Water electrolysis systems and energy systems
The water electrolysis system addresses cross-leakage and gas mixing issues by using separate channels and controlled water management to maintain balanced pressures, improving reliability and efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- HONDA MOTOR CO LTD
- Filing Date
- 2024-11-11
- Publication Date
- 2026-05-21
AI Technical Summary
Existing water electrolysis systems suffer from cross-leakage of generated gases and mixing of gases due to electrolyte membrane deterioration or improper channel filling, leading to inefficiencies and reduced reliability.
A water electrolysis system with separate channels for oxygen and hydrogen gas generation, each filled with water, and gas-liquid separators to manage and store water, along with controlled water supply and discharge channels to maintain equal pressures and prevent gas mixing, even in the event of membrane deterioration.
The system effectively suppresses cross-leakage and gas mixing, enhancing the reliability and efficiency of water electrolysis and energy systems by maintaining balanced pressures and separating gases effectively.
Smart Images
Figure 2026084309000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a water electrolysis system and an energy system.
Background Art
[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, technical developments related to water electrolysis systems and energy systems that contribute to energy efficiency have been carried out.
[0003] For example, Japanese Patent Application Laid-Open No. 9-139217 discloses an energy system including a water electrolysis system and a fuel cell system. In the water electrolysis system, water supplied from a water tank is electrolyzed by a water electrolysis device to generate hydrogen gas and oxygen gas. The fuel cell system generates electricity by the electrochemical reaction of the hydrogen gas and oxygen gas generated in the water electrolysis system.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] Better water electrolysis systems and energy systems are desired.
[0006] The present disclosure aims to solve the above-described problems.
Means for Solving the Problems
[0007] One aspect of the present disclosure is a water electrolysis apparatus having an electrolyte membrane, a first channel and a second channel provided on both sides of the electrolyte membrane, wherein oxygen gas is generated in the first channel and hydrogen gas is generated in the second channel by electrolysis of water, a first gas-liquid separator and a second gas-liquid separator capable of storing water, a water supply channel for supplying the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator to the water electrolysis apparatus, a first discharge channel for discharging the oxygen gas generated in the first channel to the first gas-liquid separator, and the second channel The water electrolysis system comprises a first channel and a second channel for leading hydrogen gas generated in the channel to the second gas-liquid separator, wherein each of the first channel and the second channel is filled with water during the electrolysis of water by the water electrolysis apparatus, and the water stored in the first gas-liquid separator and the water filling the first channel are connected to each other, and the water stored in the second gas-liquid separator and the water filling the second channel are connected to each other, and the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator are connected to each other.
[0008] Another aspect of the present disclosure is an energy system comprising the water electrolysis system described above and a fuel cell system that generates electricity using hydrogen gas and oxygen gas produced by the water electrolysis system, wherein water generated during power generation by the fuel cell system is supplied to at least one of the first gas-liquid separator and the second gas-liquid separator. [Effects of the Invention]
[0009] This disclosure may provide better water electrolysis and energy systems. [Brief explanation of the drawing]
[0010] [Figure 1] Figure 1 is a schematic diagram of an energy system. [Figure 2] Figure 2 is a schematic diagram of a water electrolysis cell. [Figure 3] Figure 3 is a schematic diagram of an energy system equipped with a water electrolysis system according to the first modified example. [Figure 4] Figure 4 is a schematic diagram of an energy system equipped with a water electrolysis system according to the second modified example. [Figure 5] Figure 5 is a schematic diagram of an energy system equipped with a water electrolysis system according to the third modified example. [Figure 6] Figure 6 is a schematic diagram of an energy system equipped with a water electrolysis system according to the fourth modified example. [Figure 7] Figure 7 is a schematic diagram of an energy system equipped with a water electrolysis system according to the fifth modified example. [Modes for carrying out the invention]
[0011] A water electrolysis system comprises a water electrolysis device having an electrolyte membrane and a first channel and a second channel provided on both sides of the electrolyte membrane. In Japanese Patent Publication No. 9-139217, for example, if water is supplied from a water tank to the first channel but not to the second channel, the gas generated and pressurized in the second channel may permeate the electrolyte membrane and flow into the first channel (cross-leakage occurs). Also, if the electrolyte membrane deteriorates (for example, if a rupture occurs in the electrolyte membrane), the generated gases may mix with each other. This disclosure can provide a water electrolysis system and energy system that can suppress cross-leakage of generated gases and can also suppress the mixing of generated gases even if the electrolyte membrane deteriorates.
[0012] Figure 1 is a schematic diagram of the energy system 12. As shown in Figure 1, the energy system 12 is a circular renewable energy system. The energy system 12 is a system that combines a fuel cell system 14 and a water electrolysis system 10. The fuel cell system 14 generates electricity through an electrochemical reaction between oxygen gas and hydrogen gas. Water is produced in the fuel cell system 14 during the power generation process. The water electrolysis system 10 generates oxygen gas and hydrogen gas by electrolyzing water. The water electrolysis system 10 utilizes the water produced in the fuel cell system 14. The fuel cell system 14 utilizes the oxygen gas and hydrogen gas produced in the water electrolysis system 10.
[0013] Such an energy system 12 can be installed, for example, on Earth or on the lunar surface. Furthermore, the energy system 12 can also be mounted on artificial satellites such as the International Space Station (ISS).
[0014] The fuel cell system 14 includes a fuel cell stack 16. The fuel cell stack 16 is a polymer electrolyte fuel cell (PEFC). The fuel cell stack 16 has a plurality of power generation cells 18 and a pair of end plates 20. The plurality of power generation cells 18 are stacked on top of each other. The pair of end plates 20 sandwich the plurality of power generation cells 18 from the stacking direction.
[0015] Detailed illustration of the power generation cell 18 is omitted. The power generation cell 18 includes a membrane electrode assembly (MEA) and a pair of separators. The membrane electrode assembly is sandwiched between the pair of separators. The membrane electrode assembly has an electrolyte membrane, an anode electrode, and a cathode electrode. The electrolyte membrane is a solid polymer electrolyte membrane. The power generation cell 18 generates electricity through an electrochemical reaction between hydrogen gas and oxygen gas. Water is generated at the cathode electrode during power generation by the power generation cell 18.
[0016] The fuel cell system 14 further comprises a first oxygen gas supply channel 22, a second oxygen gas supply channel 24, an oxygen gas discharge channel 26, a gas-liquid separator 28, and a first drain channel 30. The first oxygen gas supply channel 22 supplies oxygen gas generated in the water electrolysis system 10 to the gas-liquid separator 28. The first oxygen gas supply channel 22 is provided with an on-off valve 32. The on-off valve 32 opens and closes the first oxygen gas supply channel 22.
