becomes less than the target pressure Pref2, the cathode-anode differential pressure (electrode pressure difference) is reduced from the conventional differential pressure Pd11 to Pd21. Is done. Therefore, it is possible to suppress or prevent the deterioration of the membrane electrode assembly due to the differential pressure between the electrodes.

  Specifically, since air (oxidized gas) pressurized by the air compressor 30 is supplied to the cathode 10c, when the air compressor 30 is stopped, the cathode pressure Pc immediately becomes atmospheric pressure. On the other hand, since hydrogen (fuel gas) is supplied to the anode 10a from a high pressure source, the anode pressure Pa does not decrease unless the anode 10a is opened to the atmosphere. In this embodiment, the anode pressure Pa is lowered by executing the fuel gas consumption process, but the step-down rate is slower than the step-down rate of the cathode pressure Pc.

  On the other hand, in this embodiment, this problem is solved by stopping the air compressor 30 after the anode pressure Pa is lowered to the target pressure Pref2. Therefore, it is possible to suppress or prevent the deterioration of the membrane electrode assembly due to the differential pressure between the electrodes.

Second embodiment:
A second embodiment will be described with reference to FIGS. FIG. 7 is an explanatory diagram schematically showing the configuration of the fuel cell system according to the second embodiment. FIG. 8 is a flowchart showing a processing routine executed when starting the fuel cell system according to the second embodiment. FIG. 9 is an explanatory diagram showing changes in the anode pressure obtained by the fuel cell system according to the second embodiment and changes in the anode pressure obtained by the conventional fuel cell system.

  In the fuel cell system 100a according to the second embodiment, even when the fuel cell system is used in an environment lower than the standard atmospheric pressure, for example, in a high altitude, it is used in the standard atmospheric pressure (flat ground). As in the case, the differential pressure between the electrodes at the time of start and stop is suppressed. The configuration of the fuel cell system 100a according to the second embodiment is the same as that of the fuel cell system 100 according to the first embodiment except that the atmospheric pressure sensor 43 is provided. A description of each component is omitted.

  In the fuel cell system 100 a according to the second embodiment, the atmospheric pressure sensor 43 is connected to the control unit 40. The control unit 40 can acquire the pressure environment in which the fuel cell system 100a is placed from the atmospheric pressure sensor 43, that is, the atmospheric pressure.

  With reference to FIGS. 7 and 8, the start-up control of the fuel cell system in the second embodiment will be described. When the start request for the fuel cell system 100a (fuel cell 10) is detected, the control unit 40 starts the start time control process. Specifically, the following steps are executed when the CPU 401 executes the fuel gas supply control module M1. This processing routine is a processing routine that is executed when the fuel cell system 100a is started, specifically, until the supply of fuel gas is started. After the fuel cell system 100a is started, another operation processing program is executed. Executed.

  The CPU 401 acquires the atmospheric pressure Pb from the atmospheric pressure sensor 43 (step S100), and determines whether or not the measured atmospheric pressure Pb is lower than the determination pressure Pbref that is lower than the standard atmospheric pressure (step S102). That is, it is determined whether or not the fuel cell system 100a is placed in an environment lower than the standard atmospheric pressure, for example, at a high altitude.

  If the CPU 401 determines that Pb <Pbref (step S102: Yes), it sets the standard atmospheric pressure Pbstd to the target pressure Pref1 (step S104). Although it is desirable that no inter-electrode differential pressure is generated, membrane electrode assemblies are generally designed so as not to be deteriorated by an anode-cathode differential pressure generated at a standard atmospheric pressure Pbstd. In addition, when the atmospheric pressure is lower, it takes time to increase the cathode pressure Pc to a pressure equal to or higher than the standard atmospheric pressure Pbstd. Therefore, in the second embodiment, the standard atmospheric pressure Pbstd is used as the target pressure Pref1 of the cathode pressure Pc used for determining whether or not to start the supply of fuel gas.

  If the CPU 401 determines that Pb <Pbref is not satisfied, that is, if the CPU 401 determines that the fuel cell system 100a is in a pressure environment of approximately the standard atmospheric pressure (step S102: No), the predetermined determination target The pressure Ptg is set to the target pressure Pref2 (step S106). As the determination target pressure Ptg, for example, the same pressure value as the target pressure Pref1 used in the first embodiment is used.

  The CPU 401 thereafter executes steps S110 to S140 described in the first embodiment.

