JP2005209610A - Control method of fuel cell and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method for improving starting performance at the time of starting of a fuel cell. <P>SOLUTION: At the time of generation stoppage processing, in the drying process S5, dry gas is fed into a reactant gas passage and the electrolyte membrane is dried up to a prescribed dry level and the moisture in the reactant gas passage is removed, and after that, in the humidifying process S6, the electrolyte membrane is humidified by a humidifying gas for a certain time, thus, at the time of stoppage, there is no moisture in the reactant gas passage and the electrolyte membrane is maintained in a desired wet state. At the time of re-starting after soaking, moisture does not remain in the reactant gas passage, the flow of reactant gas is not disturbed and a desired moisture remains uniformly in the electrolyte membrane, therefore cation penetrates easily and starting can be made smoothly. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  This invention relates to a fuel cell power generation stop control method for continuing a power generation operation by supplying a reaction gas to a reaction gas flow path provided on both sides of an anode electrode and a cathode electrode that are held with an electrolyte membrane sandwiched between them. The present invention relates to a fuel cell control method and apparatus for improving moisture removal capability during scavenging and improving startability during restart after power generation is stopped.

  In general, a polymer electrolyte fuel cell is an electrolyte membrane / electrode structure in which an anode electrode and a cathode electrode are provided on both sides of an electrolyte membrane made of a polymer ion exchange membrane (cation exchange membrane). : MEA)) is sandwiched and held by a separator in which a reaction gas flow path is formed (a power generation cell) structure.

  In this fuel cell, a fuel gas supplied to the anode electrode through the reaction gas flow path, for example, a gas mainly containing hydrogen (hereinafter also referred to as a hydrogen-containing gas) is hydrogen cationized on the electrode catalyst, It moves to the cathode electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy. Note that an oxidant gas, for example, a gas containing mainly oxygen or air (hereinafter also referred to as an oxygen-containing gas) is supplied to the cathode electrode through the reaction gas flow path. Hydrogen ions, electrons and oxygen react to produce water.

  By the way, in this type of fuel cell, in order to maintain ionic conductivity, it is necessary to appropriately humidify the electrolyte membrane made of the polymer ion exchange membrane. Furthermore, water produced by the reaction is present at the cathode electrode as described above. For this reason, when starting the fuel cell below freezing point (below the freezing temperature of water), the water in the fuel cell easily freezes, and it is pointed out that the electrochemical reaction is difficult to occur in the fuel cell. Yes.

  Therefore, for example, in Patent Document 1, when the power generation operation is stopped, a dry purge fluid, for example, nitrogen gas, is supplied to the reaction gas channel to scavenge (purge) the water in the reaction gas channel. It is described that this is preferable in terms of improving the starting capability of the fuel cell when frozen.

Japanese translation of PCT publication No. 2003-510786 ([0047], [0048])

  However, the technique according to Patent Document 1 merely describes that it is preferable to purge the reaction gas channel with nitrogen gas, which is a dry non-reactive gas, when the power generation operation is stopped. In this case, the MEA is extremely dried in the vicinity of the reaction gas inlet in the surface of the power generation cell. On the other hand, the dry gas is humidified while moving in the gas flow path in the separator. There is a problem in that the removal and discharge of moisture near the outlet of the reaction gas is insufficient.

  As a result, the membrane resistance value of the electrolyte membrane at the reaction gas inlet is increased, the gas diffusivity near the reaction gas outlet is hindered, and a sufficient load cannot be applied at the time of restart. There is a problem that the sex will deteriorate.

  Further, in the long term, the durability of the MEA may be deteriorated due to the repeated state where the MEA is extremely dry and the state where the MEA is wet.

  The present invention has been made in view of such problems, and provides a fuel cell control method and apparatus capable of improving the water removal capability (discharge capability) during scavenging. Objective.

  Another object of the present invention is to provide a fuel cell control method and apparatus capable of preventing deterioration of durability of the MEA.

  Furthermore, an object of the present invention is to provide a fuel cell time control method and an apparatus thereof that can improve the startability upon restart after power generation is stopped.

  Still another object of the present invention is to provide a fuel cell control method and apparatus capable of promptly starting even under an environment below the freezing temperature of water and immediately shifting to normal operation. And

  In this section, in order to facilitate understanding of the present invention, a description will be given with reference numerals in the accompanying drawings. Therefore, the contents described in this section should not be construed as being limited to those having the reference numerals.

  The control method for a fuel cell according to the present invention includes a reaction gas flow path (46, 48) on both sides of an anode electrode (20a) and a cathode electrode (20c) that are held with an electrolyte membrane (20b) interposed therebetween, and the reaction gas In a control method of a fuel cell that performs a power generation operation by supplying a reaction gas to a flow path, a scavenging signal detection step that detects an input of a scavenging signal, and a scavenging process that performs a scavenging process when the input of the scavenging signal is detected Steps (S5, S6), and when the scavenging signal is detected, the scavenging process step dries the membrane (S5) and humidifies the membrane after drying the membrane. A humidifying step (S6). (Invention of Claim 1)

  According to the present invention, the moisture is removed from the reaction gas channel by drying the electrolyte membrane during the scavenging process, and then the electrolyte membrane is humidified. Has no moisture and the electrolyte membrane becomes wet. For this reason, the flow of the reaction gas is not hindered, and moisture remains in the electrolyte membrane, so that cations are easily transmitted and good power generation can be performed.

  The scavenging process is performed during idling while the vehicle is temporarily stopped, in addition to the power generation stop process described later. By performing the scavenging process, it is possible to smoothly shift from idling to traveling. Needless to say, the present invention can also be applied to stationary or portable fuel cells other than those mounted on a vehicle.

  In this case, it is preferable that the degree of drying of the electrolyte membrane is detected during the drying step (S5b), and the drying step is terminated when a predetermined degree of drying is reached (invention of claim 2).

  For example, the degree of drying of the electrolyte membrane in the drying step can be determined based on the membrane resistance value of the electrolyte membrane (the invention according to claim 3).

  The degree of drying of the electrolyte membrane in the drying step can be determined based on the differential value of the membrane resistance value of the electrolyte membrane (the invention according to claim 4).

  Furthermore, the degree of drying of the electrolyte membrane in the drying step can be determined based on a gas pressure difference between the supply port and the discharge port of the reaction gas flow path (the invention according to claim 5).

  Furthermore, the degree of drying of the electrolyte membrane in the drying step can be determined based on the differential value of the gas pressure difference between the supply port and the discharge port of the reaction gas channel (the invention according to claim 6). .

