JP2006278085A - Fuel cell mobile body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell vehicle capable of guaranteeing protection of a fuel cell and reliability of a system. <P>SOLUTION: When a fuel cell is unable to continue generation of power, supply to the fuel cell of hydrogen gas and air is stopped to stop power generation, and the mobile body is made to run by an EV running with power from a power storage device. During the EV running, it is judged whether scavenge of an anode electrode is needed, and if so, the mobile body is made to run with enough power left needed for the next start-up and the scavenge, and if not, it is made to run with only a power left needed for the next start-up. The EV running is to be finished whenever a power capacity reaches a preset power level. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell moving body capable of operating the moving body with respective electric powers of a fuel cell and a power storage means.

2. Description of the Related Art Conventionally, in a vehicle equipped with a fuel cell, various technologies have been proposed that allow the vehicle to continue running even when the power generation function of the fuel cell is impaired. For example, in the automobile described in Patent Document 1, two fuel cells are mounted, and even when the power generation function of one fuel cell is impaired, electric power is obtained from the other fuel cell and the battery is charged to travel. Can be made. In addition, the automobile described in Patent Document 2 includes a power supply unit including a fuel cell and a capacitor, and the motor can be driven by the electric power stored in the capacitor.
Japanese Patent Laying-Open No. 2003-333707 (FIG. 1) JP-A-7-264715 (FIG. 1)

  However, in the automobile described in Patent Document 1, since it is necessary to mount a plurality of fuel cells, there are problems that the weight and cost increase and the control system becomes complicated. Therefore, as described in Patent Document 2, when a fuel cell can no longer generate power without mounting a plurality of fuel cells, it is possible to continue running by using the residual power of the capacitor.

  However, if the remaining power of the capacitor is exhausted, the processing necessary for scavenging the reaction gas flow path of the fuel cell when the fuel cell system is exposed to a freezing environment when the power generation of the fuel cell is subsequently stopped. The fuel cell cannot be protected.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a fuel cell moving body capable of continuing operation and protecting the fuel cell even when the fuel cell cannot generate power. And

  The present invention provides a fuel cell that generates power by reacting a reaction gas, and can store at least a part of the power generated by the fuel cell, and stores the power stored in a drive source of a mobile body equipped with the fuel cell. A power storage unit that can be supplied; a continuous power generation determination unit that determines whether or not to continue power generation of the fuel cell; a scavenging unit that scavenges the flow path of the reactive gas with a scavenging gas; Scavenging possibility judging means for judging propriety, and moving body operating means for operating the moving body by obtaining electric power from the power storage means when it is judged that continuation of power generation of the fuel cell is impossible. When operating with power obtained from the power storage means, when it is determined that scavenging is necessary, the remaining power of the power storage means is operated with at least the power required for the scavenging means secured. .

  According to the present invention, even when the fuel cell can no longer generate power, the operation can be continued by obtaining electric power from the power storage means, and the fuel cell is protected even when operating in a low temperature environment. be able to.

  Further, the scavenging possibility determination unit can determine that scavenging is necessary when there is a possibility that water remaining in the fuel cell may freeze during the stoppage of power generation of the fuel cell.

  Thus, by performing scavenging when it is determined that the water inside the fuel cell may be frozen, for example, deterioration of the film in the fuel cell can be prevented.

  According to the fuel cell moving body of the present invention, even when power generation cannot be performed, the operation can be continued and the fuel cell can be protected in a low temperature environment. As a result, it becomes possible to improve the reliability and merchantability of the system.

FIG. 1 is a configuration diagram showing a fuel cell moving body of the present embodiment, FIG. 2 is a configuration diagram showing a fuel cell system mounted on the fuel cell moving body, FIG. 3 is a flowchart showing processing in a control unit, and FIG. It is a flowchart which shows the process at the time of EV driving | running | working. In the following description, an automobile will be described as an example of the moving object V.
As shown in FIG. 1, the fuel cell moving body 1 of the present embodiment includes a moving body V, a fuel cell FC, a fuel cell system F1, a power storage device (power storage means) 10, a motor (drive source) M, And a switching device 30.

  As shown in FIG. 2, the fuel cell system F1 includes a fuel cell FC, an air supply unit 2, a hydrogen supply unit 3, a cooling unit 4, a control unit 5, and the like.

  The fuel cell FC includes a membrane electrode structure (MEA; Membrane) in which an anode electrode (hydrogen electrode) containing a catalyst is provided on one side of a solid polymer electrolyte membrane and a cathode electrode (oxygen electrode) containing a catalyst on the other side. Electrode Assembly) has a structure in which a plurality of single cells each having a conductive separator on each side are stacked in the thickness direction.

