Water electrolysis device and operation controlling method for water electrolysis device

Abstract

In order to provide a water electrolysis device and an operation controlling method for the water electrolysis device which, when the operation is stopped, are capable of reducing energy consumption and suppressing deterioration of an electrolyte membrane due to hydrogen peroxide generated in a cathode-side hydrogen flow passage when the operation is stopped, this operation controlling method for a water electrolysis device having at least one water electrolysis cell which is divided into an anode-side oxygen flow passage 5 and a cathode-side hydrogen flow passage 6 by an electrolyte membrane, electrolyzes pure water supplied to the oxygen flow passage 5, and discharges hydrogen from the hydrogen flow passage 6 comprises: supplying pure water to the oxygen flow passage 5 during the operation of the water electrolysis device; when the operation of the water electrolysis device is stopped, stopping the supply of pure water to the oxygen flow passage 5, and supplying pure water to the hydrogen flow passage 6 for a prescribed period of time and discharging the same to the outside; and then stopping the supply of pure water to the hydrogen flow passage 6.

Description

Water electrolysis device and method for controlling operation of water electrolysis device

[0001] The present disclosure relates to a water electrolysis device and an operation control method for a water electrolysis device that can reduce energy consumption and suppress deterioration of an electrolyte membrane due to hydrogen peroxide generated in a hydrogen flow path on the cathode side when operation is stopped.

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

[0003] Japanese Patent Application Laid-Open No. 2003-293179

[0004] The water electrolysis device has multiple water splitting cells stacked on top of each other. During operation, pure water is supplied to the oxygen flow path on the anode side of the water splitting cells. ２ 0 → 0 ２ +4H ＋ +4e － The reaction causes oxygen to be generated in the oxygen flow path. ＋ is in the hydrogen flow path on the cathode side through the electrolyte membrane, ＋ +4e － →2H ２ The reaction generates hydrogen.

[0005] When the operation of the water electrolysis device is stopped and the supply of pure water to the oxygen flow path is stopped, part of the oxygen generated in the oxygen flow path moves into the hydrogen flow path through the electrolyte membrane and combines with the hydrogen remaining in the hydrogen flow path to generate hydrogen peroxide. ２ O ２ +Fe ２ ＋ →HO*+OH － +Fe ３ ＋ This reaction generates HO* (hydroxyl radicals). Hydroxyl radicals are electrically unstable and highly reactive radical molecules that attack the electrolyte membrane, breaking down its polymer chain bonds and causing damage and deterioration of the membrane.

[0006] In particular, when using a solar cell device or wind power generation device, which are affected by weather, as a power source, or in an environment where the hydrogen storage tank that compresses and stores hydrogen produced by the water electrolysis device is likely to be nearly full, the operation of the water electrolysis device will frequently be stopped, which increases the opportunities for hydrogen peroxide to be generated, thereby accelerating damage and deterioration of the electrolyte membrane.

[0007] In Patent Document 1, pure water continues to flow on both the anode and cathode sides to prevent metal ions from eluting from the piping on the cathode side when the operation is stopped, resulting in a large amount of energy consumption when the operation is stopped.

[0008] The present invention has been made to solve the above-mentioned problems, and has an object to provide a water electrolysis device and an operation control method for the water electrolysis device that can reduce energy consumption during shutdown and suppress deterioration of an electrolyte membrane due to hydrogen peroxide generated in a hydrogen flow path on the cathode side during shutdown.

[0009] In order to solve the above-mentioned problems and achieve the object, the water electrolysis device of the present invention is a water electrolysis device having one or more water electrolysis cells separated by an electrolyte membrane into an oxygen flow path on an anode side and a hydrogen flow path on a cathode side, electrolyzing pure water supplied to the oxygen flow path and discharging hydrogen from the hydrogen flow path, the water electrolysis device comprising: a water feed pump for delivering pure water; an oxygen-side supply pipe for supplying pure water from the water feed pump to the oxygen flow path via a first on-off valve; and a hydrogen-side supply pipe for supplying pure water from the water feed pump to the hydrogen flow path via a second on-off valve. and a control unit that performs control such that, when operation of the water electrolysis apparatus is stopped, the supply of pure water to the oxygen flow path via the oxygen-side supply piping is stopped by closing the first on-off valve and opening the second on-off valve, and the supply of pure water to the hydrogen flow path via the hydrogen-side supply piping for a predetermined time and discharging the pure water to the outside, and then stops the supply of pure water to the hydrogen flow path via the hydrogen-side supply piping.

