WO2011070618A1 - Système de pile à combustible et procédé pour arrêter le fonctionnement de cette pile - Google Patents

Système de pile à combustible et procédé pour arrêter le fonctionnement de cette pile Download PDF

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Publication number
WO2011070618A1
WO2011070618A1 PCT/JP2009/006736 JP2009006736W WO2011070618A1 WO 2011070618 A1 WO2011070618 A1 WO 2011070618A1 JP 2009006736 W JP2009006736 W JP 2009006736W WO 2011070618 A1 WO2011070618 A1 WO 2011070618A1
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WIPO (PCT)
Prior art keywords
unit
blocking
fuel
fuel cell
oxidant
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PCT/JP2009/006736
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English (en)
Japanese (ja)
Inventor
鬼頭理
吉永典裕
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株式会社 東芝
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Priority to PCT/JP2009/006736 priority Critical patent/WO2011070618A1/fr
Publication of WO2011070618A1 publication Critical patent/WO2011070618A1/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
    • H01M8/10—Fuel cells with solid electrolytes
    • H01M8/1009—Fuel cells with solid electrolytes with one of the reactants being liquid, solid or liquid-charged
    • H01M8/1011—Direct alcohol fuel cells [DAFC], e.g. direct methanol fuel cells [DMFC]
    • 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
    • H01M8/04—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
    • 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
    • H01M8/04302—Processes for controlling fuel cells or fuel cell systems applied during specific periods applied during start-up
    • 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
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04388—Pressure; Ambient pressure; Flow of anode reactants at the inlet or inside the fuel cell
    • 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
    • H01M8/04313—Processes for controlling fuel cells or fuel cell systems characterised by the detection or assessment of variables; characterised by the detection or assessment of failure or abnormal function
    • H01M8/0438—Pressure; Ambient pressure; Flow
    • H01M8/04395—Pressure; Ambient pressure; Flow of cathode reactants at the inlet or inside the fuel cell
    • 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 that directly supplies liquid fuel.
  • the fuel cell is operated with fuel and oxidant supplied.
  • the electrode catalyst used in the fuel cell tends to deteriorate when it comes into contact with the oxidant.
  • a fuel cell that directly supplies fuel is smaller in weight and volume than a fuel cell in which fuel is chemically reacted and then supplied (indirectly supplied) because it does not have a structure for chemically reacting fuel. Therefore, a fuel cell that directly supplies fuel is mainly mounted on a portable device.
  • the installed fuel cell has a large number of repetitions of start, operation, stop processing, and stop state.
  • start, operation, stop processing, and stop state When the fuel cell is stopped, unreacted fuel and oxidant supplied in the flow path of the fuel cell stay in the flow path. Since no current flows through the load in the fuel cell in the shutdown state, there is a high possibility that the electrode catalyst will be deteriorated by the oxidant remaining in the fuel cell.
  • a fuel cell system includes an anode electrode supplied with liquid fuel, a cathode electrode supplied with an oxidant, and a proton disposed between the anode electrode and the cathode electrode.
  • a power generation unit including a conductive electrolyte membrane; a load connected to the power generation unit and consuming power of the power generation unit; a first cutoff unit that shuts off the liquid fuel directly supplied to the anode electrode; After blocking the second blocking unit that blocks the oxidant supplied to the cathode electrode, a second command unit that issues an instruction to block the second blocking unit, and the second blocking unit A first command unit that issues an instruction to shut off the first shut-off unit, and a load stop unit that gives an instruction to release the load after the first shut-off unit shuts off. .
  • the fuel cell system operation stop method of the present invention is arranged between the anode electrode to which fuel is directly supplied during operation, the cathode electrode to which oxidant is supplied during operation, and the anode electrode and the cathode electrode.