  In this case, the degree of drying of the electrolyte membrane in the drying step is the membrane resistance value of the electrolyte membrane, the differential value of the membrane resistance value, the gas pressure difference between the supply port and the discharge port of the reaction gas channel, And determination based on at least one of the differential values of the gas pressure difference (the invention according to claim 7).

  In the drying step, the electrolyte membrane can be dried by supplying a dry gas to the reaction gas channel (the invention according to claim 8).

  Here, if the supply time of the drying gas in the drying step is a predetermined time, the control to a desired degree of drying is simple (the invention according to claim 9).

  The dry gas is preferably a dry gas that has been heated to a high temperature through a high temperature process (for example, the compressor 102 → the direct supply channel 101 → the air supply channel 98) (the invention according to claim 10).

  In the humidification step, the electrolyte membrane can be humidified by supplying a humidified gas to the reaction gas flow path (the invention according to claim 11).

  Even in this case, if the humidifying gas is supplied to the reaction gas channel in the humidifying step for a predetermined time, the control to the desired degree of drying is simple (the invention according to claim 12).

  Further, as a way of humidification in the humidification step, the electrolyte membrane can be humidified with a large load connected to the anode electrode and the cathode electrode (the invention according to claim 13).

  The scavenging signal is preferably input when the fuel cell is stopped (the invention according to claim 14). In this case, reaction gas channels (46, 48) are provided on both sides of the anode electrode (20a) and the cathode electrode (20c) that are held with the electrolyte membrane (20b) interposed therebetween, and the reaction gas is supplied to the reaction gas channel. A fuel cell power generation stop control method for stopping power generation by performing power generation operation and performing power generation stop processing based on input of a power generation stop signal (Ig = 0). A power generation stop signal detection step (S3) for detecting an input of a stop signal, a drying step (S5) for drying the electrolyte membrane when an input of a power generation stop signal is detected, and after the electrolyte membrane is dried, the electrolyte membrane And a humidifying step (S6) for humidifying.

  According to the present invention, when the power generation is stopped, the electrolyte membrane is dried to remove moisture from the reaction gas channel, and then the electrolyte membrane is humidified. There is no moisture and the electrolyte membrane becomes wet. Therefore, at the time of restart, since no moisture remains in the reaction gas flow path, the flow of the reaction gas is not hindered, and since moisture remains in the electrolyte membrane, the cation is easily transmitted. Thus, power generation is performed well.

  That is, a sufficient load can be applied at the time of restarting, and the startability is improved. In addition, there is no freezing in the reaction gas flow path even in an environment below the freezing temperature of water, and further, since moisture remains in the electrolyte membrane, a quick start can be performed reliably and immediately You can move on to driving.

  The fuel cell described above has an electrolyte membrane / electrode structure (20) provided with the anode electrode (20a) and the cathode electrode (20c) which are held with the electrolyte membrane (20b) interposed therebetween, and the electrolyte membrane A power generation cell in which the electrode structure is held between separators (22, 24) and the reaction gas flow path (46, 48) is provided in a portion of the separator facing the electrolyte membrane / electrode structure ( A so-called fuel cell stack (12) having a stack structure in which a plurality of 14) are stacked is also included (the invention according to claim 15).

  The control device for a fuel cell according to the present invention is provided with reaction gas flow paths (46, 48) on both sides of an anode electrode (20a) and a cathode electrode (20c) that are held with an electrolyte membrane (20b) interposed therebetween, and the reaction gas In a fuel cell control apparatus that performs a power generation operation by supplying a reaction gas to a flow path, a scavenging signal detector (60) that detects the input of a scavenging signal, and when the scavenging signal input is detected, A drying device (102) for drying, and a humidifier (103) for humidifying the membrane after drying the membrane are provided (the invention according to claim 16).

  According to the present invention, when the scavenging signal detector detects the input of the scavenging signal, moisture is removed from the reaction gas flow path by drying the electrolyte membrane with the dryer, and then the electrolyte membrane is humidified with the humidifier. I am doing so. For this reason, after processing according to the input of the scavenging signal, there is no moisture in the reaction gas flow path of the fuel cell, and the electrolyte membrane becomes wet. Since no water remains in the reaction gas flow path, the flow of the reaction gas is not hindered. Also, since water remains in the electrolyte membrane, the cation easily permeates and the power generation is good. Is possible.

  According to this invention, at the time of scavenging (for example, at the time of power generation stop processing), moisture is removed from the reaction gas flow path by drying the electrolyte membrane, and then the electrolyte membrane is humidified. At times (for example, when stopped), there is no moisture in the reaction gas flow path, and the electrolyte membrane becomes wet.

  Therefore, the water removal capability (discharge capability) during scavenging can be improved.

  In addition, since the electrolyte membrane does not repeat between an extremely dry state and a wet state, it is possible to prevent deterioration in durability of the electrolyte membrane / electrode structure, that is, MEA.

  Furthermore, when restarting after scavenging is completed (for example, after power generation is stopped), no moisture remains in the reaction gas flow path, so that the flow of the reaction gas is not hindered, and moisture remains in the electrolyte membrane. Therefore, it becomes easy for the cations to permeate, and power generation is performed (started) satisfactorily.

  For example, it is possible to apply a sufficient load at the time of restart and the startability is improved.

  In addition, there is no freezing in the reaction gas flow path even in an environment below the freezing temperature of water, and since moisture remains in the electrolyte membrane, a quick start is reliably performed and normal operation is immediately performed. Can be migrated to.

  FIG. 1 is an explanatory diagram of a schematic configuration of a fuel cell system 10 that implements a fuel cell control method according to an embodiment of the present invention and includes an embodiment of a fuel cell control device.

  The fuel cell system 10 includes a fuel cell stack 12, and the fuel cell stack 12 is configured as a stacked body in which a plurality of power generation cells 14 are stacked in the arrow A direction. At both ends in the stacking direction of the fuel cell stack 12, a positive terminal plate 16a and a negative terminal plate 16b, and end plates 18a and 18b are sequentially provided. The fuel cell stack 12 is formed by tightening the end plates 18a, 18b with a tie rod or the like (not shown).

  Each power generation cell 14 includes an electrolyte membrane / electrode structure 20 and metal separators 22 and 24 that sandwich the electrolyte membrane / electrode structure 20. The separators 22 and 24 are integrally formed with a sealing material so as to cover the periphery of a communication hole described later and the outer periphery of the electrode surface (power generation surface).

  FIG. 2 is an exploded perspective view of the power generation cell 14 which is a constituent element of the fuel cell stack 12 constituting the fuel cell system 10 shown in FIG.

