Renewable energy hydrogen production system

Abstract

The invention discloses a renewable energy hydrogen production system which comprises a flow battery and a hydrazine oxidation hydrogen production system, and the flow battery is used for being connected with a renewable energy system; the hydrazine oxidation hydrogen production system is used for being connected with the renewable energy source system and the flow battery so as to supply power to the hydrazine oxidation hydrogen production system; the hydrazine oxidation hydrogen production system comprises an electrolytic bath, a first storage tank storing a hydrazine solution and a second storage tank storing a water solution, and a first positive electrode, a first negative electrode and a first ion exchange membrane are arranged in the electrolytic bath; the first ion exchange membrane divides the electrolytic cell into a first chamber for arranging the first positive electrode and a second chamber for arranging the first negative electrode; the first storage tank is communicated with the first chamber to form a circulation loop; the second storage tank is communicated with the second chamber to form a circulation loop, so that the aqueous solution circulates in the second storage tank and the second chamber, and the aqueous solution is electrolyzed in the second chamber to generate hydrogen. The system cost can be reduced, and the green electricity proportion can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of hydrogen production, and in particular relates to a renewable energy hydrogen production system. Background Art

[0002] In the technology of hydrogen production from renewable energy power generation, it is difficult to ensure the stable power consumption and local area network stability of the green hydrogen synthesis load due to the volatility and intermittency of renewable energy power generation. When renewable energy power generation is in large supply, electricity may be abandoned, and when renewable energy power generation is short of electricity, it needs to be connected to the public grid, which leads to a decrease in the proportion of green electricity for hydrogen production. In order to solve the technical difficulties of hydrogen production from renewable energy power generation, the method of using renewable energy power generation power supply, configuring a high proportion of energy storage, and connecting to the public grid is usually used to achieve stable hydrogen production, resulting in high overall system costs, high green hydrogen costs, and a low proportion of green electricity. Summary of the invention

[0003] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0004] To this end, an embodiment of the present invention proposes a renewable energy hydrogen production system that can reduce system costs and increase the proportion of green electricity.

[0005] The renewable energy hydrogen production system of the embodiment of the present invention includes:

[0006] A liquid flow battery, wherein the liquid flow battery is used to be connected to a renewable energy system so as to charge and store energy through the renewable energy system;

[0007] A hydrazine oxidation hydrogen production system, wherein the hydrazine oxidation hydrogen production system is connected to a renewable energy system and the liquid flow battery, so as to supply power to the hydrazine oxidation hydrogen production system through the renewable energy system or the liquid flow battery;

[0008] The hydrazine oxidation hydrogen production system comprises:

[0009] An electrolytic cell, wherein the electrolytic cell has a first positive electrode, a first negative electrode and a first ion exchange membrane, wherein the first ion exchange membrane divides the electrolytic cell into a first chamber for arranging the first positive electrode and a second chamber for arranging the first negative electrode;

[0010] a first storage tank storing a hydrazine solution, wherein the first storage tank is connected to the first chamber and forms a circulation loop so that the hydrazine solution circulates in the first storage tank and the first chamber;

[0011] A second storage tank storing an aqueous solution is connected to the second chamber to form a circulation loop so that the aqueous solution circulates in the second storage tank and the second chamber, and the aqueous solution is electrolyzed in the second chamber to generate hydrogen.

[0012] The renewable energy hydrogen production system of the embodiment of the present invention can improve the stability of renewable energy hydrogen production power supply through the joint operation of a liquid flow battery and a hydrazine oxidation hydrogen production system, reduce the voltage and power consumption required for the hydrazine oxidation reaction, achieve efficient water electrolysis, and the converted nitrogen and water will not pollute the environment, thereby reducing system costs and increasing the proportion of green electricity.

[0013] In some embodiments, the hydrazine oxidation hydrogen production system further includes a first pump and a second pump, wherein the first pump is provided on a circulation loop between the first storage tank and the first chamber, and the second pump is provided on a circulation loop between the second storage tank and the second chamber;

[0014] And / or, the first storage tank has a first feed inlet, the first feed inlet is used to add hydrazine solution to the first storage tank, and the second storage tank has a second feed inlet, the second feed inlet is used to add aqueous solution to the second storage tank.

[0015] In some embodiments, the flow battery comprises:

[0016] A battery stack, wherein the inner cavity of the battery stack has a second positive electrode, a second negative electrode and a second ion exchange membrane, and the second ion exchange membrane divides the inner cavity of the battery stack into a third chamber for arranging the second positive electrode and a fourth chamber for arranging the second negative electrode;

[0017] A third storage tank storing a positive electrode electrolyte, wherein the third storage tank is connected to the third chamber to form a circulation loop so that the positive electrode electrolyte circulates between the third storage tank and the third chamber;

[0018] a fourth tank storing a negative electrode electrolyte, the fourth tank being connected to the fourth chamber to form a circulation loop so that the negative electrode electrolyte circulates between the fourth tank and the fourth chamber;

[0019] A heat exchanger is provided on the pipeline for allowing the hydrazine solution to flow from the first chamber to the first storage tank, and / or on the pipeline for allowing the aqueous solution to flow from the second chamber to the second storage tank. The pipeline for allowing the positive electrode electrolyte to flow from the third storage tank to the third chamber and the pipeline for allowing the negative electrode electrolyte to flow from the fourth storage tank to the fourth chamber are both connected to the heat exchanger to perform heat exchange on the positive electrode electrolyte and the negative electrode electrolyte flowing to the battery stack.

