Water electrolysis device

Abstract

To cool and purify water for water electrolysis to feed a sufficient amount of water to a water electrolytic cell while preventing a water purifier from being deteriorated.SOLUTION: A water electrolysis device 1 comprises: a water electrolysis cell for generating hydrogen and oxygen via a water electrolysis reaction; a water tank for storing water used for the water electrolysis cell; a heat-exchanger for cooling the water fed from the water tank, that is connected to the water tank; a water purifier for purifying the water cooled by the heat-exchanger, that is connected to the heat-exchanger; a first channel 92 through which the water fed from the water tank flows into the water electrolysis cell through the heat-exchanger and the water purifier; a second channel 93 through which the water fed from the water tank directly flows into the water electrolysis cell without going through the heat-exchanger and the water purifier; and a third channel through which the water flows from the water electrolysis cell to the water tank.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water electrolysis device. [Background technology]

[0002] In recent years, efforts to achieve the Sustainable Development Goals (SDGs) have been expanding. In response, energy control systems that utilize renewable energy sources such as solar, wind, and geothermal power have been attracting attention, replacing the conventional method of generating electricity using fossil fuels such as oil, coal, and liquefied natural gas.

[0003] In this type of power control system, the amount of power generated fluctuates greatly depending on factors such as weather, season, and location. Furthermore, the power consumption of the consumer (load) such as a home or a store also fluctuates. Therefore, a surplus or shortage of power occurs depending on the balance between power generation and power consumption. Therefore, efforts have recently been made to stabilize the power supply using fuel cells and water electrolysis devices. Patent Document 1 discloses an energy control system using fuel cells and water electrolysis devices.

[0004] A water electrolysis device generates hydrogen by performing a water electrolysis reaction using water and electricity. The water used in the water electrolysis reaction is reused via a circulation circuit (flow path). However, the purity of the water used in the water electrolysis reaction gradually decreases due to the peeling and elution of various materials, such as metals and resins, from the components constituting the flow path and the electrodes of the water electrolysis cell. Repeated use of such water accelerates the deterioration of the water electrolysis device (changes in the state of the electrolyte membrane and electrode catalysts constituting the water electrolysis cell). Deterioration of the water electrolysis device reduces the efficiency of the water electrolysis reaction. Furthermore, reaction losses become thermal energy, causing the water temperature to rise. Therefore, when water for water electrolysis is reused, it must be cooled and purified. Patent Document 2 discloses a water reclamation device for water electrolysis that includes a cooler and a purifier. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 103059 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-166278 Summary of the Invention [Problem to be solved by the invention]

[0006] On the other hand, if the water reclamation device for water electrolysis includes a cooler (heat exchanger) and a purifier (water purifier), the cooler and purifier act as resistance to the water flow, reducing the amount of circulating water supplied. In this case, oxygen bubbles generated by the water electrolysis reaction remain at the electrode interface and interfere with the water electrolysis reaction, reducing the effective area where the water electrolysis reaction can occur and thereby reducing the performance of the water electrolysis cell.

[0007] Furthermore, the operating temperature of the water electrolysis cell is preferably 50 to 80°C, but temperatures above 50°C reduce the durability of the water purifier.

[0008] Furthermore, when water is circulated by utilizing the buoyancy of gas generated by the water electrolysis reaction without using a pump, if the water flow path becomes complex, water pressure loss occurs in the cooler or water purifier, making it impossible to supply a sufficient amount of water to the water electrolysis cell.

[0009] The present invention has been made in consideration of these problems, and one of its objects is to cool and purify water for water electrolysis and supply a sufficient amount of the water to a water electrolysis cell while suppressing deterioration of the water purifier. [Means for solving the problem]

[0010] According to one embodiment of the present invention, there is provided a water electrolysis device comprising: a water electrolysis cell that produces hydrogen and oxygen through a water electrolysis reaction; a water tank that stores water used in the water electrolysis cell; a heat exchanger connected to the water tank that cools water supplied from the water tank; a water purifier connected to the heat exchanger that purifies the water cooled by the heat exchanger; a first flow path through which water supplied from the water tank flows to the water electrolysis cell via the heat exchanger and the water purifier; a second flow path through which water supplied from the water tank flows directly to the water electrolysis cell without passing through the heat exchanger and the water purifier; and a third flow path through which water flows from the water electrolysis cell to the water tank.

