Control device and electrolysis system of electrolysis system

Abstract

This invention provides a control device for an electrolysis system and an electrolysis system. The control device (11) of the electrolysis system (10) includes a degradation prediction unit (244) and a supply current control unit (242), wherein the degradation prediction unit predicts the degradation degree of each of the water electrolysis reactor (72) and the booster reactor (150); the supply current control unit controls the supply current supplied to the water electrolysis reactor and the supply current supplied to the booster reactor, and the supply current control unit can constantly control the supply current supplied to the reactor with a higher degradation degree between the water electrolysis reactor and the booster reactor, and can adaptively control the supply current supplied to the reactor with a lower degradation degree between the water electrolysis reactor and the booster reactor. Accordingly, further degradation of the reactor with a higher degradation degree between the water electrolysis reactor and the booster reactor can be suppressed.

Description

Technical Field

[0001] This invention relates to a control device for an electrolysis system and an electrolysis system. Background Technology

[0002] In recent years, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy, research and development are underway to develop electrolysis systems that can help improve energy efficiency.

[0003] For example, Japanese Patent Publication No. 7421581 discloses an electrolysis system having a water electrolysis device and a pressure boosting device. The water electrolysis device electrolyzes water by supplying current to a water electrolysis stack. The pressure boosting device pressurizes hydrogen gas by supplying current to a pressure boosting stack, wherein the pressure boosting stack is filled with hydrogen gas produced by the water electrolysis stack. The electrolysis system is controlled by a control device. Summary of the Invention

[0004] We are looking forward to a better control device and electrolysis system.

[0005] The purpose of this invention is to solve the above-mentioned technical problems.

[0006] The first aspect of the present invention is a control device for an electrolysis system, comprising a water electrolysis device and a booster device, wherein the water electrolysis device electrolyzes water by supplying current to a water electrolysis reactor; the booster device boosts the pressure of hydrogen by supplying current to a booster reactor into which hydrogen is introduced from the water electrolysis reactor, wherein the device comprises a degradation prediction unit and a supply current control unit, the degradation prediction unit predicting the degradation degree of each of the water electrolysis reactor and the booster reactor; the supply current control unit controlling the supply current supplied to the water electrolysis reactor and the supply current supplied to the booster reactor, the supply current control unit being able to constantly control the supply current supplied to the reactor with a higher degradation degree between the water electrolysis reactor and the booster reactor and being able to adaptively control the supply current supplied to the reactor with a lower degradation degree between the water electrolysis reactor and the booster reactor.

[0007] The second aspect of the present invention is an electrolysis system having the control device of the first aspect.

[0008] According to the present invention, a control device and an electrolysis system with better performance can be obtained.

[0009] The above-described objectives, features, and advantages should be readily understood through the description of the following embodiments with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of an energy system with an electrolysis system involved in the implementation method.

[0011] Figure 2 This is a cross-sectional diagram illustrating the water electrolysis unit.

[0012] Figure 3 This is a cross-sectional diagram illustrating the boost unit.

[0013] Figure 4 This is a block diagram illustrating the control device.

[0014] Figure 5 This is a flowchart illustrating the control method of the electrolysis system. Detailed Implementation

[0015] In an electrolysis system, a portion of the hydrogen produced by the electrolysis of water in a water electrolyzer is directed through an electrolyte membrane to the oxygen transport channel. The flow rate of hydrogen through the electrolyte membrane varies depending on factors such as the pressure within the oxygen transport channel and the temperature of the water electrolyzer. Therefore, even when a constant current is supplied to the water electrolyzer, the flow rate of hydrogen extracted from it varies. Under these conditions, when a constant current is supplied to a booster reactor to pressurize the hydrogen, the amount of hydrogen present in the channels used to guide the hydrogen produced by the water electrolyzer to the booster reactor increases or decreases, sometimes making it impossible to efficiently pressurize the hydrogen through the booster reactor.

[0016] To adjust the amount of hydrogen present in the flow channels used to guide hydrogen produced by a water electrolyzer into the electrolyzer, for example, when the supply current to the water electrolyzer is adaptively controlled and the supply current to the booster reactor is constantly controlled, the water electrolyzer is more prone to degradation than the booster reactor. On the other hand, when the supply current to the water electrolyzer is constantly controlled and the supply current to the booster reactor is adaptively controlled, the booster reactor is more prone to degradation than the water electrolyzer. The present invention provides a control device and an electrolysis system capable of suppressing the deviation between the degradation degree of the water electrolyzer and the booster reactor, while simultaneously enabling efficient hydrogen pressurization via the booster reactor.

[0017] Figure 1 This is a schematic diagram of an energy system 12 having an electrolysis system 10 according to the embodiment. Figure 1 As shown, energy system 12 is a regenerative energy system. Energy system 12 is a system combining fuel cell system 14 and electrolysis system 10. Fuel cell system 14 generates electricity and water through the electrochemical reaction of oxygen and hydrogen. Electrolysis system 10 electrolyzes water to produce oxygen and hydrogen. Electrolysis system 10 utilizes the water produced in fuel cell system 14. Fuel cell system 14 utilizes the oxygen and hydrogen produced in electrolysis system 10.

[0018] Such an energy system 12 can be installed on the surface of the Earth or the Moon. Alternatively, the energy system 12 can also be mounted on artificial satellites such as the International Space Station (ISS).

[0019] The fuel cell system 14 has a fuel cell stack 16. The fuel cell stack 16 is a solid polymer fuel cell (PEFC). The fuel cell stack 16 has multiple power generation units 18 and a pair of end plates 20. The multiple power generation units 18 are stacked on top of each other. The pair of end plates 20 clamp the multiple power generation units 18 from the stacking direction.

[0020] Detailed illustrations of the power generation unit 18 are omitted. The power generation unit 18 comprises a membrane electrode assembly (MEA) and a pair of separators. The MEA is held in place by the separators. The MEA has an electrolyte membrane, an anode electrode, and a cathode electrode. The electrolyte membrane is a solid polymer electrolyte membrane. The power generation unit 18 generates electricity through the electrochemical reaction of hydrogen and oxygen. During power generation in the power generation unit 18, water is generated at the cathode electrode.

[0021] The fuel cell system 14 also includes an oxygen tank 22, an oxygen supply channel 24, an oxygen discharge channel 26, a gas-liquid separator 28, an oxygen circulation channel 30, and a first drainage channel 32. The oxygen tank 22 is filled with high-pressure oxygen. The oxygen supply channel 24 supplies the oxygen from the oxygen tank 22 to the fuel cell stack 16. An on / off valve 34 is provided on the oxygen supply channel 24. The on / off valve 34 opens and closes the oxygen supply channel 24.

[0022] Oxygen exhaust passage 26 connects the fuel cell stack 16 and the gas-liquid separator 28 to each other. Oxygen exhaust gas (exhaust gas) discharged from the fuel cell stack 16 flows through oxygen exhaust passage 26. The oxygen exhaust gas contains unreacted oxygen that has not reacted in the power generation unit 18. Additionally, the oxygen exhaust gas contains water (water vapor) generated at the cathode electrode of the power generation unit 18.

[0023] Gas-liquid separator 28 separates the oxygen waste gas discharged from oxygen discharge channel 26 into gas and liquid components. Specifically, gas-liquid separator 28 removes moisture from the oxygen waste gas. Gas-liquid separator 28 stores the water (liquid water) separated from the oxygen waste gas. Oxygen circulation channel 30 connects gas-liquid separator 28 and oxygen supply channel 24. Oxygen circulation channel 30 guides the oxygen waste gas, after moisture removal by gas-liquid separator 28, to oxygen supply channel 24. Oxygen pump 36 is installed on oxygen circulation channel 30. Oxygen pump 36 delivers the oxygen waste gas flowing in oxygen circulation channel 30 to oxygen supply channel 24.

[0024] The first drain channel 32 is a flow channel for discharging water stored in the gas-liquid separator 28 to the outside of the gas-liquid separator 28. A first drain valve 38 is provided on the first drain channel 32. The first drain valve 38 is an on / off valve for opening and closing the first drain channel 32.

