JP2009259526A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology which restrains degradation of a catalyst layer in a fuel cell. <P>SOLUTION: The fuel cell system 1000 is provided with a fuel cell 100, a secondary battery 200, and a control part 500. The fuel cell 100 is provided with an electrolyte film 11, an inner electrode 18, inserted inside the electrolyte film 11 and capable of connecting with the secondary battery 200, and a catalyst electrode layer 14 arranged on either side of the electrolyte film 11. The control part 500 makes the secondary battery 200 impress voltage so as the internal electrode 18 has a higher voltage than that of the catalyst electrode layer 14 during power generation stoppage of the fuel cell 100, and carries out catalyst recovery treatment of moving catalyst 60, which has moved into the electrolyte film 11 during power generation of the fuel cell 100 back to the catalyst electrode layer 14 side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel cell.

  The fuel cell includes an electrolyte membrane sandwiched between electrode layers, and receives supply of hydrogen and oxygen as reaction gases to each electrode layer, and generates electric power by the electrochemical reaction. The electrode layer is usually provided with a catalyst layer on which a catalyst for promoting the fuel cell reaction is supported (Patent Document 1, etc.).

JP 2007-214036 A JP 2005-317467 A

  By the way, it is known that the catalyst in the catalyst layer is eluted into the electrolyte membrane when the fuel cell is used for a long period of time or when the output of the fuel cell is significantly changed. The elution of the catalyst causes deterioration of the fuel cell, such as a decrease in fuel cell performance. However, until now, the actual situation is that no sufficient contrivance has been made for suppressing the deterioration of the catalyst layer due to the elution of the catalyst.

  An object of this invention is to provide the technique which suppresses deterioration of the catalyst layer in a fuel cell.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A fuel cell system comprising a fuel cell, an external power source, and a control unit for controlling the output of the fuel cell system, wherein the fuel cell is inserted into an electrolyte membrane and the membrane of the electrolyte membrane, An internal electrode connected to an external power source, and a catalyst electrode layer disposed on both surfaces of the electrolyte membrane, the control unit, by the external power source during the power generation stop of the fuel cell, A fuel cell system that performs a catalyst recovery process in which a voltage is applied so that the voltage is higher than that of the catalyst electrode layer.
According to this fuel cell system, the catalyst eluted from the catalyst electrode layer into the electrolyte membrane during power generation of the fuel cell can be moved toward the catalyst electrode layer while the fuel cell is stopped. Therefore, deterioration of the catalyst layer in the fuel cell can be suppressed.

[Application Example 2]
The fuel cell system according to application example 1, wherein the control unit repeatedly increases or decreases the voltage in the catalyst recovery process.
According to this fuel cell system, elution of the catalyst deposited in the electrolyte membrane to the catalyst electrode layer can be promoted by increasing or decreasing the voltage. Therefore, deterioration of the catalyst layer in the fuel cell can be suppressed.

[Application Example 3]
The fuel cell system according to Application Example 1 or Application Example 2, wherein the control unit is configured to change the output request from an external load connected to the fuel cell system a predetermined number of times during operation of the fuel cell. Alternatively, when the output request is larger than a predetermined request amount, the fuel cell system executes the catalyst recovery process after causing the fuel cell to output in response to the output request.
According to this fuel cell system, the catalyst recovery process is executed after power generation is performed so that the amount of catalyst elution into the electrolyte membrane increases in the fuel cell. Therefore, deterioration of the catalyst layer in the fuel cell can be suppressed.

[Application Example 4]
4. The fuel cell system according to any one of Application Examples 1 to 3, wherein the internal electrode is a member having a plurality of pores capable of proton conduction in the thickness direction, and the electrolyte membrane extends along the thickness direction. The fuel cell system is inserted so as to overlap the catalyst electrode layer when viewed.
According to this fuel cell system, the internal electrode for applying a voltage in the catalyst recovery process can function as a catalyst trap layer that elutes during fuel cell power generation. Therefore, deterioration of the catalyst layer in the fuel cell can be further suppressed.

[Application Example 5]
The fuel cell system according to any one of Application Examples 1 to 4, wherein the catalyst electrode layer includes an anode and a cathode, and the internal electrode is inserted closer to the cathode than the anode. Fuel cell system.
According to this fuel cell system, a larger amount of the catalyst deposited in the electrolyte membrane can be moved to the catalyst layer on the cathode side by the catalyst recovery process. Accordingly, it is possible to suppress deterioration of the cathode-side catalyst electrode layer.