  The effect of the starting fuel gas supply control in the second embodiment will be described with reference to FIG. In FIG. 9, the broken line L1 indicates the change over time of the cathode pressure Pc, the alternate long and short dash line L2 indicates the change over time of the conventional anode pressure, and the alternate long and short dash line L3 indicates the change over time of the anode pressure in this embodiment. In the present embodiment, when the atmospheric pressure Pb is lower than the standard atmospheric pressure Pbstd, for example, when indicating the atmospheric pressure in a high altitude, the fuel gas is discharged after the cathode pressure Pc exceeds the standard atmospheric pressure Pbstd which is the target pressure Pref2. Start supplying. Accordingly, even at high altitudes, the cathode-anode differential pressure (electrode differential pressure) can be set to about Pd3 at the standard atmospheric pressure Pbstd, which is a problem when the fuel cell system 100a is used at high altitudes. Deterioration of the membrane electrode assembly due to mechanical stress can be suppressed or prevented. On the other hand, in the conventional fuel cell system, the inter-electrode differential pressure Pd1 in the high altitude is not taken into consideration. Therefore, when the fuel cell system is used in the high altitude, the membrane electrode assembly includes However, a large differential pressure was applied, and deterioration of the membrane electrode assembly due to mechanical stress could not be avoided.

  Furthermore, when the atmospheric pressure is not the standard atmospheric pressure, it takes time to reach the target pressure Pref1 (Ptg) determined based on the standard atmospheric pressure Pbstd. However, in the second embodiment, the atmospheric pressure is the standard atmospheric pressure. When the pressure is not atmospheric pressure, the standard atmospheric pressure Pbstd lower than the target pressure Pref1 (Ptg) is used as the target pressure Pref1, so that the deterioration of the membrane electrode assembly can be prevented and the start-up time of the fuel cell system 100 can be shortened. .

-Control at the time of stop of the fuel cell system according to the second example In the fuel cell system 100a according to the second example, the atmospheric pressure Pb is also applied to the process at the time of stop of the fuel cell system 100a in the same manner as the process at the start. When the acquired atmospheric pressure Pb is less than the determination atmospheric pressure Pbref, the target pressure Pref2 = Pbstd + α is set. If the acquired atmospheric pressure Pb is equal to or higher than the determination atmospheric pressure Pbref, the target pressure Pref2 is set to the determination target pressure Ptg + α. The specific processing after setting the target pressure Pref2 is as described with reference to FIG. 5 in the first embodiment.

  As a result, even at high altitudes, the cathode-anode differential pressure (interelectrode differential pressure) can be set to about the inter-electrode differential pressure at the standard atmospheric pressure Pbstd, which becomes a problem when the fuel cell system 100a is used at high altitudes. Deterioration of the membrane electrode assembly due to mechanical stress can be suppressed or prevented.

  Further, when the atmospheric pressure is the standard atmospheric pressure, it takes time to reach the target pressure Pref2 determined based on the standard atmospheric pressure Pbstd on the assumption that the atmospheric pressure is not the standard atmospheric pressure. In the embodiment, when the atmospheric pressure is the standard atmospheric pressure, the target pressure Pref2 higher than the target pressure Pref2 is used, so that the deterioration of the membrane electrode assembly is prevented and the stop time of the fuel cell system 100 is shortened. Can do.

・ Basic operation of the fuel cell system:
The processes at the start and stop of the fuel cell systems 100 and 100a are as described above, and the basic operation of the fuel cell systems 100 and 100a from start to stop will be briefly described below. For example, when the fuel cell systems 100 and 100a are mounted on a vehicle, the control unit 40 adjusts the discharge amount of the air compressor 30 in accordance with a required output input via an accelerator operated by the driver. To do. Electric power required by the load is generated from the fuel cell 10 by an electromotive reaction of the fuel gas and the oxidizing gas, and electric power required for the load is output from the fuel cell 10.

  The fuel cell systems 100 and 100a in the above embodiments can be used by being mounted on a moving body, for example, a vehicle such as a two-wheeled vehicle or a four-wheeled vehicle, or a ship.

Other examples:
(1) In each of the above embodiments, the cathode pressure Pc and the anode pressure Pa are detected using the oxidizing gas pressure sensor 43 and the fuel gas pressure sensor 42, respectively, and whether or not the cathode pressure Pc> Pref2 and the anode pressure Pa <Pref1. Judging. Here, as shown in FIG. 10, the cathode pressure Pc and the anode pressure Pa have a characteristic of decreasing or increasing with time. Therefore, the pressure change with respect to the time T may be obtained empirically in advance, and it may be determined whether the cathode pressure Pc> Pref1 and the anode pressure Pa <Pref2 are satisfied according to the time. FIG. 10 is an explanatory diagram showing an example of temporal changes in the anode pressure Pa and the cathode pressure Pc at the start of operation of the fuel cell system.