[0025] The fuel cell system 14 also includes a hydrogen tank 40, a hydrogen supply channel 42, a hydrogen discharge channel 44, a gas-liquid separator 46, a hydrogen circulation channel 48, and a second drainage channel 50. The hydrogen tank 40 is filled with high-pressure hydrogen. The hydrogen supply channel 42 supplies the hydrogen in the hydrogen tank 40 to the fuel cell stack 16. An on / off valve 52 is provided on the hydrogen supply channel 42. The on / off valve 52 opens and closes the hydrogen supply channel 42.

[0026] A hydrogen exhaust channel 44 connects the fuel cell stack 16 to the gas-liquid separator 46. Hydrogen exhaust gas (exhaust gas) discharged from the fuel cell stack 16 flows through the hydrogen exhaust channel 44. The hydrogen exhaust gas contains unreacted hydrogen that did not react in the power generation unit 18. Additionally, the hydrogen exhaust gas contains moisture that has permeated through the electrolyte membrane from the cathode electrode of the power generation unit 18 and is directed to the anode electrode.

[0027] A gas-liquid separator 46 separates the hydrogen waste gas discharged from the hydrogen discharge channel 44 into gas and liquid components. Specifically, the gas-liquid separator 46 removes moisture from the hydrogen waste gas. The gas-liquid separator 46 stores the water (liquid water) separated from the hydrogen waste gas. A hydrogen circulation channel 48 connects the gas-liquid separator 46 and the hydrogen supply channel 42. The hydrogen circulation channel 48 guides the hydrogen waste gas, after moisture removal by the gas-liquid separator 46, to the hydrogen supply channel 42. A hydrogen pump 54 is installed on the hydrogen circulation channel 48. The hydrogen pump 54 sends the hydrogen waste gas flowing in the hydrogen circulation channel 48 to the hydrogen supply channel 42.

[0028] The second drain channel 50 is a flow channel for discharging water stored in the gas-liquid separator 46 to the outside of the gas-liquid separator 46. A second drain valve 56 is provided on the second drain channel 50. The second drain valve 56 is an on / off valve for opening and closing the second drain channel 50.

[0029] The fuel cell system 14 can have structural elements other than those described above. That is, the fuel cell system 14 can, for example, have a cooling device for circulating a cooling medium in the fuel cell stack 16.

[0030] The electrolysis system 10 includes a gas-liquid separator 58, a water electrolysis device 60, and a booster device 62. A water supply channel 64 is connected to the gas-liquid separator 58 of the electrolysis system 10. The water supply channel 64 is connected to a first drain channel 32 and a second drain channel 50. The water supply channel 64 directs water from the first drain channel 32 and water from the second drain channel 50 to the gas-liquid separator 58. A pump 66 and an on / off valve 68 are provided on the water supply channel 64. The pump 66 delivers water flowing in the water supply channel 64 to the gas-liquid separator 58. The on / off valve 68 opens and closes the water supply channel 64. The gas-liquid separator 58 has a water storage section 70. The water stored in the storage section 70 of the gas-liquid separator 58 is used by the water electrolysis device 60.

[0031] In the water electrolysis device 60, oxygen and hydrogen are produced by electrolyzing water (pure water). The water electrolysis device 60 is, for example, a solid polymer water electrolysis device.

[0032] The water electrolysis device 60 includes a water electrolysis stack 72, a first power source 73, a water electrolysis supply channel 74, a water electrolysis discharge channel 76, a first oxygen delivery channel 78, a gas-liquid separator 80, a third drainage channel 82, and a second oxygen delivery channel 84. The water electrolysis stack 72 comprises multiple water electrolysis units 86 and a pair of end plates 88. The multiple water electrolysis units 86 are stacked on top of each other. The pair of end plates 88 clamp the multiple water electrolysis units 86 from the stacking direction.

[0033] Figure 2 This is a cross-sectional diagram illustrating water electrolysis unit 86. Figure 2 In this context, the X direction represents the stacking direction of multiple water electrolysis units 86. For example... Figure 2 As shown, in the water electrolysis unit 86, water is supplied to the cathode electrode 110. The water electrolysis unit 86 generates oxygen at the anode electrode 112 and hydrogen at the cathode electrode 110 by electrolyzing water.

[0034] The water electrolysis unit 86 is a differential pressure water electrolysis unit where the pressure of oxygen in the anode electrode 112 is higher than the pressure of water in the cathode electrode 110. Alternatively, the water electrolysis unit 86 can be an isobaric water electrolysis unit where the pressure of oxygen in the anode electrode 112 is approximately equal to the pressure of water in the cathode electrode 110. The water electrolysis apparatus 60, for example, is capable of generating 14.7 MPa of oxygen at the anode electrode 112.

[0035] In the water electrolysis unit 86, water supply connection hole 94, water discharge connection hole 96, and oxygen discharge connection hole 98 are arranged to penetrate the water electrolysis unit 86 along the X direction. The water supply connection holes 94 of the multiple water electrolysis units 86 are interconnected. The water discharge connection holes 96 of the multiple water electrolysis units 86 are interconnected. The oxygen discharge connection holes 98 of the multiple water electrolysis units 86 are interconnected.

[0036] A water supply connection hole 94 and a water discharge connection hole 96 are provided on the outer periphery of the water electrolysis unit 86. An oxygen discharge connection hole 98 is provided in the center of the water electrolysis unit 86. The water supply connection hole 94 supplies water to the cathode electrode 110. The water discharge connection hole 96 discharges the water flowing through the cathode electrode 110 and the hydrogen gas generated at the cathode electrode 110 to the outside. The oxygen discharge connection hole 98 discharges the oxygen generated at the anode electrode 112 to the outside.

[0037] The water electrolysis unit 86 has a membrane electrode structure 100, a pair of partitions 102, and a frame member 104. The membrane electrode structure 100 is held by the pair of partitions 102. The frame member 104 is formed in a ring shape to surround the membrane electrode structure 100. A sealing member 106 is provided between the frame member 104 and the partitions 102 to prevent fluid (water and hydrogen) from flowing out.

[0038] The partition 102 is made of, for example, stainless steel. The partition 102 is coated, for example, with a material containing niobium. Below, in... Figure 2 In this context, the separator 102 located in the X1 direction of the membrane electrode structure 100 is sometimes referred to as the "first electrolytic separator 102a", and the separator 102 located in the X2 direction of the membrane electrode structure 100 is referred to as the "second electrolytic separator 102b".

[0039] The membrane electrode structure 100 includes an electrolyte membrane 108, a cathode electrode 110, and an anode electrode 112. The electrolyte membrane 108 is sandwiched between the cathode electrode 110 and the anode electrode 112. The electrolyte membrane 108 is an ion exchange membrane. Specifically, the electrolyte membrane 108 is, for example, a proton exchange membrane (PEM). A proton exchange membrane is, for example, a fluorine polymer membrane. Alternatively, the electrolyte membrane 108 can be an anion exchange membrane (AEM). The electrolyte membrane 108 prevents oxygen generated by the anode electrode 112 from passing through to the cathode electrode 110.

[0040] The cathode electrode 110 has a cathode catalyst layer 114, a protective sheet 116, and a cathode power supply 118. The cathode catalyst layer 114 is bonded to a surface 108a (the surface of the electrolyte membrane 108 facing the X1 direction) of the electrolyte membrane 108. The cathode power supply 118 also functions as a diffusion layer supplying water to the cathode catalyst layer 114. The cathode power supply 118 has a portion formed by a porous component. The protective sheet 116 is disposed between the cathode catalyst layer 114 and the cathode power supply 118. The protective sheet 116 prevents the electrolyte membrane 108 from being damaged by the high-pressure oxygen generated at the anode electrode 112 pushing it towards the cathode power supply 118. A plurality of through holes 120 are formed on the protective sheet 116.

[0041] The anode electrode 112 has an anode catalyst layer 122 and an anode power supply 124. The anode catalyst layer 122 is bonded to another surface 108b of the electrolyte membrane 108 (the surface of the electrolyte membrane 108 facing the X2 direction). The anode catalyst layer 122 may contain, for example, iridium, ruthenium, etc. The anode power supply 124 also functions as a gas diffusion layer for discharging oxygen generated by the anode catalyst layer 122. The anode power supply 124 has a portion formed by a porous component.