[0011] According to this aspect, the water electrolysis device includes water flow paths with different functions. In the first flow path, water is cooled by a heat exchanger and then purified by a water purifier. This allows water to be purified while suppressing deterioration of the water purifier. In addition, in the second flow path, water flowing out of the water tank flows into the water electrolysis cell without passing through the heat exchanger or water purifier. This eliminates resistance from the heat exchanger and water purifier, allowing the amount of water flowing into the water electrolysis cell to be increased and a decrease in water temperature to be suppressed. In other words, by using this aspect, water can be purified while suppressing deterioration of the water purifier, and a sufficient amount of water can be supplied to the water electrolysis device at a temperature appropriate for the water electrolysis reaction.

[0012] The water electrolysis apparatus may further include a pump provided upstream or downstream of the water tank.

[0013] According to this aspect, the pump can maintain the flow rate of water regardless of the flow path.

[0014] The water electrolysis apparatus may further include a control valve provided in the second flow path; a temperature sensor provided immediately before the water electrolysis cell; and a control device that controls the flow rate of water in the second flow path using the control valve based on the temperature detected by the temperature sensor.

[0015] According to this aspect, the amount of water flowing from the second flow path can be controlled, and water at an optimum temperature can be supplied to the water electrolysis cell.

[0016] The water electrolysis apparatus may further include a control valve provided in the first flow path, a temperature sensor provided upstream of the water electrolysis cell, and a control device that controls the flow rate of water in the first flow path with the control valve based on the temperature detected by the temperature sensor.

[0017] According to this aspect, the temperature of the water flowing into the water electrolysis cell can be controlled to an appropriate temperature by the control valve.

[0018] The water electrolysis apparatus may further include a pump provided in the first flow path downstream of the heat exchanger, a temperature sensor provided immediately before the water electrolysis cell, and a control device that controls the flow rate of the pump based on the temperature detected by the temperature sensor.

[0019] According to this aspect, the temperature of the water flowing into the water electrolysis cell can be controlled by the pump.

[0020] The water electrolysis apparatus may further include a cooling mechanism provided in a cooling circuit that supplies cooling water to the heat exchanger, a temperature sensor provided upstream of the water electrolysis cell, and a control device that controls operation of the cooling mechanism based on the temperature detected by the temperature sensor.

[0021] According to this aspect, the cooling capacity of the heat exchanger (pump, flow rate control valve, or blower) can be adjusted, and the temperature of the water supplied to the water electrolysis cell can be controlled.

[0022] The water electrolysis apparatus may further include a pump provided in the first flow path downstream of the water purifier, a first temperature sensor provided upstream of the water electrolysis cell, a second temperature sensor provided in a cooling circuit that supplies cooling water to the heat exchanger, and a control device that controls a flow rate of the pump, wherein when the temperature of the second temperature sensor is higher than the temperature of the first temperature sensor, the control device operates the pump to increase the flow rate of water from the first flow path.

[0023] According to this aspect, when the temperature of the water to be supplied is low, such as when the water electrolysis cell is started up, the temperature of the water can be increased.

[0024] The water electrolysis apparatus may further include a fourth flow path connecting the second flow path to a location between the heat exchanger and the water purifier, and a second control valve provided in the fourth flow path, wherein the control device opens the second control valve when the temperature detected by the second temperature sensor is higher than the temperature detected by the first temperature sensor.

[0025] According to this aspect, the water heated by the heat exchanger is sent to the water electrolysis cell without losing heat in the water purifier, and the temperature of the water can be increased when the water electrolysis cell is started up.

[0026] In the water electrolysis apparatus, the water supplied from the water tank may flow from the heat exchanger to the water purifier. [Effects of the Invention]

[0027] According to one embodiment of the present invention, it is possible to cool and purify water for water electrolysis and supply a sufficient amount of the water to the water electrolysis cell while suppressing deterioration of the water purifier. [Brief explanation of the drawings]

[0028] [Figure 1] 1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 2] 1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 3]1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a block diagram of a control device according to an embodiment of the present invention. [Figure 5] FIG. 2 is a functional block diagram of a control unit according to an embodiment of the present invention. [Figure 6] 1 is a flowchart of a control method according to an embodiment of the invention. [Figure 7] 1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 8] 1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 9] 1 is a flowchart of a control method according to an embodiment of the invention. [Figure 10] 1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 11] 1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 12] 1 is a flowchart of a control method according to an embodiment of the invention. [Figure 13] 1 is an overall configuration diagram of a water electrolysis device according to an embodiment of the present invention. [Figure 14] 1 is a flowchart of a control method according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] Hereinafter, each embodiment of the invention disclosed in this application will be described with reference to the drawings. However, the present invention can be embodied in various forms without departing from the spirit of the invention, and should not be construed as being limited to the description of the embodiments exemplified below.

