WO2013183745A1 - Système de pile à combustible - Google Patents

Système de pile à combustible Download PDF

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Publication number
WO2013183745A1
WO2013183745A1 PCT/JP2013/065783 JP2013065783W WO2013183745A1 WO 2013183745 A1 WO2013183745 A1 WO 2013183745A1 JP 2013065783 W JP2013065783 W JP 2013065783W WO 2013183745 A1 WO2013183745 A1 WO 2013183745A1
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WO
WIPO (PCT)
Prior art keywords
fuel cell
gas
oxidant
cell stack
cell system
Prior art date
Application number
PCT/JP2013/065783
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English (en)
Japanese (ja)
Inventor
竜也 菅原
金沢　卓磨
Original Assignee
本田技研工業株式会社
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Publication of WO2013183745A1 publication Critical patent/WO2013183745A1/fr

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/043—Processes for controlling fuel cells or fuel cell systems applied during specific periods
    • H01M8/04303—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during shut-down
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04223—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells
    • H01M8/04228—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids during start-up or shut-down; Depolarisation or activation, e.g. purging; Means for short-circuiting defective fuel cells during shut-down
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M2008/1095—Fuel cells with polymeric electrolytes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a fuel cell system including a fuel cell that generates electricity by electrochemically reacting a fuel gas and an oxidant gas.
  • a fuel cell system equipped with a polymer-electrolyte fuel cell (PEFC)
  • hydrogen fuel gas
  • oxygen oxidant gas
  • the fuel gas and the oxidant gas are reacted electrochemically to generate electricity.
  • the applicant of the present application has proposed a cross leak detection technique according to Patent Document 1 as one approach for detecting a phenomenon (cross leak) that induces such a problem.
  • a cross leak detection technique according to Patent Document 1
  • Patent Document 1 does not describe or suggest technical matters for suppressing deterioration of the electrolyte membrane.
  • An object of the present invention is to provide a fuel cell system that contributes to extending the life of a fuel cell.
  • the invention according to (1) includes a fuel cell that generates electricity by electrochemically reacting a fuel gas and an oxidant gas, and an oxidant gas for supplying the fuel cell to the fuel cell.
  • An oxidant gas supply flow path, an oxidant off gas discharge flow path for discharging the reacted oxidant off gas from the fuel cell, and the oxidant gas supply flow path are provided to oxidize the fuel cell.
  • a circulating flow path communicating with the circulating flow path, and a circulation pump for sending an oxidant off-gas from the branching section to the merging section; and a circulation pump disposed in the circulating flow path from the divergence section to the merging section.
  • a check valve that suppresses the flow of the oxidant off-gas in the direction, and a control unit that performs control to drive the circulation pump when the fuel cell is stopped.
  • a fuel cell system having a long-life fuel cell can be obtained.
  • the invention according to (2) is the fuel cell system according to (1), which is disposed on the downstream side of the compressor and the upstream side of the merging portion in the oxidant gas supply flow path.
  • An inlet side sealing valve that seals the flow of the oxidant gas from the compressor to the inlet side of the fuel cell through the junction, and the downstream side of the branch part of the oxidant off-gas discharge channel.
  • an outlet side sealing valve that seals a flow of the oxidant off-gas from the outlet side of the fuel cell to the exhaust side through the branch portion.
  • the oxidant off-gas can be circulated without introducing new oxygen using the circulation flow path as a closed space, oxygen remaining on the cathode side of the fuel cell
  • a fuel cell system having a long-life fuel cell can be obtained by quickly removing hydrogen and hydrogen.
  • the invention according to (3) is the fuel cell system according to (1), wherein the circulation pump adopts a can structure in which a rotor and a stator of a motor unit are sealed with a can.
  • the circulation pump adopts a can structure in which the rotor and stator of the motor unit are sealed with a can, the life of the motor unit in the fuel cell and the circulation pump is further extended. Can be achieved.
  • the invention according to (4) is the fuel cell system according to (2), wherein the circulation pump adopts a can structure in which a rotor and a stator of a motor unit are sealed with a can.