[0017] The second oxygen gas supply passage 24 connects the gas-liquid separator 28 and the fuel cell stack 16 to each other. The second oxygen gas supply passage 24 introduces the oxygen gas in the gas-liquid separator 28 into the fuel cell stack 16. The oxygen gas discharge passage 26 connects the fuel cell stack 16 and the gas-liquid separator 28 to each other. The oxygen exhaust gas (off-gas) discharged from the fuel cell stack 16 flows through the oxygen gas discharge passage 26. The oxygen exhaust gas contains unreacted oxygen gas that did not react in the power generation cell 18. Further, the oxygen exhaust gas contains moisture generated at the cathode electrode of the power generation cell 18.
[0018] The gas-liquid separator 28 separates the oxygen exhaust gas introduced from the oxygen gas discharge passage 26 into gas and liquid. That is, the gas-liquid separator 28 removes water vapor from the oxygen exhaust gas. The gas-liquid separator 28 stores the water (liquid water) separated from the oxygen exhaust gas.
[0019] The first drain passage 30 is a passage for discharging the water stored in the gas-liquid separator 28 to the outside of the gas-liquid separator 28. A first drain pump 34 is provided in the first drain passage 30. The first drain pump 34 sends the water stored in the gas-liquid separator 28 to the water electrolysis system 10.
[0020] The fuel cell system 14 further includes a first hydrogen gas supply passage 36, a second hydrogen gas supply passage 38, a hydrogen gas discharge passage 40, a gas-liquid separator 42, and a second drain passage 44. The first hydrogen gas supply passage 36 supplies the hydrogen gas generated in the water electrolysis system 10 to the gas-liquid separator 42. An on-off valve 46 is provided in the first hydrogen gas supply passage 36. The on-off valve 46 opens and closes the first hydrogen gas supply passage 36.
[0021] The second hydrogen gas supply channel 38 connects the gas-liquid separator 42 and the fuel cell stack 16. The second hydrogen gas supply channel 38 introduces hydrogen gas from the gas-liquid separator 42 into the fuel cell stack 16. The hydrogen gas discharge channel 40 connects the fuel cell stack 16 and the gas-liquid separator 42. Hydrogen exhaust gas (off-gas) discharged from the fuel cell stack 16 flows through the hydrogen gas discharge channel 40. The hydrogen exhaust gas contains unreacted hydrogen gas that did not react in the power generation cell 18. The hydrogen exhaust gas also contains moisture that has permeated the electrolyte membrane from the cathode electrode of the power generation cell 18 and been guided to the anode electrode.
[0022] The gas-liquid separator 42 separates the hydrogen exhaust gas introduced from the hydrogen gas discharge passage 40 into gas and liquid. In other words, the gas-liquid separator 42 removes water vapor from the hydrogen exhaust gas. The gas-liquid separator 42 stores the water (liquid water) separated from the hydrogen exhaust gas.
[0023] The second drainage channel 44 is a channel for discharging the water stored in the gas-liquid separator 42 to the outside of the gas-liquid separator 42. The second drainage channel 44 is equipped with a second drainage pump 48. The second drainage pump 48 sends the water stored in the gas-liquid separator 42 to the water electrolysis system 10.
[0024] The fuel cell system 14 may include components other than those described above. That is, the fuel cell system 14 may include, for example, a cooling device for circulating a cooling medium to the fuel cell stack 16.
[0025] The water electrolysis system 10 comprises a water electrolysis device 50, a first gas-liquid separator 52, a second gas-liquid separator 54, a water supply channel 56, a first outlet channel 58, an oxygen gas storage section 60, a second outlet channel 62, and a hydrogen gas storage section 64.
[0026] The water electrolysis device 50 generates oxygen gas and hydrogen gas by electrolyzing water (pure water). The water electrolysis device 50 has an isobaric water electrolysis stack 66 and a power supply 68. The isobaric water electrolysis stack 66 includes a plurality of water electrolysis cells 70 and a pair of end plates 71. The plurality of water electrolysis cells 70 are stacked on top of each other. The pair of end plates 71 sandwich the plurality of water electrolysis cells 70 from the stacking direction.
[0027] Figure 2 is a schematic diagram of a water electrolysis cell 70. As shown in Figure 2, the water electrolysis cell 70 comprises an electrolyte membrane 72, a first electrode catalyst layer 74, a second electrode catalyst layer 76, a first power supply 78, a second power supply 80, a first support member 82, and a second support member 84. The electrolyte membrane 72 is an ion exchange membrane capable of exchanging ions. The electrolyte membrane 72 is, for example, a proton exchange membrane (PEM). The electrolyte membrane 72 may also be an anion exchange membrane (AEM).
[0028] The first electrode catalyst layer 74 is laminated on one side of the electrolyte membrane 72. The second electrode catalyst layer 76 is laminated on the other side of the electrolyte membrane 72. The first power supply unit 78 is laminated on the first electrode catalyst layer 74. The first power supply unit 78 is formed to be porous. The second power supply unit 80 is laminated on the second electrode catalyst layer 76. The second power supply unit 80 is formed to be porous.
[0029] The first support member 82 and the second support member 84 sandwich the electrolyte membrane 72. A first channel 86 is formed in the first support member 82. The first channel 86 is adjacent to the first power supply 78. A second channel 88 is formed in the second support member 84. The second channel 88 is adjacent to the second power supply 80. The first channel 86 and the second channel 88 are provided on both sides of the electrolyte membrane 72.
[0030] As shown in Figures 1 and 2, the power supply 68 applies a voltage between the first power supply 78 and the second power supply 80 of the water electrolysis cell 70. The power supply 68 is a DC power supply. In the isobaric water electrolysis stack 66, when a voltage is applied between the first power supply 78 and the second power supply 80, water is electrolyzed, generating oxygen gas in the first channel 86 and hydrogen gas in the second channel 88. When water electrolysis is performed, the pressure in the first channel 86 and the pressure in the second channel 88 are the same (see Figure 2).
[0031] As shown in Figure 1, the first gas-liquid separator 52 is capable of storing water. The first drainage channel 30 is connected to the first gas-liquid separator 52. In other words, the first drainage pump 34 sends the water stored in the gas-liquid separator 28 to the first gas-liquid separator 52.
[0032] The second gas-liquid separator 54 is capable of storing water. The second drainage channel 44 is connected to the second gas-liquid separator 54. In other words, the second drainage pump 48 sends the water stored in the gas-liquid separator 42 to the second gas-liquid separator 54. The capacity of the second gas-liquid separator 54 is the same as the capacity of the first gas-liquid separator 52.
[0033] The water supply channel 56 supplies water to the isobaric water electrolysis stack 66. The water supply channel 56 has a first water supply channel 90, a second water supply channel 92, and an introduction channel 94. The first water supply channel 90 is connected to the first gas-liquid separator 52. The second water supply channel 92 is connected to the second gas-liquid separator 54. The introduction channel 94 is connected to the first water supply channel 90 and the second water supply channel 92.
[0034] The introduction channel 94 combines the water supplied from the first water supply channel 90 and the water supplied from the second water supply channel 92 and introduces them into the isobaric water electrolysis stack 66. The introduction channel 94 is equipped with a water pump 96. The water pump 96 sends the water stored in the first gas-liquid separator 52 and the water stored in the second gas-liquid separator 54 to the isobaric water electrolysis stack 66. The introduction channel 94 introduces water into the first channel 86. The introduction channel 94 does not introduce water into the second channel 88.
