Water electrolysis apparatus, and operation control method of water electrolysis apparatus

Abstract

To provide a water electrolysis apparatus and an operation control method of the water electrolysis apparatus that can reduce energy consumption when operation is stopped, and can suppress deterioration of a polymer electrolyte due to hydrogen peroxide generated in a hydrogen flow path on a cathode side when the operation is stopped.SOLUTION: Provided is an operation control method of a water electrolysis apparatus separated into an oxygen flow path 5 on an anode side and a hydrogen flow path 6 on a cathode side by a polymer electrolyte, electrolyzing pure water supplied to the oxygen flow path 5, and having one or more water electrolytic cells for discharging hydrogen from the hydrogen flow path 6. When the water electrolysis apparatus is in operation, the pure water is supplied to the oxygen flow path 5, and when the operation of the water electrolysis apparatus is stopped, the supply of the pure water to the oxygen flow path 5 is stopped. In addition, after the pure water supplied to the hydrogen flow path 6 for a prescribed time is discharged outside, the supply of the pure water to the hydrogen flow path 6 is stopped.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water electrolysis device and a method for controlling the operation of a water electrolysis device that can suppress energy consumption during operation stop and suppress deterioration of an electrolyte membrane caused by hydrogen peroxide generated in a hydrogen flow path on the cathode side during operation stop.

Background Art

[0002] A water electrolysis device is known in which an electrolyte membrane such as a solid polymer is used as a diaphragm to separate an anode side and a cathode side, and pure water is supplied to the anode side while electrolyzing to generate oxygen from the anode side and hydrogen from the cathode side (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A water electrolysis device has a plurality of water decomposition cells stacked thereon. During operation, pure water is supplied to an oxygen flow path on the anode side of the water decomposition cell, and the pure water is decomposed by the reaction of 2H20→02+4H + +4e - to generate oxygen in the oxygen flow path. On the other hand, H + generates hydrogen by the reaction of 4H + +4e - →2H2 in the hydrogen flow path on the cathode side through the electrolyte membrane.

[0005] Here, when the operation stops and the supply of pure water to the oxygen flow path stops, a part of the oxygen generated in the oxygen flow path moves into the hydrogen flow path through the electrolyte membrane, combines with the hydrogen staying in the hydrogen flow path, and hydrogen peroxide is generated. This hydrogen peroxide is, for example, H2O2+Fe2 + →HO*+OH -+Fe3 + The reaction of + generates HO* (hydroxyl radical). Hydroxyl radical is an electrically unstable and highly reactive radical molecule, and attacks such as breaking the polymer chain bonds of the electrolyte membrane occur, resulting in a phenomenon where the electrolyte membrane is damaged and deteriorated.

[0006] In particular, when using a solar cell device or a wind power generation device affected by the weather as a power source, or in an environment where the storage amount of a hydrogen storage tank for compressing and storing the generated hydrogen is likely to be in a state close to full, frequent operation stops occur. In this case, the chance of hydrogen peroxide generation increases, and as a result, damage and deterioration of the electrolyte membrane progress.

[0007] In Patent Document 1, in order to prevent metal ion elution from the piping on the cathode side during operation stop, pure water is continuously flowed through both the anode side and the cathode side, so the energy consumption in the operation stop state is large.

[0008] The present invention has been made to solve the above problems, and at the time of operation stop, it is possible to suppress energy consumption and suppress deterioration of the electrolyte membrane caused by hydrogen peroxide generated in the hydrogen flow path on the cathode side at the time of operation stop, and to provide a water electrolysis device and a method for controlling the operation of the water electrolysis device.

Means for Solving the Problems

[0009] In order to solve the above-described problems and achieve the object, a water electrolysis apparatus according to the present invention is separated by an electrolyte membrane into an oxygen flow path on the anode side and a hydrogen flow path on the cathode side, electrolyzes pure water supplied to the oxygen flow path, and has one or more water electrolysis cells that discharge hydrogen from the hydrogen flow path. The water electrolysis apparatus includes a water supply pump that sends out pure water, an oxygen-side supply pipe that supplies pure water from the water supply pump to the oxygen flow path via a first on-off valve, a hydrogen-side supply pipe that supplies pure water from the water supply pump to the hydrogen flow path via a second on-off valve, and during operation of the water electrolysis apparatus, the water supply pump is driven, the first on-off valve is opened, and the second on-off valve is closed to supply pure water to the oxygen flow path via the oxygen-side supply pipe. When the operation of the water electrolysis apparatus is stopped, the first on-off valve is closed, the second on-off valve is opened, the supply of pure water to the oxygen flow path via the oxygen-side supply pipe is stopped, and after supplying pure water to the hydrogen flow path via the hydrogen-side supply pipe for a predetermined time and discharging it to the outside, control is performed to stop the supply of pure water to the hydrogen flow path via the hydrogen-side supply pipe.