  • the circulation pump adopts a can structure in which the rotor and the stator of the motor unit are sealed with a can, oxygen and hydrogen remaining on the cathode side of the fuel cell can be quickly removed. In addition to the removal effect, the life of the motor unit in the fuel cell and the circulation pump can be further extended.
  • a fuel cell system having a long-life fuel cell can be obtained.
  • FIG. 1 is a schematic configuration diagram of a fuel cell system according to an embodiment of the present invention. It is explanatory drawing showing the internal structure of a circulation pump. In the fuel cell system concerning the embodiment of the present invention, it is an explanatory view showing the flow of the air at the time of normal operation. In the fuel cell system concerning the embodiment of the present invention, it is an explanatory view showing the flow of the air at the time of operation stop. It is a flowchart figure showing the flow of the EGR process performed at the time of the driving
  • the present inventors have proposed that oxygen and hydrogen (cross leak) remaining at the cathode of the fuel cell when the fuel cell is stopped. I thought it was important to remove as early as possible from the time of shutdown.
  • a circulation channel for circulating the oxidant off-gas is provided on the cathode side of the fuel cell, and provided in the circulation channel when the fuel cell is stopped. The idea that the oxidant off-gas should be circulated to the cathode side of the fuel cell by driving the circulation pump has been obtained.
  • a fuel cell system includes a fuel cell that generates electricity by electrochemically reacting a fuel gas and an oxidant gas, and an oxidant for supplying the oxidant gas to the fuel cell.
  • the branch portion disposed in the oxidant off-gas discharge passage, and the junction portion disposed on the downstream side of the compressor in the oxidant gas supply passage are the electric compressor for supplying the gas.
  • a circulation channel that communicates with the circulation channel, a circulation pump that is disposed in the circulation channel and that feeds an oxidant off-gas from the branch portion to the merge portion, and is disposed in the circulation channel and is coupled to the merge portion from the branch portion.
  • the order toward the club A check valve that suppresses the flow of the oxidant off-gas that is in the opposite direction to the direction, and a control unit that performs control to drive the circulation pump when the fuel cell is stopped. The most important feature.
  • oxygen and hydrogen remaining on the cathode side of the fuel cell can be quickly removed by circulating the oxidant off-gas to the cathode side of the fuel cell.
  • FIG. 1A is a schematic configuration diagram of a fuel cell system 11 according to an embodiment of the present invention.
  • FIG. 1B is an explanatory diagram illustrating the internal configuration of the circulation pump 69.
  • a fuel cell system 11 includes a fuel cell stack (corresponding to a “fuel cell” of the present invention) 13, an anode gas supply / exhaust system 15, and a cathode gas supply / exhaust system.
  • a system 17, a diluter 19, and a control unit 21 are provided.
  • the fuel cell system 11 is mounted as a power source in an unillustrated automobile.
  • the fuel cell stack 13 is a polymer electrolyte fuel cell (Polymer Fuel Cell: PEFC), and is configured by stacking a plurality of fuel cells 23 as shown in FIG. 1A. In the example of the fuel cell stack 13 in FIG. 1A, one fuel cell 23 is representatively shown.
  • the fuel battery cell 23 shown in FIG. 1A is configured by sandwiching, for example, a fluororesin-based solid polymer electrolyte membrane 29 between flat plate-like anodes 25 and a cathode 27 provided to face each other. The anode 25 and the cathode 27 are sandwiched from the outside by a pair of separators 30a and 30b.
  • As anode 25 and cathode 27 what carried platinum or a platinum alloy as a catalyst on conductive carbon can be used, for example.
  • hydrogen H 2 (corresponding to “fuel gas” of the present invention) is supplied to the anode 25, thereby causing an oxidation reaction of hydrogen H 2 shown in the formula (1). .
  • oxygen O 2 (corresponding to the “oxidant gas” of the present invention) is supplied to the cathode 27, whereby the reduction of oxygen O 2 shown in the formula (2) is performed.
  • a reaction takes place.
  • 2H + (hydrogen ion; proton) in the formula (2) is supplied from the anode 25 side through the solid polymer electrolyte membrane 29 having cation exchange properties (proton conductivity).
  • 2e ⁇ (electron charge) in the formula (2) is supplied from the anode 25 side through a conductive line (not shown).
  • the anode 25 and the cathode 27 are supplied.