[0020] In some embodiments, the flow battery is a Ce-based flow battery. In an initial state, the positive electrolyte and the negative electrolyte in the flow battery are the same and both include a supporting electrolyte and Ce. 3+ ion.

[0021] In some embodiments, the positive electrolyte and the negative electrolyte in the liquid flow battery in the initial state also include Cr3+ Ion, V 3+ Any of the ions;

[0022] And / or, the supporting electrolyte is an acidic medium, and the supporting electrolyte comprises at least methanesulfonic acid;

[0023] And / or, the second positive electrode is a TiC / TiO 2 Coated carbon-based electrode, or carbon-based electrode with boron-doped titanium dioxide coating;

[0024] And / or, the liquid flow battery includes a third pump and a fourth pump, the third pump is arranged on the circulation loop between the third storage tank and the third chamber, and the fourth pump is arranged on the circulation loop between the fourth storage tank and the fourth chamber.

[0025] In some embodiments, the battery stack has multiple battery cells, a positive current collector plate and a negative current collector plate, each of the battery cells has the second positive electrode, the second negative electrode and the second ion exchange membrane, and the positive current collector plate and the negative current collector plate connect the multiple battery cells in series to form the battery stack.

[0026] In some embodiments, it also includes:

[0027] An oxygen generator, the oxygen generator having an oxygen-generating catalytic layer and a third feed port, the third feed port being used to replenish the aqueous solution into the oxygen generator, the oxygen generator being connected to the third storage tank to form a circulation loop, the positive electrode electrolyte being regenerated in the oxygen generator and generating oxygen in the oxygen generator;

[0028] A hydrogen generator, the hydrogen generator having a hydrogen production catalytic layer and a fourth feed port, the fourth feed port is used to add aqueous solution to the hydrogen generator, the hydrogen generator is connected to the fourth storage tank and forms a circulation loop, the negative electrode electrolyte is regenerated in the hydrogen generator and hydrogen is generated in the hydrogen generator.

[0029] In some embodiments, the oxygen generator further comprises a first circulation pump, a first heater and a first agitator, and the hydrogen generator further comprises a second circulation pump, a second heater and a second agitator;

[0030] And / or, the oxygen generator is connected to a first pressure gauge and a first compressor, and the hydrogen generator is connected to a second pressure gauge and a second compressor.

[0031] In some embodiments, the oxygen-generating catalytic layer includes a first substrate layer and first catalytic particles, wherein the first substrate layer is carbon felt, graphite felt, titanium mesh, SiO 2Any one of the particle fixed beds, wherein the first catalytic particles are IrO 2 or RuO 2 Particles;

[0032] The hydrogen production catalytic layer comprises a second substrate layer and a second catalytic particle, wherein the second substrate layer is carbon felt, graphite felt, titanium mesh, SiO 2 Any one of the particle fixed beds, wherein the second catalytic particles are MoS 2 Or Mo 2 C particles.

[0033] In some embodiments, a dryer, a gas-liquid separator and a hydrogen purification device are also included, wherein the dryer is connected to the hydrogen outlet of the hydrogen generator, and the gas-liquid separator and the hydrogen purification device are connected to the hydrogen outlet of the second storage tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of a renewable energy hydrogen production system according to an embodiment of the present invention.

[0035] Reference numerals:

[0036] 1. Hydrazine oxidation hydrogen production system; 11. Electrolyzer; 12. First positive electrode; 13. First negative electrode; 14. First ion exchange membrane; 15. First chamber; 16. Second chamber; 17. First storage tank; 18. Second storage tank;

[0037] 2. Liquid flow battery; 21. Battery stack; 22. Second positive electrode; 23. Second negative electrode; 24. Second ion exchange membrane; 25. Third chamber; 26. Fourth chamber; 27. Third storage tank; 28. Fourth storage tank;

[0038] 31. First pump; 32. Second pump; 33. Third pump; 34. Fourth pump; 35. First feed inlet; 36. Second feed inlet; 37. Third feed inlet; 38. Fourth feed inlet; 39. Heat exchanger;

[0039] 4. oxygen generator; 41. oxygen catalyst layer; 42. first circulation pump; 43. first heater; 44. first agitator; 45. first pressure gauge; 46. first compressor;

[0040] 5. Hydrogen generator; 51. Hydrogen catalyst layer; 52. Second circulation pump; 53. Second heater; 54. Second stirrer; 55. Second pressure gauge; 56. Second compressor;

[0041] 61. Dryer; 62. Gas-liquid separator; 63. Hydrogen purification device;

[0042] 7. Renewable energy systems;

[0043] 8. Energy management system. DETAILED DESCRIPTION

[0044] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0045] The inventors realized that when renewable energy is used to generate hydrogen, the load fluctuation range of green hydrogen produced by renewable energy is narrow, load fluctuation operation is difficult to control, hydrogen purity is difficult to control, efficiency is low, power consumption is high, a large amount of heat is generated in the electrolysis hydrogen production process that is not recycled, gas purity is reduced under load fluctuation conditions, and energy consumption is high in the purification separation / compression process. These problems result in high energy consumption in renewable energy power generation and hydrogen production, low overall system efficiency, and a narrow load fluctuation range.