  • a proton-conducting electrolyte membrane that generates output power by a reaction between the fuel and the oxidant, a load for consuming the power of the power generation unit, and a fuel to the power generation unit And a controller for controlling the supply of the oxidant and the load;
  • a method of stopping the operation of the fuel cell system comprising: a voltage detection unit that measures an output voltage of the power generation unit, and shutting off the supply of the oxidant to the cathode electrode, After shutting off the supply of the oxidant, the step of comparing the output voltage value obtained from the voltage detection unit with a predetermined voltage value, and when the output voltage value reaches the predetermined voltage value, And a step of shutting off the fuel supply to the anode electrode and a step of
  • FIG. 1 is a block diagram of a DMFC system according to a first embodiment.
  • the block diagram showing the function of the DMFC system concerning a 1st embodiment.
  • the flowchart which shows the operation stop processing method of the DMFC system which concerns on 1st Embodiment.
  • the perspective view which shows the modification of the 1st interruption
  • the perspective view which shows the modification of the 2nd interruption
  • FIG. 3 is a diagram illustrating a change in output voltage of the DMFC system in the first embodiment.
  • FIG. 3 is a diagram showing a decrease rate of the output voltage of the DMFC system in the first embodiment.
  • FIG. 3 is a diagram illustrating deterioration factors of the DMFC system in the first embodiment.
  • FIG. The figure (Drawing 14 (a)) which shows how to obtain the reference voltage value concerning a 2nd embodiment, and the principal part enlarged view (Drawing 14 (b)).
  • the flowchart which shows the operation stop processing method of the DMFC system which concerns on 2nd Embodiment.
  • DMFC direct methanol fuel cell
  • FIG. 1 shows a cross-sectional view of the power generation unit 11 according to the first embodiment.
  • An anode electrode 14 including an anode substrate 12 and an anode catalyst layer 13 to which liquid fuel is directly supplied; a cathode electrode 17 including a cathode substrate 15 and a cathode catalyst layer 16 to which an oxidant is supplied; and the anode electrode 14 and A proton conductive electrolyte membrane 18 is provided between the cathode electrodes 17.
  • An anode catalyst layer 13 is provided on the proton conductive electrolyte membrane 18 on the anode electrode 14 side, and an anode substrate 12 is provided on the outer surface of the anode catalyst layer 13.
  • a cathode catalyst layer 16 is provided on the proton conductive electrolyte membrane 18 side of the cathode electrode 17, and a cathode substrate 15 is provided on the outer surface of the cathode catalyst layer 16.
  • FIG. 2 shows the DMFC system 21 according to the first embodiment.
  • the DMFC system 21 includes a power generation unit 11, a control unit 28, and peripheral auxiliary devices (a fuel supply unit 22, an oxidant supply unit 25, a voltage detection unit 30, a load 29, and a load release unit 36). Yes.
  • the anode electrode 14 is connected to the fuel feeding part 22 through a pipe.
  • a first blocking part 23 is provided between the anode electrode 14 and the fuel feeding part 22.
  • the anode electrode 14 is connected with the 3rd interruption
  • the fuel sent to the fuel feeding part 22 passes through the first blocking part 23, is supplied to the anode electrode 14, and undergoes an oxidation reaction in the anode catalyst layer 13.
  • the product resulting from this reaction and unreacted fuel are discharged to the outside of the power generation unit 11 through the third blocking unit 24. Further, a product of this reaction and a part of the unreacted fuel move to the cathode electrode 17 through the proton conductive electrolyte membrane 18.
  • the cathode electrode 17 is connected to the oxidant gas supply unit 25 through a tube.
  • a second blocking part 26 is provided between the cathode electrode 17 and the oxidant gas supply part 25.
  • the cathode electrode 17 is provided with a fourth blocking part 27 via another discharge pipe.
  • a gaseous oxidant, such as air, sent to the oxidant air supply part 25 passes through the second blocking part 26 and is supplied to the cathode electrode 17 to undergo a reduction reaction at the cathode catalyst layer 16.
  • the product resulting from this reaction and the unreacted oxidant are discharged to the outside of the power generation unit 11 through the fourth blocking unit 27. Further, a product of this reaction and a part of the unreacted oxidant move to the anode electrode 14 through the proton conductive electrolyte membrane 18.
  • a pump can be used as the fuel liquid feeding part 22 and the oxidant air feeding part 25, for example.
  • a valve can be used, for example.