  • An electric potential difference (OCV; Open Circuit Voltage) is generated between the fuel cell stack 13 and the fuel cell stack 13 can generate power.
  • the anode 25 and the cathode 27 of the fuel cell stack 13 in a state capable of generating power in this way are electrically connected to an electric load (for example, a battery or a motor for driving an automobile not shown) via a conductive wire (not shown). Then, the DC power generated by the fuel cell stack 13 is configured to be supplied to the electric load.
  • the anode gas supply / exhaust system 15 has a function of supplying or discharging hydrogen (fuel gas) to the anode 25 side of the fuel cell stack 13. As shown in FIG. 1A, the anode gas supply / exhaust system 15 having such a function communicates between a hydrogen tank 31 that stores high-pressure hydrogen (fuel gas) and the hydrogen tank 31 and the inlet side 13a1 of the fuel cell stack 13.
  • the hydrogen discharge pipe 39 communicating between the side 13a2 and the diluter 19, the gas-liquid separator 41 and the purge valve 43 disposed in the hydrogen discharge pipe 39, and the gas-liquid separator 41 and the ejector 35 are communicated.
  • a hydrogen reflux pipe 45 to be connected.
  • the hydrogen tank 31 functions as a hydrogen (fuel gas) supply source.
  • the shut-off valve 34 has a function of supplying high-pressure hydrogen stored in the hydrogen tank 31 to an appropriate pressure, or shutting off the supply.
  • the ejector 35 has a function of mixing and recirculating the hydrogen supplied from the hydrogen tank 31 and the hydrogen (fuel offgas) recirculated through the hydrogen recirculation pipe 45.
  • the hydrogen mixed by the ejector 35 is supplied to the anode 25 of the fuel cell stack 13.
  • the anode gas circulation part 37 has a function of bringing hydrogen (anode gas) flowing therethrough into direct contact with the anode 25.
  • the gas-liquid separator 41 has a function of separating water (condensation water) contained therein from hydrogen (anode offgas) discharged from the fuel cell stack 13.
  • the water separated and recovered by the gas-liquid separator 41 is temporarily stored in a tank section (not shown) of the gas-liquid separator 41, for example, and then discharged to the diluter 19 via a pipe (not shown). .
  • the purge valve 43 has a function of discharging (purging) impurities such as nitrogen contained in hydrogen (fuel offgas) discharged from the fuel cell stack 13 during normal operation of the fuel cell stack 13 (during normal power generation). .
  • the purge valve 43 is closed at normal times when the impurity concentration in the fuel off-gas is not more than a predetermined value. In other words, the purge valve 43 operates so as to be opened at the time of abnormality when the impurity concentration in the fuel off gas exceeds a predetermined value.
  • the impurity concentration in the fuel off gas may be calculated based on the detection value of a hydrogen concentration sensor (not shown) that detects the concentration of hydrogen in the anode off gas.
  • the cathode gas supply / exhaust system 17 has a function of supplying air (oxidant gas) containing oxygen to the cathode 27 of the fuel cell stack 13 and discharging the supplied air containing oxygen from the cathode 27.
  • the cathode gas supply / exhaust system 17 having such a function includes an electric compressor 51 and an air supply pipe (communication gas oxidizer gas of the present invention) that connects the compressor 51 and the fuel cell stack 13 in communication.
  • An air recirculation pipe (this corresponds to an “off gas discharge flow path”) 59, an outlet side sealing valve 61, a back pressure valve 63, a humidifier 65, an air supply pipe 53 and an air discharge pipe 59.
  • 67 (corresponding to “circulation flow path” of the invention), a circulation pump 69, and a check valve 71.
  • the compressor 51 has a function of compressing the air taken in from the air introduction port 51 a and sending it out to the fuel cell stack 13.
  • the inlet side sealing valve 55 is disposed in the air supply pipe 53 on the downstream side of the compressor 51 and on the upstream side of the merging portion 75.
  • the inlet-side sealing valve 55 has a function of sealing a flow of new air (oxidant gas) from the compressor 51 to the inlet side 13c1 of the fuel cell stack 13 via a junction 75 described later.