[0042] A support member 126 is provided between the first electrolysis separator 102a and the cathode power supply body 118 to support the membrane electrode structure 100. A communication channel 128 is formed on the support member 126. The communication channel 128 guides water introduced from the water supply communication hole 94 into the cathode power supply body 118. In addition, the communication channel 128 guides the water-hydrogen mixture in the cathode power supply body 118 into the water discharge communication hole 96.

[0043] A load application mechanism 130 is provided between the second electrolytic separator 102b and the anode power supply body 124 to apply force to the anode power supply body 124 in the X1 direction. The load application mechanism 130 includes, for example, a leaf spring 132, a retainer 134, and a conductive sheet 136.

[0044] An annular component 138 is provided between the second electrolytic separator 102b and the outer periphery of the electrolyte membrane 108. The annular component 138 contacts the other surface 108b of the electrolyte membrane 108 in a liquid-tight and gas-tight manner.

[0045] An annular sealing member 140 is disposed between the annular member 138 and the load application mechanism 130. The sealing member 140 contacts the second electrolytic separator 102b and the electrolyte membrane 108 in a liquid-tight and airtight manner, respectively. A space (anode chamber 142) for accommodating the anode electrode 112 is formed inside the sealing member 140. The load application mechanism 130 is disposed in the anode chamber 142. The leaf spring 132 and the retainer 134 constituting the load application mechanism 130 are made of stainless steel, for example. The leaf spring 132 and the retainer 134 are coated with a niobium-containing material, for example.

[0046] like Figure 1 As shown, the first power source 73 is a DC power source. The first power source 73 supplies current to the water electrolysis reactor 72. In other words, the first power source 73 applies a voltage (see reference) between the cathode power supply 118 and the anode power supply 124 of the water electrolysis unit 86. Figure 1 and Figure 2 ).

[0047] The water electrolysis supply channel 74 connects the gas-liquid separator 58 and the water electrolysis stack 72. The water electrolysis supply channel 74 is connected to the water supply communication port 94 of the water electrolysis unit 86 (see reference). Figure 2 The water electrolysis supply channel 74 directs the water stored in the gas-liquid separator 58 to the water electrolysis reactor 72. A water pump 143 is installed on the water electrolysis supply channel 74. The water pump 143 delivers the water flowing in the water electrolysis supply channel 74 to the water electrolysis reactor 72.

[0048] The water electrolysis discharge channel 76 connects the gas-liquid separator 58 and the water electrolysis stack 72. The water electrolysis discharge channel 76 is connected to the water discharge communication hole 96 of the water electrolysis unit 86 (see reference). Figure 2 The water electrolysis discharge channel 76 directs the mixture of hydrogen produced by the cathode electrode 110 of the water electrolysis unit 86 and unelectrolyzed water to the gas-liquid separator 58. The gas-liquid separator 58 separates the mixture from the water electrolysis discharge channel 76. The water separated from the mixture is stored in the storage section 70 of the gas-liquid separator 58.

[0049] The oxygen delivery channel 78 and the oxygen discharge connection hole 98 of the water electrolysis unit 86 (see reference) Figure 2 The first oxygen delivery channel 78 directs oxygen generated by the water electrolysis reactor 72 to the gas-liquid separator 80. The gas-liquid separator 80 separates the oxygen from the oxygen delivered from the first oxygen delivery channel 78. That is, the gas-liquid separator 80 removes water from the oxygen. The gas-liquid separator 80 is capable of storing the water (liquid water) separated from the oxygen.

[0050] The third drainage channel 82 directs the water stored in the gas-liquid separator 80 to the gas-liquid separator 58. A third drainage valve 144 is provided on the third drainage channel 82. The third drainage valve 144 is an on / off valve for opening and closing the third drainage channel 82.

[0051] The second oxygen delivery channel 84 directs oxygen, after moisture removal by the gas-liquid separator 80, to the oxygen tank 22. A first back pressure valve 146 is installed on the second oxygen delivery channel 84. The first back pressure valve 146 opens when the pressure of the oxygen extracted from the water electrolysis reactor 72 is above a predetermined oxygen pressure threshold. The first back pressure valve 146 closes when the pressure of the oxygen extracted from the water electrolysis reactor 72 is below the oxygen pressure threshold.

[0052] The water electrolysis device 60 can have structural elements other than those described above. For example, the water electrolysis device 60 can have an ion exchange resin for purifying the water supplied to the water electrolysis reactor 72.

[0053] The booster unit 62 includes a booster stack 150, a second power source 152, a booster supply channel 154, a booster discharge channel 156, a first hydrogen delivery channel 158, a gas-liquid separator 160, a fourth drainage channel 162, and a second hydrogen delivery channel 164. The booster stack 150 boosts the hydrogen produced by the water electrolysis stack 72. The booster stack 150 includes multiple booster units 166 and a pair of end plates 168. The multiple booster units 166 are stacked on top of each other. The pair of end plates 168 clamp the multiple booster units 166 from the stacking direction of the multiple booster units 166.

[0054] Figure 3 This is a cross-sectional view of the boost unit 166. Figure 3 In this context, the Y direction is the stacking direction of the multiple boost units 166. For example... Figure 3 As shown, in the boost unit 166, humidified hydrogen gas is supplied to the anode electrode 186. The boost unit 166 supplies current to the anode electrode 186 and the cathode electrode 188, causing the cathode electrode 188 to generate hydrogen gas. In the boost device 62, for example, the cathode electrode 188 can generate hydrogen gas at a pressure of 70 MPa.

[0055] In the booster unit 166, the supply connection port 170, the discharge connection port 172, and the hydrogen discharge connection port 174 are arranged to extend through the booster unit 166 in the Y direction. The supply connection ports 170 of the plurality of booster units 166 are interconnected. The discharge connection ports 172 of the plurality of booster units 166 are interconnected. The hydrogen discharge connection ports 174 of the plurality of booster units 166 are interconnected.

[0056] A supply connection port 170 and an exhaust connection port 172 are provided on the outer periphery of the boost unit 166. A hydrogen exhaust connection port 174 is provided in the center of the boost unit 166. The supply connection port 170 supplies hydrogen to the anode electrode 186. The exhaust connection port 172 discharges the hydrogen (unreacted hydrogen) flowing through the anode electrode 186 to the outside. The hydrogen exhaust connection port 174 discharges the hydrogen generated at the cathode electrode 188 to the outside.

[0057] The boost unit 166 has a membrane electrode structure 176, a pair of partitions 178, and a frame member 180. The membrane electrode structure 176 is held by the pair of partitions 178. The frame member 180 is formed in an annular shape to surround the membrane electrode structure 176. A sealing member 182 is provided between the frame member 180 and the partitions 178 to prevent fluid (water and hydrogen) from flowing out.

[0058] The partition 178 is, for example, made of titanium. Below, in Figure 3 In this context, the separator 178 located in the Y1 direction of the membrane electrode structure 176 is sometimes referred to as the "first boost separator 178a", and the separator 178 located in the Y2 direction of the membrane electrode structure 176 is referred to as the "second boost separator 178b".

[0059] The membrane electrode structure 176 includes an electrolyte membrane 184, an anode electrode 186, and a cathode electrode 188. The electrolyte membrane 184 is sandwiched between the anode electrode 186 and the cathode electrode 188. The electrolyte membrane 184 is an ion exchange membrane. Specifically, the electrolyte membrane 184 is, for example, a proton exchange membrane (PEM). A proton exchange membrane is, for example, a fluorine polymer membrane. Alternatively, the electrolyte membrane 184 can be an anion exchange membrane (AEM). The electrolyte membrane 184 prevents hydrogen gas generated by the cathode electrode 188 from passing through to the anode electrode 186.

[0060] The anode electrode 186 has an anode catalyst layer 190, a protective sheet 192, and an anode power supply 194. The anode catalyst layer 190 is bonded to a surface 184a (the surface of the electrolyte membrane 184 facing the Y1 direction) of the electrolyte membrane 184. The anode power supply 194 also functions as a gas diffusion layer supplying hydrogen to the anode catalyst layer 190. The anode power supply 194 has a portion formed by a porous component. The protective sheet 192 is disposed between the anode catalyst layer 190 and the anode power supply 194. The protective sheet 192 prevents the electrolyte membrane 184 from being damaged by the high-pressure hydrogen gas generated at the cathode electrode 188 pushing it towards the anode power supply 194. A plurality of through holes 196 are formed on the protective sheet 192.