[0010] Furthermore, 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 an outlet side of the hydrogen flow path, and 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, and the control unit changes the third on-off valve from open to closed and the fourth on-off valve from closed to open when the pure water is supplied to the hydrogen flow path during the operation shutdown, thereby discharging the pure water to the outside from the external discharge pipe.

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

[0012] In addition, in the water electrolysis device according to the present invention, in the above invention, the plurality of water electrolysis cells are stacked to form a plurality of water splitting units connected in series.

[0013] Furthermore, in the water electrolysis device according to the present invention, in the above invention, the power source for the water splitting cell is a solar power generation device or a wind power generation device, hydrogen discharged from the water splitting cell is stored in a hydrogen storage tank, and the control unit stops 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 of hydrogen in the hydrogen storage tank is equal to or greater than a predetermined amount.

[0014] Furthermore, the present invention provides a method for controlling the operation of a water electrolysis apparatus having one or more water electrolysis cells separated by an electrolyte membrane into an oxygen flow path on an anode side and a hydrogen flow path on a cathode side, electrolyzing pure water supplied to the oxygen flow path and discharging hydrogen from the hydrogen flow path, the method comprising the steps of: supplying pure water to the oxygen flow path during operation of the water electrolysis apparatus; and, when operation of the water electrolysis apparatus is stopped, stopping the supply of pure water to the oxygen flow path; and supplying pure water to the hydrogen flow path for a predetermined time and discharging it to the outside, and then stopping the supply of pure water to the hydrogen flow path.

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

[0016] Fig. 1 is a conceptual diagram illustrating a water electrolysis apparatus and a method for controlling operation of the water electrolysis apparatus according to the present embodiment. Fig. 2 is a front view schematically illustrating the configuration and stacking arrangement of water splitting cells that constitute the water electrolysis apparatus. Fig. 3 is a cross-sectional view of the separator shown in Fig. 2 taken along line A-A. Fig. 4 is a block diagram illustrating the configuration of the water electrolysis apparatus. Fig. 5 is a flowchart illustrating the procedure for controlling operation of the water electrolysis apparatus 10 by the control unit C.

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

[0018] <Overview> Figure 1 is a conceptual diagram illustrating a water electrolysis system 10 and an operation control method for the water electrolysis system 10 according to this embodiment. As shown in Figure 1, in a water splitting cell 1, an electrolyte layer 4 is interposed between an oxygen electrode 2 on the anode side and a hydrogen electrode 3 on the cathode side, and this electrolyte layer 4 separates the oxygen electrode 2 from the hydrogen electrode 3. Pure water for water splitting is supplied to the anode side, and an oxygen flow path 5 is formed to discharge the pure water containing oxygen resulting from the water splitting. Hydrogen ions generated in the oxygen flow path 5 and permeating the electrolyte layer 4 become hydrogen on the cathode side. A hydrogen flow path 6 is formed to discharge the pure water containing this hydrogen.

[0019] FIG. 1( a ) shows the water electrolysis system 10 in operation. During operation of the water electrolysis system 10, pure water is supplied to the oxygen flow path 5, oxygen-containing pure water is discharged from the oxygen flow path 5, and hydrogen-containing pure water is discharged from the hydrogen flow path 6. When the water electrolysis system 10 stops operating, as shown in FIG. 1( b ), oxygen is mostly present in the oxygen flow path 5 and hydrogen is mostly present in the hydrogen flow path 6, resulting in an open circuit voltage (0 CV) state in the fuel cell and a hydrogen electrode 3 at 0 V. In this state, when oxygen permeates the electrolyte layer 4 and moves to the hydrogen flow path 6, the hydrogen and oxygen retained in the hydrogen flow path 6 combine to produce hydrogen peroxide. As described above, this hydrogen peroxide generates HO* (hydroxyl radicals), which attack the electrolyte layer 4 and create holes in the electrolyte membrane, degrading its function as a permeable membrane.