  • the anode electrode 14 is connected to the load releasing means 36 by wiring, and the load releasing means 36 is connected to the load 29 by wiring.
  • the cathode electrode 17 is connected to a load 29 by wiring.
  • the load 29 is released by the load release means 36.
  • the electric power of the power generation unit 11 is consumed by the load 29.
  • Each of the anode electrode 14 and the cathode electrode 17 is connected to the voltage detection unit 30 by wiring.
  • the output voltage (V1) of the power generation unit 11 is measured by the voltage detection unit 30.
  • FIG. 3 is a block diagram showing functions of the control unit 28.
  • the control unit 28 controls peripheral auxiliary devices of the DMFC system 21.
  • the control unit 28 includes a second command unit 32 that shuts off the supply of the oxidant to the cathode electrode 15, a storage unit 34 that stores a voltage reference value (V0: a predetermined voltage value), and a voltage that the storage unit stores.
  • a comparison unit 35 that compares the magnitude relationship between the reference value (V0) and the voltage value (V1) of the power generation unit 11 detected by the voltage detection unit 30, and a first command unit that blocks the supply of fuel to the anode electrode 14 31 and a load stopping unit 33 that gives an instruction to release the load 29 to the load releasing means 36.
  • the first command unit 31 controls the first blocking unit 23 and the third blocking unit 24 to block the supply of fuel to the anode electrode 14 and the discharge of fuel and products from the anode electrode 14.
  • the second command unit 32 controls the second blocking unit 26 and the fourth blocking unit 27 to block the supply of oxide to the cathode electrode 17 and the discharge of oxides and products from the cathode electrode 17.
  • the reference voltage V0 stored in the storage unit 34 is a value smaller than the voltage value in the operating state of the power generation unit 11.
  • the control unit 28 also controls each of the fuel feeding unit 22, the oxidant feeding unit 25, the load 29, and the voltage detection unit 30.
  • FIG. 4 is a flowchart showing a process for stopping the operation of the DMFC system 21.
  • step S0 the DMFC system 21 is in an operating state, and the control unit 28 opens the first blocking unit 23, the third blocking unit 24, the second blocking unit 26, and the fourth blocking unit 27. It is set. In the operating state, both fuel and oxidant are supplied to the power generation unit 11, and products, unreacted fuel, oxidant, and the like are discharged from the power generation unit 11 to the outside.
  • the operation stop process of the DMFC system 21 is performed by the steps S1 to S6 described below, and the DMFC system 21 enters the operation stop state (S7). For example, when the operation switch provided in the DMFC fuel cell system 21 is turned off, the operation stop process is started (step S1).
  • step S2 supply of the oxidizing agent is shut off. That is, when the operation switch is turned off, the second command unit stops the oxidant gas supply unit 26, closes the second blocking unit 26, and closes the fourth blocking unit 27. Immediately after the second blocking part 26 and the fourth blocking part 27 are closed, an oxidant stays between the first blocking part 26 and the second blocking part 27. However, since the fuel is supplied to the anode electrode 14, the oxidant is continuously consumed for the reaction, and as a result, the concentration of the oxidant gradually increases between the second blocking part 26 and the fourth blocking part 27. Becomes smaller. As the concentration of the oxidizing agent between the second blocking unit 26 and the fourth blocking unit 27 decreases, the output voltage of the power generation unit 11 decreases.
  • step S3 the voltage detection unit 31 measures the output voltage of the power generation unit 11, and the measured output voltage is sent to the control unit 28.
  • step S4 the comparison unit 35 determines whether or not the output voltage of the power generation unit 11 detected by the voltage detection unit 31 has dropped to the reference voltage (V0) stored in the storage unit 34.
  • the process proceeds to step S5.
  • the reference voltage (V0) indicates that the oxidant staying in the cathode electrode 17 (between the first blocking unit 26 and the second blocking unit 27) is lower than the operating state. Value.
  • the output voltage of the power generation unit 11 may decrease as time passes due to deterioration. For this reason, it is preferable that the reference voltage (V0) be a value lower than an output voltage expected when the power generation unit 11 is deteriorated.