[0030] In the drawings referred to in this embodiment, identical parts or parts having similar functions are denoted by the same or similar reference numerals (reference numerals with A, B, etc. added). Also, for convenience of explanation, the dimensional ratios in the drawings may differ from the actual ratios, and some components may be omitted from the drawings.

[0031] In this specification, the term "connection" includes not only a case where two components are directly connected, but also a case where two components are indirectly connected via another component.

[0032] First Embodiment Hereinafter, the water electrolysis device according to this embodiment will be described with reference to the drawings.

[0033] (1-1. Configuration of Water Electrolysis Device 1) Figure 1 is an overall configuration diagram of a water electrolysis apparatus 1 according to the present embodiment. As shown in Figure 1, the water electrolysis apparatus 1 includes a water electrolysis cell 10, a water tank 20, a heat exchanger 30, a water purifier 40, and flow paths (pipes) 91, 92, 93, and 94. In this embodiment, the water electrolysis apparatus 1 can be connected to external devices via SV1 to 5. For convenience of explanation, the external devices will be omitted in one embodiment of the present invention.

[0034] The water electrolysis cell 10 includes an anode 11, a cathode 12, an electrolyte membrane (partition) 13, a water inlet 14, a water outlet 15, and a hydrogen supply port 16. The anode 11 and the cathode 12 can be made of an appropriate conductive material, such as a metal or carbon material. A catalyst is provided on the anode 11 and the cathode 12. The electrolyte membrane 13 separates the anode 11 and the cathode 12, allowing ions to move through the electrolyte membrane 13. In the water electrolysis cell 10, water flowing in through the water inlet 14 undergoes an electrolysis reaction, producing hydrogen and oxygen. The hydrogen is discharged from the hydrogen supply port 16 and stored in a hydrogen tank via a valve SV5. The used water and oxygen are supplied (discharged) from the water outlet 15 to a flow path 91 (also referred to as the "third flow path").

[0035] The water tank 20 includes a water receiving inlet 21, a water supply inlet 22, an oxygen outlet 23, and a water replenishment inlet 24. The water tank 20 may be located above the water electrolysis cell 10. Water discharged from the water outlet 15 of the water electrolysis cell 10 flows together with oxygen through a flow path 91 (also referred to as the "third flow path") toward the water tank 20. At this time, the water moves upward due to the buoyancy of the oxygen and is stored in the water tank 20 from the water receiving inlet 21. The oxygen stored in the water tank 20 is discharged from the oxygen outlet 23. When the amount of water in the water tank 20 decreases, city water can be introduced into the water tank 20 via a valve SV1 and the water replenishment inlet 24. The oxygen is released to the outside via a valve SV2.

[0036] Water stored in the water tank 20 is supplied from the water supply port 22. The supplied water flows toward the water electrolysis cell 10 through a flow path 92 (also referred to as a "first flow path") or a flow path 93 (also referred to as a "second flow path"). The water flowing through the flow path 92 passes through the heat exchanger 30 and the water purifier 40, in that order. The water flowing through the flow path 93 does not pass through the heat exchanger 30 or the water purifier 40. The flow paths 92 and 93 merge to form a flow path 94, and the water flowing through the flow path 94 flows into the water electrolysis cell 10 through the water inlet 14. Note that, although the present embodiment illustrates an example in which the flow paths 92 and 93 merge, water inlets 14 corresponding to the flow paths 92 and 93 may be provided, respectively. In this case, the flow path 94 may not be provided.

[0037] The heat exchanger 30 is connected to the water tank 20 via a flow path 92. The heat exchanger 30 has a cooling circuit 95. In the heat exchanger 30, the heat of the water flowing through the flow path 92 is transferred to the outside via the cooling circuit 95 and valves SV3 and SV4. In this way, the heat exchanger 30 can cool the water to be used for water electrolysis flowing through the flow path 92 before it passes through the water purifier 40.