  As shown in FIG. 2, one end edge of the power generation cell 14 in the direction of arrow B communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant gas, for example, oxygen-containing gas, which is one reaction gas, An oxidant gas supply communication hole 30a for supply, a cooling medium discharge communication hole 32b for discharging the cooling medium, and a fuel gas discharge communication for discharging a fuel gas, for example, a hydrogen-containing gas, which is the other reaction gas. The holes 34b are arranged in the arrow C direction (vertical direction).

  The other end edge of the power generation cell 14 in the direction of the arrow B communicates with each other in the direction of the arrow A, the fuel gas supply communication hole 34a for supplying the fuel gas, and the cooling medium supply communication hole for supplying the cooling medium. 32a and an oxidant gas discharge communication hole 30b for discharging the oxidant gas are arranged in the direction of arrow C.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 20b in which a perfluorosulfonic acid thin film is impregnated with water, and an anode electrode 20a and a cathode electrode 20c that are held between the solid polymer electrolyte membrane 20b. (See FIG. 1 and FIG. 2).

  The anode electrode 20a and the cathode electrode 20c include a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer, respectively. Have. The electrode catalyst layer is bonded to both surfaces of the solid polymer electrolyte membrane 20b.

  On the surface 22a of the separator 22 facing the electrolyte membrane / electrode structure 20, an oxidant gas flow path (also called a reaction gas flow path) communicating with the oxidant gas supply communication hole 30a and the oxidant gas discharge communication hole 30b. ) 46 is provided. The oxidant gas channel 46 is formed between, for example, a plurality of grooves extending in the arrow B direction and the cathode electrode 20c.

  A fuel gas flow path (also referred to as a reaction gas flow path) 48 that communicates with the fuel gas supply communication hole 34 a and the fuel gas discharge communication hole 34 b is formed on the surface 24 a of the separator 24 that faces the electrolyte membrane / electrode structure 20. It is formed. The fuel gas channel 48 is formed, for example, between a plurality of grooves that extend in the direction of arrow B and the anode electrode 20a.

  A cooling medium flow path 50 is formed between the surface 22b of the separator 22 and the surface 24b of the separator 24 to guide the cooling medium supplied from the cooling medium supply communication hole 32a to the cooling medium discharge communication hole 32b. The cooling medium flow path 50 is integrally configured to extend in the direction of arrow B by superimposing a plurality of grooves provided in the metal separator 22 and a plurality of grooves provided in the separator 24.

  In FIG. 1 again, the fuel cell system 10 is mounted on a vehicle such as an automobile, for example. Basically, the fuel cell stack 12 and a control unit 60 that controls the entire fuel cell system 10 in an integrated manner. And a fuel gas supply system 62 and an oxidant gas supply system 64.

  In the fuel cell stack 12, a plurality of power generation cells (fuel cells) 14 are electrically connected in series, and a power generation current If is output from the positive terminal plate 16a.

  In this case, the voltage value Vc of the voltage (the voltage between the separators 24 and 22) generated in each power generation cell 14 is taken into the control unit 60 that also functions as a voltage sensor via an electric wire (not shown).

  The generated current If output from the positive terminal plate 16a is passed through a current sensor 68 to a load 72 including a traveling motor and an auxiliary machine (compressor 102, switching valve 118, various valves, etc.) via a load controller 70. Supplied.

  The current value (the sign uses If) of the generated current If is detected by the current sensor 68 and taken into the control unit 60. The controller 60 calculates the power generation voltage Vs (voltage between the terminal plates 16a and 16b) of the fuel cell stack 12 by adding the voltage value Vc of each power generation cell 14, and manages the power generation as Vs × If.

  One end plate 18 a has an air supply port 78 a for supplying air to the oxidant gas flow path 46 of each power generation cell 14 through the oxidant gas supply communication hole 30 a and an unused exhaust discharged from the power generation cell 14. An air discharge port 78b for discharging air containing oxygen through the oxidant gas discharge communication hole 30b and a cooling medium supply port 112a are provided.

  The other end plate 18b has a hydrogen supply port 76a for supplying hydrogen gas to the fuel gas flow path 48 of each power generation cell 14 through the fuel gas supply communication hole 34a, and an unused exhaust discharged from the power generation cell 14. A hydrogen discharge port 76b for discharging exhaust gas containing hydrogen gas through the fuel gas discharge communication hole 34b and a cooling medium discharge port 112b are provided.

  The fuel gas supply system 62 includes a hydrogen supply channel 82 that supplies fuel gas to the fuel cell stack 12, a hydrogen discharge channel 83 that exhausts exhaust gas containing unused fuel gas from the fuel cell stack 12, and an exhaust gas ( A hydrogen circulation channel 84 for returning the hydrogen-containing gas) to the fuel supply stack 12 by returning it to the hydrogen supply channel 82.

  The hydrogen supply channel 82 is depressurized by a hydrogen tank 86 for storing high-pressure hydrogen, a regulator 88 for reducing the pressure of fuel gas supplied from the hydrogen tank 86 through a hydrogen supply valve (normally closed on / off valve) 87. The fuel gas is supplied to the fuel cell stack 12, the ejector 90 for sucking the exhaust gas from the hydrogen circulation channel 84 and returning it to the fuel cell stack 12, and the pressure of the fuel gas supplied to the fuel cell stack 12 are detected And a pressure sensor 92 is provided. The pressure value Ph of the fuel gas detected by the pressure sensor 92 is taken into the control unit 60.

  The hydrogen discharge flow path 83 is provided with a purge valve 94 for discarding the exhaust gas discharged from the fuel cell stack 12.

  The oxidant gas supply system 64 disposes an air supply flow path 98 for supplying oxidant gas (air) to the fuel cell stack 12 and exhaust gas containing unused air discharged from the fuel cell stack 12 to the outside. The air discharge channel 100 is provided.

  The air supply flow path 98 includes a compressor 102 for compressing and outputting the air, an intercooler 104 as a cooling device for cooling the compressed air output from the compressor 102 and heated to a high temperature, and the cooled compressed air. Humidifier 103 that supplies moisture as humidified air, and switching that controls the mixing ratio of the low-temperature humidified air supplied through intercooler 104 and humidifier 103 and the high-temperature dry air supplied directly from compressor 102 A valve 105, a high-temperature dry air direct supply passage 101, and a pressure sensor 109 that detects the pressure of an oxidant gas (air) supplied to the fuel cell stack 12 are provided. The supply pressure value Pin of the oxidant gas detected by the pressure sensor 109 is taken into the control unit 60.