[0010] Further, in the water electrolysis apparatus according to the present invention, in the above invention, a third on-off valve is provided in a hydrogen-side discharge pipe connecting the outlet side of the hydrogen flow path, an external discharge pipe is connected between the outlet side of the hydrogen flow path and the third on-off valve, a fourth on-off valve is provided in the external discharge pipe, and the control unit closes the third on-off valve and opens the fourth on-off valve to discharge pure water from the external discharge pipe to the outside when supplying pure water to the hydrogen flow path at the time of stopping the operation.

[0011] Further, in the water electrolysis apparatus according to the present invention, in the above invention, an oxygen-side discharge pipe connected to the outlet side of the oxygen flow path is connected to an oxygen-side gas-liquid separator, oxygen is discharged through the oxygen-side gas-liquid separator, a hydrogen-side discharge pipe connected to the outlet side of the hydrogen flow path is connected to a hydrogen-side gas-liquid separator, hydrogen is discharged through the hydrogen-side gas-liquid separator, and pure water supplied to the water electrolysis cell through the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator circulates.

[0012] In addition, the water electrolysis device according to the present invention is characterized in that, in the above invention, a plurality of the water electrolysis cells are connected in series, with a plurality of stacked water decomposition units.

[0013] Further, the water electrolysis device according to the present invention is characterized in that, in the above invention, the power source of the water decomposition cell is a solar power generation device or a wind power generation device, the hydrogen discharged from the water decomposition cell is stored in a hydrogen storage tank, and the control unit stops the operation of the water electrolysis device when there is a power shortage in the power source generated by the solar power generation device or the wind power generation device or when the remaining amount in the hydrogen storage tank is equal to or more than a predetermined amount.

[0014] Moreover, a method for controlling the operation of a water electrolysis device according to the present invention is a method for controlling the operation of a water electrolysis device having one or more water electrolysis cells separated by an electrolyte membrane into an oxygen flow path on the anode side and a hydrogen flow path on the cathode side, electrolyzing pure water supplied to the oxygen flow path, and discharging hydrogen from the hydrogen flow path, During the operation of the water electrolysis device, pure water is supplied to the oxygen flow path. When the operation of the water electrolysis device is stopped, the supply of pure water to the oxygen flow path is stopped, and pure water is supplied to the hydrogen flow path for a predetermined time and discharged to the outside, and then the supply of pure water to the hydrogen flow path is stopped.

Advantages of the Invention

[0015] According to the present invention, at the time of operation stop, energy consumption can be suppressed, and deterioration of the electrolyte membrane due to hydrogen peroxide generated in the hydrogen flow path on the cathode side at the time of operation stop can be suppressed.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, with reference to the accompanying drawings, a water electrolysis device and an operation control method of the water electrolysis device according to the present embodiment will be described.

[0018] <SUMMARY> FIG. 1 is a diagram showing the concept of a water electrolysis device 10 and an operation control method of the water electrolysis device 10 according to the present embodiment. As shown in FIG. 1, in the water electrolysis cell 1, an electrolyte layer 4 is interposed between the oxygen electrode 2 on the anode side and the hydrogen electrode 3 on the cathode side, and the electrolyte layer 4 separates the oxygen electrode 2 and the hydrogen electrode 3. On the anode side, pure water for water electrolysis is supplied, and an oxygen flow path 5 for discharging pure water containing electrolyzed oxygen is formed. On the cathode side, hydrogen ions generated in the oxygen flow path 5 and permeating through the electrolyte layer 4 become hydrogen, and a hydrogen flow path 6 for discharging pure water containing this hydrogen is formed.