  The air supply means 2 supplies air (oxygen) as an oxidant gas to the cathode electrode of the fuel cell FC. The compressor 20 and the cathode on the upstream side (inlet side) of the compressor 20 and the fuel cell FC. The cathode gas flow path 21a that connects the electrode, the cathode off-gas flow path 21b that includes the back pressure valve 22 that is connected to the cathode electrode on the downstream side (outlet side) of the fuel cell FC, and the like. The compressor 20 is a mechanical supercharger that sucks and pressurizes atmospheric air.

  The hydrogen supply means 3 supplies hydrogen gas to the anode electrode of the fuel cell FC, and includes a high-pressure hydrogen tank 23 having a shutoff valve 24, and the upstream side (inlet side) of the high-pressure hydrogen tank 23 and the fuel cell FC. The anode gas flow path 25a that connects to the anode electrode, the anode off-gas flow path 25b that includes the discharge valve 26 that is connected to the anode electrode on the downstream side (exit side) of the fuel cell FC, and the like.

  The cooling means 4 includes a cooling medium flow path 41 for allowing a predetermined cooling medium to flow into the fuel cell FC, a radiator 42, a pump 43 for circulating the cooling medium in the cooling medium flow path 41, and the like. The cooling means 4 keeps the temperature of the fuel cell FC at a temperature suitable for power generation.

  The fuel cell system F1 is connected to a gas flow path 27 having an air introduction valve 28 that connects the cathode gas flow path 21a and the anode gas flow path 25a to each other. The cathode gas channel 21a has a pressure sensor P1 for detecting the pressure in the channel, the anode gas channel 25a has a similar pressure sensor P2, and the cooling medium channel 41 has a cooling medium flow. A temperature sensor T1 for detecting the temperature is provided. The fuel cell FC is provided with a current sensor I for detecting an output current during power generation. The voltage is not limited to the current sensor I, and a voltage may be detected.

  The control unit 5 includes a CPU (Central Processing Unit), a memory, an input / output interface, and the like, and is connected to a compressor 20, a back pressure valve 22, a shutoff valve 24, a discharge valve 26, an air introduction valve 28, a pump 43, and the like. The rotation output of the compressor provided in the compressor 20 and the opening / closing operations of the back pressure valve 22, the shutoff valve 24, the discharge valve 26 and the air introduction valve 28 can be controlled. The control unit 5 is connected to an ignition switch S, a timer TM, and a temperature sensor T2. The control unit 5 is connected to a signal based on switching the ignition switch S on and off, and a signal based on the passage of a predetermined time by the timer TM. The signals based on the outside air temperature by the temperature sensor T2 are transmitted respectively. The control unit 5 is connected to the pressure sensors P1 and P2, the temperature sensor T1, and the current sensor I, although the control lines are not shown.

  Although not shown, a humidifier for humidifying air or hydrogen gas is provided in the cathode gas passage 21a and the anode gas passage 25a, and unreacted exhausted from the fuel cell FC is provided on the anode electrode side. An ejector for reusing the hydrogen gas is provided.

  The power storage device 10 can store the power generated by the fuel cell FC, and is constituted by a battery or a capacitor. For example, a lead storage battery, a lithium ion secondary battery, a lithium polymer secondary battery, a nickel hydride storage battery, a nickel cadmium storage battery, or the like is used as the battery, and a so-called electric double layer capacitor is used as the capacitor.

  As shown in FIG. 1, the switch 30 is connected to the fuel cell FC, the power storage device 10, the compressor 20, and the motor M via electric wires. In the fuel cell moving body 1 of the present embodiment, during normal travel of the moving body V, electric power is supplied from the fuel cell FC to the motor M and the compressor 20 as indicated by a solid line arrow, and the electric power is obtained from the fuel cell FC. When no longer possible, electric power is supplied from the power storage device 10 to the motor M as indicated by the long dashed arrow, and during scavenging when the fuel cell FC stops generating power, as indicated by the short dashed arrow, Electric power is supplied to the compressor 20. Further, for example, when the required power increases suddenly such as sudden acceleration when the moving body V travels, the motor M is driven by obtaining power from both the fuel cell FC and the power storage device 10.