  In the air discharge channel 100, a temperature sensor 106 that detects the air outlet temperature of the fuel cell stack 12, a pressure sensor 107 that detects the air outlet pressure, and a pressure of the oxidant gas supplied to the fuel cell stack 12 are controlled. A pressure regulating valve 108 is provided. The air outlet temperature value Ta and the air outlet pressure value Pout detected by the temperature sensor 106 and the pressure sensor 107 are taken into the control unit 60.

  The control unit 60 has a CPU (Central Processing Unit) and functions as a calculation / control / storage / processing unit, and also functions as a timer as a timing unit.

  The control unit 60 is also connected to an activation switch 138 that functions as an ignition switch of the fuel cell system 10 and an accelerator opening sensor that indicates an accelerator opening (not shown). When the power generation start signal (Ig = 1) corresponding to the on state is supplied from the start switch 138 to the control unit 60 that also functions as a power generation stop signal detector, the power generation operation start processing is performed, and the control unit 60 enters the off state. A power generation operation stop process is performed by supplying a corresponding power generation stop signal (Ig = 0). In this embodiment, the power generation stop signal (Ig = 0) is a scavenging signal in a broad sense because a scavenging process to be described later is performed in response to the input of this signal.

  In this case, a scavenging signal output switch is provided separately from the start switch 138 and connected to the control unit 60. If the scavenging signal is input when the scavenging signal output switch is turned on, for example, the vehicle is temporarily stopped. The configuration may be changed so that the scavenging process can be performed even during idling.

  Therefore, the control unit 60 also functions as a scavenging signal detector in a broad sense including the meaning of a power generation stop signal detector. In this embodiment, as described above, the control unit 60 functions as a power generation stop signal detector.

  Then, the CPU of the control unit 60 performs various inputs (signal Ig from the start switch 138, each cell voltage value Vc, generated current value If, air supply pressure value Pin, air outlet pressure value Pout, hydrogen inlet pressure value Ph, By executing a program corresponding to the air outlet temperature Ta, etc., the rotation speed of the compressor 102, the opening degree of the regulator 88, the switching position of the switching valve 105, the control of the load controller 70, etc. are performed, and predetermined power generation The current If is generated and supplied to the load controller 70, and the entire fuel cell system 10 is controlled overall.

  The fuel cell system 10 according to this embodiment is basically configured and operates as described above. Next, a more detailed operation of the fuel cell system 10 is based on the flowchart shown in FIG. I will explain.

  First, in step S1, when the start switch 138 is turned from the off state to the on state by the user's operation (Ig = 0 → 1), in step S2, the fuel cell system 10 is started and the normal power generation operation of the fuel cell stack 12 is performed. Is done.

  When the normal power generation operation is continued, in the fuel gas supply system 62, the fuel gas supplied from the hydrogen tank 86 is adjusted to a predetermined pressure via the regulator 88, and the fuel cell is supplied via the hydrogen supply channel 82 via the ejector 90. The hydrogen is supplied to the hydrogen supply port 76 a of the stack 12.

  The fuel gas supplied to the hydrogen supply port 76a is supplied to the anode electrode 20a along the fuel gas flow path 48 through the fuel gas supply communication hole 34a constituting each power generation cell 14, and moves along the anode electrode 20a. Exhaust gas containing unused hydrogen gas containing is discharged from the hydrogen discharge port 76 b to the hydrogen discharge flow path 83 through the fuel gas discharge communication hole 34 b and sent to the hydrogen circulation flow path 84.

  The exhaust gas discharged to the hydrogen circulation channel 84 is returned to the hydrogen supply channel 82 under the suction action of the ejector 90 and then supplied again as fuel gas into the fuel cell stack 12. This fuel gas is a gas containing moisture, that is, a humidified gas.

  On the other hand, air is supplied from the compressor 102 as compressed air in which the outside air is compressed. During normal operation, humidified air (humidified gas) that has been cooled through the intercooler 104 and the humidifier 103 is supplied to the air via the switching valve 105. It is supplied to the flow path 98.

  The air, that is, the oxidant gas, is supplied from the air supply port 78a to the cathode electrode 20c along the oxidant gas flow path 46 through the oxidant gas supply communication hole 30a constituting each power generation cell 14, and along the cathode electrode 20c. After the movement, exhaust gas containing unused air is discharged from the air discharge port 78b to the air discharge channel 100 through the oxidant gas discharge communication hole 30b.

  As a result, in each power generation cell 14, hydrogen, which is the fuel gas supplied to the anode electrode 20a, reacts with oxygen in the oxidant gas supplied to the cathode electrode 20c to generate power.

  The power generation process will be described in detail. The hydrogen gas is hydrogen ionized at the anode electrode 20a to generate hydrogen ions and electrons. Hydrogen ions reach the cathode electrode 20c side with moisture in the electrolyte membrane 20b. The generated electrons reach the cathode electrode 20c from the anode electrode 20a through the negative terminal plate 16b through the external load (load controller 70, load 72, auxiliary machine, etc.), and through the current sensor 68 through the positive terminal plate 16a. To do. Then, on the cathode electrode 20c side of the electrolyte membrane 20b, oxygen combines with hydrogen ions and electrons to become water.

  Thus, in the power generation cell (also referred to as a fuel cell) 14, when hydrogen ions generated in the anode electrode 20a move through the electrolyte membrane 20b to the cathode electrode 20c, water molecules are accompanied. Therefore, in order to maintain the conductivity of hydrogen ions, the electrolyte membrane 20b is required to be in a wet state containing moisture.

  In this case, in the oxidant gas supply system 64, the gas pressure of the oxidant gas is adjusted to a predetermined pressure via the pressure adjustment valve 108 based on the target generated current value If, and the gas flow rate of the oxidant gas is changed. The flow rate is adjusted to a predetermined flow rate by controlling the rotation speed of the compressor 102.

  On the other hand, in the fuel gas supply system 62, the gas pressure of hydrogen gas is adjusted to a predetermined pressure via the regulator 88, and the gas flow rate of hydrogen gas is adjusted to a predetermined flow rate via the ejector 90.

  When the above-described normal power generation operation is performed, as shown in step S3, the user operates the start switch 138 to stop the operation, and the start switch 138 is switched from the on state to the off state. Input to the unit 60. That is, when the power generation stop signal (Ig = 0) that transitions from the high level 1 to the low level 0 is detected by the control unit 60, when the power generation is stopped including the scavenging process step described below triggered by this power generation stop signal detection step Processing is performed.

  When the input of the power generation stop signal (Ig = 0) is detected, in step S4, the control unit 60 closes the hydrogen supply valve 87 attached to the hydrogen tank 86 and supplies new fuel gas from the hydrogen tank 86. After performing the fuel gas supply stop process for stopping the process, the process of optimizing the residual moisture state of the electrolyte membrane 20b and the oxidant gas flow path 46, which is a scavenging process including the drying process of step S5 and the humidification process of step S6, is performed. I do.