  For example, under standard atmospheric pressure, it may be determined whether the cathode pressure Pc is equal to or higher than the target pressure Pref1 by determining whether the determination time T1 has elapsed. Further, in an atmospheric pressure environment lower than the standard atmospheric pressure Pbstd, for example, in a highland, a correction coefficient k for atmospheric pressure change is obtained empirically in advance, and a correction determination time T11 (= T1 ×) obtained by correcting the determination time T1. k) may be used. For example, the correction coefficient k has a characteristic of increasing as the atmospheric pressure decreases. In this way, by using time as a variable, the advantages described in the above embodiments can be obtained without providing the oxidizing gas pressure sensor 43. FIG. 10 shows an example of changes over time in the anode pressure Pa and the cathode pressure Pc at the start of operation of the fuel cell system. By using the determination time T in the same manner when the operation of the fuel cell system is stopped, Even without the gas pressure sensor 42, the advantages described in the above embodiments can be obtained.

(2) In the second embodiment, the target for the cathode pressure Pc or the anode pressure Pa is determined using the atmospheric pressure sensor 43 depending on whether the atmospheric pressure Pb is lower than the determination target pressure Pbref lower than the standard atmospheric pressure Pbstd. The pressures Pref1 and Pref2 are determined. However, the target pressures Pref1 and Pref2 used when the atmospheric pressure Pb is lower than the determination target pressure Pbref may be used without detecting the atmospheric pressure Pb. In this case, without providing the atmospheric pressure sensor 43, damage to the membrane electrode assembly in an environment where the atmospheric pressure Pb is lower than the standard atmospheric pressure Pbstd can be reduced or prevented.

(3) In each of the above embodiments, the anode pressure Pa or the cathode pressure Pc is used to suppress or reduce the so-called increase in the inter-electrode differential pressure, or to reduce the inter-electrode differential pressure. The fuel gas introduction valve 51 and the air compressor 30 may be controlled in accordance with the atmospheric pressure Pb detected using the pressure to suppress an increase in the inter-electrode differential pressure. For example, when starting the fuel cell system, control may be performed to delay the opening timing of the fuel gas introduction valve 51 after the operation of the air compressor 30 starts as the atmospheric pressure becomes lower. Alternatively, the discharge amount of the air compressor 30 may be increased as the atmospheric pressure becomes lower. Furthermore, both controls may be combined. Further, when the fuel cell system is stopped, the time until the air compressor 30 is stopped may be delayed as the atmospheric pressure becomes lower. By providing the above configuration, it is possible to suppress or reduce an increase in the inter-electrode differential pressure applied to the membrane electrode assembly as the atmospheric pressure changes.

  As mentioned above, although this invention was demonstrated based on the Example and the modification, Embodiment mentioned above is for making an understanding of this invention easy, and does not limit this invention. The present invention can be changed and improved without departing from the spirit and scope of the claims, and equivalents thereof are included in the present invention.

It is explanatory drawing which shows typically the structure of the fuel cell system which concerns on a 1st Example. It is explanatory drawing which shows typically the internal structure of the control part with which the fuel cell system which concerns on a 1st Example is provided. It is a flowchart which shows the process routine performed when starting the fuel cell system which concerns on a 1st Example. It is explanatory drawing which shows the change of the anode pressure obtained by the fuel cell system which concerns on a 1st Example, and the change of the anode pressure obtained by the conventional fuel cell system. It is a flowchart which shows the process routine performed when stopping the fuel cell system which concerns on a 1st Example. It is explanatory drawing which shows the change of the cathode pressure obtained by the fuel cell system which concerns on a 1st Example, and the change of the cathode pressure obtained by the conventional fuel cell system. It is explanatory drawing which shows typically the structure of the fuel cell system which concerns on a 2nd Example. It is a flowchart which shows the process routine performed when starting the fuel cell system which concerns on a 2nd Example. It is explanatory drawing which shows the change of the anode pressure obtained by the fuel cell system which concerns on a 2nd Example, and the change of the anode pressure obtained by the conventional fuel cell system. It is explanatory drawing which shows the relationship between anode pressure and cathode pressure, and time passage.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 10a ... Anode 10c ... Cathode 11 ... Oxidation gas supply part 12 ... Oxidation gas discharge part 13 ... Fuel gas supply part 14 ... Fuel off-gas discharge part 20 ... High-pressure hydrogen tank 21 ... Fuel gas supply pipe 30 ... Air compressor 31 ... oxidizing gas supply pipe 32 ... oxidizing gas discharge pipe 35 ... humidification module 40 ... control unit 401 ... central processing unit (CPU)
DESCRIPTION OF SYMBOLS 402 ... Memory 403 ... Input / output interface 404 ... Internal bus 41 ... Oxidation gas pressure sensor 42 ... Fuel gas pressure sensor 50 ... Fuel gas pressure control valve 51 ... Fuel gas introduction valve 52 ... Fuel gas purge valve 53 ... Oxidation gas pressure control valve

Claims (13)