[0046] like Figure 1 As shown, the renewable energy hydrogen production system of the embodiment of the present invention includes a liquid flow battery 2 and a hydrazine oxidation hydrogen production system 1. The liquid flow battery 2 is used to connect with the renewable energy system 7 so as to charge and store energy for the liquid flow battery 2 through the renewable energy system 7; the hydrazine oxidation hydrogen production system 1 is used to connect with the renewable energy system 7 and the liquid flow battery 2 so as to supply power to the hydrazine oxidation hydrogen production system 1 through the renewable energy system 7 or the liquid flow battery 2. That is to say, when the output of the renewable energy system 7 is large, the renewable energy system 7 generates electricity to supply the liquid flow battery 2 for charging and energy storage, and supplies power to the hydrazine oxidation hydrogen production system 1 for hydrogen production. When the output of the renewable energy system 7 is small or the output is predicted to be small in the next period, the liquid flow battery 2 is started to discharge, and the liquid flow battery 2 and the renewable energy system 7 are used to jointly supply power to the hydrazine oxidation hydrogen production system 1, or the liquid flow battery 2 is used to supply power to the hydrazine oxidation hydrogen production system 1 alone, so as to realize the continuous and stable operation of the hydrazine oxidation hydrogen production system 1.

[0047] The hydrazine oxidation hydrogen production system 1 comprises an electrolyzer 11, a hydrazine (N 2 H 4 The electrolytic cell 11 is provided with a first storage tank 17 for storing a hydrazine solution and a second storage tank 18 for storing an aqueous solution. The electrolytic cell 11 is provided with a first positive electrode 12, a first negative electrode 13 and a first ion exchange membrane 14. The first ion exchange membrane 14 divides the electrolytic cell 11 into a first chamber 15 for arranging the first positive electrode 12 and a second chamber 16 for arranging the first negative electrode 13. The first storage tank 17 is connected to the first chamber 15 to form a circulation loop so that the hydrazine solution circulates in the first storage tank 17 and the first chamber 15. The second storage tank 18 is connected to the second chamber 16 to form a circulation loop so that the aqueous solution circulates in the second storage tank 18 and the second chamber 16. The aqueous solution is electrolyzed in the second chamber 16 to generate hydrogen.

[0048] The process of hydrazine oxidation to produce hydrogen is as follows: the electrolyzer 11 is powered by the renewable energy system 7 or the flow battery 2, the hydrazine solution stored in the first storage tank 17 enters the first chamber 15 of the electrolyzer 11, and under the action of the first positive electrode 12, the hydrazine in the first chamber 15 is oxidized and converted into nitrogen and water, and then flows out with the hydrazine solution, and flows back to the first storage tank 17, wherein the nitrogen can be discharged into the atmosphere after passing through the gas-liquid separator 62, the treatment device and other equipment. The aqueous solution stored in the second storage tank 18 enters the second chamber 16 of the electrolyzer 11, and under the action of the first negative electrode 13, the water is electrolyzed (proton reduced) to generate hydrogen, which flows out with the aqueous solution and flows back to the second storage tank 18, wherein the hydrogen can be discharged after passing through the compressor, the gas-liquid separation device, the hydrogen purification device 63 and other equipment, and is stored or supplied to hydrogen users.

[0049] The positive electrode of the electrolyzer 11 uses the hydrazine oxidation reaction (HzOR) to replace the water decomposition positive electrode reaction, i.e., the oxygen evolution reaction (OER), in the traditional water electrolysis hydrogen production process. Due to the slow reaction kinetics and high energy barrier of the oxygen evolution reaction, the water electrolysis hydrogen production has high voltage, high power consumption, and low efficiency. The overpotential of the hydrazine oxidation reaction (HzOR) is lower than that of the oxygen evolution reaction (OER). Therefore, the voltage and power consumption required for the electrolyzer 11 using the hydrazine oxidation reaction (HzOR) at the positive electrode are reduced, and efficient water electrolysis can be achieved. The positive electrode hydrazine of the electrolyzer 11 is oxidized and converted into nitrogen and water, which is environmentally friendly.

[0050] The renewable energy hydrogen production system of the embodiment of the present invention can improve the stability of renewable energy hydrogen production power supply through the joint operation of the liquid flow battery 2 and the hydrazine oxidation hydrogen production system 1, reduce the voltage and power consumption required for the hydrazine oxidation reaction, achieve efficient water electrolysis, and the converted nitrogen and water will not pollute the environment, thereby reducing system costs and increasing the proportion of green electricity.