  In this residual moisture state optimization process, before the power generation is completely stopped, the residual moisture in the oxidant gas channel 46, which is the air channel constituting each power generation cell 14, and the residual moisture in the electrolyte membrane 20b are determined. This is a processing step of confirming and satisfying the optimum moisture residual condition in which a predetermined amount of moisture remains in the electrolyte membrane 20 b and no moisture remains in the oxidant gas flow path 46.

  Then, when the optimum moisture residual condition is satisfied, the power generation stop process shown in the next step S7 is performed, so that the start switch 138 is switched from the off state to the on state at a time after the time when the power generation stop process is performed. At the time of restarting, it is ensured that the flow of the reaction gas is not hindered because no moisture remains in the oxidant gas flow path 46, and the water ions remain in the electrolyte membrane 20b, so that hydrogen ions remain. This is to ensure that (positive ions) are easily transmitted, and as a result, normal power generation can be reliably started. That is, by performing the power generation stop processing after step S5, quick start-up is reliably performed even in an environment below the freezing temperature of water, and it is possible to immediately shift to normal power generation operation.

  Actually, depending on the power generation operation status, the residual moisture state of the electrolyte membrane 20b and the oxidant gas flow path 46 may have the following three modes.

  (I) A state in which droplet water remains in the oxidant gas flow path 46 (both the electrolyte membrane 20b and the oxidant gas flow path 46 are wet). (Ii) A state in which moisture remains in the electrolyte membrane 20b (only the electrolyte membrane 20b is wet). (Iii) The electrolyte membrane 20b is in a dry state (both the electrolyte membrane 20b and the oxidant gas channel 46 are in a dry state). And at the time of a power generation stop, it is preferable to be stopped in the state (ii) (optimum moisture residual condition / optimum stop condition).

  In this embodiment, the optimum moisture remaining condition (ii) is, first, to determine whether moisture remains in the oxidant gas flow path 46, in order to determine whether the supply pressure value Pin and the discharge pressure of air. It is determined whether or not the pressure difference (pressure loss) α (α = Pin−Pout) from the value Pout is equal to or less than a predetermined pressure value (threshold value) ΔP (α ≦ ΔP). Second, in order to determine the wet state of the electrolyte membrane 20b, it is determined whether or not the membrane resistance value Rm of the electrolyte membrane 20b is equal to or less than a predetermined membrane resistance value (threshold value) Rt that is a threshold value ( Rm ≦ Rt).

  FIG. 4 shows change characteristics of the pressure difference α and the membrane resistance value Rm when the internal residual moisture of the power generation cell 14 is changed from a low state (dry state) to a high state (humidified state). The pressure difference α becomes a large value when the residual moisture in the oxidant gas flow path 46 constituting the power generation cell 14 is large, and becomes a small value as it decreases. On the other hand, the membrane resistance value Rm becomes a large value when the residual moisture in the electrolyte membrane 20b is small, and becomes a small value as it increases.

  In FIG. 4, a predetermined pressure value ΔP and a predetermined film resistance value Rt, which are the above-described determination criteria, are described. Therefore, in this embodiment, the optimum moisture residual condition range when power generation is stopped is a range from the intersection of the predetermined membrane resistance value Rt and the membrane resistance value Rm to the intersection of the predetermined pressure value ΔP and the pressure difference α.

  Next, processing examples from step S3 to step S7 will be described with reference to the waveform diagram of FIG.

  As shown in FIG. 5A, when a power generation stop signal (Ig = 0) that transitions from high level 1 to low level 0 is detected by the control unit 60 at time t0 (step S3), power generation is stopped. As shown in FIG. 5B, the control unit 60 immediately closes the hydrogen supply valve 87 attached to the hydrogen tank 36, and the hydrogen gas that is the fuel gas from the hydrogen tank 36 is started. The new supply is stopped (step S4).

  During the normal power generation operation in step S2, the water content of each electrolyte membrane 20b (electrolyte membrane / electrode structure 20) is as shown in FIG. 6 with respect to the gas inlet (oxidant gas supply communication hole 30a, fuel gas supply communication). The moisture content increases from W2 to W5 from the hole 34a) to the gas outlet (oxidant gas discharge communication hole 30b, fuel gas discharge communication hole 34b) toward the downstream of the gas. As a result, it has a considerable water content. Therefore, moisture remains in the gas flow channel, particularly the oxidant gas flow channel 46.

  Therefore, as a process at the time of stopping, first, in step S5, a drying process is executed in order to remove excess moisture, and in step S5, a drying process using a drying gas is performed in step S5a.

  Therefore, at time t0, the air switching valve 105 switches the air flow path from the humidifier 103 side flow path directly to the supply flow path 101 side, and the pressure adjustment valve 108 is opened to maximize the rotation speed of the compressor 102. To. As a result, as shown in FIG. 5D, the oxidant gas is changed from the humidified gas to a high-temperature dry gas. That is, high-temperature dried air with a maximum gas flow rate that is directly supplied from the compressor 102 functioning as a dryer, bypassing the intercooler 104 and the humidifier 103, and directly supplied through the direct supply passage (bypass) 101 ( High-temperature dry gas) is supplied to the air supply port 78 a through the air supply flow path 98.

  This high-temperature dry air moves from the air supply port 78a through the oxidant gas supply communication hole 30a, along the oxidant gas flow path 46 of each power generation cell 14, and passes through the oxidant gas discharge communication hole 30b. The air is discharged from 78b and is further discharged to the outside air outside the vehicle through the pressure adjusting valve 108 through the air discharge passage 100. At this time, residual moisture in the oxidant gas flow path 46 is discharged (purged) from the air discharge port 78b to the air discharge flow path 100 by the dry gas, and the oxidant gas flow path 46 is dried, that is, dried. Scavenging (dry purging) is performed.

  When dry gas is supplied to the oxidant gas channel 46, hydrogen gas is circulated in the fuel gas channel 48 by the ejector 90 until time t1, as shown in FIG. 5C. Therefore, predetermined power generation is continued in each power generation cell 14. That is, the circulating hydrogen supplied to the ejector 90 through the hydrogen discharge port 76b and the hydrogen discharge flow path 83 at time t0 is supplied from the ejector 90 to the fuel cell stack 12 until time t1.