[0038] The water purifier 40 is connected to the heat exchanger 30 via a flow path 92. The water purifier 40 uses, for example, an ion exchange resin. Specifically, the ion exchange resin may be an anion exchange resin (such as a styrene-divinylbenzene copolymer or polyacrylamide) that captures negatively charged ions (anions) and exchanges them with other anions, or a cation exchange resin (such as a styrene-divinylbenzene copolymer, phenol-formaldehyde resin, or acrylic acid resin) that captures positively charged ions (cations) and exchanges them with other cations, or a combination thereof. The water purifier 40 has the function of increasing the purity of the water flowing through the flow path 92.

[0039] In this embodiment, the water electrolysis device 1 includes water flow paths 92 and 93, which have different functions. In the flow path 92 (first flow path), water is cooled by the heat exchanger 30 and then purified by the water purifier 40. This allows water to be purified while suppressing deterioration of the water purifier 40. Furthermore, in the flow path 93 (second flow path), water supplied from the water tank 20 flows into the water electrolysis cell 10 without passing through the heat exchanger 30 and the water purifier 40. As a result, the water passing through the flow path 93 does not encounter resistance from the heat exchanger 30 and the water purifier 40, which increases the amount of water flowing into the water electrolysis cell 10 and suppresses a decrease in water temperature. In other words, by using this embodiment, water can be purified while suppressing deterioration of the water purifier 40, and a sufficient amount of water can be supplied to the water electrolysis cell 10 at a temperature appropriate for the water electrolysis reaction.

[0040] Second Embodiment In this embodiment, an example in which the water electrolysis device has a pump will be described.

[0041] (2-1. Configuration of water electrolysis device 1A) 2 is a diagram showing the overall configuration of a water electrolysis apparatus 1A according to this embodiment. As shown in FIG. 2, the water electrolysis apparatus 1A includes a water electrolysis cell 10, a water tank 20, a heat exchanger 30, a water purifier 40, and flow paths (pipes) 91, 92, and 93, as well as a pump 50.

[0042] The pump 50 is provided downstream of the water tank 20. There are no particular limitations on the type of pump 50. When the pump 50 is provided, there is no need to use the buoyancy of oxygen to move water in the flow path 93. This eliminates the need to place the water tank 20 above the water electrolysis cell 10, which increases the degree of freedom in the placement of the components of the water electrolysis apparatus 1 and enables the flow rate of water supplied to the water electrolysis cell 10 to be maintained.

[0043] In this embodiment, the pump 50 is provided downstream of the water tank 20, but the present invention is not limited to this. The pump 50 may be provided upstream of the water tank 20.

[0044] Third Embodiment In this embodiment, an example in which the water electrolysis device has a pump and a control valve will be described.

[0045] (3-1. Configuration of water electrolysis device 1B) Fig. 3 is an overall configuration diagram of a water electrolysis apparatus 1B according to this embodiment. As shown in Fig. 3, the water electrolysis apparatus 1B includes a water electrolysis cell 10, a water tank 20, a heat exchanger 30, a water purifier 40, flow paths (pipes) 91, 92, 93, 94, a pump 50, a control valve 60, a temperature sensor 70, and a control device 80.

[0046] The control valve 60 is provided in the flow path 93 downstream of the pump 50. The type of the control valve 60 is not particularly limited. The control valve 60 opens and closes in response to commands from the control device 80. This makes it possible to control the flow rate of water supplied from the water tank through the flow path 93.

[0047] The temperature sensor 70 is provided immediately before the water inlet 14 of the water electrolysis cell 10. The temperature sensor 70 measures the temperature of the water flowing into the water electrolysis cell 10.

[0048] The control device 80 is connected to each device, including the control valve 60 and the temperature sensor 70. Figure 4 is a block diagram of the control device 80. The control device 80 has at least a control unit 801, a memory unit 803, a display unit 805, and a communication unit 807. In this embodiment, the control device 80 controls the opening and closing operation of the control valve 60 based on the temperature of the water flowing into the water electrolysis cell 10 (the temperature of the water in the flow path 94).

[0049] The control unit 801 controls the operation of each device in the water electrolysis system 1. The control unit 801 includes, for example, a processor equipped with an arithmetic processing device exemplified by a CPU (Central Processing Unit) and memories exemplified by a ROM (Read On Memory) and a RAM (Random Access Memory). The control unit 801 monitors the temperature of the water flowing into the water electrolysis cell 10 (the temperature of the water in the flow path 94) and controls each device.

[0050] The storage unit 803 may be a memory, a semiconductor memory such as an SSD (Solid State Drive), a magnetic recording medium (magnetic tape, magnetic disk, etc.), an optical recording medium, a magneto-optical recording medium, or a storage element that can store data. The storage unit 803 has a function of storing a control program and various information used in the control program.