[0061] The cathode electrode 188 has a cathode catalyst layer 198 and a cathode power supply 200. The cathode catalyst layer 198 is bonded to another surface 184b of the electrolyte membrane 184 (the surface of the electrolyte membrane 184 facing the Y2 direction). The cathode power supply 200 also functions as a gas diffusion layer for discharging hydrogen produced by the cathode catalyst layer 198. The cathode power supply 200 has a portion formed by porous components.

[0062] A support member 202 is provided between the first boost partition 178a and the anode power supply body 194 to support the membrane electrode structure 176. A communication channel 204 is formed on the support member 202. The communication channel 204 guides hydrogen introduced from the supply communication hole 170 into the anode power supply body 194. In addition, the communication channel 204 guides unreacted hydrogen in the anode power supply body 194 to exit the communication hole 172.

[0063] A load application mechanism 206 is provided between the second boosting partition 178b and the cathode power supply 200 to apply force to the cathode power supply 200 in the Y1 direction. The load application mechanism 206 includes, for example, a leaf spring 208, a retainer 210, and a conductive sheet 212.

[0064] An annular component 214 is provided between the second booster diaphragm 178b and the outer periphery of the electrolyte membrane 184. The annular component 214 contacts the other surface 184b of the electrolyte membrane 184 in a liquid-tight and gas-tight manner.

[0065] An annular sealing member 216 is disposed between the annular member 214 and the load application mechanism 206. The sealing member 216 contacts the second booster diaphragm 178b and the electrolyte membrane 184 in a liquid-tight and airtight manner, respectively. A space (cathode chamber 218) for accommodating the cathode electrode 188 is formed inside the sealing member 216. The load application mechanism 206 is disposed in the cathode chamber 218. The leaf spring 208 and the retainer 210 constituting the load application mechanism 206 are made of, for example, an iron-containing material. The leaf spring 208 and the retainer 210 are coated with, for example, a niobium-containing material.

[0066] like Figure 1 As shown, the second power supply 152 is a DC power supply. The second power supply 152 supplies current to the boost stack 150. In other words, the second power supply 152 applies a voltage between the cathode power supply 200 and the anode power supply 194 of the boost unit 166 (see reference). Figure 1 and Figure 2 ).

[0067] A booster supply channel 154 connects the gas-liquid separator 58 and the booster stack 150. The booster supply channel 154 directs hydrogen from the gas-liquid separator 58 to the booster stack 150. A hydrogen pump 220 is installed on the booster supply channel 154. The hydrogen pump 220 delivers the hydrogen flowing through the booster supply channel 154 to the booster stack 150. Furthermore, the hydrogen supplied from the booster supply channel 154 to the booster stack 150 contains a suitable amount of water vapor. This water vapor is used to humidify the electrolyte membrane 184 of the booster unit 166.

[0068] The boosted discharge channel 156 connects the gas-liquid separator 58 and the booster reactor 150. The boosted discharge channel 156 directs unreacted hydrogen gas and water vapor from the booster reactor 150 to the gas-liquid separator 58.

[0069] The hydrogen delivery channel 158 and the hydrogen discharge connection hole 174 of the booster unit 166 (see reference) Figure 3 The first hydrogen delivery channel 158 directs the hydrogen produced by the booster reactor 150 to the gas-liquid separator 160. The gas-liquid separator 160 separates the hydrogen from the hydrogen delivered from the first hydrogen delivery channel 158 into liquid and gas components. That is, the gas-liquid separator 160 removes water from the hydrogen. The gas-liquid separator 160 is capable of storing the water (liquid water) separated from the hydrogen.

[0070] The fourth drainage channel 162 directs the water stored in the gas-liquid separator 160 to the gas-liquid separator 58. A fourth drainage valve 222 is provided on the fourth drainage channel 162. The fourth drainage valve 222 is an on / off valve for opening and closing the fourth drainage channel 162.

[0071] The second hydrogen delivery channel 164 directs hydrogen, after moisture removal by the gas-liquid separator 160, to the hydrogen tank 40. A second back pressure valve 224 is provided on the second hydrogen delivery channel 164. The second back pressure valve 224 opens when the pressure of the hydrogen discharged from the booster reactor 150 is above a predetermined hydrogen pressure threshold. The second back pressure valve 224 closes when the pressure of the hydrogen discharged from the booster reactor 150 is below the hydrogen pressure threshold.

[0072] The booster device 62 can have structural elements other than those mentioned above.

[0073] like Figure 1 As shown, the energy system 12 includes a first ion measuring unit 226, a second ion measuring unit 228, a third ion measuring unit 230, a fourth ion measuring unit 232, and a fifth ion measuring unit 234. The first ion measuring unit 226 is installed in the water electrolysis device 60. The second ion measuring unit 228 is installed in the booster device 62. The third ion measuring unit 230 is installed in the gas-liquid separator 58. The fourth ion measuring unit 232 and the fifth ion measuring unit 234 are installed in the fuel cell system 14.

[0074] The first ion measuring unit 226 measures the amount of dissolved ions (ion dissolution) from the water electrolysis reactor 72. The first ion measuring unit 226 also measures the amount of dissolved ions contained in the oxygen generated by the water electrolysis reactor 72. Specifically, the first ion measuring unit 226 is installed in the gas-liquid separator 80 of the water electrolysis device 60. The first ion measuring unit 226 measures, for example, the amount of dissolved ions present in the water stored in the gas-liquid separator 80 at predetermined time intervals.

[0075] In the water electrolysis unit 86, fluoride ions are sometimes dissolved due to the decomposition of the electrolyte membrane 108. Niobium ions are sometimes dissolved due to the peeling of the coatings on the separator 102, leaf spring 132, and retainer 134. Additionally, iron ions are sometimes dissolved from the peeled portions of the coatings in the water electrolysis unit 86. Iridium and ruthenium ions are sometimes dissolved due to the deterioration of the anode catalyst layer 122 in the water electrolysis unit 86.

[0076] The first ion measuring unit 226 can measure, for example, fluoride ions, niobium ions, iron ions, iridium ions, ruthenium ions, etc. The first ion measuring unit 226 can sequentially measure the amount of dissolved ions present in the water stored in the gas-liquid separator 80. The first ion measuring unit 226 can directly measure the amount of dissolved ions from the oxygen generated by the water electrolysis reactor 72.

[0077] The second ion measuring unit 228 measures the amount of dissolved ions from the booster reactor 150. Specifically, the second ion measuring unit 228 is installed in the gas-liquid separator 160 of the booster device 62. The second ion measuring unit 228 measures, for example, the amount of dissolved ions present in the water stored in the gas-liquid separator 160 at predetermined time intervals.

[0078] In the boost unit 166, fluoride ions may sometimes dissolve due to the decomposition of the electrolyte membrane 184. Niobium ions may sometimes dissolve due to the peeling of the coatings on the leaf spring 208 and the retainer 210. Additionally, iron ions may sometimes dissolve from the peeled portion of the coating in the boost unit 166. Titanium ions may sometimes dissolve due to the deterioration of the separator 178 in the boost unit 166.

[0079] The second ion measuring unit 228 can measure, for example, fluoride ions, niobium ions, iron ions, titanium ions, etc. The second ion measuring unit 228 can sequentially measure the amount of dissolved ions present in the water stored in the gas-liquid separator 160. The second ion measuring unit 228 can directly measure the amount of dissolved ions from hydrogen gas pressurized by the booster reactor 150.

[0080] A third ion measuring unit 230 is provided in the gas-liquid separator 58. The third ion measuring unit 230 measures the amount of dissolved ions present in the water stored in the gas-liquid separator 58 at predetermined time intervals, for example. The third ion measuring unit 230 can sequentially measure the amount of dissolved ions present in the water stored in the gas-liquid separator 58.

[0081] A fourth ion measuring unit 232 is provided in the gas-liquid separator 28 of the fuel cell system 14. The fourth ion measuring unit 232 measures the amount of dissolved ions present in the water stored in the gas-liquid separator 28 at predetermined time intervals. The fourth ion measuring unit 232 can sequentially measure the amount of dissolved ions present in the water stored in the gas-liquid separator 28.