  • the inlet side sealing valve 55 is opened during normal power generation of the fuel cell stack 13. However, the inlet side sealing valve 55 operates so as to be closed when power generation of the fuel cell stack 13 is stopped. The reason will be described later in detail.
  • the cathode gas circulation unit 57 is provided along the cathode 27 of the fuel cell stack 13 and has a function of bringing air containing oxygen (cathode gas) flowing therethrough directly into contact with the cathode 27.
  • the outlet side sealing valve 61 is disposed on the downstream side of the branching portion 73 and on the upstream side of the humidifier 65 in the air discharge pipe 59.
  • the outlet side sealing valve 61 has a function of sealing the flow of old air (oxidant offgas) from the outlet side 13c2 of the fuel cell stack 13 to the exhaust side of the diluter 19 through a branching portion 73 described later.
  • the outlet side sealing valve 61 is opened during normal power generation of the fuel cell stack 13, similarly to the inlet side sealing valve 55. However, similarly to the inlet side sealing valve 55, the outlet side sealing valve 61 operates so as to be closed when the operation of the fuel cell stack 13 is stopped (when power generation is stopped). The reason will be described later in detail.
  • a normally closed solenoid valve can be suitably used as the inlet-side sealing valve 55 and the outlet-side sealing valve 61.
  • the inlet side sealing valve 55 and the outlet side sealing valve 61 are preferably kept closed when the operation of the fuel cell stack 13 is stopped. When this closing action is continued, no power is required and power is saved. It is because it can contribute to.
  • the back pressure valve 63 is disposed downstream of the humidifier 65 and upstream of the diluter 19 in the air discharge pipe 59.
  • the back pressure valve 63 has a function of adjusting the flow velocity (pressure) of air in the cathode gas circulation portion 57.
  • the back pressure valve 63 can be configured by, for example, a throttle valve that can variably adjust the throttle amount.
  • the humidifier 65 is disposed so as to straddle the air supply pipe 53 and the air discharge pipe 59.
  • the humidifier 65 has a function of humidifying the air from the compressor 51 toward the cathode gas circulation part 57.
  • the solid polymer electrolyte membrane 29 used in the present embodiment works to increase the power generation efficiency of the fuel cell stack 13 by exhibiting good cation exchange properties (proton conductivity) in a water-containing state. Therefore, the humidifier 65 can increase the power generation efficiency of the fuel cell stack 13 by maintaining the solid polymer electrolyte membrane 29 in a water-containing state during normal operation of the fuel cell stack 13.
  • the humidifier 65 has a hollow fiber membrane (not shown) inside. Through this hollow fiber membrane, moisture is exchanged between the air (relatively dry) toward the cathode gas circulation part 57 and the humid air (oxidant off-gas) discharged from the cathode gas circulation part 57. It is configured to be
  • the circulation pump 69 is provided in the air recirculation pipe 67.
  • the circulation pump 69 is driven by a motor unit 93 (see FIG. 1B) described later to discharge air (oxidant) from the outlet side 13c2 of the fuel cell stack 13. Off-gas) from the branching portion 73 toward the merging portion 75.
  • the circulation pump 69 includes an air supply turbine 81, a drive shaft 83 fixed to the air supply turbine 81, a pair of bearings 85 and 87, a rotor 89, and a stator 91 in a casing 79.
  • a motor unit 93 configured to include the motor unit 93.
  • the drive shaft 83 of the air supply turbine 81 is rotatably supported via a pair of bearings 85 and 87, for example.
  • the drive shaft 83 is rotationally driven by the motor unit 93.
  • the air supply turbine 81 is rotationally driven by the motor unit 93 via the drive shaft 83.
  • the inlet side sealing valve 55 and the outlet side sealing valve 61 close the air supply pipe 53 and the air discharge pipe 59, respectively.
  • the air supply pipe 53 ⁇ the inlet side 13c1 of the fuel cell stack 13 ⁇ the cathode gas circulation part 57 ⁇ the outlet side 13c2 of the fuel cell stack 13 ⁇ the air discharge pipe 59 ⁇ the branching part 73 ⁇ air reflux.
  • An annular air flow passage 77 (see FIG. 1A) is formed that sequentially passes through the pipe 67 ⁇ the joining portion 75 ⁇ the air supply pipe 53.