  • step S5 the fuel supply is shut off. That is, the first command unit 31 stops the fuel feeding unit 23, closes the first blocking unit 23, and then closes the third blocking unit 24.
  • step S6 the load stop unit 33 of the control unit 29 instructs the load release unit 36 to release the load 29.
  • step S7 the DMFC system 21 is stopped.
  • the first blocking part 23, the second blocking part 26, the third blocking part 24, and the fourth blocking part 27 are closed, so that the anode electrode 14 and the cathode electrode 17 Intrusion is blocked.
  • the second command unit 32, the first command unit 31, the load stop unit 33, the storage unit 34, and the comparison unit 35 are configured as one circuit. These processors may be independent from each other. Further, the operation stop process of the control unit 28 may be configured such that one program is stored in a recording medium such as a memory, and called and operated by a general-purpose CPU when necessary.
  • the first blocking section 23, the second blocking section 26, the third blocking section 24, and the fourth blocking section 27 are provided.
  • the fuel cell system 21 When having a one-pass (dead-end flow path) configuration, the first blocking portion 23 and the second blocking portion 26 are provided without the third blocking portion 24 and the fourth blocking portion 27. It is also good.
  • valves are used as the first blocking portion 23, the second blocking portion 26, the third blocking portion 24, and the fourth blocking portion 27. Instead, a wall (shutter) may be used.
  • FIG. 5 is a diagram illustrating the power generation unit 11 in a state where the first blocking unit is opened (a) and in a closed state (b) when a wall is used as the first blocking unit 23.
  • blocking part 232 is comprised by the two walls which cover the fuel supply port 233 of the electric power generation part 11, and can open and close two walls.
  • the blocking unit 232 can block the supply of fuel to the power generation unit 11 by closing the two walls.
  • FIG. 6 is a diagram illustrating the power generation unit 11 in a state where the second blocking unit 26 is opened (a) and in a closed state (b) when a wall is used as the second blocking unit 26.
  • blocking part 262 is comprised by the two walls which cover the oxidizing agent supply port 263 of the electric power generation part 11, and interrupts supply of the oxidizing agent to the electric power generation part 11 by closing two walls. be able to.
  • the power generation unit 11 shown in FIG. 2 was produced as follows.
  • an anode catalyst layer 13 made of platinum ruthenium-supported carbon and a cathode catalyst layer 16 made of platinum were formed on both surfaces of a commercially available proton conductive electrolyte membrane 18.
  • a commercially available diffusion layer made of a porous layer was formed on the anode catalyst layer 13, and a flow path for supplying fuel was disposed on the diffusion layer.
  • the diffusion layer on the anode catalyst layer 13 and the flow path are combined to form an anode electrode 14. That is, the anode substrate 12 includes a diffusion layer and a flow path.
  • a porous laminated diffusion layer was also formed on the cathode catalyst layer 16, and a flow path for supplying an oxidant was disposed on the diffusion layer.
  • the diffusion layer on the cathode catalyst layer 16 and the flow path are combined to form a cathode electrode 17. That is, the cathode substrate 15 includes a diffusion layer and a flow path.
  • the anode catalyst layer 13 and the diffusion layer, or the cathode catalyst layer 16 and the diffusion layer are collectively referred to as a membrane electrode assembly (MEA: not shown).
  • MEA membrane electrode assembly
  • a commercially available fuel feed pump (fuel feed section 22) is used for the anode electrode 14 with 50M of 1.4M aqueous methanol solution, and a commercially available air feed pump (oxidant feed section 25) is used for the cathode electrode 17. Air was sent at 1000 ccm.
  • ccm is a unit representing a flow rate (cm 3 ) per minute.
  • the temperature of the power generation unit 11 was controlled to 65 ° C. with a commercially available heater and a temperature controller.
  • a commercially available electronic load device was used for the load 29, and a commercially available PC in which a program for executing the flowchart shown in FIG.
  • the operation stop processing was repeated every day for 22 days according to the steps shown in S1 to S6 of FIG. 4, and the test of observing the output voltage of the power generation unit 11 during operation was performed.