[0082] A fifth ion measuring unit 234 is provided in the gas-liquid separator 46 of the fuel cell system 14. The fifth ion measuring unit 234 measures the amount of dissolved ions present in the water stored in the gas-liquid separator 46 at predetermined time intervals, for example. The fifth ion measuring unit 234 can sequentially measure the amount of dissolved ions present in the water stored in the gas-liquid separator 46.

[0083] The third ion measuring unit 230, the fourth ion measuring unit 232, and the fifth ion measuring unit 234 can, for example, measure fluoride ions, niobium ions, iron ions, iridium ions, ruthenium ions, titanium ions, etc.

[0084] The energy system 12 has a control device 11. Figure 4 This is a block diagram illustrating the control device 11. (For example...) Figure 4 As shown, the control device 11 includes an arithmetic unit 236 and a storage unit 238. The arithmetic unit 236 is composed of a processor, such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). That is, the arithmetic unit 236 is composed of processing circuitry.

[0085] The calculation unit 236 includes a control unit 240, a supply current control unit 242, a degradation prediction unit 244, a dissolved ion quantity information acquisition unit 246, and a judgment unit 248. The control unit 240 is responsible for the overall control of the energy system 12. The supply current control unit 242 controls the supply current supplied to the water electrolyzer 72 and the supply current supplied to the booster reactor 150. That is, the supply current control unit 242 controls the first power source 73 and the second power source 152. The degradation prediction unit 244 predicts the degradation degree of each of the water electrolyzer 72 and the booster reactor 150. The dissolved ion quantity information acquisition unit 246 acquires first dissolved ion quantity information and second dissolved ion quantity information. The first dissolved ion quantity information is related to the dissolved ion quantity from the water electrolyzer 72. The second dissolved ion quantity information is related to the dissolved ion quantity from the booster reactor 150.

[0086] The control unit 240, supply current control unit 242, degradation prediction unit 244, dissolved ion quantity information acquisition unit 246, and determination unit 248 can be implemented by the arithmetic unit 236 executing a program stored in the storage unit 238. Furthermore, at least a portion of the control unit 240, supply current control unit 242, degradation prediction unit 244, dissolved ion quantity information acquisition unit 246, and determination unit 248 can be implemented using integrated circuits such as ASICs (Application Specific Integrated Circuits) and FPGAs (Field-Programmable Gate Arrays). Additionally, at least a portion of the control unit 240, supply current control unit 242, degradation prediction unit 244, dissolved ion quantity information acquisition unit 246, and determination unit 248 can be constructed using electronic circuits containing discrete components.

[0087] Storage unit 238 comprises volatile memory (not shown) and non-volatile memory (not shown). Examples of volatile memory include RAM (Random Access Memory). The volatile memory serves as the processor's working memory, temporarily storing data required for processing or computation. Examples of non-volatile memory include ROM (Read Only Memory) and flash memory. The non-volatile memory serves as storage memory, storing programs, tables, maps, etc. At least a portion of storage unit 238 may also be provided in a processor, integrated circuit, etc., as described above.

[0088] Next, the control of the electrolysis system 10 will be explained. Figure 5 This is a flowchart illustrating the control method of the electrolysis system 10.

[0089] like Figure 5As shown, in step S1, the control unit 240 drives the energy system 12. Specifically, as... Figure 1 As shown, the control unit 240 controls the fuel cell system 14 to start generating electricity. Specifically, the control unit 240 controls the on / off valve 34 to open the oxygen supply channel 24. Oxygen filled in the oxygen tank 22 is then supplied to the fuel cell stack 16 through the oxygen supply channel 24. Additionally, the control unit 240 controls the on / off valve 52 to open the hydrogen supply channel 42. Hydrogen filled in the hydrogen tank 40 is then supplied to the fuel cell stack 16 through the hydrogen supply channel 42. The fuel cell stack 16 generates electricity through the electrochemical reaction of oxygen and hydrogen. The electrical power generated by the fuel cell stack 16 can be used to drive the energy system 12. Furthermore, the electrical power generated by the fuel cell stack 16 can be used to charge a battery (not shown).

[0090] The oxygen exhaust gas (exhaust gas) from the fuel cell stack 16 is directed to the gas-liquid separator 28 through the oxygen discharge channel 26. The gas-liquid separator 28 removes moisture from the oxygen exhaust gas. The moisture removed from the oxygen exhaust gas is stored in the gas-liquid separator 28. The control unit 240 drives the oxygen pump 36. Accordingly, the oxygen exhaust gas after moisture removal is directed from the gas-liquid separator 28 to the oxygen supply channel 24 through the oxygen circulation channel 30.

[0091] The hydrogen exhaust gas (exhaust gas) from the fuel cell stack 16 is directed to the gas-liquid separator 46 through the hydrogen exhaust channel 44. The gas-liquid separator 46 removes moisture from the hydrogen exhaust gas. The moisture removed from the hydrogen exhaust gas is stored in the gas-liquid separator 46. The control unit 240 drives the hydrogen pump 54. Accordingly, the hydrogen exhaust gas after moisture removal is directed from the gas-liquid separator 46 to the hydrogen supply channel 42 through the hydrogen circulation channel 48.

[0092] The control unit 240 controls the first drain valve 38 to open the first drain channel 32 and controls the on / off valve 68 to open the water supply channel 64. Additionally, the control unit 240 drives the pump 66. Accordingly, water stored in the gas-liquid separator 28 is introduced into the gas-liquid separator 58 through the first drain channel 32 and the water supply channel 64. Drainage from the gas-liquid separator 28 to the gas-liquid separator 58 is performed at appropriate times.

[0093] The control unit 240 controls the second drain valve 56 to open the second drain channel 50 and controls the on / off valve 68 to open the water supply channel 64. Additionally, the control unit 240 drives the pump 66. Accordingly, water stored in the gas-liquid separator 46 is introduced into the gas-liquid separator 58 through the second drain channel 50 and the water supply channel 64. Drainage from the gas-liquid separator 46 to the gas-liquid separator 58 is performed at appropriate times.

[0094] Additionally, the control unit 240 controls the water electrolysis device 60 to produce oxygen and hydrogen. Specifically, the control unit 240 drives the water pump 143 and controls the first power supply 73 to supply current to the water electrolysis reactor 72. When the water pump 143 is driven, as... Figure 1and Figure 2 As shown, water stored in the storage section 70 of the gas-liquid separator 58 is supplied to the cathode electrode 110 of the water electrolysis unit 86 through the water electrolysis supply channel 74. Figure 2 As shown, water supplied to the cathode electrode 110 moves from the cathode electrode 110 to the anode electrode 112 within the electrolyte membrane 108. In the anode electrode 112, water is electrolyzed to produce hydrogen ions and oxygen. The hydrogen ions produced by the anode electrode 112 move from the anode electrode 112 to the cathode electrode 110 within the electrolyte membrane 108. In the cathode electrode 110, hydrogen ions bond to produce hydrogen gas. Unreacted water and hydrogen gas supplied to the cathode electrode 110 are discharged to the gas-liquid separator 58 through the water discharge port 96 and the water electrolysis discharge channel 76 (see reference). Figure 1 ).

[0095] like Figure 1 As shown, oxygen produced by the water electrolysis reactor 72 is directed to the gas-liquid separator 80 via the first oxygen delivery channel 78. The gas-liquid separator 80 removes moisture from the oxygen. The moisture removed from the oxygen is stored in the gas-liquid separator 80. The water stored in the gas-liquid separator 80 is drained into the gas-liquid separator 58 via the third drainage channel 82 at appropriate times. The oxygen after moisture removal is directed to the second oxygen delivery channel 84. When the pressure of the oxygen produced by the water electrolysis reactor 72 is above the oxygen pressure threshold, the first back pressure valve 146 is opened, and oxygen is filled into the oxygen tank 22.