  The hydrogen gas pressure shown in FIG. 5C is the pressure detected by the pressure sensor 92 at the hydrogen supply port 76a, and the supply of hydrogen gas from the hydrogen tank 86 is stopped at time t0. The gas pressure is designed to gradually decrease from time t0 and stabilize at a predetermined pressure value at time t1. The predetermined pressure value is designed to be higher than atmospheric pressure. Since the purge valve 94 is not opened after the time point t0, the state where the gas pressure value in the fuel gas passage 48 is higher than the atmospheric pressure is maintained. In this way, the drying process of step S5 is performed.

  That is, as shown in FIG. 5D, until the time t0, the fuel gas and the humidified oxidant gas are supplied to the reaction gas flow paths 46 and 48, and after the time t0 until the time t4, the fuel gas and the high temperature gas are heated. The dried oxidant gas is supplied to the reaction gas channels 46 and 48. The time from time t0 to time t4 is called a scavenging period or a purge period.

  At time t0, the drying degree determination process in step S5b is further performed. In this drying degree determination process, the degree of drying of the electrolyte membrane 20b is detected during the drying step, and it is determined whether or not a predetermined degree of drying has been reached.

  In this embodiment, the degree of drying of the electrolyte membrane 20b is determined based on the membrane resistance value Rm of the electrolyte membrane 20b.

  This film resistance value Rm is obtained by decreasing the load value, for example, the resistance value intermittently (in the form of a pulse) within the load controller 70 (by increasing the load), as shown in FIG. The generated current value If is increased or decreased in a pulse manner.

  At this time, the fluctuation current value ΔIf of the generated current value If is calculated. Further, as shown in FIG. 5F, the fluctuation voltage value ΔVc corresponding to the cell voltage Vc is calculated, and the membrane resistance value Rm is calculated as Rm. = ΔVc / ΔIf (see (g) of FIG. 5).

  Then, it is determined whether or not the obtained film resistance value Rm exceeds a predetermined film resistance value (threshold value) Rt that is a threshold value (Rm> Rt). The membrane resistance value Rm can also be obtained as an AC impedance by changing the load sinusoidally.

  In the vicinity of the time point t0, the electrolyte membrane 20b is in a sufficiently wet state, so that the membrane resistance value Rm is equal to or less than the predetermined resistance value Rt.

  In the vicinity of time t0, the determination in step S5b is not satisfied, and hence the drying gas processing in step S5a and the drying degree determination processing in step S5b, that is, the drying process in step S5 are continued until the determination in step S5b is satisfied. The

  In this embodiment, as the drying gas is continuously supplied, the film resistance value Rm increases after time t3, and at time t4, the film resistance value Rm becomes the predetermined film resistance value Rt, and the drying degree determination process in step S5b is performed. To establish.

  The drying degree determination process can also be determined based on the time differential value Rm ′ of the membrane resistance value Rm of the electrolyte membrane 20b, as schematically shown in FIG. In this case, it is determined whether or not the time differential value Rm ′ of the membrane resistance value Rm exceeds a predetermined differential value Rt ′ (Rm ′> Rt ′).

  The degree of drying of the electrolyte membrane 20b in step S5b can also be determined based on the gas pressure difference between the supply port and the discharge port of the reaction gas channel. For example, in order to determine whether or not moisture remains in the oxidant gas flow path 46, the supply pressure value Pin of the air supply port 78a and the discharge pressure value Pout of the air discharge port 78b are used as pressure sensors 109 and 107, respectively. The gas pressure difference (pressure loss) α (α = Pin−Pout) is calculated, and it is determined whether or not the calculated gas pressure difference α is equal to or less than a predetermined pressure value (threshold value) ΔP ( α ≦ ΔP).

  As shown in (i) of FIG. 5, at time t0, excess moisture remains in the oxidant gas flow path 46, so the gas pressure difference α is larger than the predetermined pressure value ΔP. By supplying a dry gas to the oxidant gas flow path 46, the residual moisture in the oxidant gas flow path 46 is purged.

  At time t2, since it is determined that the gas pressure difference α is equal to or less than the predetermined pressure difference ΔP, the supply of the dry gas is stopped at time t4 after the elapse of a predetermined time T24. It is estimated that the membrane resistance value Rm of the electrolyte membrane 20b is the predetermined membrane resistance value Rt.

  The degree of drying of the electrolyte membrane 20b can also be determined based on the time differential value α ′ of the gas pressure difference α, as shown in FIG. Since the time differential value α ′ becomes the predetermined differential value ΔP ′ at the time point t3, the supply of the dry gas is stopped at the time point t4 after the elapse of the predetermined time T34, so that the membrane of the electrolyte membrane 20b at the time point t4. It is estimated that the resistance value Rm is the predetermined film resistance value Rt.

  At the time t4 when the drying process of step S5 is completed, each electrolyte membrane 20b (electrolyte membrane / electrode structure 20) has a gas inlet (oxidant gas supply communication hole) as schematically shown in FIG. 30a, from the fuel gas supply communication hole 34a) to the gas outlet (oxidant gas discharge communication hole 30b, fuel gas discharge communication hole 34b) downstream of the gas, the moisture content increases from W1 to W3. However, as a whole, the moisture content is small and dry (W1 <W2 <W3 <W5).

  Therefore, when the drying process of step S5 is completed, that is, when the drying degree determination process of step S5b is established, the humidification process of step S6a constituting the humidification process S6 that humidifies the electrolyte membrane 20b to a certain degree (uniform) next. Gas treatment is performed.

  In order to perform the humidified gas treatment, as shown in FIG. 5D and the like, at time t4, the air switching valve 105 switches the air flow path directly from the supply flow path side to the humidifier 103 side flow path. During a predetermined time T45 until t5, humidified scavenging (humidity purge) is performed in which the humidified oxidant gas and the humidified hydrogen gas are supplied to the reaction gas flow paths 46 and 48, respectively.

  Since the dry gas is supplied until the membrane resistance value Rm reaches the constant value Rt, and then the humidified gas is supplied for a predetermined time T45, the humidification degree determination process in step S6b is performed for a predetermined time after the time t4. When T45 has elapsed, the degree of humidification is determined to be appropriate.

  In the humidification process, instead of the humidified gas treatment S6a, a constant load (power generation) in which the load connected to the load controller 70 is increased as shown by the dotted line at time t4 to t5 in FIG. By setting the current value pIf), for example, even when the dry gas is supplied, the power generation cell 14 generates power, so that the electrolyte membrane 20b can be humidified to a predetermined wet state.

  At the time point t5 when the drying process in step S6 is completed, each electrolyte membrane 20b (electrolyte membrane / electrode structure 20) has a gas inlet (oxidant gas supply communication hole) as schematically shown in FIG. 30a, from the fuel gas supply communication hole 34a) to the gas outlet (oxidant gas discharge communication hole 30b, fuel gas discharge communication hole 34b) from the gas downstream toward the gas outlet, with a desired water content W4 and a uniform distribution state (W1 <W2 <W3 <W4 <W5).