  Note that the present invention can be realized in various forms, for example, in the form of a fuel cell system including a fuel cell, a vehicle equipped with the fuel cell system, and the like.

A. First embodiment:
FIG. 1 is a block diagram showing an electrical configuration of a fuel cell system as an embodiment of the present invention. FIG. 1 shows an example of an electrical connection mode in a normal operation state of the fuel cell system 1000, and wiring in a state where electricity is not conducted is shown by a broken line for convenience.

  This fuel cell system 1000 includes a fuel cell 100, a secondary battery 200, a DC / DC converter 300, a DC / AC inverter 400, and a control unit 500. The control unit 500 controls the fuel cell system 1000 in response to a request from the external load 2000. The control unit 500 can be configured by a microcomputer, for example. The fuel cell 100 has a stack structure in which power generation modules 110 that are a plurality of power generation bodies are stacked. Each power generation module 110 is connected in series.

  FIG. 2 is a schematic cross-sectional view showing the configuration of an arbitrary power generation module 110 in the fuel cell 100. The power generation module 110 includes a membrane electrode assembly 10 that is a power generation body, and two separators 20 and 30 that sandwich the membrane electrode assembly 10. The membrane electrode assembly 10 includes an electrolyte membrane 11 which is a solid polymer thin film showing good proton conductivity in a wet state, and the electrolyte membrane 11 is sandwiched between an anode 12 and a cathode 13. An internal electrode 18 is inserted into the electrolyte membrane 11. The internal electrode 18 is interposed in the electrolyte membrane 11 by bonding two electrolyte membranes from both sides. The internal electrode 18 is disposed closer to the cathode 13 than the anode 12.

  FIG. 3 is a schematic view showing the electrolyte membrane 11 through the internal electrode 18 when viewed along the thickness direction, and the electrolyte membrane 11 is indicated by a broken line. The internal electrode 18 is formed of a mesh member having a size comparable to that of the electrolyte membrane 11 in which conductive wires 18w are arranged in a lattice pattern. During power generation, protons pass through the pores 18 h formed by the wires 18 w of the internal electrode 18. The internal electrode 18 has a terminal portion 18 t provided so as to protrude from the electrolyte membrane 11, and can conduct electricity from the outside of the electrolyte membrane 11. The function of the internal electrode 18 will be described later.

  A catalyst layer 14 for promoting a power generation reaction is provided on the outer surfaces of the anode 12 and the cathode 13 (FIG. 2) in contact with the electrolyte membrane 11. A gas diffusion layer 15 is provided on the outer surfaces of the anode 12 and the cathode 13 that are not in contact with the electrolyte membrane 11 so as to spread the supplied reaction gas over the entire surface. In addition, as a catalyst of the catalyst layer 14, platinum (Pt) can be used, for example. As the gas diffusion layer 15, for example, carbon paper can be used.

  The two separators 20 and 30 can be configured by conductive gas-impermeable plate-like members (for example, metal plates). The anode separator 20 is disposed on the anode 12 side of the membrane electrode assembly 10, and the cathode separator 30 is disposed on the cathode 13 side of the membrane electrode assembly 10. Each of the two separators 20 and 30 is provided with gas flow paths 21 and 31 for inducing a reaction gas on the side in contact with the electrodes 12 and 13. The gas flow paths 21 and 31 are provided as a plurality of flow path grooves that run side by side over the entire power generation region used for power generation.

  When the reaction gas is supplied to the electrodes 12 and 13 through the gas flow passages 21 and 31, protons are conducted from the anode 12 side to the cathode 13 side through the moisture in the membrane of the electrolyte membrane 11, and electrochemical. The membrane electrode assembly 10 generates electricity by the reaction. The generated electricity is collected by the separators 20 and 30. Note that the two separators 20 and 30 may have other configurations, for example, a multi-layered separator having a flow path for the refrigerant.

  The fuel cell 100 (FIG. 1) outputs the generated power of each power generation module 110 via the anode terminal 120 and the cathode terminal 130 provided at the end in the stacking direction. The anode terminal 120 is connected to the anode DC wiring DCLa, and the cathode terminal 130 is connected to the cathode DC wiring DCLc. The fuel cell 100 is further connected to two DC wirings DCLs and DCLi. Specifically, the separator DC wiring DCLs is connected to the cathode separator 30 of each power generation module 110, and the internal electrode DC wiring DCLi is connected to the terminal portion 18 t of the internal electrode 18 of each power generation module 110.