[0096] Furthermore, the control unit 240 controls the booster device 62 to pressurize the hydrogen. That is, the control unit 240 drives the hydrogen pump 220 and controls the second power supply 152 to supply current to the booster stack 150. When the hydrogen pump 220 is driven, as... Figure 1 and Figure 3 As shown, hydrogen gas in the gas-liquid separator 58, along with a suitable amount of moisture, is supplied to the anode electrode 186 of the boost unit 166 through the boost supply channel 154. Figure 3 As shown, hydrogen ions are generated in the anode electrode 186. The hydrogen ions generated by the anode electrode 186 move from the anode electrode 186 to the cathode electrode 188 in the electrolyte membrane 184. In the cathode electrode 188, the hydrogen ions bond to generate hydrogen gas. Unreacted hydrogen gas and water supplied to the anode electrode 186 are returned to the gas-liquid separator 58 (see reference 188) through the discharge port 172 and the pressurized discharge channel 156. Figure 1 ).

[0097] like Figure 1As shown, hydrogen generated by cathode electrode 188 is directed to gas-liquid separator 160 via first hydrogen delivery channel 158. Gas-liquid separator 160 removes moisture from the hydrogen. The moisture removed from the hydrogen is stored in gas-liquid separator 160. The water stored in gas-liquid separator 160 is drained into gas-liquid separator 58 via fourth drain channel 162 at appropriate times. Hydrogen after moisture removal is directed to second hydrogen delivery channel 164. When the pressure of hydrogen generated by booster reactor 150 is above the hydrogen pressure threshold, second back pressure valve 224 is opened, and hydrogen is filled into hydrogen tank 40.

[0098] like Figure 5 As shown, after step S1, the process proceeds to step S2. In step S2, the dissolved ion quantity information acquisition unit 246 acquires first dissolved ion quantity information and second dissolved ion quantity information. The first dissolved ion quantity information is information related to the amount of dissolved ions from the water electrolysis reactor 72. The first dissolved ion quantity information is information acquired based on the amount of dissolved ions in the oxygen generated by the water electrolysis reactor 72. In this embodiment, the dissolved ion quantity information acquisition unit 246 acquires the first dissolved ion quantity information based on information output from the first ion measuring unit 226 to the control device 11. That is, the dissolved ion quantity information acquisition unit 246 can acquire, for example, information related to the amount of dissolved ions such as fluoride ions, niobium ions, iron ions, iridium ions, and ruthenium ions. Furthermore, the dissolved ion quantity can be the dissolved ion concentration or the cumulative value of dissolved ions that have dissolved since a predetermined time point.

[0099] The second dissolved ion quantity information is information related to the dissolved ion quantity from the booster reactor 150. This second dissolved ion quantity information is obtained based on the dissolved ion quantity in the hydrogen gas pressurized by the booster reactor 150. In this embodiment, the dissolved ion quantity information acquisition unit 246 acquires the second dissolved ion quantity information based on information output from the second ion measuring unit 228 to the control device 11. That is, the dissolved ion quantity information acquisition unit 246 can, for example, acquire information related to the dissolved ion quantities of fluoride ions, niobium ions, iron ions, titanium ions, etc.

[0100] In this embodiment, when one of the first and second dissolved ion quantity information cannot be obtained and the other of the first and second dissolved ion quantity information can be obtained, the dissolved ion quantity information acquisition unit 246 estimates one of the first and second dissolved ion quantity information based on information related to the amount of dissolved ions in the water stored in the storage unit 70 and the other of the first and second dissolved ion quantity information.

[0101] Specifically, for example, if the first ion measuring unit 226 malfunctions, the dissolved ion quantity information acquisition unit 246 cannot acquire the first dissolved ion quantity information from the first ion measuring unit 226. In this case, the dissolved ion quantity information acquisition unit 246 estimates the first dissolved ion quantity information, for example, based on information related to the amount of dissolved ions in the water stored in the storage unit 70 of the gas-liquid separator 58 and second dissolved ion quantity information. Furthermore, the dissolved ion quantity information acquisition unit 246 can acquire information related to the amount of dissolved ions in the water stored in the storage unit 70 of the gas-liquid separator 58 based on information output from the third ion measuring unit 230 to the control device 11.

[0102] The water stored in the storage section 70 of the gas-liquid separator 58 contains dissolved ions from the water electrolysis reactor 72 and dissolved ions from the booster reactor 150. That is, dissolved ions from the water electrolysis reactor 72, along with oxygen produced by the water electrolysis reactor 72, are directed to the gas-liquid separator 28 via the first oxygen delivery channel 78, the gas-liquid separator 80, the second oxygen delivery channel 84, the oxygen tank 22, the oxygen supply channel 24, the fuel cell stack 16, and the oxygen exhaust channel 26. Therefore, dissolved ions from the water electrolysis reactor 72 are contained in the water stored in the gas-liquid separator 28 of the fuel cell system 14. The water stored in the gas-liquid separator 28 is directed to the gas-liquid separator 58 via the first drainage channel 32 and the water supply channel 64. Additionally, water stored in the gas-liquid separator 80 of the water electrolysis device 60 can be drained into the storage section 70 of the gas-liquid separator 58 via the third drainage channel 82. Therefore, the water stored in the storage section 70 of the gas-liquid separator 58 contains dissolved ions from the water electrolysis reactor 72.

[0103] Dissolved ions from the booster reactor 150, along with hydrogen pressurized by the booster reactor 150, are guided to the gas-liquid separator 46 via a first hydrogen delivery channel 158, a gas-liquid separator 160, a second hydrogen delivery channel 164, a hydrogen tank 40, a hydrogen supply channel 42, a fuel cell stack 16, and a hydrogen exhaust channel 44. Therefore, dissolved ions from the booster reactor 150 are contained in the water stored in the gas-liquid separator 46 of the fuel cell system 14. The water stored in the gas-liquid separator 46 is guided to the gas-liquid separator 58 via a second drain channel 50 and a water supply channel 64. Additionally, water stored in the gas-liquid separator 160 of the booster unit 62 can be drained into the storage section 70 of the gas-liquid separator 58 via a fourth drain channel 162. Therefore, the water stored in the storage section 70 of the gas-liquid separator 58 contains dissolved ions from the booster reactor 150.

[0104] Therefore, the dissolved ion quantity information acquisition unit 246 can estimate the first dissolved ion quantity information based on information related to the amount of dissolved ions in the water stored in the storage unit 70 of the gas-liquid separator 58 and the second dissolved ion quantity information. In this case, the dissolved ion quantity information acquisition unit 246 can, for example, consider information related to the amount of dissolved ions in the water stored in the gas-liquid separator 28 of the fuel cell system 14 and information related to the amount of dissolved ions in the water stored in the gas-liquid separator 46 of the fuel cell system 14. Accordingly, the first dissolved ion quantity information can be estimated with higher accuracy. In addition, the dissolved ion quantity information acquisition unit 246 can acquire information related to the amount of dissolved ions in the water stored in the gas-liquid separator 28 based on information output from the fourth ion measuring unit 232 to the control device 11. The dissolved ion quantity information acquisition unit 246 can acquire information related to the amount of dissolved ions in the water stored in the gas-liquid separator 46 based on information output from the fifth ion measuring unit 234 to the control device 11.

[0105] Furthermore, for example, if the second ion measuring unit 228 malfunctions, the dissolved ion quantity information acquisition unit 246 cannot acquire the second dissolved ion quantity information from the second ion measuring unit 228. In this case, the dissolved ion quantity information acquisition unit 246 estimates the second dissolved ion quantity information, for example, based on information related to the amount of dissolved ions in the water stored in the storage unit 70 of the gas-liquid separator 58 and the first dissolved ion quantity information. In this case, the dissolved ion quantity information acquisition unit 246 may, for example, consider information related to the amount of dissolved ions in the water stored in the gas-liquid separator 28 of the fuel cell system 14 and information related to the amount of dissolved ions in the water stored in the gas-liquid separator 46 of the fuel cell system 14. Accordingly, the second dissolved ion quantity information can be estimated with higher accuracy.

[0106] After step S2, the process proceeds to step S3. In step S3, the degradation prediction unit 244 predicts the degradation degree of both the water electrolysis reactor 72 and the booster reactor 150. Specifically, the degradation prediction unit 244 predicts the degradation degree of the water electrolysis reactor 72 based on first dissolved ion quantity information. That is, the degradation prediction unit 244 can, for example, predict the degradation degree of the electrolyte membrane 108 of the water electrolysis reactor 72 based on information related to the dissolved ion quantity of fluoride ions (first dissolved ion quantity information). In addition, the degradation prediction unit 244 can, for example, predict the degradation degree of the anode catalyst layer 122 of the water electrolysis reactor 72 based on information related to the dissolved ion quantity of at least one of iridium ions and ruthenium ions (first dissolved ion quantity information). Moreover, the degradation prediction unit 244 can, for example, predict the degradation degree of the partition 102 and the like of the water electrolysis reactor 72 based on information related to the dissolved ion quantity of at least one of niobium ions and iron ions (first dissolved ion quantity information).