  • FIG. 7 is a diagram showing a change in the output voltage of the power generation unit 11 during the operation for 22 days after the start of the test.
  • the horizontal axis in FIG. 7 indicates the number of days from the start of the test, and the vertical axis indicates the output voltage value of the power generation unit 11 during operation measured by the voltage detection unit 30.
  • the output voltage was 0.528 V on the first day from the start of the experiment, but gradually decreased as the number of days passed, and became 0.486 V on the 22nd day, which was 42 mV lower than the 1st day.
  • FIG. 8 shows the decrease rate of the output voltage.
  • the horizontal axis in FIG. 8 indicates the number of days from the start of the test, and the vertical axis indicates the ratio of the output voltage for each day to the output voltage on the first day. Based on the first day, the output voltage on the 22nd day was 92%.
  • FIG. 9 shows the results of comparing the degradation factors that cause the output voltage to be reduced into four factors for the output voltage on the seventh day and the twenty-first day of the test of the power generation unit 11.
  • the vertical axis in FIG. 9 indicates the amount of decrease in output voltage as voltage loss.
  • the increase in pressure of the four factors that cause the output voltage to decrease is the amount of voltage loss due to the decrease in the active surface area of the cathode catalyst, the amount recovered by anodic polarization, the increase in cathode overvoltage, The increase in anode overvoltage and the amount of electrical contact resistance are shown.
  • the amount recovered by anodic polarization represents the value of voltage loss due to flooding.
  • the increase in anode overvoltage represents the value of voltage loss due to a decrease in methanol oxidation ability of the anode catalyst.
  • the electrical contact resistance component represents the value of voltage loss due to an increase in electrical contact resistance.
  • the cathode overvoltage increase can be reduced because the deterioration of the cathode electrode is prevented by preventing the oxidant from staying in the fuel cell in the operation stop state.
  • FIG. 10 shows the change in output voltage for 22 days after the start of the test.
  • FIG. 10 corresponds to FIG. 7, the horizontal axis indicates the number of days from the start of the test, and the vertical axis indicates the output voltage value.
  • the output voltage was 0.516 mV on the first day of the test, it gradually decreased and became 0.413 V on the 21st day, which was 103 mV lower than the first day.
  • FIG. 11 shows a decrease rate of the output voltage.
  • FIG. 11 corresponds to FIG. 8, the horizontal axis indicates the number of days from the start of the test, and the vertical axis indicates the ratio of the output voltage of the day to the output voltage of the first day. Based on the first day, the output voltage on the 22nd day was 80%.
  • FIG. 12 shows the deterioration factors that cause the output voltage to decrease with respect to the output voltages on the 7th and 21st days from the start of the test, the amount recovered by anodic polarization, the amount of increase in cathode overvoltage, the amount of increase in anode overvoltage, and the electrical contact. The result of decomposing into 4 factors of resistance and comparing is shown.
  • FIG. 12 corresponds to FIG. The increase in cathode overvoltage was 7.0 mV on the seventh day from the start of the test, but was 40.4 mV on the 21st day of the test.
  • the temperature of the fuel cell becomes higher than the temperature outside the power generation unit, which is the temperature in the shutdown state.
  • the inside of the power generation unit and the outside air are blocked by the first blocking unit 23, the second blocking unit 26, the third blocking unit 24, and the fourth blocking unit 27 during the shutdown process. Therefore, in the operation stop state, a differential pressure is generated between the inside of the power generation unit and the outside air.
  • this differential pressure is large, the volume of the fuel and oxidant in the power generation unit 11 when the operation is stopped is greatly reduced, so that the outside air may enter the power generation unit as the fuel and oxidant are reduced.
  • a fuel cell that indirectly supplies fuel has a higher temperature during operation than a fuel cell that directly supplies fuel, and thus the amount of outside air that enters may increase.
  • a structure for replenishing the power generation unit with the inert agent is required. For this reason, the size of the fuel cell may be increased.