[0020] For this reason, in this embodiment, as shown in FIG. 1( c), when the operation of the water electrolysis apparatus 10 is stopped, the supply of pure water to the oxygen flow path 5 is stopped, and pure water is supplied to the hydrogen flow path 6 for a predetermined time and then discharged to the outside, and then the supply of pure water to the hydrogen flow path 6 is stopped. As a result, hydrogen peroxide generated in the hydrogen flow path 6 is discharged to the outside of the water splitting cell 1 by the pure water supplied to the hydrogen flow path 6, thereby suppressing deterioration of the electrolyte layer 4 as shown in FIG. 1( b). It is preferable that this discharged pure water containing hydrogen peroxide is discarded to the outside without being circulated. The predetermined time for supplying pure water to the hydrogen flow path 6 is the time for hydrogen peroxide to disappear from the hydrogen flow path 6. It is preferable that the predetermined time be at least several times the amount of water in the hydrogen flow path 6 and the time until the pure water containing hydrogen peroxide in the hydrogen flow path 6 is discarded. This predetermined time may be the time for hydrogen peroxide to disappear from the hydrogen flow path 6, determined through experiments or the like.

[0021] This prevents deterioration of the electrolyte layer 4 due to hydrogen peroxide when operation is stopped, and since no pure water is supplied to the oxygen flow path 5 and pure water is supplied to the hydrogen flow path 6 only for a specified period of time, energy consumption when operation is stopped can be reduced.

[0022] <Configuration of Water Electrolysis Cell> FIG. 2 is a front view schematically illustrating the configuration and stacking arrangement of a water splitting cell 1 constituting a water electrolysis apparatus 10. FIG. 3 is a cross-sectional view of the separator 7 shown in FIG. 2 along line A-A. As shown in FIG. 2, in the water splitting cell 1A(1), a catalyst layer 2b is provided on the anode side of the electrolyte layer 4, and a 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 side 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, the oxygen flow path 5 forms a serpentine flow path extending in the +Z direction while connecting flow paths extending in the ±X directions from an inlet opening 5a, through which pure water is supplied, in a zigzag pattern. Oxygen is discharged from an outlet opening 5b at the opposite end. Meanwhile, a diffusion layer 3a is provided on the cathode side of the catalyst layer 3b. The diffusion layer 3a and catalyst layer 3b function as the hydrogen electrode 3. A separator 8 is provided on the other side of the diffusion layer 3a, and a hydrogen flow path 6 is formed on the diffusion layer 3a side of the separator 8. Like the oxygen flow path 5, the hydrogen flow path 6 forms a serpentine flow path connected in a zigzag pattern in the +Z direction and discharges hydrogen. Water-splitting cells 1B(1) having the same configuration as the water-splitting cell 1A are stacked in the left-right direction (A direction: ±Y direction) of the paper. While FIG. 2 shows two water-splitting cells 1A and 1B stacked together, several tens of water-splitting cells 1 are typically stacked to form a water-splitting unit. When stacking water-splitting cells 1, the separator 8 functions as a separator for the water-splitting cells 1A(1) and 1B(1), and is an integrated type with the hydrogen flow path 6 and the oxygen flow path 5 formed on opposing sides. These water-splitting units are connected in series. When the water splitting cells 1 are stacked, the separators 7 and 8 may be alternately rotated by 90 degrees around the Y axis to facilitate external connection to the oxygen flow channel 5 and the hydrogen flow channel 6 .

[0023] The electrolyte layer 4 is a solid polymer electrolyte membrane that functions as a cation-permeable membrane. Examples of materials that can be used for the electrolyte layer 4 include Nafion (registered trademark, manufactured by DuPont), a fluorine-based polymer membrane, and Aciplex (trade name, manufactured by Asahi Kasei Corporation), a hydrocarbon-based polymer membrane. The anode-side catalyst layer 2b contains, for example, an Ir / IrRuOX catalyst. The cathode-side catalyst layer 3b is, for example, carbon containing a platinum catalyst. The diffusion layers 2a and 3a can be porous materials such as titanium fiber sintered compacts or titanium powder sintered compacts plated with Au / Pt / Ir.