  One of the two DC wirings DCLc and DCLi is selectively connected to the DC power supply line DCL1 via the first changeover switch CS1. Similarly, one of the two DC wirings DCLa and DCLs is selectively connected to the DC power supply line DCL2 via the second changeover switch CS2. In the figure, the DC wirings DCLa and DCLc are electrically connected to the DC power supply lines DCL1 and DCL2, respectively, by the first and second changeover switches CS1 and CS2.

  DC power supply lines DCL 1 and DCL 2 are connected to DC / AC inverter 400. The DC / AC inverter 400 is connected to the external load 2000. Secondary battery 200 is connected to DC power supply lines DCL 1 and DCL 2 via DC / DC converter 300. An open / close switch SS is provided between the DC / DC converter 300 and the DC / AC inverter 400. In the figure, the open / close switch SS is closed, and the external load 2000, the fuel cell 100, and the secondary battery 200 are electrically connected.

  The secondary battery 200 is an auxiliary power source that can be charged and discharged, and can be constituted by, for example, a lithium ion battery. The DC / DC converter 300 controls charging / discharging of the secondary battery 200 by variably adjusting the voltage levels of the DC power supply lines DCL1 and DCL2 according to an instruction from the control unit 500. DC / AC inverter 400 converts DC power output from DC power supply lines DCL 1 and DCL 2 into AC power and supplies the AC power to external load 2000. The frequency of the AC power at that time is controlled by an instruction from the control unit 500.

  By the way, in addition to the control of the DC / DC converter 300 and the DC / AC inverter 400, the control unit 500 further controls the switching operation of the first and second selector switches CS1 and CS2 and the opening / closing operation of the opening / closing switch SS. . As a result, the control unit 500 realizes switching between two types of electrical connection modes in the fuel cell system 1000, and other electrical connection modes will be described later.

  In the electrical connection mode during normal operation in FIG. 1, the control unit 500 supplies the generated power of the fuel cell 100 to the external load 2000 in response to the output request, and the output of the fuel cell 100 is less than the required output. The secondary battery 200 compensates for the shortage. In addition, when regenerative power (AC power) is generated by the external load 2000, the control unit 500 converts the regenerative power into DC power by the DC / AC inverter 400 and the secondary via the DC / DC converter 300. The battery 200 is charged.

  By the way, in fuel cells, it is generally known that the catalyst of the catalyst layer 14 (FIG. 2) elutes into the electrolyte membrane when it is repeatedly started and stopped or when the output voltage is significantly changed in a short time. ing. Here, “when the output voltage is significantly changed in a short time” is, for example, a case where the voltage of each power generation module 110 is changed from about 1.0 V to 0 V in about 1 second. It is known that the elution of the catalyst during power generation is particularly remarkable on the cathode side. If the catalyst is eluted, the power generation capacity of the fuel cell is reduced, which causes deterioration of the fuel cell. Therefore, the control unit 500 suppresses deterioration of the fuel cell due to catalyst elution by performing the following control in the fuel cell system 1000.

  FIG. 4 is a flowchart showing a control procedure of the fuel cell system 1000 by the control unit 500. In the electrical connection mode shown in FIG. 1, the control unit 500 causes the fuel cell 100 and the secondary battery 200 to output power in response to a request from the external load 2000 (step S <b> 10). At this time, the control unit 500 measures the number of times that the output request from the external load 2000 fluctuates (output request fluctuation number).

  When the output request from the external load 2000 is interrupted, the control unit 500 stops power generation by the fuel cell 100 (step S20). At this time, if the output request fluctuation frequency while the fuel cell 100 continues to generate power is greater than a predetermined frequency (for example, 10 or more), the control unit 500 performs a catalyst recovery process described below. Is executed (step S30). First, the controller 500 controls the first and second changeover switches CS1 and CS2 and the open / close switch SS to change the electrical connection mode of the fuel cell system 1000 from the connection mode during normal operation to the catalyst recovery process. The connection mode is switched (step S40).

  FIG. 5 is a block diagram showing an electrical connection mode of the fuel cell system 1000 when the catalyst recovery process is executed. FIG. 5 is substantially the same as FIG. 1 except that the electrical connection is changed. As in FIG. 1, the wiring in a state where electricity is not conducted is indicated by a broken line. In this electrical connection mode, the open / close switch SS is opened, and the electrical connection between the external load 2000 and the fuel cell system 1000 is interrupted. Further, the secondary battery 200 is connected to the internal electrode 18 and the cathode separator 30 via the two DC wirings DCLi and DCLs by the two changeover switches CS1 and CS2.