  • a fuel cell that directly supplies fuel such as a direct methanol fuel cell has a small difference between the temperature during operation and the shutdown state. Therefore, since the volume change when the operation state is changed from the operation state to the operation stop state is small, it is possible to realize the system of the present embodiment that installs a blocking portion and suppresses the intrusion of the outside air.
  • the volume change accompanying the temperature change is smaller in the liquid than in the gas. Therefore, when the fuel supplied to the anode electrode 14 is liquid, it is easier to realize the present invention than when the fuel is gas.
  • FIG. 13 shows a change in the output voltage of the power generation unit 11 over time when the operation stop process of the first embodiment is performed in the DMFC system 21 in the operating state.
  • the horizontal axis indicates the elapsed time from the start of measurement.
  • the vertical axis represents the output voltage value of the power generation unit 11 measured by the voltage detection unit 30.
  • Vo for determining that the oxygen concentration of the cathode electrode 17 is low and the first blocking unit 23 and the third blocking unit 24 may be closed is set to 0.25V. . This is a small value with respect to about 0.48 V that is the output voltage during operation, and it can be said that the concentration of the oxidant in the cathode electrode 17 is lower than that during operation. Moreover, even if the power generation unit 11 deteriorates, the output voltage of the deteriorated power generation unit 11 to be used is expected to be larger than 0.25V.
  • the voltage detection unit 30 measures the output voltage and transmits it to the control unit 28, and it takes some time for the control unit 28 to close the first blocking unit 23 and the third blocking unit 24, When the first blocking part 23 and the third blocking part 24 are closed, the oxygen concentration of the cathode electrode 17 is expected to further decrease.
  • the time from closing the second blocking part 26 and the fourth blocking part 27 to closing the first blocking part 23 and the third blocking part 24 is about It was about 2 seconds.
  • the DMFC system 21 can be brought into the shutdown state after the oxygen in the cathode electrode 17 is consumed during the shutdown process of the DMFC system 21. Accordingly, it is possible to prevent the cathode catalyst layer 16 provided in the DMFC system 21 from being deteriorated in the operation stop state.
  • This embodiment is different from the first embodiment in that the voltage detection unit detects the amount of change in the output voltage per unit time (voltage change rate ⁇ V1 / ⁇ t) instead of the output voltage V1 of the power generation unit 11.
  • the storage unit stores a reference change rate ( ⁇ V0 / ⁇ t) instead of the reference voltage V0
  • the comparison unit stores the voltage change rate ( ⁇ V1 / ⁇ t) and the reference change rate (instead of comparing the output voltage V1 and the reference voltage V0).
  • ⁇ V0 / ⁇ t) is compared, and when the relationship of ⁇ V1 / ⁇ t ⁇ ⁇ V0 / ⁇ t is satisfied, the first command unit issues an instruction to block the first blocking unit. Since other configurations are the same as those of the first embodiment, the same configurations as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
  • the control unit 28 loads the second command unit 32 that blocks the supply of the oxidant to the cathode electrode 15, the first command unit 31 that blocks the supply of fuel to the anode electrode 14, and the load release means 36. Detected by the load stop unit 33 that gives an instruction to release the terminal 29, the storage unit 34 that stores the reference change rate ( ⁇ V0 / ⁇ t), and the reference change rate ( ⁇ V0 / ⁇ t) and the voltage detection unit 30 that the storage unit 34 stores And a comparison unit 35 for comparing the magnitude relationship of the voltage change rate (V1 / ⁇ t) of the generated power generation unit 11.
  • FIG. 14A is a diagram illustrating an example of how to set the reference change rate ( ⁇ V0 / ⁇ t) from the diagram illustrating the change in the output voltage after the operation stop process illustrated in FIG. 13 is performed.
  • FIG. 14B is an enlarged view showing the inside of the broken line square of FIG.
  • the output voltage is a constant value during operation, decreases when the operation is stopped, and then stabilizes at the same value.
  • the output voltage has an inflection point 105 while decreasing.
  • the slope (voltage change rate) of the approximate line of the output voltage decreases until the inflection point 105 is reached after the operation stop process is performed.