  Next, in the power generation stop process in step S7, the operation of all the auxiliary machines such as the stop of the compressor 102 is stopped at time t5. Therefore, after time t5, the pressure difference α becomes zero. In addition, after time t5, the control unit 60 enters a so-called sleep state. When the control unit 60 detects the input of the power generation stop signal (Ig = 0) that transitions from the high level to the low level shown in FIG. 5A at time t0, the control unit 60 at that time t0. As shown in FIG. 5B, the supply of hydrogen gas from the hydrogen tank 86 is continued without closing the hydrogen supply valve 87, and the supply of the oxidant gas shown in FIG. At the time point t5 or the time point t4 when the operation is stopped, the control unit 60 may close the hydrogen supply valve 87 and stop the supply of hydrogen gas.

  However, as described above, the supply of hydrogen gas from the hydrogen tank 86 is stopped at the time t0 (see FIG. 5B) or reduced, so that the chemical reaction in the power generation cell 14 occurs after this time t0. In the direction of inactivation, the generation of moisture is reduced, and accordingly, the scavenging period T02 of the drying gas from the time t0 when the start switch 138 is turned off, that is, the drying time can be shortened.

  FIG. 9 shows the configuration of a fuel cell system 10A according to another embodiment of the present invention. In the fuel cell system 10A, a humidifier 150, a heater 152, and a switching valve 154 for switching between these are provided between the regulator 88 on the fuel gas supply system 62 side and the ejector 90, as compared with the fuel cell system 10 in FIG. ing.

  In the fuel cell system 10A according to the other embodiment, during normal power generation up to the time point t0, in the oxidant gas supply system 64, the high-temperature compressed air from the compressor 102 is converted into the intercooler 104, the humidifier 103, and the air supply flow. The fuel gas supplied from the hydrogen tank 86 is humidified through the humidifier 150 in the fuel gas supply system 62 and supplied to the reaction gas flow path 46 as the oxidant gas that has been cooled and humidified through the path 98. The fuel gas thus supplied is supplied to the reaction gas channel 48 through the ejector 90 and the hydrogen supply channel 82.

  Next, between time t0 and t4, in the oxidant gas supply system 64, the high-temperature dry oxidant gas (high-temperature dry gas) supplied from the compressor 102 is directly supplied to the supply channel 101 and the air supply channel 98. In the fuel gas supply system 62, the fuel gas supplied from the hydrogen tank 86 is converted into a high-temperature and dry gas through the heater 152, and the ejector 90 and the hydrogen supply channel 82 are supplied. Is supplied to the reaction gas channel 48.

  Next, between time t4 and time t5, in the oxidant gas supply system 64, the high-temperature compressed air from the compressor 102 is cooled and humidified through the intercooler 104, the humidifier 103, and the air supply flow path 98. While being supplied to the reaction gas channel 46 as a gas, the fuel gas supplied from the hydrogen tank 86 is humidified through the humidifier 150, and this humidified fuel gas is passed through the ejector 90 and the hydrogen supply channel 82. 48. Thereby, the electrolyte membrane 20b is maintained in a desired uniform wet state.

  FIG. 10 shows a configuration of a fuel cell system 10B according to still another embodiment of the present invention. In the fuel cell system 10B, a chemically stable gas, here, nitrogen gas is used as the scavenging gas. On / off valves 172, 174, 176, 178 and 180 are provided, and a humidifier 162 and a heater 164 are provided in parallel at the discharge port of the nitrogen tank 160.

  In this still another fuel cell system 10B, during normal power generation up to time t0, the valves 174, 176, 178, 180 are closed and shut off, and the valve 172 is opened and communicated. Further, both the heater 164 and the humidifier 162 are inactivated.

  In a non-operating state, a low-temperature humidified oxidant gas is supplied to the reaction gas flow path 46 through the intercooler 104, the humidifier 103, and the air supply flow path 98 and is also supplied from the hydrogen tank 86. The fuel gas is humidified through the humidifier 150, and the humidified fuel gas is supplied to the reaction gas channel 48 through the ejector 90 and the hydrogen supply channel 82, thereby generating power.

  Next, during the period from time t0 to time t4 when the power generation stop signal (Ig = 0) is input, the compressor 102 is inactivated, and the valve 172 and the valve 87 are closed, and the oxidant gas and the fuel gas. Is interrupted.

  At this time, the valve 178 is closed, while the valves 174, 176, 180 are opened, and the heater 164 is activated. Thereby, the nitrogen gas supplied from the nitrogen tank 160 is supplied as the high-temperature dry gas to the reaction gas channel 46 and the reaction gas channel 48 through the air supply channel 98 and the hydrogen supply channel 82, respectively. In this case, since power generation is not performed in the power generation cell 14, moisture is not generated, and dry scavenging can be performed in a short time.

  Next, between time points t4 and t5, the heater 164 is deactivated and the valve 180 is closed, while the humidifier 162 is activated and the valve 178 is opened. Thereby, the nitrogen gas supplied from the nitrogen tank 160 is supplied as the humidified gas to the reaction gas channel 46 and the reaction gas channel 48 through the air supply channel 98 and the hydrogen supply channel 82, respectively. Thereby, the electrolyte membrane 20b is maintained in a desired uniform wet state.

  As described above, according to the above-described embodiment, during the power generation stop process, the dry gas is passed through the reaction gas channels 46 and 48 to dry the electrolyte membrane 20b to a predetermined degree of drying, and from the reaction gas channels 46 and 48, Since the water is removed and the electrolyte membrane 20b is then humidified for a certain period of time, when the operation is stopped, the reaction gas channels 46 and 48 have no water and the electrolyte membrane 20b is in a desired uniform wet state. The retained optimum moisture residual condition is established.

  Therefore, after being left for an arbitrary period of time and at the time of restarting after so-called soaking, since no moisture remains in the reaction gas flow paths 46 and 48, the flow of the reaction gas is not hindered, and the electrolyte membrane 20b Since an appropriate amount of water remains uniformly in the, it becomes easier for cations to permeate and power generation is started well. That is, a sufficient load can be applied at the time of restarting, and the startability is improved. In addition, a quick start can be reliably performed even in an environment below the freezing temperature of water, and a normal operation can be immediately started.

  Actually, regarding the startability at the time of restart, when the optimal moisture residual condition is satisfied, when the optimal moisture residual condition is not satisfied and there is a large amount of residual moisture in the oxidant gas flow path 46, and when the optimal moisture residual condition is not satisfied. Examples of experiments in each case where the electrolyte membrane 20b is in a dry state are shown in FIGS.