[0024] <Configuration of Water Electrolysis Apparatus> Figure 4 is a block diagram showing the configuration of the water electrolysis apparatus 10. Solid lines indicate a water circuit system, and dashed lines indicate a control system. As shown in Figure 4, water such as industrial water is supplied from a pipe L1 to a pure water generator 11 by a water supply pump 19. The pure water generator 11 generates pure water using an activated carbon filter, a reverse osmosis membrane, an ion exchange membrane, or the like. The generated pure water is supplied to a pure water tank 12 via a pipe L2, and the pure water tank 12 stores the pure water.

[0025] The pure water in the pure water tank 12 is supplied to the pipe L3 or the pipe L12 by the water supply pump 13. 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, so that the pure water is supplied to the pipe L3. The pipe L3 branches into pipes L4 and L5, and the pure water in the pipe L4 is delivered to the oxygen-side gas-liquid separator 14, and the pure water in the pipe L5 is delivered 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 pipes L6 and L7. A heat exchanger HE1 is interposed between pipes L6 and L7, and cooling water from a cooling tower is used to suppress a rise in the temperature of the pure water. Pipes L3, L4, L6, and L7 correspond to oxygen-side supply pipes.

[0027] The oxygen-containing pure water discharged from the oxygen flow path 5 is delivered to the oxygen-side gas-liquid separator 14 via pipe L8, and while the oxygen is discharged via pipe L21, the pure water is supplied to the oxygen-side supply pipe. Pipe L8 corresponds to the oxygen-side discharge pipe. Pipe L10, which branches off from pipe L6, is connected to deliver the pure water to the ion exchanger 15. The ion exchanger 15 removes impurities from the pure water and supplies it to the pure water tank 12 via pipes L11 and L2. Therefore, the pure water supplied to the oxygen flow path 5 is circulated while the impurities are removed. Heat exchanger HE2 in pipe L10 suppresses a rise in the temperature of the pure water supplied to the ion exchanger 15. Cooling water from the cooling tower is used for heat exchanger HE2.

[0028] On the other hand, for the hydrogen-containing pure water discharged from the hydrogen flow path 6, a pipe (hydrogen-side discharge pipe) is provided that connects the outlet side of the hydrogen flow path 6 to the hydrogen-side gas-liquid separator 16, and this pipe is equipped with an on-off valve V3. A pipe L13 is provided as an external discharge pipe that branches off from between this on-off valve V3 and the outlet side of the hydrogen flow path 6. This pipe L13 is equipped with an on-off valve V4. During operation, on-off valve V3 is open and on-off valve V4 is closed. During operation shutdown, on-off valve V3 is closed and on-off valve V4 is open.

[0029] During operation, the hydrogen-containing pure water discharged from the hydrogen flow path 6 is sent to the hydrogen-side gas-liquid separator 16, and the hydrogen is discharged to the hydrogen storage tank 20 side via pipe L22. The pure water in the hydrogen-side gas-liquid separator 16 is returned to the pure water tank 12 via pipe L9. In other words, the pure water from the hydrogen flow path 6 is also circulated.

[0030] On the other hand, when operation is stopped, on-off valve V1 is closed, on-off valve V2 is open, on-off valve V3 is closed, and on-off valve V4 is open, and pure water from the pure water tank 12 is supplied by the water supply pump 13 from the inlet side of the hydrogen flow path 6 via pipe L12 for a predetermined time. 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 via pipe L13. The water supply pump 13 stops operating after the predetermined time. The power source 9 for the water splitting cell 1 is the power source of the solar power generation device 30. The power source 9 may also be a wind power generation device.