[0051] In some embodiments, the flow battery 2 includes a stack 21, a third tank 27 storing a positive electrode electrolyte, and a fourth tank 28 storing a negative electrode electrolyte. The inner cavity of the stack 21 has a second positive electrode 22, a second negative electrode 23, and a second ion exchange membrane 24. The second ion exchange membrane 24 divides the inner cavity of the stack 21 into a third chamber 25 for arranging the second positive electrode 22 and a fourth chamber 26 for arranging the second negative electrode 23. The third tank 27 is connected to the third chamber 25 and forms a circulation loop so that the positive electrode electrolyte circulates in the third tank 27 and the third chamber 25. The fourth tank 28 is connected to the fourth chamber 26 and forms a circulation loop so that the negative electrode electrolyte circulates in the fourth tank 28 and the fourth chamber 26.

[0052] During the charging process of the liquid flow battery 2, the renewable energy system 7 generates electricity and supplies power to the liquid flow battery 2, the positive electrolyte is transported from the third storage tank 27 into the third chamber 25, and the negative electrolyte is transported from the fourth storage tank 28 into the fourth chamber 26, the positive electrolyte and the negative electrolyte undergo an electrochemical redox reaction in the battery stack 21, and the positive electrolyte in the third chamber 25 flows back into the third storage tank 27, and the negative electrolyte in the fourth chamber 26 flows back into the fourth storage tank 28, thereby realizing energy storage.

[0053] During the discharge process, the positive electrode electrolyte in the third storage tank 27 flows into the third chamber 25, and the negative electrode electrolyte in the fourth storage tank 28 flows into the fourth chamber 26. At the same time, after the positive electrode ions in the positive electrode electrolyte are reduced and the negative electrode ions in the negative electrode electrolyte are oxidized in the battery stack 21, they flow back to the third storage tank 27 and the fourth storage tank 28 respectively, and the liquid flow battery 2 discharges to the power load.

[0054] In the embodiment of the present invention, a heat exchanger 39 is provided on the pipeline for allowing the hydrazine solution to flow from the first chamber 15 to the first storage tank 17 and / or the pipeline for allowing the aqueous solution to flow from the second chamber 16 to the second storage tank 18. The pipeline for allowing the positive electrode electrolyte to flow from the third storage tank 27 to the third chamber 25 and the pipeline for allowing the negative electrode electrolyte to flow from the fourth storage tank 28 to the fourth chamber 26 are both connected to the heat exchanger 39 to perform heat exchange on the positive electrode electrolyte and the negative electrode electrolyte flowing to the battery stack 21.

[0055] That is, in the hydrazine oxidation hydrogen production system 1, the heat of the electrolysis reaction in the electrolytic cell 11 is transmitted to the heat exchanger 39 by the hydrazine solution flowing from the first chamber 15 to the first storage tank 17, and / or the aqueous solution flowing from the second chamber 16 to the second storage tank 18, so as to heat the positive electrode electrolyte flowing from the third storage tank 27 to the third chamber 25 and the negative electrode electrolyte flowing from the fourth storage tank 28 to the fourth chamber 26 in the liquid flow battery 2, thereby increasing the reaction rate of the liquid flow battery 2 and realizing the recovery and utilization of the reaction heat of the electrolytic cell 11.

[0056] For example, the pipeline for allowing the hydrazine solution to flow from the first chamber 15 to the first storage tank 17 and the pipeline for allowing the aqueous solution to flow from the second chamber 16 to the second storage tank 18 are both connected to the hot side medium flow channel of the corresponding first heat exchanger 39, and the pipeline for allowing the positive electrode electrolyte to flow from the third storage tank 27 to the third chamber 25 and the pipeline for allowing the negative electrode electrolyte to flow from the fourth storage tank 28 to the fourth chamber 26 are both connected to the cold side medium flow channel of the corresponding second heat exchanger 39. There is a connecting pipe between the corresponding first heat exchanger 39 and the second heat exchanger 39. The medium in the connecting pipe absorbs heat in the first heat exchanger 39 and then flows to the second heat exchanger 39 to release heat, thereby realizing heat transfer.

[0057] For another example, the pipeline for allowing the hydrazine solution to flow from the first chamber 15 to the first storage tank 17 and the pipeline for allowing the aqueous solution to flow from the second chamber 16 to the second storage tank 18 are both connected to the hot side medium flow channel of the corresponding first heat exchanger 39, and the pipeline for allowing the positive electrode electrolyte to flow from the third storage tank 27 to the third chamber 25 and the pipeline for allowing the negative electrode electrolyte to flow from the fourth storage tank 28 to the fourth chamber 26 are both connected to the cold side medium flow channel of the corresponding first heat exchanger 39, and the solution in the hot side medium flow channel and the solution in the cold side medium flow channel located in the same first heat exchanger 39 are indirectly heat exchanged.

[0058] In some embodiments, the renewable energy hydrogen production system further includes an oxygen generator 4 and a hydrogen generator 5. The oxygen generator 4 has an oxygen production catalyst layer 41 and a third feed port 37. The third feed port 37 is used to add aqueous solution to the oxygen generator 4. The oxygen generator 4 is connected to the third storage tank 27 to form a circulation loop. The positive electrode electrolyte is regenerated in the oxygen generator 4 and oxygen is generated in the oxygen generator 4. The hydrogen generator 5 has a hydrogen production catalyst layer 51 and a fourth feed port 38. The fourth feed port 38 is used to add aqueous solution to the hydrogen generator 5. The hydrogen generator 5 is connected to the fourth storage tank 28 to form a circulation loop. The negative electrode electrolyte is regenerated in the hydrogen generator 5 and hydrogen is generated in the hydrogen generator 5.