  As can be seen from the characteristic 201 in FIG. 11, when the optimum moisture residual condition is established at the time of stop and the system is restarted, the voltage of each power generation cell 14 is stabilized and the generated current value If immediately reaches the desired current value. However, when there is a large amount of residual moisture at the time of stopping, as shown in the characteristic 202, when restarting, the voltage of each power generation cell 14 is not stable, and the power generation current If rises slowly, and power generation stops at time ta. You can see that In the state where the power generation has stopped, the inside of the oxidant gas flow path 46 is almost filled with water. In addition, as shown in the characteristic 203, when the engine is in a dry state at the time of stoppage, the power generation current If does not increase easily at the time of restart, and it takes a very long time to reach a desired current value. .

  Further, as can be seen from FIG. 12, when restarting at a temperature below the freezing point, the cooling medium flows through the cooling medium flow path 50, and the outlet of the cooling medium detected by the temperature sensor at the cooling medium discharge port on the end plate 18b side. As can be seen from the characteristic 211, the temperature Tw reaches a predetermined temperature in a relatively short time when the optimum moisture residual condition is established and restarted, that is, the low temperature start time is shortened but stopped. It can be seen that sometimes the temperature of the cooling medium does not easily increase as shown by the characteristics 212 and 213 when there is a lot of residual moisture, when it is dry when it is stopped, and when it is restarted.

1 is a block diagram of a fuel cell system to which an embodiment of the present invention is applied. It is explanatory drawing of how to flow the oxidizing gas in a power generation cell, a cooling medium, and fuel gas. It is a flowchart with which operation | movement description of the fuel cell system of the example of FIG. 1 is provided. It is explanatory drawing of the optimal moisture residual condition establishment range. It is a wave form chart for explanation of processing at the time of stop. It is a schematic diagram which shows the in-plane distribution of the water content of the electrolyte membrane during electric power generation. It is a schematic diagram which shows in-plane distribution of the water content of the electrolyte membrane after scavenging using dry gas. It is a schematic diagram which shows in-plane distribution of the water content of the electrolyte membrane after scavenging using humidification gas. It is a block diagram of the fuel cell system to which other embodiment of this invention was applied. It is a block diagram of the fuel cell system to which further another embodiment of this invention was applied. It is a characteristic view which shows the experimental example of the difference in the electric power generation current characteristic based on the difference in the residual moisture at the time of restart after a stop. It is a characteristic view which shows the experimental example of the difference in the temperature rise characteristic of a cooling medium based on the difference in the residual water | moisture content at the time of restart after a stop.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10A, 10B ... Fuel cell system 12 ... Fuel cell stack 14 ... Power generation cell 20 ... Electrolyte membrane and electrode structure 20a ... Anode electrode 20b ... Solid polymer electrolyte membrane (electrolyte membrane)
20c ... Cathode electrode 22, 24 ... Separator 46 ... Oxidant gas channel 48 ... Fuel gas channel 60 ... Control unit

Claims (16)

In a control method of a fuel cell in which a reaction gas channel is provided on both sides of an anode electrode and a cathode electrode that are held with an electrolyte membrane interposed therebetween, and a power generation operation is performed by supplying a reaction gas to the reaction gas channel,
A scavenging signal detection process for detecting the input of the scavenging signal;
A scavenging process step of performing a scavenging process when detecting the input of the scavenging signal,
The scavenging process step includes
A drying step of drying the membrane when detecting the input of the scavenging signal;
A fuel cell control method comprising: a humidifying step of humidifying the membrane after the membrane is dried. The fuel cell control method according to claim 1,
A method of controlling a fuel cell, wherein the degree of drying of the membrane is detected during the drying step, and the drying step is terminated when a predetermined degree of drying is reached. The fuel cell control method according to claim 2, wherein:
The degree of drying of the membrane in the drying step is determined based on the membrane resistance value of the membrane. In the fuel cell power generation control method according to claim 2,
The degree of drying of the membrane in the drying step is determined based on a differential value of the membrane resistance value of the membrane. The fuel cell control method according to claim 2, wherein:
The degree of drying of the membrane in the drying step is determined based on a gas pressure difference between a supply port and a discharge port of the reaction gas channel. The fuel cell control method according to claim 2, wherein:
The degree of drying of the membrane in the drying step is determined based on a differential value of a gas pressure difference between a supply port and a discharge port of the reaction gas channel. The fuel cell control method according to claim 2, wherein:
The degree of drying of the film in the drying step is the film resistance value of the film, the differential value of the film resistance value, the gas pressure difference between the supply port and the discharge port of the reaction gas channel, and the gas pressure difference. A determination method based on at least one of the differential values of the fuel cell. The fuel cell control method according to claim 1,
In the drying step, a dry gas is supplied to the reaction gas channel to dry the electrolyte membrane. The fuel cell control method according to claim 8, wherein
The method for controlling a fuel cell, wherein the drying gas supply time in the drying step is a predetermined time. The fuel cell control method according to claim 8, wherein
The method for controlling a fuel cell, wherein the dry gas is a dry gas that has been heated to a high temperature through a temperature increasing step. The fuel cell control method according to claim 1,
In the humidification step, a humidification gas is supplied to the reaction gas flow path to humidify the electrolyte membrane. The fuel cell control method according to claim 11,
In the humidification step, a supply time of the humidified gas supplied to the reaction gas flow path is set to a predetermined time. The fuel cell control method according to claim 1,
In the humidification step, the membrane is humidified with a large load connected to the anode electrode and the cathode electrode. In the fuel cell control method according to any one of claims 1 to 13,
The method of controlling a fuel cell, wherein the scavenging signal is input when the fuel cell is stopped. In the fuel cell control method according to any one of claims 1 to 14,
The fuel cell has an electrolyte membrane / electrode structure provided with the anode electrode and the cathode electrode that are held with the electrolyte membrane sandwiched therebetween, the electrolyte membrane / electrode structure is held with a separator interposed therebetween, and A fuel cell control method comprising a stack structure in which a plurality of power generation cells each provided with the reaction gas flow path are provided in a portion of the separator facing the electrolyte membrane / electrode structure. In a control device for a fuel cell that performs a power generation operation by providing a reaction gas channel on both sides of an anode electrode and a cathode electrode that are held with an electrolyte membrane interposed therebetween, and supplying a reaction gas to the reaction gas channel,
A scavenging signal detector for detecting the input of the scavenging signal;
A dryer for drying the membrane when detecting the input of the scavenging signal;
A fuel cell control device comprising: a humidifier for humidifying the membrane after the membrane is dried.

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