  In this state, the control unit 500 controls the DC / DC converter 300 to intermittently apply the voltage so that the voltage of the internal electrode 18 becomes higher than that of the cathode separator 30 for a predetermined time (for example, several seconds). (Step S50 in FIG. 4). The number and time of voltage application may be adjusted according to the number of load fluctuations measured by the control unit 500. The applied voltage may be about 1 V, for example, and may be adjusted according to the power output from the fuel cell 100 during normal operation. After step S60, the control unit 500 switches the electrical connection mode of the fuel cell system 1000 again to the connection mode during normal operation (FIG. 1), ends the catalyst recovery process, and operates the fuel cell system 1000. Is finished (step S60).

  6A and 6B are explanatory views for explaining the effect of the catalyst recovery process. FIGS. 6A and 6B schematically show the inside of the electrolyte membrane 11 in an arbitrary power generation module 110. Specifically, FIG. 6A shows the state of the electrolyte membrane 11 and the anode-side and cathode-side catalyst layers 14 during power generation of the fuel cell 100, and FIG. 6B shows the same region. The state during execution of the catalyst recovery process is shown.

  As described above, the platinum 60 (catalyst 60) supported on the carbon particles 50 of the catalyst layer 14 on the cathode side by the power generation of the fuel cell 100 elutes into the electrolyte membrane 11 and is closer to the cathode than the anode. In some cases (FIG. 6A). In the fuel cell 100 of the present embodiment, the internal electrode 18 interposed in the electrolyte membrane 11 functions as a trap layer for trapping the eluted platinum 60, and a large amount of platinum is formed on the outer surface of the wire 18w of the internal electrode 18. 60 is deposited.

  Here, during power generation of the fuel cell 100, a potential difference occurs so that the cathode side potential becomes higher, and the voltage changes according to the output demand of the external load. Due to this voltage change, the elution of platinum 60 is promoted. On the other hand, during the catalyst recovery process, as shown in FIG. 6B, the potential of the internal electrode 18 is high and the potential of each catalyst layer 14 is low between each catalyst layer 14 and the internal electrode 18. Thus, the voltage is applied intermittently. That is, in the catalyst recovery process, a potential change is generated in the cathode-side catalyst layer 14 that is opposite in polarity to that during power generation. Therefore, in the catalyst recovery process, the platinum 60 deposited in the vicinity of the internal electrode 18 can be eluted toward each catalyst layer 14. In this embodiment, since the internal electrode 18 is disposed closer to the cathode than the anode, more platinum 60 can be moved to the catalyst layer 14 of the cathode.

  Thus, according to the configuration of the present embodiment, even when the catalyst is eluted into the electrolyte membrane during power generation of the fuel cell, the catalyst recovery process is performed while the power generation of the fuel cell is stopped. The catalyst that has eluted inside can be eluted and deposited again on the electrode side. Therefore, deterioration of the catalyst layer in the fuel cell can be suppressed.

B. Second embodiment:
FIG. 7 is a block diagram showing a configuration of a fuel cell system as a second embodiment of the present invention. FIG. 7 is substantially the same as FIG. 1 except that a second opening / closing switch SS2 and an opening / closing switch group SSG are provided instead of the second changeover switch CS2. In addition, the control process which the control part 500 performs in this fuel cell system 1000B is the same as the process demonstrated in 1st Example except the point demonstrated below (FIG. 5).

The second open / close switch SS2 is provided between the anode DC wiring DCLa and the DC power supply line DCL2. The open / close switch group SSG is a switch group including _n open / close switches SS _{1 to} SS n connected to the cathode separator 30 of each power generation module 110 and the DC power supply line DCL 2 (n is the number of the power generation modules 110). The open / close switches SS _{1 to} SS _n of the second open / close switch SS 2 and the open / close switch group SSG are controlled by the control unit 500.

The fuel cell system 1000B performs a normal operation for supplying electric power according to the output request of the external load 2000 according to the electrical connection mode shown in the figure. Specifically, in this electrical connection mode, the cathode DC wiring DCLc and the anode DC wiring DCLa are connected to the DC power supply lines DCL1 and DCL2, respectively, by the first changeover switch CS1 and the second opening / closing switch SS2. In addition, all the open / close switches SS _{1 to} SS _{n of the} open / close switch group SSG are opened.