[0107] Furthermore, the degradation prediction unit 244 predicts the degree of degradation of the booster reactor 150 based on the second dissolved ion quantity information. That is, the degradation prediction unit 244 can, for example, predict the degree of degradation of the electrolyte membrane 184 of the booster reactor 150 based on information related to the dissolved ion quantity of fluoride ions (the second dissolved ion quantity information). The degradation prediction unit 244 can, for example, predict the degree of degradation of the separator 178 and the like of the booster reactor 150 based on information related to the dissolved ion quantity of at least one of niobium ions, iron ions, and titanium ions (the second dissolved ion quantity information).

[0108] After step S3, the process proceeds to step S4. In step S4, the determination unit 248 determines whether the amount of dissolved ions from the water electrolysis reactor 72 reaches a first threshold and whether the amount of dissolved ions from the booster reactor 150 reaches a second threshold. The first and second thresholds are predetermined and stored in the storage unit 238. If the determination unit 248 determines that the amount of dissolved ions from the water electrolysis reactor 72 has not reached the first threshold and the determination unit 248 determines that the amount of dissolved ions from the booster reactor 150 has not reached the second threshold (which is not the case in step S4), the process proceeds to step S5.

[0109] In step S5, the supply current control unit 242 performs supply current control. That is, the supply current control unit 242 constantly controls the supply current supplied to the reactor with a higher degree of degradation in the water electrolysis reactor 72 and the booster reactor 150, and adaptively controls the supply current supplied to the reactor with a lower degree of degradation in the water electrolysis reactor 72 and the booster reactor 150. Accordingly, further degradation of the reactor with a higher degree of degradation in the water electrolysis reactor 72 and the booster reactor 150 can be suppressed.

[0110] In the water electrolyzer 72, a portion of the hydrogen produced by the cathode electrode 110 permeates through the electrolyte membrane 108 and is directed to the anode electrode 112. The flow rate of hydrogen permeating the electrolyte membrane 108 varies depending on the pressure within the first oxygen delivery channel 78 and the temperature of the water electrolyzer 72. Therefore, even if the current supplied to the water electrolyzer 72 and the booster reactor 150 is constant, the amount of hydrogen present in the channels (gas-liquid separator 58, etc.) used to guide the hydrogen produced by the water electrolyzer 72 to the booster reactor 150 is prone to increase or decrease and is not constant. In this case, it is sometimes impossible to efficiently boost the hydrogen pressure through the booster reactor 150.

[0111] However, in this embodiment, by adaptively controlling the supply current of the water electrolyzer 72 and the booster reactor 150, which have a lower degree of degradation, the amount of hydrogen present in the flow channels (gas-liquid separator 58, etc.) used to guide the hydrogen produced by the water electrolyzer 72 to the booster reactor 150 can be adjusted. That is, it is possible to suppress the amount of hydrogen in the gas-liquid separator 58 from becoming excessively low or excessively high. Accordingly, the hydrogen can be pressurized efficiently by the booster reactor 150. After this, the process proceeds to step S6.

[0112] In step S6, the determination unit 248 determines whether there is a drive stop request from the energy system 12. If the determination unit 248 determines that there is no drive stop request from the energy system 12 (no in step S6), the process proceeds to step S2. If the determination unit 248 determines that there is a drive stop request from the energy system 12 (yes in step S6), the process proceeds to step S7.

[0113] In step S7, the control unit 240 stops the drive of the energy system 12. That is, the current supply control unit 242 stops supplying current to the water electrolyzer 72 and the booster reactor 150. Accordingly, the drive of the water electrolyzer 72 and the booster reactor 150 respectively stops. In addition, the control unit 240 stops supplying oxygen and hydrogen to the fuel cell stack 16. After this, Figure 5 The processing is complete.

[0114] If the determination unit 248 determines that the amount of dissolved ions from the water electrolysis reactor 72 has reached the first threshold, or if the determination unit 248 determines that the amount of dissolved ions from the booster reactor 150 has reached the second threshold (yes in step S4), the process proceeds to step S8.

[0115] In step S8, the determination unit 248 determines whether the amount of dissolved ions from the water electrolysis reactor 72 reaches a third threshold and whether the amount of dissolved ions from the booster reactor 150 reaches a fourth threshold. The third threshold is greater than the first threshold. The fourth threshold is greater than the second threshold. The third and fourth thresholds are predetermined and stored in the storage unit 238.

[0116] If the determination unit 248 determines that the amount of dissolved ions from the water electrolysis reactor 72 has not reached the third threshold and the determination unit 248 determines that the amount of dissolved ions from the booster reactor 150 has not reached the fourth threshold (no in step S8), the process proceeds to step S9.

[0117] In step S9, the supply current control unit 242 performs supply current suppression control to suppress the supply current to the water electrolyzer 72 and the booster reactor 150. Specifically, while suppressing the supply current to the water electrolyzer 72 and the booster reactor 150, the supply current control unit 242 constantly controls the supply current supplied to the reactor with a higher degree of degradation in the water electrolyzer 72 and the booster reactor 150, and adaptively controls the supply current supplied to the reactor with a lower degree of degradation in the water electrolyzer 72 and the booster reactor 150. That is, the current supplied to the water electrolyzer 72 and the booster reactor 150 in the supply current suppression control is smaller than the current supplied to the water electrolyzer 72 and the booster reactor 150 in the supply current control (step S5). Accordingly, it is possible to further suppress the further degradation of the water electrolyzer 72 and the booster reactor 150 and to efficiently boost the hydrogen pressure through the booster reactor 150. After this, the process proceeds to step S6.

[0118] If the determination unit 248 determines that the amount of dissolved ions from the water electrolysis reactor 72 has reached the third threshold, or if the determination unit 248 determines that the amount of dissolved ions from the booster reactor 150 has reached the fourth threshold (yes in step S8), the process proceeds to step S10.

[0119] In step S10, the current supply control unit 242 stops supplying current to the water electrolyzer 72 and the booster reactor 150. Accordingly, the operation of each of the water electrolyzer 72 and the booster reactor 150 stops. This prevents further degradation of the water electrolyzer 72 and the booster reactor 150. In this case, the control unit 240 can stop supplying oxygen and hydrogen to the fuel cell stack 16. After this, Figure 5 The processing is complete.

[0120] According to this embodiment, the supply current control unit 242 constantly controls the supply current supplied to the reactor with a higher degree of degradation in the water electrolyzer 72 and the booster reactor 150, and adaptively controls the supply current supplied to the reactor with a lower degree of degradation in the water electrolyzer 72 and the booster reactor 150. Accordingly, further degradation of the reactor with a higher degree of degradation in the water electrolyzer 72 and the booster reactor 150 can be suppressed. Furthermore, since the amount of hydrogen present in the flow channel for guiding hydrogen produced by the water electrolyzer 72 to the booster reactor 150 can be adjusted, the hydrogen can be pressurized efficiently by the booster reactor 150.

[0121] Regarding the above-described embodiments, the following notes are further disclosed.

[0122] (Postscript 1)

[0123] The control device (11) of the electrolysis system (10) of the present invention includes a water electrolysis device (60) and a booster device (62), wherein the water electrolysis device electrolyzes water by supplying current to a water electrolysis reactor (72); the booster device boosts the hydrogen by supplying current to a booster reactor (150) into which hydrogen is introduced from the water electrolysis reactor, wherein the device includes a degradation prediction unit (244) and a supply current control unit (242), the degradation prediction unit predicting the degradation degree of the water electrolysis reactor and the booster reactor respectively; the supply current control unit controlling the supply current supplied to the water electrolysis reactor and the supply current supplied to the booster reactor, the supply current control unit being able to constantly control the supply current supplied to the reactor with a higher degradation degree between the water electrolysis reactor and the booster reactor and being able to adaptively control the supply current supplied to the reactor with a lower degradation degree between the water electrolysis reactor and the booster reactor.