[0035] The first outlet channel 58 connects the isobaric water electrolysis stack 66 and the first gas-liquid separator 52. The first outlet channel 58 leads the oxygen gas generated in the first channel 86 and unreacted water to the first gas-liquid separator 52. Both the first outlet channel 58 and the first channel 86 are filled with water. The first gas-liquid separator 52 separates the oxygen gas led from the first channel 86 of the isobaric water electrolysis stack 66 from the water.
[0036] The oxygen gas storage unit 60 stores the oxygen gas separated into gas and liquid form by the first gas-liquid separator 52. The oxygen gas storage unit 60 has two oxygen gas tanks 98, an oxygen gas inlet passage 100, and an oxygen gas outlet passage 102. The two oxygen gas tanks 98 are installed in parallel with each other. The two oxygen gas tanks 98 have the same capacity. The oxygen gas inlet passage 100 connects the first gas-liquid separator 52 to each of the two oxygen gas tanks 98. The oxygen gas outlet passage 102 connects each of the two oxygen gas tanks 98 to the first oxygen gas supply passage 22.
[0037] The second outlet channel 62 connects the isobaric water electrolysis stack 66 and the second gas-liquid separator 54. The second outlet channel 62 leads the hydrogen gas generated in the second channel 88 to the second gas-liquid separator 54. The second gas-liquid separator 54 separates the hydrogen gas led from the second channel 88 of the isobaric water electrolysis stack 66 from the water.
[0038] The hydrogen gas storage unit 64 stores the hydrogen gas separated into gas and liquid form by the second gas-liquid separator 54. The hydrogen gas storage unit 64 has four hydrogen gas tanks 104, a hydrogen gas inlet passage 106, and a hydrogen gas outlet passage 108. The four hydrogen gas tanks 104 are arranged in parallel with each other. The capacities of the four hydrogen gas tanks 104 are the same. The capacities of the hydrogen gas tanks 104 and the oxygen gas tank 98 are the same. That is, the capacity of the hydrogen gas storage unit 64 is twice the capacity of the oxygen gas storage unit 60. The hydrogen gas inlet passage 106 connects the second gas-liquid separator 54 to each of the four hydrogen gas tanks 104. The hydrogen gas outlet passage 108 connects each of the four hydrogen gas tanks 104 to the first hydrogen gas supply passage 36.
[0039] The water electrolysis system 10 may include components other than those described above. In the water electrolysis system 10, the water stored in the first gas-liquid separator 52 and the water filling the first channel 86 are connected to each other by the water present in the first water supply channel 90 and the water present in the introduction channel 94. Furthermore, the water stored in the first gas-liquid separator 52 and the water filling the first channel 86 are connected to each other by the water present in the first outlet channel 58.
[0040] The water stored in the second gas-liquid separator 54 and the water filling the second channel 88 are connected to each other by the water present in the second outlet channel 62. The water stored in the first gas-liquid separator 52 and the water stored in the second gas-liquid separator 54 are connected to each other by the water present in the first water supply channel 90 and the water present in the second water supply channel 92.
[0041] The energy system 12 may include a control device (not shown) that controls the entire system, consisting of the fuel cell system 14 and the water electrolysis system 10.
[0042] Next, the basic operation of the energy system 12 will be described. In the water electrolysis system 10, in the initial state before water electrolysis is started, the water stored in the second gas-liquid separator 54 flows into the second channel 88 via the second outlet channel 62. That is, the second channel 88 is filled with water.
[0043] When the water electrolysis system 10 is driven, the water pump 96 is driven and a voltage is applied between the first power supply unit 78 and the second power supply unit 80 by the power supply unit 68. When the water pump 96 is driven, the water stored in the first gas-liquid separator 52 and the water stored in the second gas-liquid separator 54 are supplied to the first channel 86 of the isobaric water electrolysis stack 66. As a result, the first channel 86 is filled with water.
[0044] Water introduced into the first channel 86 is guided to the first electrode catalyst layer 74 via the first power supply 78. In the first electrode catalyst layer 74 (anode catalyst layer), water is electrolyzed to produce hydrogen ions and oxygen gas.
[0045] Hydrogen ions, along with water, move through the electrolyte membrane 72 from the first electrode catalyst layer 74 to the second electrode catalyst layer 76 (cathode catalyst layer). This supplies hydrogen ions to the second electrode catalyst layer 76 and humidifies the electrolyte membrane 72. In the second electrode catalyst layer 76, hydrogen ions combine to generate hydrogen gas.
[0046] The unreacted water supplied to the first electrode catalyst layer 74 and the oxygen gas generated in the first electrode catalyst layer 74 are led from the first flow path 86 through the first outlet flow path 58 to the first gas-liquid separator 52. The oxygen gas led to the first gas-liquid separator 52 is stored in the oxygen gas tank 98 via the oxygen gas introduction path 100. By introducing oxygen gas into the oxygen gas tank 98, the pressure of the oxygen gas stored in the oxygen gas storage section 60 can be increased to a predetermined set pressure.
[0047] The hydrogen gas generated in the second electrode catalyst layer 76 is guided from the second flow path 88 through the second outlet flow path 62 to the second gas-liquid separator 54. The hydrogen gas guided to the second gas-liquid separator 54 is stored in the hydrogen gas tank 104 via the hydrogen gas introduction path 106. By introducing hydrogen gas into the hydrogen gas tank 104, the pressure of the hydrogen gas stored in the hydrogen gas storage section 64 can be increased to a predetermined set pressure. The pressure of the hydrogen gas stored in the hydrogen gas storage section 64 and the pressure of the oxygen gas stored in the oxygen gas storage section 60 are the same.
[0048] In the water electrolysis system 10, during the electrolysis of water by the isobaric water electrolysis stack 66, the first channel 86 and the second channel 88 are each filled with water. This suppresses the permeation of the generated gases (oxygen gas and hydrogen gas) through the electrolyte membrane 72. In other words, it suppresses cross-leakage of the generated gases.
[0049] The ratio of hydrogen gas to oxygen gas produced by the electrolysis of water using the isobaric water electrolysis stack 66 is 2:1. That is, the amount of hydrogen gas produced per unit time by the isobaric water electrolysis stack 66 is twice the amount of oxygen gas produced per unit time by the isobaric water electrolysis stack 66. In contrast, the volume of the hydrogen gas storage unit 64 is twice the volume of the oxygen gas storage unit 60.
[0050] In this case, the force exerted by the oxygen gas in the first gas-liquid separator 52 on the water surface and the force exerted by the hydrogen gas in the second gas-liquid separator 54 on the water surface can be made equal to each other. In the following explanation, the force exerted by the oxygen gas in the first gas-liquid separator 52 on the water surface will be referred to as the "first force," and the force exerted by the hydrogen gas in the second gas-liquid separator 54 on the water surface will be referred to as the "second force."