  Next, the operation of the fuel cell moving body of the present embodiment will be described with reference to FIGS. 3 and 4 (refer to FIGS. 1 and 2 as appropriate). In the following, the case where the scavenging process is performed with air using the anode electrode side as the scavenging gas will be described. In this case, the scavenging means of the present invention is constituted by the compressor 20 and the gas flow path 27 provided with the air introduction valve 28, and the flow path of the present invention is constituted by the anode gas flow path 25a and the anode off-gas flow path 25b. .

  As shown in FIG. 3, in step 100 (hereinafter abbreviated as S100), when the ignition switch S of the moving body V is switched on, the shut-off valve 24 (see FIG. 2) opens and the compressor 20 (see FIG. 2). ) Is driven (S101). As a result, hydrogen gas (reactive gas) is supplied to the anode electrode of the fuel cell FC, and air is supplied to the cathode electrode. At the anode electrode, hydrogen ions are generated by the action of the catalyst, and these hydrogen ions pass through the solid polymer electrolyte membrane. To the cathode. In the anode electrode, electrons are generated when hydrogen ions are generated, and the electrons move to the cathode electrode via an external load such as the motor M or the compressor 20. Hydrogen ions and electrons that have moved to the cathode electrode react with oxygen in the air by the action of the catalyst on the cathode electrode to produce water. Further, water also permeates from the cathode electrode to the anode electrode via the solid polymer electrolyte membrane due to the pressure of air supplied to the anode electrode side. Further, as necessary, the pump 43 is driven and controlled so that the temperature of the fuel cell FC becomes a temperature suitable for power generation.

  In S102, it is determined whether or not the fuel cell FC can continue to generate power. The determination as to whether or not power generation can be continued is, for example, the case where the temperature of the cooling medium of the fuel cell FC, the pressure of the cathode or anode, and the output current of the fuel cell FC are out of the allowable range. . These are determined by the detection output from the current sensor I from the temperature sensor T1 and the pressure sensors P1 and P2 input to the control unit 5. The processing step in S102 corresponds to the continuous power generation determination unit in the present embodiment.

  If it is determined in S102 that the fuel cell FC is unable to continue power generation (Yes), the compressor 20 is stopped, air is supplied to the fuel cell FC, and the shutoff valve 24 is closed to close the fuel cell FC. The supply of hydrogen gas to each is stopped to stop power generation (S103). Then, as shown by the long dashed arrow in FIG. 1, the vehicle is switched to EV (Electric Vehicle) running using only the electric power stored in the power storage device 10 (S104). Note that the processing in S104 corresponds to the moving body operating means in the present embodiment.

  In this EV traveling, as shown in FIG. 4, it is determined whether or not the anode electrode needs to be scavenged with air during the EV traveling (S110). The determination in S110 is made based on whether or not the temperature of the fuel cell system F1 is expected to fall to a temperature at which water generated during power generation is frozen between the stop of power generation of the fuel cell FC and the next startup. When it is determined that the water is frozen, scavenging is required, and when it is determined that the water is not frozen, scavenging is not required. Note that whether or not the water remaining in the fuel cell system F1 is expected to be frozen is determined using a temperature sensor T2 (see FIG. 2) mounted on the moving body V or the like. For example, based on past meteorological data (temperature transition) or the like, whether the outside air temperature is expected to reach a predetermined value or less, or whether the temperature of the fuel cell system F1 is expected to be cooled to a predetermined value or less. to decide. If it is determined in S110 that it is necessary to scavenge (Yes), the end threshold value of the power capacity necessary for the power storage device 10 is set to a value considering scavenging in S111. For example, as the end threshold value in this case, a power obtained by adding the power necessary for scavenging and the power necessary for the next activation is set.

  In S112, when it is determined that the power capacity remaining in the power storage device 10 has reached the end threshold set in S111, the switch 30 is controlled to stop the supply of power from the power storage device 10 to the motor M. Then, the EV traveling is finished (S113). If it is not necessary to scavenge in S110 (No), the end threshold value of the power capacity necessary for the power storage device 10 is set to a value that does not consider scavenging in S114. For example, the power required for the next activation is set as the end threshold in this case. Thereafter, the processing from S112 onward is executed in the same manner as described above. If it is determined in S111 and S114 that the fuel cell FC does not need to be activated next time, only the power required for scavenging may be set in S111, and the required power may be set to zero in S114. Further, S110 in FIG. 4 corresponds to the operation of the scavenging possibility determination unit in the present embodiment.