  FIG. 8 is a block diagram showing an electrical connection mode of the fuel cell system 1000B when the catalyst recovery process is executed. FIG. 8 is almost the same as FIG. 7 except that the electrical connection is changed. When the catalyst recovery process is executed, the internal electrode DC wiring DCLi and the DC power supply line DCL1 are electrically connected by the first changeover switch CS1. In addition, the first open / close switch SS is opened, the electrical connection between the fuel cell 100 and the secondary battery 200 and the external load 2000 is cut off, the second open / close switch SS2 is opened, and the anode DC wiring DCLa The electrical connection with the DC power supply line DCL2 is also cut off.

Furthermore, this electrical connection secondary battery 200 to close the opening and closing switch SS ₁ for opening and closing switches SSG in manner between the cathode separator 30 and the internal electrode 18, so that the voltage of the internal electrode 18 is higher, such as about A voltage of 1 V is applied for a predetermined unit time (for example, a unit time of 1 second or less). Next, the open / close switch SS ₁ is opened, the open / close switch SS ₂ is closed, and a voltage is similarly applied between the cathode separator 30 and the internal electrode 18. The controller 500 continuously applies a voltage to each power generation module 110 in a similar manner, and rotates such a voltage application process so that the voltage is applied to each power generation module 110 a predetermined number of times. Run it. The voltage value of the voltage applied to each power generation module 110, the number of times of application, and the application time are adjusted according to the number of load fluctuations measured by the control unit 500 and the amount of power output from the fuel cell 100. It is also good.

  9A and 9B are explanatory diagrams for explaining the effect of the catalyst recovery process. FIG. 9A is substantially the same as FIG. 6A, and FIG. 9B is substantially the same as FIG. 6B except that the voltage application state inside the electrolyte membrane 11 is different. In the catalyst recovery process in the fuel cell system 1000 of the first embodiment, a voltage is applied between the internal electrode 18 and each of the catalyst layers 14 on the anode side and the cathode side. On the other hand, in the catalyst recovery process of the fuel cell system 1000B of the second embodiment, a voltage is applied only between the internal electrode 18 and the catalyst layer 14 on the cathode side. As a result, the platinum 60 eluted and deposited inside the electrolyte membrane 11 can be moved toward the catalyst layer 14 on the cathode side. Thus, according to the fuel cell system 1000B of the second embodiment, it is possible to suppress the deterioration of the catalyst layer 14 on the cathode side.

C. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

C1. Modification 1:
In the above embodiment, the catalyst recovery process is performed after the power generation of the fuel cell 100 is stopped. However, the catalyst recovery process may be executed at another timing. For example, it may be executed always before starting the power generation of the fuel cell 100, or may be executed as one of the recovery means when a decrease in the power generation capacity of the fuel cell 100 is detected. good. For example, when the fuel cell system 1000 is mounted on a moving body such as a vehicle, the fuel cell system 1000 may be periodically executed while the moving body is stopped.

C2. Modification 2:
In the above embodiment, the voltage is intermittently applied between the internal electrode 18 and the cathode-side catalyst layer 14 in the catalyst recovery process. However, the voltage may be continuously applied. However, in the catalyst recovery process, it is preferable to apply the voltage intermittently, and even when the voltage is continuously applied, it is preferable to sequentially change the voltage value of the applied voltage. The reason for this is that the catalyst in the vicinity of the internal electrode 18 can be eluted again by repeatedly increasing and decreasing the applied voltage in this way.

C3. Modification 3:
In the above embodiment, the power of the secondary battery 200 that functions as an auxiliary power source of the fuel cell 100 is used for the catalyst recovery process. However, a separate external power source may be used. In this case, the selector switches CS1 and CS2 and the open / close switch SS can be omitted.

C4. Modification 4:
In the above embodiment, the internal electrode 18 is provided in each power generation module 110 of the fuel cell 100. However, the internal electrode 18 may be provided only in some power generation modules 110. For example, the internal electrode 18 may be provided in the power generation module 110 in which a relatively large amount of catalyst elution is detected by experiments or the like.

C5. Modification 5:
In the above embodiment, the internal electrode 18 is configured by a mesh member having substantially the same size as the electrolyte membrane 11, but may be configured by a member having another shape. However, if the internal electrode 18 is formed of a mesh member, it is possible to suppress a decrease in proton conductivity in the electrolyte membrane 11 due to the insertion of the internal electrode 18. Further, the mesh-like internal electrode 18 can trap more catalyst eluted in the electrolyte membrane. The internal electrode 18 may include a reducing compound that promotes oxidation / reduction of the eluted catalyst.