[0051] As a result, the water pressure in the first channel 86 and the water pressure in the second channel 88 become the same, so even if the electrolyte membrane 72 deteriorates (for example, if the electrolyte membrane 72 ruptures), the mixing of the generated gases (hydrogen gas and oxygen gas) with each other can be suppressed. Therefore, the reliability of the water electrolysis system 10 is improved.
[0052] Furthermore, the water stored in the first gas-liquid separator 52 and the water stored in the second gas-liquid separator 54 are connected to each other by the water present in the first water supply channel 90 and the water present in the second water supply channel 92. In this case, the water levels in the first gas-liquid separator 52 and the second gas-liquid separator 54 change so that the first and second pressing forces are equal, thereby suppressing the generation of differential pressure between the first channel 86 and the second channel 88.
[0053] In the fuel cell system 14, when the on-off valve 32 opens the first oxygen gas supply passage 22, oxygen gas stored in the oxygen gas storage section 60 is introduced into the fuel cell stack 16 via the first oxygen gas supply passage 22, the gas-liquid separator 28, and the second oxygen gas supply passage 24. Also, when the on-off valve 46 opens the first hydrogen gas supply passage 36, hydrogen gas stored in the hydrogen gas storage section 64 is introduced into the fuel cell stack 16 via the first hydrogen gas supply passage 36, the gas-liquid separator 42, and the second hydrogen gas supply passage 38.
[0054] The fuel cell stack 16 generates electricity through an electrochemical reaction between hydrogen gas and oxygen gas. The oxygen exhaust gas is discharged to the gas-liquid separator 28 via the oxygen gas discharge passage 26. In the gas-liquid separator 28, the oxygen exhaust gas is separated into gas and liquid. The oxygen exhaust gas from which the water has been removed is guided to the second oxygen gas supply passage 24 and reused. When sending the water stored in the gas-liquid separator 28 to the first gas-liquid separator 52, the operation of the water electrolysis system 10 is stopped to sufficiently reduce the oxygen gas pressure in the first gas-liquid separator 52.
[0055] The hydrogen exhaust gas is discharged to the gas-liquid separator 42 via the hydrogen gas discharge passage 40. In the gas-liquid separator 42, the hydrogen exhaust gas is separated into gas and liquid. The hydrogen exhaust gas from which the water has been removed is led to the second hydrogen gas supply passage 38 and reused. When sending the water stored in the gas-liquid separator 42 to the second gas-liquid separator 54, the operation of the water electrolysis system 10 is stopped to sufficiently reduce the pressure of the hydrogen gas in the second gas-liquid separator 54.
[0056] According to this embodiment, since the first channel 86 and the second channel 88 are each filled with water during the electrolysis of water by the water electrolysis device 50, it is possible to suppress the permeation of the generated gas through the electrolyte membrane 72 (the occurrence of cross-leakage).
[0057] Furthermore, the water stored in the first gas-liquid separator 52 and the water filling the first channel 86 are interconnected, and the water stored in the second gas-liquid separator 54 and the water filling the second channel 88 are interconnected. This allows the pressure in the first channel 86 and the pressure in the second channel 88 to be made equal by adjusting the force exerted by the oxygen gas in the first gas-liquid separator 52 on the water surface and the force exerted by the hydrogen gas in the second gas-liquid separator 54 on the water surface. This prevents the generated gases from mixing with each other even if the electrolyte membrane 72 deteriorates (for example, if the electrolyte membrane 72 ruptures).
[0058] Furthermore, the water electrolysis system 10 is configured such that the water stored in the first gas-liquid separator 52 and the water stored in the second gas-liquid separator 54 can communicate with each other. In this case, the water levels in the first gas-liquid separator 52 and the second gas-liquid separator 54 can be adjusted so that the force exerted by the oxygen gas on the water stored in the first gas-liquid separator 52 is equal to the force exerted by the hydrogen gas on the water stored in the second gas-liquid separator 54. Thus, a better water electrolysis system 10 and energy system 12 can be obtained.
[0059] The water electrolysis system 10 is not limited to the configuration described above. The capacities of the two oxygen gas tanks 98 do not have to be the same. The capacities of the four hydrogen gas tanks 104 do not have to be the same. The oxygen gas storage unit 60 may have one or more oxygen gas tanks 98. The hydrogen gas storage unit 64 may have one, two, three or five or more hydrogen gas tanks 104. The capacity of the hydrogen gas storage unit 64 may be the same as or less than the capacity of the oxygen gas storage unit 60.
[0060] In the water electrolysis system 10, the introduction channel 94 may introduce water into the second channel 88 without introducing water into the first channel 86 of the isobaric water electrolysis stack 66. Alternatively, the introduction channel 94 may introduce water into both the first channel 86 and the second channel 88.
[0061] (First variation) Next, a water electrolysis system 10A according to the first modified example will be described. In the water electrolysis system 10A according to the first modified example, the same reference numerals are used for components identical to those in the water electrolysis system 10 described above, and their detailed descriptions are omitted. In this modified example, components identical to those in the water electrolysis system 10 described above will produce the same effects.
[0062] Figure 3 is a schematic diagram of an energy system 12 equipped with a water electrolysis system 10A according to the first modified example. As shown in Figure 3, the water electrolysis system 10A comprises a water electrolysis device 50, a first gas-liquid separator 52a, a second gas-liquid separator 54a, a water supply channel 56a, a first outlet channel 58a, and a second outlet channel 62a.
[0063] The first gas-liquid separator 52a has two first tank sections 110 and an oxygen gas outlet 112. Water can be stored in the first tank sections 110. The first tank sections 110 also function as oxygen gas tanks 98a for storing oxygen gas. That is, the first gas-liquid separator 52a also functions as an oxygen gas storage section 60a for storing oxygen gas. The two first tank sections 110 are arranged in parallel. The volumes of the two first tank sections 110 are the same. The oxygen gas outlet 112 connects each of the two first tank sections 110 to the first oxygen gas supply section 22. The oxygen gas stored in each first tank section 110 communicates with each other via the oxygen gas outlet 112.
[0064] The second gas-liquid separator 54a has four second tank sections 114 and a hydrogen gas outlet 116. Water can be stored in the second tank sections 114. The second tank sections 114 also function as hydrogen gas tanks 104a for storing hydrogen gas. That is, the second gas-liquid separator 54a also functions as a hydrogen gas storage section 64a for storing hydrogen gas. The four second tank sections 114 are arranged in parallel. The volumes of the four second tank sections 114 are the same. The hydrogen gas outlet 116 connects each of the four second tank sections 114 to the first hydrogen gas supply line 36. The hydrogen gas stored in each second tank section 114 communicates with each other via the hydrogen gas outlet 116.
[0065] The pressure of the hydrogen gas stored in the second gas-liquid separator 54a and the pressure of the oxygen gas stored in the first gas-liquid separator 52a are the same.