[0019] FIG. 1(a) shows a state in which the water electrolysis device 10 is in operation, in which pure water is supplied to the oxygen flow path 5, pure water containing oxygen is discharged from the oxygen flow path 5, and pure water containing hydrogen is discharged from the hydrogen flow path 6. Here, when the water electrolysis device 10 stops operating, as shown in FIG. 1(b), most of the oxygen is present in the oxygen flow path 5 and most of the hydrogen is present in the hydrogen flow path 6, and it becomes an open circuit voltage (OCV) state in the fuel cell and the hydrogen electrode becomes 0V. In this state, when oxygen penetrates the electrolyte layer 4 and moves to the hydrogen flow path 6, hydrogen and oxygen staying in the hydrogen flow path 6 combine to generate hydrogen peroxide. As described above, this hydrogen peroxide generates HO* (hydroxyl radical), attacks the electrolyte layer 4, and holes are formed in the electrolyte membrane, deteriorating its function as a permeation membrane.

[0020] Therefore, in this embodiment, as shown in Fig. 1(c), when the operation of the water electrolysis device 10 is stopped, the supply of pure water to the oxygen flow path 5 is stopped, and after supplying pure water to the hydrogen flow path 6 for a predetermined time and discharging it to the outside, the supply of pure water to the hydrogen flow path 6 is stopped. As a result, the hydrogen peroxide generated in the hydrogen flow path 6 is discharged outside the water electrolysis cell 1 by the pure water supplied into the hydrogen flow path 6, and deterioration of the electrolyte layer 4 as shown in Fig. 1(b) can be suppressed. Note that the pure water containing the discharged hydrogen peroxide may be discarded outside without being circulated. In addition, the supply of pure water to the hydrogen flow path 6 for a predetermined time is the time when the hydrogen peroxide in the hydrogen flow path 6 disappears. For example, it is at least several times the amount of water in the hydrogen flow path 6 and is preferably the time until the pure water containing the hydrogen peroxide in the hydrogen flow path 6 is discarded. Further, this predetermined time may be the time when the hydrogen peroxide disappears from the hydrogen flow path 6 obtained by experiments or the like.

[0021] Thereby, it is possible to prevent deterioration of the electrolyte layer 4 due to hydrogen peroxide during operation stop, and since there is no supply of pure water to the oxygen flow path 5 and the supply of pure water to the hydrogen flow path 6 is only for a predetermined time, energy consumption during operation stop can be suppressed.

[0022] <Configuration of Water Electrolysis Cell> FIG. 2 is a front view schematically showing the configuration and stacked arrangement relationship of the water electrolysis cell 1 constituting the water electrolysis apparatus 10. Further, FIG. 3 is a cross-sectional view taken along line A-A of the separator 7 shown in FIG. 2. As shown in FIG. 2, in the water electrolysis cell 1A(1), the catalyst layer 2b is provided on the anode side of the electrolyte layer 4, and the catalyst layer 3b is provided on the cathode side of the electrolyte layer 4. A diffusion layer 2a is provided on the anode side of the catalyst layer 2b. The diffusion layer 2a and the catalyst layer 2b function as the oxygen electrode 2. A separator 7 is provided on the other surface of the diffusion layer 2a, and an oxygen flow path 5 is formed on the diffusion layer 2a side of the separator 7. As shown in FIG. 3, this oxygen flow path 5 forms a serpentine flow path extending in the +Z direction while connecting in a zigzag manner the flow paths extending in the ±X direction from the inlet opening 5a to which pure water is supplied, and discharges oxygen from the outlet opening 5b at the opposite end. On the other hand, a diffusion layer 3a is provided on the cathode side of the catalyst layer 3b. The diffusion layer 3a and the catalyst layer 3b function as the hydrogen electrode 3. A separator 8 is provided on the other surface of the diffusion layer 3a, and a hydrogen flow path 6 is formed on the diffusion layer 3a side of the separator 8. This hydrogen flow path 6 forms a serpentine flow path connected in a zigzag manner in the +Z direction, similar to the oxygen flow path 5, and discharges hydrogen. The water electrolysis cell 1B(1) having the same configuration as this water electrolysis cell 1A is stacked in the left-right direction (A direction: ±Y direction) of the paper surface. FIG. 2 shows the stacked state of the two water electrolysis cells 1A and 1B, but usually, several tens of water electrolysis cells 1 are stacked to form a water electrolysis unit. When stacking the water electrolysis cells 1, the separator 8 has the function of the separator of the water electrolysis cell 1A(1) and the water electrolysis cell 1B(1), and is an integrated type formed on both opposing surfaces of the hydrogen flow path 6 and the oxygen flow path 5. These water electrolysis units are connected in series. When stacking the water electrolysis cells 1, the separators 7 and 8 may be alternately rotated 90 degrees around the Y axis so that external connection to the oxygen flow path 5 and the hydrogen flow path 6 can be easily performed.