  • the slope of the tangent of the output voltage at a point in time until the inflection point 105 is reached after the operation stop process is taken as the reference change rate.
  • one point in time for obtaining the reference change rate until reaching the inflection point 105 is determined as follows.
  • intersection 102 of the approximate line 100 along the output voltage in the operating state and the tangent 101 of the output voltage at the inflection point 105 is obtained.
  • a straight line passing through the intersection 102 and parallel to the vertical axis is drawn to obtain an intersection 103 with a curve representing a change in output voltage.
  • the slope of the tangent line 104 of the output voltage at this intersection 103 is obtained and used as the reference change rate ( ⁇ V0 / ⁇ t).
  • the reference change rate ( ⁇ V0 / ⁇ t) obtained from FIG. 14 (a) is ⁇ 0.041 (V / sec).
  • the voltage change rate ( ⁇ V1 / ⁇ t) at the inflection point 105 obtained from FIG. 14A is ⁇ 0.183 (V / sec).
  • the output voltage at the intersection 103 is 0.462 V, and the output voltage of the power generation unit 11 after passing through the intersection 103 is compared with the output voltage (0.48 V) in the operating state, and therefore, the difference is within the cathode electrode 17. It is determined that the remaining oxidant is consumed in the reaction.
  • FIG. 15 is a flowchart showing a process of stopping the operation of the DMFC system 21 in the present embodiment.
  • step S0 the DMFC system 21 is in an operating state, and the control unit 28 opens the first blocking unit 23, the third blocking unit 24, the second blocking unit 26, and the fourth blocking unit 27. It is set. In the operating state, both fuel and oxidant are supplied to the power generation unit 11, and products, unreacted fuel, and the like are discharged from the power generation unit 11 to the outside.
  • the operation stop process of the DMFC system 21 is performed by the steps S1 to S6 described below, and the DMFC system 21 enters the operation stop state (S7). For example, when the operation switch provided in the DMFC fuel cell system 21 is turned off, the operation stop process is started (step S1).
  • step S 3 the voltage detection unit 31 measures the voltage change rate ( ⁇ V1 / ⁇ t) of the power generation unit 11, and the measured voltage change rate ( ⁇ V1 / ⁇ t) is sent to the comparison unit 35 of the control unit 28.
  • step S4 the comparison unit 35 determines whether or not the detected voltage change rate ( ⁇ V1 / ⁇ t) is smaller than the reference change rate ( ⁇ V0 / ⁇ t) stored in the storage unit 34.
  • the process proceeds to step S5.
  • the process returns to step S3.
  • the present embodiment it is possible to consume oxygen remaining in the cathode electrode 17 by determining when to cut off the fuel supply based on the voltage change rate of the power generation unit 11 after the supply of the oxidant is cut off. . Therefore, for example, when it is difficult to predict the deterioration of the power generation unit 11 depending on the use environment, or when the output of the power generation unit 11 is variable, it may be difficult to set the voltage reference value V0. Even in such a case, by using the determination method of the present embodiment, it is possible to appropriately prevent the cathode catalyst layer 16 provided in the DMFC system 21 from being deteriorated in the operation stop state.
  • control unit 28 the power generation unit 11, the fuel liquid supply unit 22, and the oxidant gas supply unit 25 are connected such that the control unit 28 supplies the fuel to the anode electrode 14 and supplies the cathode electrode 17 with the oxidant.
  • Other forms are possible if controlled.
  • control unit 28 may be configured to block the supply of fuel to the anode electrode 14 by controlling the fuel feeding unit 22. Further, the control unit 28 may be configured to block the supply of the oxidant to the cathode electrode 17 by controlling the oxidant gas supply unit 25.
  • the DMFC system 21 has a structure having one power generation unit 11, but a configuration in which a plurality of power generation units 11 are connected is also possible.
  • the present invention can be implemented in a fuel cell that uses another fuel such as an ethanol aqueous solution as a fuel.