[0066] The water supply channel 56a includes a first water supply channel 90a, a second water supply channel 92a, a connecting channel 118, and an introduction channel 94a. The first water supply channel 90a connects the two first tank sections 110 to each other. As a result, the water stored in each first tank section 110 is connected to each other via the water present in the first water supply channel 90a. The second water supply channel 92a connects the four second tank sections 114 to each other. As a result, the water stored in each second tank section 114 is connected to each other via the water present in the second water supply channel 92a.
[0067] The connecting channel 118 connects the first water supply channel 90a and the second water supply channel 92a to each other. As a result, the water stored in each first tank section 110 and the water stored in each second tank section 114 are connected to each other. The introduction channel 94a connects the second water supply channel 92a and the isobaric water electrolysis stack 66 to each other. A water pump 96 is provided in the introduction channel 94a.
[0068] The water pump 96 sends water stored in the first tank section 110 and water stored in the second tank section 114 to the isobaric water electrolysis stack 66. The introduction channel 94a introduces water into the first channel 86 of the isobaric water electrolysis stack 66. The introduction channel 94a does not introduce water into the second channel 88 of the isobaric water electrolysis stack 66.
[0069] The first discharge channel 58a discharges the oxygen gas and unreacted water generated in the first channel 86 to the first tank section 110. The second discharge channel 62a discharges the hydrogen gas generated in the second channel 88 to the second tank section 114.
[0070] The first channel 86 and the second channel 88 are each filled with water. The water stored in the first tank section 110 and the water filling the first channel 86 are connected to each other by the water present in the water supply channel 56a. Furthermore, the water stored in the first tank section 110 and the water filling the first channel 86 are connected to each other by the water present in the first outlet channel 58a. The water stored in the second tank section 114 and the water filling the second channel 88 are connected to each other by the water present in the second outlet channel 62a.
[0071] In this modified example, the force exerted by the oxygen gas stored in the two oxygen gas tanks 98a on the water surface (first pressure) and the force exerted by the hydrogen gas stored in the four hydrogen gas tanks 104a on the water surface (second pressure) are equal. Therefore, the pressure in the first channel 86 and the pressure in the second channel 88 can be made equal. Thus, the same effect as the water electrolysis system 10 described above is achieved.
[0072] In this modified configuration, the first gas-liquid separator 52a functions as an oxygen gas storage unit 60a and the second gas-liquid separator 54a functions as a hydrogen gas storage unit 64a, thus making the configuration of the water electrolysis system 10A more compact.
[0073] The water electrolysis system 10A is not limited to the configuration described above. The capacities of the two first tank sections 110 do not have to be the same. The capacities of the four second tank sections 114 do not have to be the same. The first gas-liquid separator 52a may have one or more first tank sections 110. The second gas-liquid separator 54a may have one, two, three, or five or more second tank sections 114. The capacity of the second gas-liquid separator 54a may be the same as or less than the capacity of the first gas-liquid separator 52a.
[0074] In the water electrolysis system 10A, the introduction channel 94a may introduce water into the second channel 88 without introducing water into the first channel 86 of the isobaric water electrolysis stack 66. Alternatively, the introduction channel 94a may introduce water into both the first channel 86 and the second channel 88.
[0075] (Second variation) Next, a water electrolysis system 10B according to the second modified example will be described. In the water electrolysis system 10B according to the second modified example, the same reference numerals are used for components identical to those in the water electrolysis systems 10 and 10A described above, and their detailed descriptions are omitted. In this modified example, components identical to those in the water electrolysis systems 10 and 10A described above will produce the same effects.
[0076] Figure 4 is a schematic diagram of an energy system 12 equipped with a water electrolysis system 10B according to a second modified example. As shown in Figure 4, the water electrolysis system 10B includes a water electrolysis device 50, a first gas-liquid separator 52b, a second gas-liquid separator 54b, a water supply channel 56b, a first outlet channel 58b, an oxygen gas storage section 60b, a second outlet channel 62b, and a hydrogen gas storage section 64b.
[0077] The volume of the second gas-liquid separator 54b is larger than the volume of the first gas-liquid separator 52b. Specifically, the volume of the second gas-liquid separator 54b is twice the volume of the first gas-liquid separator 52b.
[0078] The water supply channel 56b has a first water supply channel 90b, a second water supply channel 92b, and an inlet channel 94b. The first water supply channel 90b is connected to the first gas-liquid separator 52b. The second water supply channel 92b is connected to the second gas-liquid separator 54b. The inlet channel 94b is connected to the first water supply channel 90b and the second water supply channel 92b.
[0079] The introduction channel 94b combines the water supplied from the first water supply channel 90b and the water supplied from the second water supply channel 92b and introduces them into the isobaric water electrolysis stack 66. The introduction channel 94b is equipped with a water pump 96. The water pump 96 sends the water stored in the first gas-liquid separator 52b and the water stored in the second gas-liquid separator 54b to the isobaric water electrolysis stack 66. The introduction channel 94b introduces water into the first channel 86. The introduction channel 94b does not introduce water into the second channel 88.
[0080] The first outlet channel 58b leads the oxygen gas and unreacted water generated in the first channel 86 to the first gas-liquid separator 52b. The second outlet channel 62b leads the hydrogen gas generated in the second channel 88 to the second gas-liquid separator 54b.
[0081] The oxygen gas storage unit 60b is configured in the same manner as the oxygen gas storage unit 60 described above. The oxygen gas introduction passage 100 of the oxygen gas storage unit 60b is provided with a first back pressure valve 122. The first back pressure valve 122 opens when the pressure of the oxygen gas in the first gas-liquid separator 52b is equal to or greater than a predetermined oxygen gas pressure threshold. The first back pressure valve 122 closes when the pressure of the oxygen gas in the first gas-liquid separator 52b is less than the oxygen gas pressure threshold.
[0082] The hydrogen gas storage unit 64b is configured similarly to the hydrogen gas storage unit 64. The hydrogen gas storage unit 64b has two hydrogen gas tanks 104. A second back pressure valve 124 is provided in the hydrogen gas introduction passage 106 of the hydrogen gas storage unit 64b. The second back pressure valve 124 opens when the pressure of the hydrogen gas in the second gas-liquid separator 54b is above a predetermined hydrogen gas pressure threshold. The second back pressure valve 124 closes when the pressure of the hydrogen gas in the second gas-liquid separator 54b is below the hydrogen gas pressure threshold. In the water electrolysis system 10B, the pressure of the hydrogen gas stored in the hydrogen gas storage unit 64b is higher than the pressure of the oxygen gas stored in the oxygen gas storage unit 60b.
[0083] In the water electrolysis system 10B, since the volume of the second gas-liquid separator 54b is twice the volume of the first gas-liquid separator 52b, the pressure of the oxygen gas in the first gas-liquid separator 52b and the pressure of the hydrogen gas in the second gas-liquid separator 54b can be made equal. Therefore, the pressure in the first flow path 86 and the pressure in the second flow path 88 can be made equal. Thus, it achieves the same effect as the water electrolysis system 10 described above.
[0084] The water electrolysis system 10B is not limited to the configuration described above. The oxygen gas storage unit 60b may have one or more oxygen gas tanks 98. The hydrogen gas storage unit 64b may have one or more hydrogen gas tanks 104. The capacity of the second gas-liquid separator 54b may be the same as or less than the capacity of the first gas-liquid separator 52b.