[0059] The hydrogen and oxygen production circuit system composed of the hydrogen generator 5 and the oxygen generator 4 and the flow battery 2 can be operated jointly or separately.

[0060] Specifically, during the charging / discharging process of the liquid flow battery 2, the hydrogen and oxygen production circuit system can be started simultaneously or as needed to realize the joint operation of the liquid flow battery 2 (as a primary circuit) and the hydrogen and oxygen production circuit system. The independent operation of hydrogen production and oxygen production by the hydrogen and oxygen production circuit system increases the storage capacity of the liquid flow battery 2, realizes the flexible decoupling operation of hydrogen production and liquid flow battery 2 charging and discharging, and improves the stability of hydrogen production power supply from renewable energy.

[0061] In the embodiment of the present invention, the hydrogen production and oxygen production of the hydrogen production and oxygen production circuit system are independently operated, and can be operated in conjunction with the hydrazine oxidation hydrogen production system 1, thereby increasing the storage capacity of the liquid flow battery 2, achieving flexible decoupling operation of hydrogen production and charging and discharging of the liquid flow battery 2, and at the same time improving the power supply stability of renewable energy hydrogen production, hydrogen production response speed and hydrogen production amount.

[0062] The following is combined with Figure 1 A specific embodiment of the renewable energy hydrogen production system according to the embodiment of the present invention is described in detail.

[0063] The renewable energy hydrogen production system of the embodiment of the present invention comprises a liquid flow battery 2, an oxygen generator 4, a hydrogen generator 5, a hydrazine oxidation hydrogen production system 1 and an energy management and control system 8, wherein the energy management and control system 8 is used to control the operation of each component.

[0064] The liquid flow battery 2 is used to be connected to the renewable energy system 7 so that the renewable energy system 7 can charge the liquid flow battery 2 to store energy.

[0065] The flow battery 2 includes a stack 21, a third tank 27 storing a positive electrolyte, and a fourth tank 28 storing a negative electrolyte. The flow battery 2 also includes a pipeline for conveying electrolyte, a pump for driving the electrolyte to flow in the pipeline, a valve for controlling the on and off of the pipeline, a heat exchanger 39 for heating the positive electrolyte and the negative electrolyte, and other components. A third pump 33 is provided on the circulation loop between the third tank 27 and the third chamber 25, and a fourth pump 34 is provided on the circulation loop between the fourth tank 28 and the fourth chamber 26. The inner cavity of the stack 21 has a second positive electrode 22, a second negative electrode 23, and a second ion exchange membrane 24. The second ion exchange membrane 24 divides the inner cavity of the stack 21 into a third chamber 25 for arranging the second positive electrode 22 and a fourth chamber 26 for arranging the second negative electrode 23. The third tank 27 is connected to the third chamber 25 and forms a circulation loop so that the positive electrolyte circulates in the third tank 27 and the third chamber 25. The fourth storage tank 28 is connected to the fourth chamber 26 to form a circulation loop so that the negative electrode electrolyte circulates in the fourth storage tank 28 and the fourth chamber 26 .

[0066] During the charging process of the liquid flow battery 2, the renewable energy system 7 generates electricity and supplies power to the liquid flow battery 2, the positive electrolyte is transported from the third storage tank 27 into the third chamber 25, and the negative electrolyte is transported from the fourth storage tank 28 into the fourth chamber 26, the positive electrolyte and the negative electrolyte undergo an electrochemical redox reaction in the battery stack 21, and the positive electrolyte in the third chamber 25 flows back into the third storage tank 27, and the negative electrolyte in the fourth chamber 26 flows back into the fourth storage tank 28, thereby realizing energy storage.

[0067] During the discharge process, the positive electrode electrolyte in the third storage tank 27 flows into the third chamber 25, and the negative electrode electrolyte in the fourth storage tank 28 flows into the fourth chamber 26. At the same time, after the positive electrode ions in the positive electrode electrolyte are reduced and the negative electrode ions in the negative electrode electrolyte are oxidized in the battery stack 21, they flow back to the third storage tank 27 and the fourth storage tank 28 respectively, and the liquid flow battery 2 discharges to the power load.