[0031] The control unit C controls the entire water electrolysis system 10. The control unit C determines to stop operation of the water electrolysis system 10 when there is a power shortage in the power source 9 generated by the solar power generation system 30 or when the remaining amount of hydrogen in the hydrogen storage tank 20 is equal to or greater than a predetermined amount that is close to full. The operation may be stopped by an external command. The control unit C obtains the remaining amount of hydrogen in the hydrogen storage tank 20 based on the detection value of the remaining amount sensor SB.

[0032] The control unit C controls the opening and closing of the on-off valves V1 to V4 corresponding to when the system is operating and when the system is stopped, and also controls the driving and stopping of the feedwater pump 13. The control unit C controls the driving and stopping of the feedwater pump 19 so that the feedwater pump 19 is driven to produce pure water when the water level falls below a predetermined level based on the detection result of the water level sensor SA in the pure water tank 12. The control unit C may also control the driving of the feedwater pump 13 based on the water levels in the oxygen-side gas-liquid separator 14 and the hydrogen-side gas-liquid separator 16.

[0033] The on-off valves V1 and V2 may be replaced by switching valves or three-way valves.Similarly, the on-off valves V3 and V4 may be replaced by switching valves or three-way valves.

[0034] <Operation Control> Figure 5 is a flowchart showing the operation control procedure of the water electrolysis apparatus 10 by the controller C. As shown in Figure 5, the controller C first determines whether or not an operation start command has been received (step S101). If an operation start command has not been received (step S101: No), this determination process is repeated. On the other hand, if an operation start command has been received (step S101: Yes), the controller C opens the on-off valve V1, closes the on-off valve V2, opens the on-off valve V3, and closes the on-off valve V4 (step S102), and supplies pure water to the oxygen flow path 5. Thereafter, the controller C drives the water supply pump 13 (step S103) to start operation.

[0035] Thereafter, the control unit C determines whether or not an operation stop command, including an operation stop determination, has been received (step S104). If an operation stop command has not been received (step S104: No), the process proceeds to step S103, where operation continues. On the other hand, if an operation stop command has been received (step S104: Yes), the control unit C closes the on-off valve V1, opens the on-off valve V2, closes the on-off valve V3, and opens the on-off valve V4 (step S105), thereby supplying pure water to the hydrogen flow path 6 and discarding the pure water containing hydrogen peroxide. Thereafter, the control unit C continues to drive the water supply pump 13 for a predetermined time, and then stops driving it (step S106), thereby terminating this process. The above process is repeated at regular intervals.

[0036] The configurations illustrated in the above embodiments and modifications are merely functional schematics and do not necessarily have to be physically configured as shown. In other words, the distribution and integration of each device is not limited to the illustrated configuration, and all or part of the devices can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc.

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

[0038] REFERENCE SIGNS LIST 1, 1A, 1B Water splitting 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 Photovoltaic power generation device C Control unit HE1, HE2 Heat exchanger L1 to L13, L21, L22 Piping SA Water level sensor SB Remaining amount sensor V1 to V4 Opening and closing valve

Claims

1. A water electrolysis apparatus 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, the water electrolysis apparatus comprising: a water supply pump for sending 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 apparatus, driving the water supply pump, opening the first on-off valve and closing the second on-off valve to supply pure water to the oxygen flow path via the oxygen-side supply pipe, and when the operation of the water electrolysis apparatus stops, closing the first on-off valve and opening the second on-off valve to stop the supply of pure water to the oxygen flow path via the oxygen-side supply pipe, and supplying pure water to the hydrogen flow path via the hydrogen-side supply pipe for a predetermined time and discharging it to the outside, and then stopping the supply of pure water to the hydrogen flow path via the hydrogen-side supply pipe, and a control unit for performing control.

2. 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 opens the third on-off valve from open to closed and opens the fourth on-off valve from closed to open to discharge pure water to the outside from the external discharge pipe when supplying pure water to the hydrogen flow path at the time of operation stop. The water electrolysis apparatus according to claim 1, characterized in that.

3. The 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. The 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 apparatus according to claim 1, characterized in that.

4. The water electrolysis apparatus 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 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. 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 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. A method for controlling the operation of a water electrolysis device, characterized by the above.

Images