[0023] The electrolyte layer 4 is a solid polymer electrolyte membrane, which has the function of a cation permeable membrane. For example, Nafion (registered trademark, manufactured by DuPont), which is a fluorine-based polymer membrane, Aciplex (trade name, manufactured by Asahi Kasei Corporation), which is a hydrocarbon-based polymer membrane, etc. can be used. The anode-side catalyst layer 2b of the electrolyte layer 4 contains, for example, an Ir / IrRuOX catalyst. Also, the cathode-side catalyst layer 3b is, for example, carbon containing a platinum catalyst. As the diffusion layer 2a and the diffusion layer 3a, a porous body such as a surface of a titanium fiber sintered body or a titanium powder sintered body with Au / Pt / Ir plating can be used.

[0024] <Configuration of the water electrolysis device> Figure 4 is a block diagram showing the configuration of the water electrolysis device 10. The solid line indicates the water circuit system, and the broken line indicates the control system. As shown in Figure 4, water such as industrial water is supplied to the pure water generator 11 from the pipe L1 by the feed water pump 19. The pure water generator 11 generates pure water using an activated carbon filter, a reverse osmosis membrane, an ion exchange membrane, etc. The generated pure water is supplied to the pure water tank 12 via the pipe L2, and the pure water tank 12 stores the pure water.

[0025] The pure water in the pure water tank 12 is supplied by the feed water pump 13 to the pipe L3 or the pipe L12 side. During operation, the on-off valve V1 of the pipe L3 is open, and the on-off valve V2 of the pipe L12 is closed, and the pure water is supplied to the pipe L3 side. The pipe L3 branches and is connected to the pipes L4 and L5. The pure water in the pipe L4 is led to the oxygen-side gas-liquid separator 14, and the pure water in the pipe L5 is led to the hydrogen-side gas-liquid separator 16.

[0026] The pure water in the oxygen-side gas-liquid separator 14 is supplied to the oxygen flow path 5 via the pipes L6 and L7. A heat exchanger HE1 is interposed between the pipes L6 and L7, and the temperature rise of the pure water is suppressed using the cooling water of the cooling tower. The pipes L3, L4, L6, and L7 correspond to the oxygen-side supply pipes.

[0027] The pure water containing oxygen discharged from the oxygen flow path 5 is led to the oxygen-side gas-liquid separator 14 via the pipe L8. Oxygen is discharged via the pipe L21, and the pure water is supplied to the oxygen-side supply pipe. Note that the pipe L8 corresponds to the oxygen-side discharge pipe. A branched pipe L10 is connected to the pipe L6 to lead the pure water to the ion exchanger 15. The ion exchanger 15 supplies the pure water with impurities removed to the pure water tank 12 via the pipes L11 and L2. Therefore, the pure water supplied to the oxygen flow path 5 will circulate while removing impurities. Note that the heat exchanger HE2 in the pipe L10 suppresses the temperature rise of the pure water supplied to the ion exchanger 15. The heat exchanger HE2 uses the cooling water of the cooling tower.

[0028] On the other hand, a pipe (hydrogen-side discharge pipe) connecting between the outlet side of the hydrogen flow path 6 and the hydrogen-side gas-liquid separator 16 is provided for the pure water containing hydrogen discharged from the hydrogen flow path 6, and an on-off valve V3 is provided in this pipe. A pipe L13 as an external discharge pipe branched from between the on-off valve V3 and the outlet side of the hydrogen flow path 6 is provided. An on-off valve V4 is provided in this pipe L13. During operation, the on-off valve V3 is open and the on-off valve V4 is closed. During a stop of operation, the on-off valve V3 is closed and the on-off valve V4 is open.