[0068] Specifically, the flow battery 2 is a Ce-based flow battery, in which the positive electrolyte and the negative electrolyte in the system are both composed of the electrolyte active material Ce. 3+ Cr 3+ (or V 3+ , or other active substance ions. In this paper, Cr 3+ reaction, explain the working principle, including but not limited to Cr 3+ or V 3+ ions), and supporting electrolyte. The supporting electrolyte is an acidic medium consisting of HCl, H2 SO 4 , perchloric acid, nitric acid, methanesulfonic acid or mixed acid, etc., methanesulfonic acid can increase the active substance Ce 3+ and Cr 3+ Solubility, preferably, the supporting electrolyte is a mixed acid of hydrochloric acid / sulfuric acid / nitric acid + methanesulfonic acid. In the initial state (i.e., the composition of the new electrolyte without charge and discharge is the same), the positive and negative electrolyte compositions are the same, and the positive electrode of the constructed battery stack 21 is Ce 3+ / Ce 4+ The second positive electrode 22 can be synthesized by chemical vapor deposition (CVD) TiC / TiO 2 Coated carbon-based electrode (carbon felt or graphite felt), or carbon-based electrode (carbon felt or graphite felt) with boron-doped titanium dioxide coating. TiC / TiO 2 Coating and boron-doped titanium dioxide coating effectively reduce the direct contact reaction of carbon-based electrodes in highly oxidizing Ce-based electrolytes and improve the corrosion resistance of the electrodes.

[0069] The operation process of the main system of Ce-based flow battery is as follows:

[0070] The negative electrode electrolyte of the Ce-based liquid flow battery flows out from the third storage tank 27, is driven by the fourth pump 34, and passes through the heat exchanger 39 to form the temperature required by the liquid flow battery 2 (for example, the operating temperature is 60 degrees Celsius). When the ambient temperature is low, the heat exchanger 39 heats the electrolyte. When the battery temperature rises (such as high current density circulation causes the battery to heat up), the heat exchanger 39 can cool the electrolyte. The negative electrode electrolyte flows into the battery stack 21 to react. The heat source of the heat exchanger 39 can be a heat source provided by an external heating device. In the embodiment of the present invention, the electrolytic heat generated by the electrolytic cell 11 in the hydrazine oxidation hydrogen production system 1 is used to achieve heat recovery.

[0071] The battery stack 21 is the power unit of the Ce-based liquid flow battery, which serves as the core component of energy exchange. The battery stack 21 has multiple battery cells, positive current collectors and negative current collectors. Each battery cell has a second positive electrode 22, a second negative electrode 23 and a second ion exchange membrane 24. The positive current collector and the negative current collector connect multiple battery cells in series to form the battery stack 21. Specifically, the battery stack 21 is composed of one or more battery cells (referred to as single cells) connected in series. The battery cell is composed of positive and negative electrodes, electrolytes and ion exchange membranes separating electrodes, and has a battery assembly with a pair of positive and negative output terminals (bipolar plates or current collectors). When the number of battery cells is ≥1, multiple groups of identical battery cells are connected in series through negative current collectors and positive current collectors to form the battery stack 21. At this time, the negative current collector and the positive current collector are negative bipolar plates and positive bipolar plates, respectively. The positive and negative electrolytes undergo electrochemical redox reactions in the battery stack 21. Electrons flow between the positive and negative electrodes in the battery stack 21 of the liquid flow battery 2 in an external circuit. During the charging process, the renewable energy system 7 generates electricity and supplies power to the liquid flow battery 2, and electrons flow from the positive electrode to the negative electrode in the external circuit.

[0072] During the normal charging process of Ce-based flow batteries, constant current or constant power is used to charge from 0V to U 1 (1.7 to 1.9V), constant current density = j normal (Can be set to 10~300mAcm -2 ). The reactant ions of the positive and negative electrolytes flow inside the battery stack 21 and undergo electrochemical redox reactions on the positive and negative electrodes. The electrochemical reactions of the active materials in the positive and negative half-cells of the battery unit and their energy storage occur simultaneously. During the charging process of the flow battery 2, the positive electrode Ce 3+ Oxidized to Ce 4+ ,Cr 3+ Reduction to Cr 2+ , flowing into the positive and negative electrode electrolyte storage tanks for storage respectively.

[0073] During the charging process, the negative electrode electrolyte after the electrochemical reaction flows out of the battery stack 21 and flows into the fourth storage tank 28 for storage.

[0074] The same is true for the positive side of the stack 21 of the Ce-based flow battery. The positive electrolyte of the flow battery 2 flows out from the third storage tank 27, is driven by the third pump 33, and passes through the heat exchanger 39 to form the temperature required by the flow battery 2 (for example, the operating temperature of the iron-chromium flow battery 2 is 60 degrees Celsius). When the ambient temperature is low, the heat exchanger 39 heats the electrolyte. When the battery temperature rises (such as high current density circulation causes the battery to heat up), the heat exchanger 39 can cool the electrolyte. The positive electrolyte flows into the stack 21 through the heat exchanger 39.

[0075] During the charging process, the positive electrode electrolyte after the electrochemical reaction flows out of the battery stack 21 and flows into the third storage tank 27 for storage.

[0076] The discharge process is similar to the charging process, except that the flow battery 2 discharges to the power load (hydrazine oxidation hydrogen production system 1 or other power load). 4+ Reduction to Ce 3+ ,Cr 2+ Oxidized to Cr 3+ , and flow back to the third storage tank 27 and the fourth storage tank 28 respectively.