  • the gas remaining in the air flow passage 77 is configured to circulate in the closed air flow passage 77 for a predetermined time described later when the operation of the fuel cell stack 13 is stopped.
  • a pump having a can structure in which the rotor 89 and the stator 91 of the motor section 93 are sealed via a cylindrical can (partition wall) 95 is used as the circulation pump 69.
  • the air (oxidant off-gas) delivered by the circulation pump 69 contains more moisture than the air introduced into the fuel cell stack 13. When this moisture enters the stator 91 of the motor part 93 in the circulation pump 69, the motor part 93 is damaged. Therefore, by adopting the above can structure as the circulation pump 69, the life of the motor section 93 is extended.
  • the check valve 71 is provided in the air recirculation pipe 67.
  • the check valve 71 has a function of suppressing the air flow in the reverse direction with respect to the forward direction from the branching portion 73 toward the merging portion 75 during normal operation of the fuel cell stack 13 (during normal power generation).
  • the check valve 71 is provided for the purpose of suppressing a decrease in power generation efficiency in the fuel cell stack 13.
  • a mechanical valve that does not require power can be preferably used from the viewpoint of contributing to power saving.
  • a T-shaped joint can be used as the branch part 73 and the junction part 75.
  • the branch portion 73 is preferably provided in the vicinity of the outlet side 13c2 of the fuel cell stack 13 in the air discharge pipe 59.
  • the merging portion 75 is preferably provided in the vicinity of the inlet side 13 c 1 of the fuel cell stack 13 in the air supply pipe 53.
  • the diluter 19 discharges the fuel off-gas (hydrogen) introduced into the diluter 19 when the purge valve 43 is open from the outlet side 13c2 of the fuel cell stack 13 through the air discharge pipe 59. It has a function of diluting with (air).
  • the fuel off-gas (hydrogen) diluted to a predetermined concentration or less with the oxidant off-gas (air) is exhausted into the atmosphere.
  • the control unit 21 has a function of controlling the operation of each member including valves and motors belonging to the anode gas supply / exhaust system 15 and the cathode gas supply / exhaust system 17.
  • the control unit 21 includes a CPU (Central processing Unit) (not shown), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output circuit (including an A / D converter and a D / A converter), and the like. Configured.
  • the CPU executes operation control of each member including a valve and a motor using the RAM as a work area in accordance with a program stored in the ROM.
  • control unit 21 performs a control to open the purge valve 43 when an impurity concentration (such as nitrogen) in the fuel off gas exceeds a predetermined value.
  • control unit 21 performs control to drive the motor unit of the compressor 51 during normal power generation of the fuel cell stack 13.
  • control unit 21 performs control to open the inlet side sealing valve 55 and the outlet side sealing valve 61 during normal power generation of the fuel cell stack 13 while closing the fuel cell stack 13 when power generation is stopped.
  • control unit 21 performs control to adjust the throttle amount of the back pressure valve (throttle valve) 63 during normal power generation of the fuel cell stack 13.
  • control part 21 performs control which drives the motor part 93 of the circulation pump 69 at the time of the electric power generation stop of the fuel cell stack 13.
  • FIG. 2A is an explanatory diagram showing the air flow during normal operation in the fuel cell system 11 according to the embodiment of the present invention.
  • FIG. 2B is an explanatory diagram showing the flow of air when operation is stopped in the fuel cell system 11 according to the embodiment of the present invention.
  • FIG. 3 is a flowchart showing the flow of the EGR process that is executed when the operation of the fuel cell system 11 according to the embodiment of the present invention is stopped.
  • the operation for quickly removing oxygen and hydrogen remaining on the cathode 27 side of the fuel cell stack 13 is performed in the cathode gas supply / exhaust system 17. Therefore, the anode gas supply / exhaust system 15 is not shown in FIGS. 2A and 2B.
  • each part during normal operation of the fuel cell system 11 is as follows. That is, as shown in FIG. 2A, the compressor 51 sends air to the fuel cell stack 13 through the air supply pipe 53 (the inlet side sealing valve 55 is opened). The air sent out by the compressor 51 is humidified through the humidifier 65 and then introduced into the inlet side 13 c 1 of the fuel cell stack 13. Thereafter, the oxygen-containing air introduced into the cathode gas circulation part 57 of the fuel cell stack 13 contacts the cathode 27 and is used for an electrochemical reaction (oxygen reduction reaction).