[0051] The display unit 805 displays the control information under the control of the control unit 801. At this time, the display unit 805 may display the control information via a GUI (Graphical User Interface). Note that the display unit 805 does not necessarily have to be provided depending on the mode of the control device 80.

[0052] The communication unit 807 includes a communication module, and transmits and receives information to and from each device under the control of the control unit 801. The communication unit 807 may be wireless or wired.

[0053] In addition to the control unit 801, storage unit 803, display unit 805, and communication unit 807, the control device 80 may also include an operation unit (buttons, switches, keyboard, etc.) and an alarm unit (light, buzzer, etc.).

[0054] Fig. 5 is a functional block diagram of the control unit 801. As shown in Fig. 5, the control unit 801 includes an acquisition unit 8011, a determination unit 8013, and an operation instruction unit 8015 as functional units.

[0055] The acquisition unit 8011 has a function of acquiring various types of information about the water electrolysis apparatus 1. Specifically, the acquisition unit 8011 acquires the temperature of the water in the flow path 94 (the temperature of the water flowing into the water electrolysis cell 10). The acquisition unit 8011 may acquire the various types of information at any time, or at predetermined time intervals.

[0056] The determination unit 8013 has a function of determining whether a predetermined condition is satisfied. For example, the determination unit 8013 determines whether the temperature of the water flowing into the water electrolysis cell 10 (the temperature of the water in the flow path 94) exceeds a set value (threshold value).

[0057] The operation instruction unit 8015 has a function of instructing the operation of each device. For example, the operation instruction unit 8015 instructs the operation of the pump 50 and the opening or closing operation of the control valve 60.

[0058] (3-2. Control method) Next, a description will be given of a control method using the control device 80. Fig. 6 is a flowchart of the control method.

[0059] First, the control device 80 acquires the temperature T1 measured by the temperature sensor 70 (step S101). At this time, it is determined whether T1 is equal to or higher than a predetermined temperature (50° C. in this example) (step S103). If the measured temperature T1 is lower than the predetermined temperature (step S103; No), the control device 80 instructs the control valve 60 to open (step S105). As a result, the water coming out of the water tank 20 passes through the flow paths 92 and 93.

[0060] On the other hand, if the measured temperature T1 is equal to or higher than the predetermined temperature (step S103; Yes), the control device 80 instructs the control valve 60 to close (step S107). As a result, water discharged from the water tank 20 flows only through the flow path 92. If the control process is to be continued after step S105 or step S107 (step S109; Yes), the process returns to step S101. If the control process is not to be continued (step S109; No), the control process ends. By using this embodiment, the flow rate of water flowing from the flow path 93 can be controlled in accordance with the temperature of the water flowing into the water electrolysis cell 10 (the temperature of the water in the flow path 94), and water at an optimal temperature can be supplied to the water electrolysis cell 10.

[0061] In this embodiment, the control valve 60 is shown to be capable of opening or closing, but the present invention is not limited to this. The control valve 60 may also control its opening degree in stages in response to instructions from the control device 80. This allows for more accurate control of the temperature of the water supplied to the water electrolysis cell 10.

[0062] Although the present embodiment illustrates an example in which the control valve 60 is provided in the flow path 93, the present invention is not limited thereto. FIG. 7 is an overall configuration diagram of a water electrolysis apparatus 1C. As shown in FIG. 7, the control valve 60 may be provided in the flow path 92. In this case, the flow rate of water flowing from the flow path 92 can be controlled according to the temperature of the water flowing into the water electrolysis cell 10 (the temperature of the water in the flow path 94), thereby enabling water of an optimal temperature to be supplied to the water electrolysis cell 10. Furthermore, the control valve 60 may be provided with a distribution valve at the branch point of the flow paths 92 and 93 that can control the distribution of water. In this case, the ratio of the flow rates of water flowing from the flow paths 92 and 93 can be controlled according to the temperature of the water flowing into the water electrolysis cell 10, thereby enabling water of an optimal temperature to be supplied to the water electrolysis cell 10.

[0063] <Fourth embodiment> In this embodiment, an example will be described in which the control device of the third embodiment is used and a pump is used to control the operation of the flow path 92. Note that descriptions of parts that overlap with the configurations described in the first to third embodiments will be omitted as appropriate.