[0077] The battery stack 21 undergoes electrochemical reactions of charging and discharging. At the same time, electrochemical side reactions will inevitably occur under normal operating conditions of the liquid flow battery 2. The side reactions will irreversibly consume electrons, resulting in an imbalance in the charge state of the positive and negative electrolytes (referred to as charge imbalance), and ultimately leading to an imbalance in the capacity of the positive and negative electrodes and a reduction in capacity.

[0078] Ce-based flow battery, the positive and negative electrochemical reactions and side reactions during the charging process are:

[0079] Positive electrode: Ce 3+ -e - =Ce 4+ , 1.65V vs SHE;

[0080] Negative electrode: Cr 3+ +e - =Cr 2+ , -0.41V vs SHE;

[0081] Hydrogen evolution side reaction: 2H + +2e - =H 2 , 0V vs SHE;

[0082] The hydrogen gas released by the hydrogen release side reaction flows into the hydrogen production generator 5 and flows out together with the hydrogen production.

[0083] The electrochemical reactions of the positive and negative electrodes during the discharge process are:

[0084] Positive electrode: Ce 4+ +e - =Ce 3+ , 1.65V vs SHE;

[0085] Negative electrode: Cr 2+ -e - =Cr 3+ , -0.41V vs SHE.

[0086] The oxygen generator 4 has an oxygen production catalytic layer 41 and a third feed port 37, the third feed port 37 is used to add aqueous solution to the oxygen generator 4, the oxygen generator 4 is connected to the third storage tank 27 to form a circulation loop, the positive electrode electrolyte is regenerated in the oxygen generator 4 and oxygen is generated in the oxygen generator 4. The hydrogen generator 5 has a hydrogen production catalytic layer 51 and a fourth feed port 38, the fourth feed port 38 is used to add aqueous solution to the hydrogen generator 5, the hydrogen generator 5 is connected to the fourth storage tank 28 to form a circulation loop, the negative electrode electrolyte is regenerated in the hydrogen generator 5 and hydrogen is generated in the hydrogen generator 5.

[0087] The circulation loop between the oxygen generator 4 and the third storage tank 27 and the circulation loop between the hydrogen generator 5 and the fourth storage tank 28 are provided with pipes for conveying electrolyte, pumps for driving the electrolyte to flow in the pipes, valves for controlling the on-off of the pipes and other components. Among them, the valve can be a three-way valve, and the pump can be shared with the third pump 33 and the fourth pump 34 in the liquid flow battery 2.

[0088] The hydrogen and oxygen production circuit system composed of the hydrogen generator 5 and the oxygen generator 4 and the flow battery 2 can be operated jointly or separately.

[0089] Specifically, during the charging / discharging process of the liquid flow battery 2, the hydrogen and oxygen production circuit system can be started simultaneously or as needed to realize the combined operation of the base liquid flow battery 2 (as a primary circuit) and the hydrogen and oxygen production circuit system. The independent operation of hydrogen production and oxygen production by the hydrogen and oxygen production circuit system increases the storage capacity of the liquid flow battery 2, realizes the flexible decoupling operation of hydrogen production and liquid flow battery 2 charging and discharging, and improves the stability of hydrogen production power supply from renewable energy.

[0090] In the embodiment of the present invention, the hydrogen production and oxygen production of the hydrogen production and oxygen production circuit system are independently operated, and can be operated in conjunction with the hydrazine oxidation hydrogen production system 1, thereby increasing the storage capacity of the liquid flow battery 2, achieving flexible decoupling operation of hydrogen production and charging and discharging of the liquid flow battery 2, and at the same time improving the power supply stability of renewable energy hydrogen production, hydrogen production response speed and hydrogen production amount.

[0091] The operation method of the oxygen generator 4 is as follows:

[0092] During the charging or discharging process of the Ce-based flow battery, the Ce in the third storage tank 27 4+ The electrolyte is discharged by entering the oxygen generator 4 to produce oxygen. The oxygen-producing catalytic layer 41 in the oxygen generator 4 includes a first substrate layer and first catalytic particles. The first substrate layer is carbon felt, graphite felt, titanium mesh, SiO 2 Any of the fixed bed of particles, the first catalytic particles are IrO 2 or RuO 2 Particles;

[0093] A first agitator 44, a first heater 43, a first pressure gauge 45, a first compressor 46 and a first circulation pump 42 are arranged in the oxygen generator 4. The oxygen production reaction rate can be improved by means of catalysis, self-circulation and heating. The first pressure gauge 45 can monitor the internal pressure and perform accidental overpressure discharge.

[0094] Ce in the positive electrolyte 4+ The oxygen production formula is: 4Ce 4+ +2H 2 O=O 2 +4H + +4Ce 3+ , the newly generated Ce 3+ The electrolyte returns to the third storage tank 27 for the Ce-based liquid flow battery to continue charging, thereby increasing the storage capacity of the Ce-based liquid flow battery.

[0095] The operation method of the hydrogen generator 5 is as follows:

[0096] During the charging or discharging process of the Ce-based liquid flow battery, the Cr in the fourth storage tank 28 2+ The electrolyte is discharged into the hydrogen generator 5 to produce hydrogen. The hydrogen production catalyst layer 51 includes a second substrate layer and a second catalytic particle. The second substrate layer is carbon felt, graphite felt, titanium mesh, SiO 2 Any of the fixed bed of particles, the second catalytic particle is MoS 2 Or Mo 2 C particles.