  • Used air that has passed through the cathode gas circulation part 57 is discharged from the outlet side 13c2 of the fuel cell stack 13 through the air discharge pipe 59 (the outlet side sealing valve 61 is opened).
  • the air thus discharged is introduced into the diluter 19 through the back pressure valve 63 after humidifying the newly supplied air in the humidifier 65.
  • the circulation pump 69 sends out air (oxidant offgas) discharged from the outlet side 13 c 2 of the fuel cell stack 13 from the branch portion 73 toward the junction portion 75. At this time, both the inlet side sealing valve 55 and the outlet side sealing valve 61 are closed. Therefore, the air (oxidant off-gas) sent out by the circulation pump 69 is introduced into the inlet side 13 c 1 of the fuel cell stack 13.
  • the air supply pipe 53 ⁇ the inlet side 13c1 of the fuel cell stack 13 ⁇ the cathode gas circulation part 57 ⁇ the outlet side 13c2 of the fuel cell stack 13 ⁇ the air discharge pipe 59 ⁇ the branch part 73 ⁇ the air recirculation pipe.
  • An annular air flow passage 77 (see FIGS. 1A and 2B) is formed that sequentially passes through 67 ⁇ merging portion 75 ⁇ air supply pipe 53.
  • the gas remaining in the air flow passage 77 operates so as to circulate in the closed air flow passage 77 when the operation of the fuel cell stack 13 is stopped.
  • the gas remaining in the air flow passage 77 (hydrogen generated on the cathode 27 side due to oxygen and cross leak) introduced into the cathode gas circulation portion 57 of the fuel cell stack 13 is blocked.
  • the air flow passage 77 it contacts the cathode 27 and is repeatedly used for electrochemical reaction (oxygen reduction reaction). Then, the amount (concentration) of oxygen and hydrogen in the gas remaining in the air flow passage 77 through the promotion of an electrochemical reaction (oxygen reduction reaction) in the sense of increasing the chance of contact with the cathode 27 (contact time). Reduce. Therefore, oxygen and hydrogen remaining on the cathode 27 side of the fuel cell stack 13 can be quickly removed.
  • FIG. 3 is a flowchart showing the flow of the EGR process that is executed when the operation of the fuel cell system 11 according to the embodiment of the present invention is stopped.
  • the EGR (Exhaust Gas Recirculation) process in the embodiment of the present invention refers to a process of recirculating exhaust gas when the fuel cell system 11 is stopped.
  • step S ⁇ b> 11 the control unit 21 monitors whether or not a command signal related to operation stop is input during normal operation of the fuel cell system 11. For example, when the ignition switch 101 (see FIG. 1A) is turned off, the control unit 21 considers that a command signal related to operation stop has been input, and starts the EGR process (“Yes” in step S11). See). That is, as a result of the monitoring in step S11, the control unit 21 advances the process flow to step S12 when the ignition switch 101 is turned off.
  • step S12 the control unit 21 operates to close the inlet side sealing valve 55.
  • the inlet side sealing valve 55 seals the flow of new air (oxidant gas) from the compressor 51 via the junction 75 to the inlet side 13c1 of the fuel cell stack 13.
  • step S13 the control unit 21 operates to close the outlet side sealing valve 61.
  • the outlet side sealing valve 61 seals the flow of old air (oxidant off-gas) from the outlet side 13c2 of the fuel cell stack 13 to the exhaust side of the diluter 19 via the branching portion 73.
  • steps S12 and S13 described above may be performed simultaneously in time, or may be performed sequentially with a time interval therebetween. Further, in the case of adopting a mode of sequentially performing time intervals with each other, the process of step S12 may be performed after step S13.
  • step S14 the control unit 21 operates to drive the motor unit 93 of the circulation pump 69.
  • the circulation pump 69 sends out air (oxidant off-gas) discharged from the outlet side 13c2 of the fuel cell stack 13 from the branching portion 73 toward the joining portion 75.