[0029] During operation, the pure water containing hydrogen discharged from the hydrogen flow path 6 is sent to the hydrogen-side gas-liquid separator 16, and hydrogen is led to the hydrogen storage tank 20 side via the pipe L22. The pure water of the hydrogen-side gas-liquid separator 16 is returned to the pure water tank 12 via the pipe L9. That is, the pure water from the hydrogen flow path 6 will also circulate.

[0030] On the one hand, when the operation stops, the on-off valve V1 is closed, the on-off valve V2 is open, the on-off valve V3 is closed, and the on-off valve V4 is open. The pure water in the pure water tank 12 is supplied from the inlet side of the hydrogen flow path 6 for a predetermined time by the water supply pump 13 through the pipe L12. As a result, the pure water containing hydrogen peroxide in the hydrogen flow path 6 is discharged from the outlet side of the hydrogen flow path 6 and discarded through the pipe L13. The water supply pump 13 stops driving after a predetermined time. Note that the power supply 9 of the water electrolysis cell 1 uses the power supply of the solar power generation device 30. Note that the power supply 9 may be a wind power generation device.

[0031] The control unit C controls the entire water electrolysis device 10. The control unit C determines to stop the operation of the water electrolysis device 10 when there is a power shortage of the power supply 9 generated by the solar power generation device 30 or when the remaining amount of the hydrogen storage tank 20 is close to full and exceeds a predetermined amount. Note that the operation stop may be an operation stop from the outside. Note that the control unit C acquires the remaining amount of the hydrogen storage tank 20 based on the detection value of the remaining amount sensor SB.

[0032] The control unit C performs opening and closing control of the on-off valves V1 to V4 corresponding to during operation and during operation stop, and also performs drive stop control of the water supply pump 13. Note that the drive stop control of the water supply pump 19 drives to generate pure water when the water level becomes equal to or lower than a predetermined water level based on the detection result of the water level sensor SA in the pure water tank 12. Note that the control unit C may perform drive control of the water supply pump 13 based on the water levels of the oxygen-side gas-liquid separator 14 and the hydrogen-side gas-liquid separator 16.

[0033] Note that instead of the on-off valves V1 and V2, a switching valve or a three-way valve may be used. Similarly, instead of the on-off valves V3 and V4, a switching valve or a three-way valve may be used.

[0034] <Operation Control> FIG. 5 is a flowchart showing the operation control procedure of the water electrolysis apparatus 10 by the control unit C. As shown in FIG. 5, first, the control unit C determines whether there is an operation start instruction (step S101). If there is no operation start instruction (step S101: No), this determination process is repeated. On the other hand, if there is an operation start instruction (step S101: Yes), the on-off valve V1 is opened, the on-off valve V2 is closed, the on-off valve V3 is opened, and the on-off valve V4 is closed (step S102), and pure water is supplied to the oxygen flow path 5. Then, the water supply pump 13 is driven (step S103) to start the operation.

[0035] Thereafter, it is determined whether there is an operation stop instruction including an operation stop determination (step S104). If there is no operation stop instruction (step S104: No), the process proceeds to step S103 to continue the operation. On the other hand, if there is an operation stop instruction (step S104: Yes), the on-off valve V1 is closed, the on-off valve V2 is opened, the on-off valve V3 is closed, and the on-off valve V4 is opened (step S105), pure water is supplied to the hydrogen flow path 6 and pure water containing hydrogen peroxide is discarded. Then, after driving the water supply pump 13 continuously for a predetermined time, the driving is stopped (step S106), and this process is terminated. Note that the above process is repeated at regular intervals.

[0036] In addition, each configuration illustrated in the above embodiments and modified examples is functionally schematic, and it is not necessarily physically configured as illustrated. That is, the form of distribution and integration of each device is not limited to that illustrated, and all or part of it can be functionally or physically distributed and integrated in any unit according to various loads and usage situations.

Industrial Applicability

[0037] The water electrolysis apparatus and the operation control method of the water electrolysis apparatus of the present invention are useful for suppressing energy consumption and suppressing deterioration of the electrolyte membrane due to hydrogen peroxide generated in the hydrogen flow path on the cathode side during operation stop when the operation stops.