[0064] (4-1. Configuration of water electrolysis device 1D) Fig. 8 is an overall configuration diagram of a water electrolysis apparatus 1D according to this embodiment. As shown in Fig. 8, the water electrolysis apparatus 1D includes a water electrolysis cell 10, a water tank 20, a heat exchanger 30, a water purifier 40, flow paths (pipes) 91, 92, 93, and 94, a pump 50D, a temperature sensor 70, and a control device 80.

[0065] In this embodiment, the pump 50D is provided in the flow path 92 downstream of the heat exchanger 30. This allows the water flowing through the pump 50D to have a low temperature. This reduces deterioration of the components of the pump 50D, improving the durability of the pump 50D. Furthermore, because deterioration of the pump 50D is reduced, there is no need to use expensive materials for the pump 50D. As a result, the cost of the water electrolysis apparatus 1D can be reduced.

[0066] (4-2. Control method) Next, a description will be given of a control method using the control device 80. Fig. 9 is a flowchart of the control method.

[0067] First, the control device 80 acquires the temperature T1 measured by the temperature sensor 70 (step S201). At this time, the control device 80 sets the flow rate of the pump 50D according to the temperature T1 (step S203). Next, the control device 80 instructs the pump 50D to operate at the set flow rate (step S205). If the control process is to be continued after step S205 (step S207; Yes), the process returns to step S201. If the control process is not to be continued (step S207; No), the control process ends.

[0068] By using this embodiment, the flow rate of water flowing through the pump 50D can be controlled, and the amount of cooled water passing through the flow path 92 can be adjusted, thereby controlling the temperature of the water flowing through the water electrolysis cell 10D.

[0069] Fifth Embodiment In this embodiment, an example will be described in which the control device of the third embodiment is used and a cooling mechanism is provided in the cooling circuit that supplies cooling water to the heat exchanger. Note that the description of parts that overlap with the configurations described in the first to fourth embodiments will be omitted as appropriate.

[0070] Fig. 10 is a diagram showing the overall configuration of a water electrolysis apparatus 1E according to this embodiment. As shown in Fig. 10, the water electrolysis apparatus 1E includes a water electrolysis cell 10, a water tank 20, a heat exchanger 30, a water purifier 40, flow paths (pipes) 91, 92, 93, and 94, a pump 50E, a temperature sensor 70, and a control device 80.

[0071] In this embodiment, the pump 50E is provided in the cooling circuit 95. The pump 50E adjusts the flow rate of cold water flowing through the cooling circuit 95 under conditions set by the control device 80. The inclusion of the pump 50E increases the cooling capacity of the heat exchanger 30 in the water electrolysis apparatus 1E. As a result, the temperature of the water supplied to the water electrolysis cell 10 can be controlled.

[0072] In this embodiment, an example has been shown in which the pump 50E is provided in the cooling circuit 95, but the present invention is not limited to this. For example, a method for increasing the cooling capacity of the heat exchanger is not limited to the pump 50E, and a control valve, a blower, or other coolers may be provided in part of the cooling circuit 95. The pump 50E, the control valve, the blower, and other coolers can be collectively referred to as a cooling mechanism.

[0073] Sixth Embodiment In this embodiment, an example of a water electrolysis apparatus having a second temperature sensor in a cooling circuit will be described. Note that descriptions of parts that overlap with the configurations described in the first to fifth embodiments will be omitted as appropriate.

[0074] (6-1. Configuration of water electrolysis equipment 1F) Fig. 11 is an overall configuration diagram of a water electrolysis apparatus 1F according to this embodiment. As shown in Fig. 11, the water electrolysis apparatus 1F includes a water electrolysis cell 10, a water tank 20, a heat exchanger 30, a water purifier 40, flow paths (pipes) 91, 92, 93, 94, and 95, a pump 50F, temperature sensors 70 and 71, and a control device 80.

[0075] In this embodiment, the temperature sensor 71 is provided in the cooling circuit 95 of the heat exchanger 30. The temperature sensor 71 measures the temperature of the water flowing through the cooling circuit 95. The pump 50F is provided in the flow path 92 on the downstream side of the heat exchanger 30.

[0076] The control device 80 is connected to each device such as the pump 50F and the temperature sensors 70 and 71. In this embodiment, the control device 80 controls the flow rate of the pump 50E based on the relationship between the temperature measured by the temperature sensor 70 and the temperature measured by the temperature sensor 71.

[0077] (6-2. Control method) Next, a description will be given of a control method using the control device 80. Fig. 12 is a flowchart of the control method.