  • an annular air flow passage 77 (see FIGS. 1A and 2B) is formed in the fuel cell system 11. Therefore, the gas remaining in the air flow passage 77 circulates in the closed air flow passage 77 when the operation of the fuel cell stack 13 is stopped.
  • step S15 the control unit 21 determines whether or not a predetermined time set in advance has elapsed since the start of driving of the circulation pump 69.
  • This predetermined time takes into account the capacity of the air flow passage 77, the component ratio of oxygen and hydrogen in the remaining gas, the delivery speed of the circulation pump 69, the activity of the catalyst (for example, platinum), etc. Based on the results of verification by (simulation), taking into account that the oxygen and hydrogen concentrations related to the electrochemical reaction through the catalyst in the remaining gas are sufficiently reduced, the time can be changed as appropriate (For example, 1 to 3 minutes) may be set.
  • step S15 If it is determined in step S15 that a predetermined time has elapsed since the start of driving of the circulation pump 69, the control unit 21 advances the process flow to step S16.
  • step S16 the control unit 21 operates to stop the driving of the circulation pump 69. Thereby, the circulation pump 69 stops its drive. As a result, the gas remaining in the air flow passage 77 stays in the closed air flow passage 77 as it is. However, in the gas remaining in the air flow passage 77, the concentration of the gas (oxygen and hydrogen) contributing to the reaction on the cathode 27 side is sufficiently reduced.
  • step S16 ends the control unit 21 ends the flow of the EGR process. Note that, when the operation of the fuel cell stack 13 is stopped, the inlet side sealing valve 55 and the outlet side sealing valve 61 continue to close. This is to prevent new air from being introduced into the annular air flow passage 77 when the fuel cell stack 13 is shut down.
  • a fuel cell system 11 includes a fuel cell stack 13 that generates electricity by electrochemically reacting a fuel gas (hydrogen) and an oxidant gas (oxygen), and an oxidant for the fuel cell stack 13.
  • a fuel gas hydrogen
  • an oxidant gas oxygen
  • Agent A recirculation pump 69 that sends out gas (air) and a reverse passage that is disposed in the circulation flow path 67 and suppresses the flow of oxidant off-gas (air) that is in the reverse direction to the forward direction from the branch portion 73 toward the junction portion 75. It is characterized by comprising a stop valve 71 and a control unit 21 that controls to drive the circulation pump 69 when the operation of the fuel cell stack 13 is stopped.
  • the control unit 21 performs control for driving the circulation pump 69.
  • the gas oxygen and hydrogen generated on the cathode 27 side due to cross leak, etc.
  • the cathode contacts with the cathode 27 and is repeatedly used for electrochemical reaction (oxygen reduction reaction).
  • the amount (concentration) of oxygen and hydrogen in the gas remaining in the air flow passage 77 through the promotion of an electrochemical reaction (oxygen reduction reaction) in the sense of increasing the chance of contact with the cathode 27 (contact time).
  • the flow of the oxidant off-gas (air) in the reverse direction with respect to the forward direction from the branching portion 73 toward the merging portion 75 is suppressed in the circulation flow path 67.
  • the structure which provides the check valve 71 is employ
  • the oxidant gas supply channel 53 is disposed on the downstream side of the compressor 51 and on the upstream side of the merging portion 75, and the fuel passes through the merging portion 75 from the compressor 51.
  • An inlet side sealing valve 55 that seals the flow of the oxidant gas (air) toward the inlet side 13c1 of the battery stack 13 and the downstream side of the branching portion 73 of the oxidant offgas discharge flow path 59 are provided.
  • the configuration further includes an outlet side sealing valve 61 that seals the flow of the oxidant off-gas from the outlet side 13c2 of the battery stack 13 to the exhaust side of the diluter 19 through the branch portion 73.
  • the air flow passage 77 including the circulation flow path 67 is formed as a narrow closed space, and the oxidant off-gas can be circulated without introducing new oxygen. Therefore, the gas (oxygen and hydrogen) remaining on the cathode 27 side of the fuel cell stack 13 can be quickly removed. Thereby, the deterioration suppression effect of the above-mentioned solid polymer electrolyte membrane 29 can be further enhanced.