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  • Life Sciences & Earth Sciences (AREA)
  • 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

L'invention porte sur un système de pile à combustible auquel un combustible liquide qui supprime la dégradation d'un catalyseur d'électrode pendant l'arrêt et le stockage est directement appliqué. Le système de pile à combustible comprend : une unité génératrice comprenant une électrode anodique à laquelle un combustible liquide est amené, une électrode cathodique à laquelle un agent oxydant est amené, et une membrane d'électrolyte conductrice de protons disposée entre l'électrode anodique et l'électrode cathodique ; une charge connectée à l'unité génératrice et qui consomme l'énergie engendrée par l'unité génératrice ; une première unité de blocage destinée à bloquer le combustible liquide directement amené à l'électrode anodique ; une seconde unité de blocage destinée à bloquer l'agent oxydant amené à l'électrode cathodique ; une seconde unité de commande destinée à émettre une instruction pour l'interruption de la seconde unité de blocage ; une première unité de commande destinée à émettre une instruction pour interrompre la première unité de blocage après l'interruption de la seconde unité de blocage ; et une unité d'arrêt de charge destinée à émettre une instruction pour l'arrêt de la charge après le blocage exécuté par la première unité de blocage.
PCT/JP2009/006736 2009-12-10 2009-12-10 Système de pile à combustible et procédé pour arrêter le fonctionnement de cette pile WO2011070618A1 (fr)

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JP2007109529A (ja) * 2005-10-14 2007-04-26 Mitsubishi Electric Corp 燃料電池発電システムの制御方法
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JP2008140772A (ja) * 2006-11-06 2008-06-19 Fuji Electric Holdings Co Ltd 燃料電池発電装置の停止方法及び燃料電池発電装置
JP2009004369A (ja) * 2007-05-18 2009-01-08 Yamaha Motor Co Ltd 燃料電池システム
JP2009151972A (ja) * 2007-12-19 2009-07-09 Honda Motor Co Ltd 燃料電池の発電停止方法、その発電起動方法及び燃料電池システム
WO2009150990A1 (fr) * 2008-06-11 2009-12-17 日産自動車株式会社 Système de piles à combustible et procédé d’arrêt associé
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Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06333586A (ja) * 1993-05-20 1994-12-02 Sanyo Electric Co Ltd 燃料電池の停止方法
JP2000512069A (ja) * 1996-06-10 2000-09-12 シーメンス アクチエンゲゼルシヤフト 高分子電解質膜形燃料電池発電装置の運転方法
JP2004179086A (ja) * 2002-11-28 2004-06-24 Nissan Motor Co Ltd 固体高分子型燃料電池システム及びその運転方法
JP2005158553A (ja) * 2003-11-27 2005-06-16 Nissan Motor Co Ltd 燃料電池システム
WO2006038448A1 (fr) * 2004-10-05 2006-04-13 Matsushita Electric Industrial Co., Ltd. Procédé de stockage pour corps de jonction d’électrode de membrane polyélectrolytique
JP2006147250A (ja) * 2004-11-17 2006-06-08 Toshiba Fuel Cell Power Systems Corp 燃料電池発電システムとその停止保管方法、停止保管プログラム
JP2006185750A (ja) * 2004-12-27 2006-07-13 Toshiba Fuel Cell Power Systems Corp 燃料電池発電システムの運転方法及び燃料電池発電システム
JP2007109529A (ja) * 2005-10-14 2007-04-26 Mitsubishi Electric Corp 燃料電池発電システムの制御方法
JP2008004432A (ja) * 2006-06-23 2008-01-10 Nissan Motor Co Ltd 燃料電池システム
JP2008140772A (ja) * 2006-11-06 2008-06-19 Fuji Electric Holdings Co Ltd 燃料電池発電装置の停止方法及び燃料電池発電装置
JP2009004369A (ja) * 2007-05-18 2009-01-08 Yamaha Motor Co Ltd 燃料電池システム
JP2009151972A (ja) * 2007-12-19 2009-07-09 Honda Motor Co Ltd 燃料電池の発電停止方法、その発電起動方法及び燃料電池システム
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WO2010026819A1 (fr) * 2008-09-04 2010-03-11 日産自動車株式会社 Système de pile à combustible et procédé de commande de système de pile à combustible

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