[0085] In the water electrolysis system 10B, the introduction channel 94b may introduce water into the second channel 88 without introducing water into the first channel 86 of the isobaric water electrolysis stack 66. Alternatively, the introduction channel 94b may introduce water into both the first channel 86 and the second channel 88.
[0086] (Third variation) Next, a water electrolysis system 10C according to the third modified example will be described. In the water electrolysis system 10C according to the third modified example, the same reference numerals are used for components identical to those in the water electrolysis systems 10, 10A, and 10B described above, and their detailed descriptions are omitted. In this modified example, components identical to those in the water electrolysis systems 10, 10A, and 10B described above will produce the same effects.
[0087] Figure 5 is a schematic diagram of an energy system 12 equipped with a water electrolysis system 10C according to a third modified example. As shown in Figure 5, the water electrolysis system 10C comprises a water electrolysis device 50, a first gas-liquid separator 52c, a second gas-liquid separator 54c, a water supply channel 56c, a first outlet channel 58c, an oxygen gas storage section 60b, a second outlet channel 62c, and a hydrogen gas storage section 64b.
[0088] The volume of the first gas-liquid separator 52c and the volume of the second gas-liquid separator 54c are the same. The water supply channel 56c has a first water supply channel 90c, a second water supply channel 92c, and an introduction channel 94c. The first water supply channel 90c is connected to the first gas-liquid separator 52c.
[0089] The second water supply channel 92c is connected to the second gas-liquid separator 54c. The introduction channel 94c is connected to the first water supply channel 90c and the second water supply channel 92c. A water pump 96 is provided in the introduction channel 94c. The introduction channel 94c supplies water to both the first channel 86 and the second channel 88. Both the first channel 86 and the second channel 88 are filled with water.
[0090] The first outlet channel 58c leads the oxygen gas and unreacted water generated in the first channel 86 to the first gas-liquid separator 52c. The second outlet channel 62c leads the hydrogen gas generated in the second channel 88 to the second gas-liquid separator 54c.
[0091] In this modified example, the water level in the second gas-liquid separator 54c is lower than the water level in the first gas-liquid separator 52c. This allows the space in the second gas-liquid separator 54c that can accommodate hydrogen gas to be larger than the space in the first gas-liquid separator 52c that can accommodate oxygen gas. Therefore, the first and second pressing forces can be made equal. Consequently, it achieves the same effect as the water electrolysis system 10 described above.
[0092] The water electrolysis system 10C is not limited to the configuration described above. The oxygen gas storage unit 60c may have one or more oxygen gas tanks 98. The hydrogen gas storage unit 64c may have one or more hydrogen gas tanks 104. The capacity of the second gas-liquid separator 54c may be greater than or less than the capacity of the first gas-liquid separator 52c.
[0093] (Fourth variation) Next, the water electrolysis system 10D according to the fourth modified example will be described. In the water electrolysis system 10D according to the fourth modified example, the same reference numerals are used for components identical to those in the water electrolysis systems 10, 10A to 10C described above, and their detailed descriptions are omitted. In this modified example, components identical to those in the water electrolysis systems 10, 10A to 10C described above will produce the same effects.
[0094] Figure 6 is a schematic diagram of an energy system 12 equipped with a water electrolysis system 10D according to the fourth modified example. As shown in Figure 6, the water electrolysis system 10D comprises a water electrolysis device 50, a first gas-liquid separator 52d, a second gas-liquid separator 54d, a water supply channel 56d, a first outlet channel 58d, an oxygen gas storage section 60d, a second outlet channel 62d, a hydrogen gas storage section 64d, and a connecting passage 132.
[0095] The capacity of the second gas-liquid separator 54d is twice the capacity of the first gas-liquid separator 52d. The water supply channel 56d has a first inlet channel 134 and a second inlet channel 136. The first inlet channel 134 connects the first gas-liquid separator 52d and the isobaric water electrolysis stack 66. A water pump 138 is provided in the first inlet channel 134. The water pump 138 sends the water stored in the first gas-liquid separator 52d to the first channel 86 of the isobaric water electrolysis stack 66.
[0096] The second inlet channel 136 connects the second gas-liquid separator 54d and the isobaric water electrolysis stack 66. A water pump 140 is provided in the second inlet channel 136. The water pump 140 sends the water stored in the second gas-liquid separator 54d to the second channel 88 of the isobaric water electrolysis stack 66.
[0097] The first channel 86 is filled with water supplied from the first inlet channel 134. The first outlet channel 58d leads the oxygen gas and unreacted water generated in the first channel 86 to the first gas-liquid separator 52d. The second channel 88 is filled with water supplied from the second inlet channel 136. The second outlet channel 62d leads the hydrogen gas and water generated in the second channel 88 to the second gas-liquid separator 54d.
[0098] The water electrolysis system 10D does not have the first back pressure valve 122 and the second back pressure valve 124 shown in Figure 4. Therefore, the pressure of the oxygen gas in the first gas-liquid separator 52d is the same as the pressure of the oxygen gas in each oxygen gas tank 98. Also, the pressure of the hydrogen gas in the second gas-liquid separator 54d is the same as the pressure of the hydrogen gas in the hydrogen gas tank 104. Therefore, the pressure of the hydrogen gas in the second gas-liquid separator 54d is twice the pressure of the oxygen gas in the first gas-liquid separator 52d.
[0099] The connecting passage 132 connects the water stored in the first gas-liquid separator 52d and the water stored in the second gas-liquid separator 54d. The connecting passage 132 is provided with an on-off valve 142. The on-off valve 142 opens and closes the connecting passage 132.
[0100] In the water electrolysis system 10D, in the initial state before starting water electrolysis, the pressure in the first gas-liquid separator 52d and the pressure in the second gas-liquid separator 54d are the same. In the initial state of the water electrolysis system 10D, the on-off valve 142 opens the communication passage 132, thereby making the water level in the first gas-liquid separator 52d and the water level in the second gas-liquid separator 54d the same. After this, with the on-off valve 142 closed on the communication passage 132, water electrolysis is started by the isobaric water electrolysis stack 66.
[0101] In this modified example, since the capacity of the second gas-liquid separator 54d is twice that of the first gas-liquid separator 52d, the force exerted by the oxygen gas in the first gas-liquid separator 52d on the water surface (first force) and the force exerted by the hydrogen gas in the second gas-liquid separator 54d on the water surface (second force) can be made equal to each other. Therefore, it produces the same effect as the water electrolysis system 10 described above.
[0102] In this modified example, the water supply channel 56d includes a first inlet channel 134 for introducing water stored in the first gas-liquid separator 52d into the first channel 86, and a second inlet channel 136 for introducing water stored in the second gas-liquid separator 54d into the second channel 88. The water electrolysis system 10D further includes a connecting passage 132 for connecting the water stored in the first gas-liquid separator 52d and the water stored in the second gas-liquid separator 54d to each other, and an on / off valve 142 for opening and closing the connecting passage 132.