[0078] First, the control device 80 acquires the temperature T1 measured by the temperature sensor 70 (step S301). Next, the control device 80 acquires the temperature T2 measured by the temperature sensor 71 (step S303). The control device 80 determines whether T2 is higher than T1 (step S305). If the measured temperature T2 is higher than T1 (step S305; Yes), the control device 80 instructs the pump 50F to increase the flow rate (step S307). If T2 is lower than T1 (step S305; No), the control device 80 instructs the pump 50F to maintain the flow rate or to decrease the pump flow rate (step S309). If the control process is to be continued after step S307 or step S309 (step S311; Yes), the process returns to step S301. If the control process is not to be continued (step S311; No), the control process ends.

[0079] By using this embodiment, when the water temperature in the water tank 20 is low and the water temperature on the cooling circuit 95 side is high, such as when the water electrolysis apparatus 1F is started up, the water temperature can be increased.

[0080] Seventh Embodiment In this embodiment, an example of a water electrolysis apparatus having a pump and a control valve provided in a flow path that does not pass through a water purifier after passing through a heat exchanger will be described. Note that descriptions of parts that overlap with the configurations described in the first to sixth embodiments will be omitted as appropriate.

[0081] (7-1. Configuration of water electrolysis device 1G) Fig. 13 is an overall configuration diagram of a water electrolysis apparatus 1G according to this embodiment. As shown in Fig. 10, the water electrolysis apparatus 1G includes a water electrolysis cell 10, a water tank 20, a heat exchanger 30, a water purifier 40, flow paths (pipes) 91, 92, 93, 94, and 96, a pump 50G, a control valve 60G, temperature sensors 70 and 71, and a control device 80.

[0082] In this embodiment, the temperature sensor 71 is provided in the cooling circuit 95 of the heat exchanger 30. The temperature sensor 71 measures the temperature of the water flowing through the cooling circuit 95.

[0083] The pump 50G is provided in the flow path 92 on the upstream side of the heat exchanger 30. However, the present invention is not limited to this, and the pump 50G may be provided on the downstream side of the water purifier 40.

[0084] A flow path 96 (also referred to as a "fourth flow path") is provided to connect a portion of the flow path 92 between the heat exchanger 30 and the water purifier 40 to the flow path 93. The flow path 96 is a bypass flow path that does not pass through the water purifier 40. A control valve 60G is provided in the flow path 96.

[0085] The control device 80 is connected to each device including the pump 50G, the control valve 60G, and the temperature sensors 70 and 71. In this embodiment, the control device 80 controls the flow rate of the pump 50G and the opening and closing operation of the control valve 60G based on the relationship between the temperature measured by the temperature sensor 70 and the temperature measured by the temperature sensor 71.

[0086] (7-2. Control method) Next, a description will be given of a control method using the control device 80. Fig. 14 is a flowchart of the control method.

[0087] First, the control device 80 acquires the temperature T1 measured by the temperature sensor 70 (step S401). Next, the control device 80 acquires the temperature T2 measured by the temperature sensor 71 (step S403). The control device 80 determines whether T2 is higher than T1 (step S405). If the measured temperature T2 is higher than T1 (step S405; Yes), the control device 80 instructs the pump 50G to increase the flow rate (step S407). At this time, the control device 80 instructs the control valve 60G to open (step S408). If T2 is lower than T1 (step S405; No), the control device 80 instructs the pump 50G to maintain the flow rate or to decrease the flow rate (step S409). At this time, the control device 80 instructs the control valve 60G to close (step S410). If the control process is to be continued after step S408 or step S410 (step S411; Yes), the process returns to step S401. If the control process is not to be continued (step S411; No), the control process ends.

[0088] In this embodiment, when the water temperature in the water tank 20 is low and the water temperature on the cooling circuit 95 side is high, such as during startup of the water electrolysis apparatus 1G, the control valve 60G is controlled to be "open" so that the water passes through the flow path 96, which is a bypass flow path, without passing through the water purifier 40 (reducing the flow rate of water passing through the water purifier 40). This prevents heat from being lost by the water purifier 40. Therefore, the temperature of the water sent to the water electrolysis cell 10 can be increased.

[0089] Although the present embodiment illustrates that the control valve 60G is provided in the flow path 96, the present invention is not limited to this. For example, another control valve may be provided in addition to the control valve 60G. The other control valve may be provided in the flow path 93. Similarly, in the present embodiment, the pump 50G may be provided in the flow path 93 instead of the flow path 92. This makes it possible to control the flow rate of low-temperature water flowing from the flow path 93. Therefore, the temperature of the water sent to the water electrolysis cell 10 can be increased.