C6. Modification 6:
In the above embodiment, the internal electrode 18 is interposed closer to the cathode than the anode of the electrolyte membrane 11, but may be interposed at another position of the electrolyte membrane 11. However, deterioration of the catalyst layer 14 on the cathode side can be suppressed by disposing it at a position closer to the cathode side. In addition, the internal electrode 18 is disposed in a region that overlaps the catalyst layer 14 when viewed along the thickness direction of the electrolyte membrane 11, but may be disposed in a region that does not overlap the catalyst layer 14. However, by disposing the catalyst in the region overlapping with the catalyst layer 14, more eluted catalyst can be trapped by the internal electrode 18, and the effect of the catalyst recovery process can be improved.

Schematic which shows the electrical structure of the fuel cell system in 1st Example. The schematic sectional drawing which shows the structure of a fuel cell. Schematic which shows the structure of an internal electrode. The flowchart which shows the control procedure of the fuel cell system by a control part. The block diagram which shows the electrical connection aspect of the fuel cell system at the time of catalyst recovery processing execution of 1st Example. Explanatory drawing which shows typically the movement of the catalyst in the catalyst recovery process of 1st Example. Schematic which shows the electrical structure of the fuel cell system in 2nd Example. The block diagram which shows the electrical connection aspect of the fuel cell system at the time of catalyst recovery processing execution of 1st Example. Explanatory drawing which shows typically the movement of the catalyst in the catalyst recovery process of 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Membrane electrode assembly 11 ... Electrolyte membrane 12 ... Anode 13 ... Cathode 14 ... Catalyst layer 15 ... Gas diffusion layer 18 ... Internal electrode 18h ... Pore 18t ... Terminal part 18w ... Wire 20, 30 ... Separator 21, 31 ... Gas flow Road 50 ... Carbon particles 60 ... Platinum 100 ... Fuel cell 110 ... Power generation module 120, 130 ... Terminal 200 ... Secondary battery 300 ... DC / DC converter 400 ... DC / AC inverter 500 ... Control unit 1000, 1000B ... Fuel cell system 2000 ... External load CS1, CS2 ... Changeover switch CS2 ... Second open / close switch DCLa ... Anode DC wiring DCLc ... Cathode DC wiring DCLi ... Internal electrode DC wiring DCLs ... Separator DC wiring DCL1 ... DC power supply line DCL2 ... DC power supply line SS, SS2 ... opening and closing Switch SSG (SS1-SSn) ... Open / close switch group

Claims (6)

A fuel cell system,
A fuel cell;
An external power supply,
A control unit for controlling the output of the fuel cell system;
With
The fuel cell
An electrolyte membrane;
An internal electrode inserted into the electrolyte membrane and connected to the external power source;
A catalyst electrode layer disposed on both surfaces of the electrolyte membrane;
With
The control unit executes a catalyst recovery process in which a voltage is applied by the external power source so that the internal electrode has a voltage higher than that of the catalyst electrode layer while the power generation of the fuel cell is stopped. . The fuel cell system according to claim 1, wherein
The control unit is a fuel cell system that repeatedly increases and decreases the voltage in the catalyst recovery process. The fuel cell system according to claim 1 or 2, wherein
When the output request from the external load connected to the fuel cell system fluctuates a predetermined number of times during operation of the fuel cell, or when the output request is larger than a predetermined request amount In addition, the fuel cell system executes the catalyst recovery process after outputting the fuel cell in response to the output request. A fuel cell system according to any one of claims 1 to 3,
The internal electrode is
It is a member having a plurality of pores capable of proton conduction in the thickness direction,
A fuel cell system, which is inserted so as to overlap the catalyst electrode layer when the electrolyte membrane is viewed along the thickness direction. A fuel cell system according to any one of claims 1 to 4, wherein
The catalyst electrode layer includes an anode and a cathode,
The fuel cell system, wherein the internal electrode is inserted closer to the cathode than the anode. A method for controlling a fuel cell comprising an electrolyte membrane sandwiched between catalyst electrode layers,
A control method in which a voltage is applied by an external power source so that an internal electrode inserted into the electrolyte membrane has a voltage higher than that of the catalyst electrode layer while power generation of the fuel cell is stopped.

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