  When the EV travel ends, as shown in FIG. 3, it is determined in S105 whether or not scavenging is necessary. When the process of S111 shown in FIG. 4 is executed, scavenging is necessary (Yes in S105), so that the process proceeds to S106 and remains in the power storage device 10 as indicated by the short dashed arrow in FIG. Scavenging is performed with the power. In this case, the air introduction valve 28 and the discharge valve 26 are opened, and the compressor 20 is driven by the electric power remaining in the power storage device 10. Thereby, air (air) is supplied to the anode electrode of the fuel cell FC through the cathode gas passage 21a, the gas passage 27, and the anode gas passage 25a. The scavenging execution time in this case is executed based on the time preset in the timer TM (see FIG. 2). Note that the scavenging execution time is not limited to the timer TM and may be processed based on the pressure on the anode electrode side. Although not shown, the water discharged from the discharge valve 26 is discharged outside the moving body V after the hydrogen concentration of the hydrogen gas is diluted to a predetermined value by a predetermined diluting device. Further, when the process of S114 shown in FIG. 4 is executed (No in S105), scavenging is not necessary, so the process is completed without scavenging.

  If it is determined in S102 that power generation by the fuel cell FC is possible (No), normal power generation is continued as it is (S107), and the ignition switch S (see FIG. 2) is controlled by the control unit 5. It is monitored whether or not is switched off (S108). If it is determined in S108 that the ignition switch S has not been turned off (No), the process returns to S102 and the subsequent processing is executed again. When the ignition switch S is turned off (Yes), the compressor 20 is stopped to stop the supply of air to the fuel cell FC, the shut-off valve 24 is closed, and the hydrogen gas to the fuel cell FC is stopped. Supply is stopped and power generation is stopped (S109). Then, the process proceeds to S105, and when it is determined that scavenging is not necessary (No), the process is terminated as it is, and when it is determined that scavenging is necessary (Yes), scavenging is performed at S106. Exit after executing. Here, the determination as to whether or not scavenging is necessary may be made based on the outside air temperature as described in S110, or may be constantly scavenged.

  The fuel cell moving body of the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the gist of the present invention. For example, although the case where air (air) is used as the scavenging gas has been described, a tank filled with an inert gas such as nitrogen is provided, and the inert gas in this tank is used as the scavenging gas during scavenging. May be. Further, the present invention is not limited to scavenging on the anode electrode side, and the back pressure valve 22 (see FIG. 2) is opened to scavenge the cathode electrode side of the fuel cell FC with the air taken in from the compressor 20. You may do it. In this case, the scavenging means of the present invention is constituted by the compressor 20, and the cathode gas passage 21a and the cathode offgas passage 21b constitute the passage of the present invention. Alternatively, all of the back pressure valve 22, the discharge valve 26, and the air introduction valve 28 may be opened to scavenge both the anode and cathode of the fuel cell FC.

  Therefore, when the fuel cell moving body 1 of the present embodiment is used in a cold region or in winter, when the fuel cell FC cannot generate power, the power storage device is caused to travel with at least power necessary for scavenging remaining. In particular, since the freezing of the polymer electrolyte membrane of the fuel cell FC can be prevented, the fuel cell FC can be reliably protected. Therefore, the merchantability and reliability of the fuel cell moving body 1 can be improved.

It is a block diagram which shows the fuel cell moving body of this embodiment. It is a block diagram which shows the fuel cell system mounted in a fuel cell moving body. It is a flowchart which shows the process in a control part. It is a flowchart which shows the process at the time of EV running.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell moving body 10 Power storage device (power storage means)
20 Compressor 21a Cathode gas flow path 21b Cathode off gas flow path 25a Anode gas flow path 25b Anode off gas flow path 27 Gas flow path 28 Air introduction valve 30 Switcher FC Fuel cell M Motor (drive source)

Claims (2)

A fuel cell that generates power by reacting reactive gases; and
Power storage means capable of storing at least part of the power generated by the fuel cell, and capable of supplying the power stored in a drive source of a mobile body equipped with the fuel cell;
Continuous power generation determination means for determining whether or not the fuel cell can continue power generation;
Scavenging means for scavenging the reaction gas flow path with scavenging gas;
A scavenging enable / disable judging means for judging whether scavenging of the reaction gas flow path is possible;
A moving body operating means for operating the moving body by obtaining electric power from the power storage means when it is determined that power generation of the fuel cell cannot be continued,
When the mobile body operates while obtaining power from the power storage means, the remaining capacity of the power storage means is operated with at least the power required for the scavenging means being secured when it is determined that scavenging is necessary. A fuel cell moving body.   The scavenging possibility determination unit determines that scavenging is necessary when there is a possibility that water remaining inside the fuel cell may freeze while the power generation of the fuel cell is stopped. Fuel cell moving body.

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