Explanation of Reference Numerals

[0038] 1, 1A, 1B Water electrolysis cell 2 Oxygen electrode 2a, 3a Diffusion layer 2b, 3b Catalyst layer 3 Hydrogen electrode 4 Electrolyte layer 5 Oxygen flow path 5a Inlet opening 5b Outlet opening 6 Hydrogen flow path 7, 8 Separator 9 Power source 10 Water electrolysis device 11 Pure water generator 12 Pure water tank 13, 19 Water supply pump 14 Oxygen side gas-liquid separator 15 Ion exchanger 16 Hydrogen side gas-liquid separator 20 Hydrogen storage tank 30 Solar power generation device C Control unit HE1, HE2 Heat exchanger L1~L13, L21, L22 Pipe SA Water level sensor SB Remaining amount sensor V1~V4 On-off valve

Claims

1. A water electrolysis device having one or more water electrolysis cells separated by an electrolyte membrane into an oxygen flow path on the anode side and a hydrogen flow path on the cathode side, electrolyzing pure water supplied to the oxygen flow path, and discharging hydrogen from the hydrogen flow path, a water supply pump for delivering pure water, an oxygen-side supply pipe for supplying pure water from the water supply pump to the oxygen flow path via a first on-off valve, a hydrogen-side supply pipe for supplying pure water from the water supply pump to the hydrogen flow path via a second on-off valve, during operation of the water electrolysis device, the water supply pump is driven, the first on-off valve is opened, the second on-off valve is closed, and pure water is supplied to the oxygen flow path via the oxygen-side supply pipe; when the operation of the water electrolysis device is stopped, the first on-off valve is closed, the second on-off valve is opened, the supply of pure water to the oxygen flow path via the oxygen-side supply pipe is stopped, and pure water is supplied to the hydrogen flow path via the hydrogen-side supply pipe for a predetermined time and discharged to the outside, and then the supply of pure water to the hydrogen flow path via the hydrogen-side supply pipe is stopped. A control unit for performing control; A water electrolysis device characterized by comprising the above.

2. A third on-off valve is provided in a hydrogen-side discharge pipe connected to the outlet side of the hydrogen flow path, an external discharge pipe is connected between the outlet side of the hydrogen flow path and the third on-off valve, and a fourth on-off valve is provided in the external discharge pipe, The control unit is characterized in that when supplying pure water to the hydrogen flow path at the time of operation stop, the third on-off valve is changed from open to closed and the fourth on-off valve is changed from closed to open to discharge the pure water from the external discharge pipe to the outside. The water electrolysis device according to claim 1.

3. An oxygen-side discharge pipe connected to the outlet side of the oxygen flow path is connected to an oxygen-side gas-liquid separator, and oxygen is discharged through the oxygen-side gas-liquid separator, A hydrogen-side discharge pipe connected to the outlet side of the hydrogen flow path is connected to a hydrogen-side gas-liquid separator, and hydrogen is discharged through the hydrogen-side gas-liquid separator, The pure water supplied to the water electrolysis cell through the oxygen-side gas-liquid separator and the hydrogen-side gas-liquid separator circulates. The water electrolysis device according to claim 1.

4. The water electrolysis device according to claim 1, characterized in that a plurality of the water electrolysis cells are connected in series with a plurality of stacked water decomposition units.

5. The power source of the water electrolysis cell is a solar power generation device or a wind power generation device, The hydrogen discharged from the water electrolysis cell is stored in a hydrogen storage tank, The control unit stops the operation of the water electrolysis device when there is a power shortage in the power source generated by the photovoltaic power generation device or the wind power generation device, or when the remaining amount of the hydrogen storage tank is equal to or more than a predetermined amount. The water electrolysis device according to any one of claims 1 to 3.

6. A method for controlling the operation of a water electrolysis device having one or more water electrolysis cells separated by an electrolyte membrane into an oxygen flow path on the anode side and a hydrogen flow path on the cathode side, electrolyzing pure water supplied to the oxygen flow path, and discharging hydrogen from the hydrogen flow path, During the operation of the water electrolysis device, pure water is supplied to the oxygen flow path. When the operation of the water electrolysis device is stopped, the supply of pure water to the oxygen flow path is stopped, and after supplying and discharging the pure water to the hydrogen flow path for a predetermined time, the supply of pure water to the hydrogen flow path is stopped. A method for controlling the operation of a water electrolysis device, characterized in that.

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