[0124] This structure can suppress further degradation of the water electrolyzer and the booster reactor, especially in those with high degradation levels. Furthermore, because the amount of hydrogen present in the flow channels used to guide hydrogen produced by the water electrolyzer to the booster reactor can be adjusted, the hydrogen can be pressurized efficiently in the booster reactor.

[0125] (Postscript 2)

[0126] In the control device of the electrolysis system described in Appendix 1, there may be a dissolved ion quantity information acquisition unit (246) that acquires information related to the dissolved ion quantity from the water electrolysis reactor, namely, first dissolved ion quantity information, and information related to the dissolved ion quantity from the booster reactor, namely, second dissolved ion quantity information. The degradation prediction unit predicts the degradation degree of the water electrolysis reactor based on the first dissolved ion quantity information and predicts the degradation degree of the booster reactor based on the second dissolved ion quantity information.

[0127] Based on this structure, the degradation degree of a water electrolyzer can be predicted with high accuracy using the first leached ion quantity information. Furthermore, the degradation degree of a booster reactor can be predicted with high accuracy using the second leached ion quantity information.

[0128] (Note 3)

[0129] In the control device of the electrolysis system described in Appendix 2, the first dissolved ion quantity information may be obtained based on the amount of dissolved ions in the oxygen generated by the water electrolysis reactor, and the second dissolved ion quantity information may be obtained based on the amount of dissolved ions in the hydrogen gas pressurized by the booster reactor.

[0130] Based on this structure, the information on the first and second dissolved ions can be obtained with high precision.

[0131] (Note 4)

[0132] In the control device of the electrolysis system described in Appendix 3, the electrolysis system may have a storage unit (70) for storing water contained in the exhaust gas from the fuel cell stack (16) and water from the water electrolysis stack, wherein the fuel cell stack (16) generates electricity through an electrochemical reaction between oxygen generated by the water electrolysis stack and hydrogen pressurized by the booster stack, and the dissolved ion quantity information acquisition unit, when one of the first dissolved ion quantity information and the second dissolved ion quantity information cannot be acquired and the other of the first dissolved ion quantity information and the second dissolved ion quantity information can be acquired, estimates one of the first dissolved ion quantity information and the second dissolved ion quantity information based on information related to the amount of dissolved ions in the water stored in the storage unit and the other of the first dissolved ion quantity information and the second dissolved ion quantity information.

[0133] Based on this structure, even if one of the first or second leached ion quantity information is unavailable, the degradation degree of the water electrolysis reactor and the booster reactor can still be predicted.

[0134] (Note 5)

[0135] In the control device of the electrolysis system described in Appendix 2, there may be a determination unit (248) that determines whether the amount of dissolved ions from the water electrolysis reactor reaches a first threshold and whether the amount of dissolved ions from the booster reactor reaches a second threshold. If the determination unit determines that the amount of dissolved ions from the water electrolysis reactor reaches the first threshold or the determination unit determines that the amount of dissolved ions from the booster reactor reaches the second threshold, the supply current control unit performs supply current suppression control to suppress the supply current supplied to the water electrolysis reactor and the booster reactor.

[0136] According to this structure, if at least one of the water electrolysis reactor and the booster reactor deteriorates to a certain extent, the supply of current to these reactors can be suppressed, thereby inhibiting further deterioration of the water electrolysis reactor and the booster reactor.

[0137] (Note 6)

[0138] In the control device of the electrolysis system described in Appendix 5, the determination unit may determine whether the amount of dissolved ions from the water electrolysis reactor reaches a third threshold greater than the first threshold and whether the amount of dissolved ions from the booster reactor reaches a fourth threshold greater than the second threshold. If the determination unit determines that the amount of dissolved ions from the water electrolysis reactor reaches the third threshold or the determination unit determines that the amount of dissolved ions from the booster reactor reaches the fourth threshold, the current supply control unit stops supplying current to the water electrolysis reactor and the booster reactor.

[0139] Based on this structure, it is possible to safely stop the operation of the water electrolyzer and the booster reactor before they become excessively degraded.

[0140] (Note 7)

[0141] The electrolysis system of the present invention has a control device as described in any one of Appendix 1 to 6.

[0142] An electrolysis system capable of achieving the effects described in Appendices 1 to 6.

[0143] The present invention has been described in detail, but it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit of the invention or the spirit of the invention derived from the content described in the technical solution and its equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the above embodiments, the order of each action or each process is only shown as an example and is not limited thereto. The same applies to the use of numerical values ​​or formulas in the description of the above embodiments.

Claims

1. A control device of an electrolysis system having a water electrolysis device and a pressure raising device, wherein the water electrolysis device electrolyzes water by supplying electric current to a water electrolysis stack; the pressure raising device raises pressure of hydrogen gas generated at the water electrolysis stack by supplying electric current to a pressure raising stack into which the hydrogen gas is introduced, characterized by having a deterioration prediction section and a supply current control section, wherein the deterioration prediction section predicts a degree of deterioration of each of the water electrolysis stack and the pressure raising stack; the supply current control section controls supply current supplied to the water electrolysis stack and supply current supplied to the pressure raising stack, the supply current control section is able to constantly control supply current supplied to the stack in which the degree of deterioration is greater of the water electrolysis stack and the pressure raising stack and is able to self-adaptively control supply current supplied to the stack in which the degree of deterioration is smaller of the water electrolysis stack and the pressure raising stack.

2. The control device of the electrolysis system according to claim 1, characterized by further having a dissolved ion amount information acquisition section that acquires information on a dissolved ion amount from the water electrolysis stack, i.e., first dissolved ion amount information, and information on a dissolved ion amount from the pressure raising stack, i.e., second dissolved ion amount information, the deterioration prediction section predicts the degree of deterioration of the water electrolysis stack based on the first dissolved ion amount information and predicts the degree of deterioration of the pressure raising stack based on the second dissolved ion amount information.

3. The control device of the electrolysis system according to claim 2, characterized in that the first dissolved ion amount information is information acquired based on a dissolved ion amount in oxygen gas generated by the water electrolysis stack, the second dissolved ion amount information is information acquired based on a dissolved ion amount in hydrogen gas raised by the pressure raising stack.

4. The control device of the electrolysis system according to claim 3, characterized in that the electrolysis system has a storage section for storing moisture contained in exhaust gas discharged from a fuel cell stack that generates electric power by electrochemical reaction of oxygen gas generated by the water electrolysis stack and hydrogen gas raised by the pressure raising stack, the dissolved ion amount information acquisition section, in a case where one of the first dissolved ion amount information and the second dissolved ion amount information cannot be acquired and the other of the first dissolved ion amount information and the second dissolved ion amount information can be acquired, estimates the one of the first dissolved ion amount information and the second dissolved ion amount information based on information on a dissolved ion amount in water stored in the storage section and the other of the first dissolved ion amount information and the second dissolved ion amount information.

5. The control device of the electrolysis system according to claim 2, characterized by having a determination section that determines whether a dissolved ion amount from the water electrolysis stack reaches a first threshold value and determines whether a dissolved ion amount from the pressure raising stack reaches a second threshold value, ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ In a case where the determination section determines that the amount of eluted ions from the water electrolysis stack reaches the first threshold value, or in a case where the determination section determines that the amount of eluted ions from the voltage boosting stack reaches the second threshold value, the supply current control section executes supply current suppression control to suppress the supply current supplied to the water electrolysis stack and the voltage boosting stack.

6. The control device of an electrolysis system according to claim 5, wherein the determination section determines whether the amount of eluted ions from the water electrolysis stack reaches a third threshold value that is larger than the first threshold value and determines whether the amount of eluted ions from the voltage boosting stack reaches a fourth threshold value that is larger than the second threshold value, In a case where the determination section determines that the amount of eluted ions from the water electrolysis stack reaches the third threshold value, or in a case where the determination section determines that the amount of eluted ions from the voltage boosting stack reaches the fourth threshold value, the supply current control section stops the supply of the current to the water electrolysis stack and the voltage boosting stack.

7. An electrolysis system, comprising: the control device according to any one of claims 1 to 6.

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