[0103] With this configuration, the on / off valve 142 opens the communication passage 132, allowing the water level of the first gas-liquid separator 52d and the water level of the second gas-liquid separator 54d to be adjusted as needed.
[0104] The water electrolysis system 10D is not limited to the configuration described above. The oxygen gas storage unit 60d may have one or more oxygen gas tanks 98. The hydrogen gas storage unit 64d may have one or more hydrogen gas tanks 104. The capacity of the second gas-liquid separator 54d may be the same as or less than the capacity of the first gas-liquid separator 52d.
[0105] (Fifth variation) Next, the water electrolysis system 10E according to the fifth modified example will be described. In the water electrolysis system 10E according to the fifth modified example, the same reference numerals are used for components identical to those in the water electrolysis systems 10, 10A to 10D described above, and their detailed descriptions are omitted. In this modified example, components identical to those in the water electrolysis systems 10, 10A to 10D described above will produce the same effects.
[0106] Figure 7 is a schematic diagram of an energy system 12 equipped with a water electrolysis system 10E according to the fifth modified example. As shown in Figure 7, the water electrolysis system 10E comprises a water electrolysis device 50, a first gas-liquid separator 52e, a second gas-liquid separator 54e, a water supply channel 56e, a first outlet channel 58e, a second outlet channel 62e, and a connecting passage 132a.
[0107] The first gas-liquid separator 52e is configured in the same manner as the first gas-liquid separator 52a (see Figure 3) described above. The second gas-liquid separator 54e is configured in the same manner as the second gas-liquid separator 54a (see Figure 3) described above. The second gas-liquid separator 54e has two second tank sections 114.
[0108] The water supply channel 56e has a first inlet channel 134a and a second inlet channel 136a. The first inlet channel 134a connects the two first tank sections 110 and the isobaric water electrolysis stack 66 to each other. A water pump 138 is provided in the first inlet channel 134a. The water pump 138 sends the water stored in the first gas-liquid separator 52e to the first channel 86 of the isobaric water electrolysis stack 66.
[0109] The second inlet channel 136a connects the two second tank sections 114 and the isobaric water electrolysis stack 66 to each other. A water pump 140 is provided in the second inlet channel 136a. The water pump 140 sends the water stored in the second gas-liquid separator 54e to the second channel 88 of the isobaric water electrolysis stack 66.
[0110] The first channel 86 is filled with water supplied from the first inlet channel 134a. The first outlet channel 58e discharges the oxygen gas and unreacted water generated in the first channel 86 to the first gas-liquid separator 52e. The second channel 88 is filled with water supplied from the second inlet channel 136a.
[0111] The connecting passage 132a connects the first inlet passage 134a and the second inlet passage 136a. The connecting passage 132a can connect the water stored in the first gas-liquid separator 52e and the water stored in the second gas-liquid separator 54e. The connecting passage 132a is provided with an on-off valve 142. The on-off valve 142 opens and closes the connecting passage 132a.
[0112] In the water electrolysis system 10E, after power generation by the fuel cell stack 16 begins, the on-off valve 142 is controlled to open the communication passage 132a. That is, in the water electrolysis system 10E, the on-off valve 142 opens the communication passage 132a after the pressure of the oxygen gas in the first gas-liquid separator 52e and the pressure of the hydrogen gas in the second gas-liquid separator 54e have decreased.
[0113] In this modified example, with the communication passage 132a open by the on-off valve 142, the water level in the second gas-liquid separator 54e becomes lower than the water level in the first gas-liquid separator 52e. This allows the space in the second gas-liquid separator 54e that can contain hydrogen gas to be larger than the space in the first gas-liquid separator 52e that can contain oxygen gas. Therefore, the first and second pressing forces can be made equal. Consequently, it achieves the same effect as the water electrolysis system 10 described above.
[0114] The water electrolysis system 10E is not limited to the configuration described above. The capacities of the two first tank sections 110 do not have to be the same. The capacities of the two second tank sections 114 do not have to be the same. The first gas-liquid separator 52e may have one or more first tank sections 110. The second gas-liquid separator 54e may have one or more second tank sections 114. The capacity of the second gas-liquid separator 54e may be larger or smaller than the capacity of the first gas-liquid separator 52e.
[0115] The following additional information is disclosed regarding the above embodiments.
[0116] (Note 1) The water electrolysis system (10, 10A~10E) of the present disclosure includes an electrolyte membrane (72), a first channel (86) and a second channel (88) provided on both sides of the electrolyte membrane, a water electrolysis device (50) that generates oxygen gas in the first channel and hydrogen gas in the second channel by electrolyzing water, a first gas-liquid separator (52, 52a~52e) and a second gas-liquid separator (54, 54a~54e) capable of storing water, a water supply channel (56, 56a~56e) for supplying the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator to the water electrolysis device, and the oxygen gas generated in the first channel The water electrolyzer includes a first outlet channel (58, 58a~58e) for leading the water to the first gas-liquid separator, and a second outlet channel (62, 62a~62e) for leading the hydrogen gas generated in the second channel to the second gas-liquid separator. The first channel and the second channel are each filled with water during the electrolysis of water by the water electrolyzer, and the water stored in the first gas-liquid separator and the water filling the first channel are connected to each other, as are the water stored in the second gas-liquid separator and the water filling the second channel, and the water stored in the first gas-liquid separator and the water stored in the second channel are connected to each other, and the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator are connected to each other.
[0117] With this configuration, since both the first and second channels are filled with water during the electrolysis of water by the water electrolyzer, it is possible to suppress the permeation of the generated gas through the electrolyte membrane (the occurrence of cross-leakage).
[0118] Furthermore, the water stored in the first gas-liquid separator and the water filling the first channel are interconnected, and the water stored in the second gas-liquid separator and the water filling the second channel are interconnected. This allows the pressure in the first channel and the pressure in the second channel to be made equal by adjusting the force exerted by the oxygen gas in the first gas-liquid separator on the water surface (first pressure) and the force exerted by the hydrogen gas in the second gas-liquid separator on the water surface (second pressure). This prevents the generated gases from mixing with each other even if the electrolyte membrane deteriorates (for example, if the electrolyte membrane 72 ruptures).
[0119] Furthermore, the water electrolysis system is configured such that the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator can communicate with each other. In this case, the water levels in the first gas-liquid separator and the second gas-liquid separator can be adjusted so that the first and second pressing forces are equal. Thus, a better water electrolysis system can be obtained.
[0120] (Note 2) The water electrolysis system described in Appendix 1 may have a water supply channel comprising: a first water supply channel (90, 90a~90c) connected to the first gas-liquid separator; a second water supply channel (92, 92a~92c) connected to the second gas-liquid separator; and an introduction channel (94, 94a~94c) connected to the first water supply channel and the second water supply channel, which combines the water supplied from the first water supply channel and the water supplied from the second water supply channel and introduces them into the water electrolysis device.
[0121] With this configuration, the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator can be connected to each other with a simple setup.