[0090] (Variation) Within the scope of the concept of the present invention, a person skilled in the art may conceive of various modifications and alterations, and it is understood that these modifications and alterations also fall within the scope of the present invention. For example, to the above-described embodiments, a person skilled in the art may appropriately add, delete, or modify components, or add, omit, or change conditions of processing, and these modifications are also included within the scope of the present invention as long as they include the gist of the present invention. [Explanation of symbols]

[0091] 1···Water electrolysis device, 1A···Water electrolysis device, 1B···Water electrolysis device, 1C···Water electrolysis device, 1D···Water electrolysis device, 1E···Water electrolysis device, 1F···Water electrolysis device, 1G···Water electrolysis device, 10···Water electrolysis cell, 10D···Water electrolysis cell, 11···Anode, 12···Cathode, 13···Electrolyte membrane, 13···Electrolyte membrane (partition), 14···Water inlet, 15···Water outlet, 16···Hydrogen supply port, 20···Water tank, 21···Water receiving port, 22···Water supply port, 23···Oxygen outlet, 24···Water supply port, 30···Heat exchanger 40···Water purifier, 50···Pump, 50D···Pump, 50E···Pump, 50F···Pump, 50G···Pump, 60···Control valve, 60···Control valve (control valve), 60G···Control valve, 70···Temperature sensor, 71···Temperature sensor, 80···Control device, 91···Flow path, 92···Flow path, 93···Flow path, 94···Flow path, 95···Cooling circuit, 96···Flow path, 801···Control unit, 803···Memory unit, 805···Display unit, 807···Communication unit, 8011···Acquisition unit, 8013···Determination unit, 8015···Operation instruction unit

Claims

1. a water electrolysis cell that generates hydrogen and oxygen through a water electrolysis reaction; a water tank for storing water used in the water electrolysis cell; a heat exchanger connected to the water tank and configured to cool the water supplied from the water tank; a water purifier connected to the heat exchanger and purifying the water cooled by the heat exchanger; a first flow path through which water supplied from the water tank flows to the water electrolysis cell via the heat exchanger and the water purifier; a second flow path through which the water supplied from the water tank flows directly to the water electrolysis cell without passing through the heat exchanger and the water purifier; a third flow path through which water flows from the water electrolysis cell to the water tank. Water electrolysis equipment.

2. A pump is provided upstream or downstream of the water tank. The water electrolysis device according to claim 1 .

3. a control valve provided in the second flow path; a temperature sensor provided immediately before the water electrolysis cell; a control device that controls the flow rate of water in the second flow path using the control valve based on the temperature detected by the temperature sensor, The water electrolysis device according to claim 1 .

4. a control valve provided in the first flow path; a temperature sensor provided upstream of the water electrolysis cell; and a control device that controls the flow rate of water in the first flow path by the control valve based on the temperature detected by the temperature sensor, The water electrolysis device according to claim 1 .

5. a pump provided in the first flow path downstream of the heat exchanger; a temperature sensor provided immediately before the water electrolysis cell; a control device that controls the flow rate of the pump based on the temperature detected by the temperature sensor, The water electrolysis apparatus according to claim 1.

6. a cooling mechanism provided in a cooling circuit that supplies cooling water to the heat exchanger; a temperature sensor provided upstream of the water electrolysis cell; and a control device that controls the operation of the cooling mechanism based on the temperature detected by the temperature sensor. The water electrolysis device according to claim 1 .

7. a pump provided in the first flow path downstream of the water purifier; a first temperature sensor provided upstream of the water electrolysis cell; a second temperature sensor provided in a cooling circuit that supplies cooling water to the heat exchanger; a control device for controlling the flow rate of the pump; When the temperature of the second temperature sensor is higher than the temperature of the first temperature sensor, the control device operates the pump to increase the flow rate of water from the first flow path. The water electrolysis device according to claim 1 .

8. a fourth flow path connecting the second flow path to a portion between the heat exchanger and the water purifier; a second control valve provided in the fourth flow path, When the temperature detected by the second temperature sensor is higher than the temperature detected by the first temperature sensor, the control device opens the second control valve. The water electrolysis apparatus according to claim 7.

9. The water supplied from the water tank flows from the heat exchanger to the water purifier. The water electrolysis apparatus according to claim 1.

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