  • the circulation pump 69 adopts a configuration in which a can structure in which the rotor 89 and the stator 91 of the motor section 93 are sealed with a can 95 is adopted. According to the fuel cell system 11 according to the embodiment of the present invention, the life of the motor unit 93 in the fuel cell stack 13 and the circulation pump 69 can be further extended.
  • Fuel Cell System 13 Fuel Cell Stack (Fuel Cell) 21 Control Unit 23 Fuel Cell 25 Anode 27 Cathode 29 Solid Polymer Electrolyte Membrane 51 Compressor 53 Air Supply Pipe (Oxidant Gas Supply Channel) 55 Inlet side sealing valve 59 Air discharge piping (oxidant off-gas discharge flow path) 61 Outlet side sealing valve 67 Circulation flow path 69 Circulation pump 71 Check valve 73 Branching section 75 Merging section

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Fuel Cell (AREA)

Abstract

La présente invention vise à obtenir un système de pile à combustible (11) ayant un empilement de pile à combustible à longue durée de vie (13). A cet effet, l'invention concerne un système de pile à combustible (11) qui comprend : l'empilement de pile à combustible (13) ; un canal d'alimentation en gaz oxydant (53) pour alimenter un gaz oxydant vers l'empilement de pile à combustible (13) ; un canal de décharge de gaz d'échappement oxydant (59) pour décharger le gaz d'échappement oxydant (air) après réaction provenant de l'empilement de pile à combustible (13) ; un compresseur (11) ; un canal de circulation (67) communiquant entre une partie de branchement (73) et une partie de confluence (75) ; une pompe de circulation (69) pour envoyer le gaz d'échappement oxydant (air) provenant de la partie de branchement (73) vers la partie de confluence (75) ; un clapet de non-retour (71) pour supprimer l'écoulement du gaz d'échappement oxydant (air) dans la direction inverse par rapport à la direction vers l'avant provenant de la partie de branchement (73) vers la partie de confluence (75) ; et un contrôleur (21) pour effectuer une commande de la pompe de circulation (69) lorsque l'empilement de pile à combustible (13) n'est pas en fonctionnement.
PCT/JP2013/065783 2012-06-07 2013-06-07 Système de pile à combustible WO2013183745A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2012129860 2012-06-07
JP2012-129860 2012-06-07

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WO2013183745A1 true WO2013183745A1 (fr) 2013-12-12

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004022487A (ja) * 2002-06-20 2004-01-22 Nissan Motor Co Ltd 燃料電池システム
JP2004111323A (ja) * 2002-09-20 2004-04-08 Nissan Motor Co Ltd 燃料電池システムのガス循環装置
JP2004281330A (ja) * 2003-03-18 2004-10-07 Tokyo Gas Co Ltd 固体酸化物形燃料電池システム
JP2006070861A (ja) * 2004-09-06 2006-03-16 Ishikawajima Harima Heavy Ind Co Ltd ポンプユニットおよび燃料電池システム
JP2007059120A (ja) * 2005-08-23 2007-03-08 Nissan Motor Co Ltd 燃料電池システム
JP2007123013A (ja) * 2005-10-27 2007-05-17 Nissan Motor Co Ltd 燃料電池システム
JP2009289540A (ja) * 2008-05-28 2009-12-10 Nissan Motor Co Ltd 燃料電池システム及びその運転方法

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004022487A (ja) * 2002-06-20 2004-01-22 Nissan Motor Co Ltd 燃料電池システム
JP2004111323A (ja) * 2002-09-20 2004-04-08 Nissan Motor Co Ltd 燃料電池システムのガス循環装置
JP2004281330A (ja) * 2003-03-18 2004-10-07 Tokyo Gas Co Ltd 固体酸化物形燃料電池システム
JP2006070861A (ja) * 2004-09-06 2006-03-16 Ishikawajima Harima Heavy Ind Co Ltd ポンプユニットおよび燃料電池システム
JP2007059120A (ja) * 2005-08-23 2007-03-08 Nissan Motor Co Ltd 燃料電池システム
JP2007123013A (ja) * 2005-10-27 2007-05-17 Nissan Motor Co Ltd 燃料電池システム
JP2009289540A (ja) * 2008-05-28 2009-12-10 Nissan Motor Co Ltd 燃料電池システム及びその運転方法

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