[0122] (Note 3) The water electrolysis system described in Appendix 2, wherein the introduction channel introduces water into only one of the first channel and the second channel, the water introduced into one of the first channel is led to one of the first gas-liquid separators and the second gas-liquid separator, and the water present in the other of the first channel and the second channel is connected to the water stored in the other of the first gas-liquid separators via either the first outlet channel or the second outlet channel.
[0123] With this configuration, even if water is introduced into only one of the first or second channels, both the first and second channels can be filled with water.
[0124] (Note 4) The water electrolysis system described in Appendix 2 or 3, wherein the introduction channel introduces water into both the first channel and the second channel, the water introduced from the introduction channel into the first channel flows to the first gas-liquid separator via the first outlet channel, and the water introduced from the introduction channel into the second channel flows to the second gas-liquid separator via the second outlet channel.
[0125] This configuration makes it easier to fill the first and second channels with water.
[0126] (Note 5) The water electrolysis system described in Appendix 1, wherein the water supply channel includes a first inlet channel (134, 134a) for introducing water stored in the first gas-liquid separator into the first channel, and a second inlet channel (136, 136a) for introducing water stored in the second gas-liquid separator into the second channel, and may further include a connecting passage (132, 132a) for connecting the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator to each other, and an on / off valve (142) for opening and closing the connecting passage.
[0127] With this configuration, the water level in the first gas-liquid separator and the water level in the second gas-liquid separator can be adjusted by opening the communication passage with the on / off valve.
[0128] (Note 6) A water electrolysis system as described in any one of the appendices 1 to 5, wherein the capacity of the second gas-liquid separator may be greater than the capacity of the first gas-liquid separator.
[0129] With this configuration, it becomes easier to make the first pressing force and the second pressing force equal to each other.
[0130] (Note 7) A water electrolysis system as described in any one of the appendices 1 to 6, further comprising an oxygen gas storage unit (60) communicating with the first gas-liquid separator for storing oxygen gas, and a hydrogen gas storage unit (64) communicating with the second gas-liquid separator for storing hydrogen gas, wherein the capacity of the hydrogen gas storage unit may be greater than the capacity of the oxygen gas storage unit.
[0131] With this configuration, it becomes easier to make the first pressing force and the second pressing force equal to each other.
[0132] (Note 8) The energy system (12) of this disclosure comprises a water electrolysis system described in any one of appendices 1 to 7, and a fuel cell system (14) that generates electricity using hydrogen gas and oxygen gas produced by the water electrolysis system, wherein water generated during power generation by the fuel cell system is supplied to at least one of the first gas-liquid separator and the second gas-liquid separator.
[0133] With this configuration, an energy system that produces the effects described in Appendices 1 to 7 can be obtained.
[0134] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. These embodiments can also be implemented in combination. For example, the order of operations and processes in the embodiments described above are given as examples only and are not limited thereto. The same applies when numerical values or mathematical formulas are used in the description of the embodiments described above. [Explanation of Symbols]
[0135] 10, 10A~10E…Water electrolysis system 12…Energy systems 14…Fuel cell systems 50...Water electrolysis device 52, 52a~52e...First gas-liquid separator 54, 54a~54e...Second gas-liquid separator 56, 56a~56e…Water supply channels 58, 58a~58e…First outlet channels 60, 60a~60d...Oxygen gas storage section 62, 62a~62e...Second discharge channel 64, 64a~64d...Hydrogen gas storage section 72...Electrolyte membrane 86...First channel 88...Second channel 90, 90a~90c...First water supply channel 92, 92a~92c...Second water supply channel 94, 94a~94c... Inlet channel 132, 132a... Connecting passage 134, 134a...First intake channel 136, 136a...Second intake channel 142... Shut-off valve
Claims
1. A water electrolysis apparatus comprising an electrolyte membrane and a first channel and a second channel provided on both sides of the electrolyte membrane, wherein oxygen gas is generated in the first channel and hydrogen gas is generated in the second channel by electrolyzing water, A first gas-liquid separator and a second gas-liquid separator capable of storing water, A water supply channel for supplying the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator to the water electrolysis apparatus, A first outlet channel that leads the oxygen gas generated in the first channel to the first gas-liquid separator, A second outlet channel for supplying the hydrogen gas generated in the second channel to the second gas-liquid separator, Equipped with, A water electrolysis system in which each of the first and second channels is filled with water during the electrolysis of water by the water electrolysis apparatus, and the water stored in the first gas-liquid separator and the water filling the first channel are connected to each other, and the water stored in the second gas-liquid separator and the water filling the second channel are connected to each other, and the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator are connected to each other.
2. A water electrolysis system according to claim 1, The aforementioned water supply channel is A first water supply channel connected to the first gas-liquid separator, A second water supply channel connected to the second gas-liquid separator, An introduction channel connected to the first water supply channel and the second water supply channel, which combines the water supplied from the first water supply channel and the water supplied from the second water supply channel and introduces them into the water electrolysis device, A water electrolysis system having the following features.
3. A water electrolysis system according to claim 2, The aforementioned introduction channel introduces water into only one of the first channel and the second channel. The water guided into one of the aforementioned flow paths is then guided into one of the gas-liquid separators, the first gas-liquid separator and the second gas-liquid separator. A water electrolysis system in which the water present in the other of the first and second flow channels is connected to the water stored in the other of the first and second gas-liquid separators via either the first or second outlet flow channel.
4. A water electrolysis system according to claim 2, The aforementioned introduction channel introduces water into both the first channel and the second channel. The water introduced from the introduction channel into the first channel flows to the first gas-liquid separator via the first outlet channel. A water electrolysis system in which water introduced from the introduction channel into the second channel flows to the second gas-liquid separator via the second outlet channel.
5. A water electrolysis system according to claim 1, The aforementioned water supply channel is A first introduction channel for introducing water stored in the first gas-liquid separator into the first flow path, A second introduction channel for introducing the water stored in the second gas-liquid separator into the second flow path, It has, A connecting passage for connecting the water stored in the first gas-liquid separator and the water stored in the second gas-liquid separator, A valve for opening and closing the aforementioned communication passage, A water electrolysis system that also includes additional features.
6. A water electrolysis system according to claim 1, A water electrolysis system in which the capacity of the second gas-liquid separator is greater than the capacity of the first gas-liquid separator.
7. A water electrolysis system according to claim 1, An oxygen gas storage unit for storing oxygen gas, which is in communication with the first gas-liquid separator, A hydrogen gas storage unit for storing hydrogen gas, which is in communication with the second gas-liquid separator, Furthermore, A water electrolysis system in which the capacity of the hydrogen gas storage section is greater than the capacity of the oxygen gas storage section.
8. A water electrolysis system according to any one of claims 1 to 7, A fuel cell system that generates electricity using hydrogen gas and oxygen gas produced by the aforementioned water electrolysis system, Equipped with, An energy system in which water generated during power generation by the fuel cell system is supplied to at least one of the first gas-liquid separator and the second gas-liquid separator.