A fuel cell system,
A fuel cell comprising an anode and a cathode;
A high-pressure fuel gas source for storing fuel gas to be supplied to the anode;
An oxidizing gas supply for supplying an oxidizing gas to the cathode;
When starting the fuel cell, it is determined whether or not the pressure on the cathode side has reached a predetermined pressure. If the pressure on the cathode side has reached the predetermined pressure, the anode is supplied from the high-pressure fuel gas source. A fuel cell system comprising: a fuel gas supply controller that starts supplying fuel gas to the fuel cell. The fuel cell system according to claim 1, further comprising:
A cathode pressure detector for detecting the pressure on the cathode side of the fuel cell;
The fuel gas supply control unit determines whether or not the cathode side pressure has reached a predetermined pressure using the cathode side pressure detected by the cathode pressure detector. The fuel cell system according to claim 2, further comprising:
Equipped with an atmospheric pressure detector to detect atmospheric pressure,
When the atmospheric pressure detected by the atmospheric pressure detector is lower than the standard atmospheric pressure, the fuel gas supply control unit sets the predetermined pressure to the standard atmospheric pressure and is detected by the cathode pressure detector. A fuel cell system that starts supplying fuel gas to the anode when the pressure on the cathode side reaches a predetermined pressure. The fuel cell system according to any one of claims 1 to 3,
The high-pressure fuel gas source is connected to the anode of the fuel cell via a fuel gas supply pipe,
The fuel gas supply controller is
A switch that is disposed in the fuel gas supply pipe and switches the fuel gas supply pipe to a communication or non-communication state;
A fuel switch comprising: a switch controller that switches the switch to a non-communication state when starting the fuel cell, and switches the switch from a non-communication state to a communication state after the cathode side pressure reaches a predetermined pressure; Battery system. A fuel cell system,
A fuel cell comprising an anode and a cathode;
A high-pressure fuel gas source for storing fuel gas to be supplied to the anode;
An oxidizing gas supply for supplying an oxidizing gas to the cathode;
When the fuel cell is stopped, it is determined whether or not the pressure on the anode side has reached a predetermined pressure. If the pressure on the anode side has reached the predetermined pressure, the cathode by the oxidizing gas supplier is determined. A fuel cell system comprising: an oxidizing gas supply control unit that stops supplying oxidizing gas to The fuel cell system according to claim 5, further comprising:
An anode pressure detector for detecting the pressure on the anode side of the fuel cell;
A fuel cell system that determines whether or not the pressure on the anode side has reached a predetermined pressure using the pressure on the anode side detected by the anode pressure detector. The fuel cell system according to claim 6, further comprising:
Equipped with an atmospheric pressure detector to detect atmospheric pressure,
When the atmospheric pressure detected by the atmospheric pressure detector is lower than the standard atmospheric pressure, the oxidizing gas supply control unit sets the predetermined pressure to the standard atmospheric pressure and is detected by the anode pressure detector. A fuel cell system that stops supply of an oxidizing gas to the cathode when the pressure on the anode side reaches a predetermined pressure. The fuel cell system according to any one of claims 5 to 7, further comprising:
A fuel gas consumption control unit for executing a fuel gas consumption process for consuming fuel gas remaining in the anode when the fuel cell is stopped;
The oxidant gas supply control unit determines whether or not the pressure on the anode side has reached a predetermined pressure after the fuel gas consumption process is executed. The fuel cell system according to any one of claims 1 to 8,
The oxidizing gas supplier is a fuel cell system which is an air compressor. A start-up control method for a fuel cell system, comprising:
When starting the fuel cell, determine whether the pressure on the cathode side of the fuel cell has reached a predetermined pressure,
A start-up control method for starting supply of fuel gas from a high-pressure fuel gas source to the anode of the fuel cell when the cathode side pressure reaches the predetermined pressure. A stop control method for a fuel cell system, comprising:
When stopping the fuel cell, determine whether the pressure on the anode side of the fuel cell has reached a predetermined pressure,
A stop-time control method for stopping supply of oxidizing gas to the cathode by the oxidizing gas supplier when the pressure on the anode side reaches the predetermined pressure. A fuel cell system,
A fuel cell comprising an anode and a cathode;
A high-pressure fuel gas source for storing fuel gas to be supplied to the anode;
An oxidizing gas supply for supplying an oxidizing gas to the cathode;
A fuel cell system comprising: a control unit that suppresses an increase in a difference between the pressure of the anode and the pressure of the cathode according to atmospheric pressure when the fuel cell is started or stopped. The fuel cell system according to claim 12, wherein
The control unit controls at least one of supply of fuel gas from the high-pressure fuel gas source to the anode and supply of oxidizing gas to the cathode by the oxidizing gas supplier according to the atmospheric pressure, A control unit for suppressing an increase in the difference between the pressure and the pressure of the cathode.

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