[0097] A second agitator 54, a second heater 53, a second pressure gauge 55, a second compressor 56 and a second circulation pump 52 are arranged in the hydrogen generator 5. The hydrogen production reaction rate is improved through catalysis, self-circulation and heating. The pressure is monitored by the second pressure gauge 55 and accidental overpressure discharge is performed.

[0098] Negative electrolyte Cr 2+ The hydrogen production equation is: 4Cr 2+ +4H + =2H 2 +4Cr 3+ , hydrogen production reactant H + H obtained from the reaction in the above oxygen generator 4 loops + , diffuses across the membrane to the negative electrode of Ce stack 21 during the charging process of Ce-based liquid flow battery, H + Flows into the hydrogen generator 5 and is reduced to H 2 The newly generated Cr 3+ The electrolyte returns to the fourth storage tank 28 for the Ce-based liquid flow battery to continue charging, thereby increasing the storage capacity of the Ce-based liquid flow battery. + Reduced to H2 , after passing through the second compressor 56 and the dryer 61, it is supplied to hydrogen users.

[0099] In the embodiment of the present invention, the hydrogen generator 5 is decoupled from the charge and discharge of the Ce-based liquid flow battery, and the hydrogen generator 5 circuit can operate independently. Since the hydrogen production principle is the discharge of the negative electrode electrolyte, the generated hydrogen has no oxygen impurities and does not require purification. According to the needs of hydrogen users, continuous and instant supply can be achieved.

[0100] Due to the above combined operation, the reactive substances Ce ions, Cr ions and H+ are conserved, and the "loop system consisting of independent hydrogen production and oxygen production systems" only needs to replenish the consumed corresponding stoichiometric volume / mass of aqueous solution to the third feed port 37 of the oxygen generator 4 and the fourth feed port 38 of the hydrogen generator 5 of the oxygen production loop.

[0101] The hydrazine oxidation hydrogen production system 1 is used to be connected to the renewable energy system 7 and the liquid flow battery 2 so as to supply power to the hydrazine oxidation hydrogen production system 1 through the renewable energy system 7 or the liquid flow battery 2 .

[0102] The hydrazine (N2H4) oxidation hydrogen production system is the main system for renewable energy hydrogen production. When the output of the renewable energy system 7 is large, the renewable energy system 7 generates electricity to supply the liquid flow battery 2 for charging and energy storage, and supplies power to the hydrazine oxidation hydrogen production system 1 for hydrogen production. When the output of the renewable energy system 7 is small or the output is predicted to be small in the next period, the liquid flow battery 2 is started to discharge, and the liquid flow battery 2 and the renewable energy system 7 are used to jointly supply power to the hydrazine oxidation hydrogen production system 1, or the liquid flow battery 2 is used alone to supply power to the hydrazine oxidation hydrogen production system 1, so as to realize the continuous and stable operation of the hydrazine oxidation hydrogen production system 1 and continuously supply hydrogen.

[0103] The hydrazine oxidation hydrogen production system 1 comprises an electrolyzer 11, a hydrazine (N 2 H 4 The electrolytic cell 11 is provided with a first storage tank 17 for storing a hydrazine solution and a second storage tank 18 for storing an aqueous solution. The electrolytic cell 11 is provided with a first positive electrode 12, a first negative electrode 13 and a first ion exchange membrane 14. The first ion exchange membrane 14 divides the electrolytic cell 11 into a first chamber 15 for arranging the first positive electrode 12 and a second chamber 16 for arranging the first negative electrode 13. The first storage tank 17 is connected to the first chamber 15 to form a circulation loop. A first pump 31 is provided on the circulation loop between the first storage tank 17 and the first chamber 15. The first pump 31 can drive the hydrazine solution to circulate in the first storage tank 17 and the first chamber 15. The second storage tank 18 is connected to the second chamber 16 to form a circulation loop. A second pump 32 is provided on the circulation loop between the second storage tank 18 and the second chamber 16. The second pump 32 can drive the aqueous solution to circulate in the second storage tank 18 and the second chamber 16. The aqueous solution is electrolyzed in the second chamber 16 to generate hydrogen.

[0104] The first storage tank 17 has a first feed inlet 35 for replenishing the hydrazine solution into the first storage tank 17 , and the second storage tank 18 has a second feed inlet 36 for replenishing the aqueous solution into the second storage tank 18 .

[0105] The process of hydrazine oxidation to produce hydrogen is:

[0106] The hydrazine solution stored in the first storage tank 17 is driven by the first pump 31 and enters the first chamber 15 of the electrolytic cell 11. Under the action of the first positive electrode 12, it is oxidized and converted into nitrogen and water, and flows out with the hydrazine solution, wherein the nitrogen can be discharged into the atmosphere after passing through the gas-liquid separator 62, the treatment device and other equipment. The aqueous solution stored in the second storage tank 18 is driven by the second pump 32 and enters the second chamber 16 of the electrolytic cell 11. Under the action of the first negative electrode 13, water is electrolyzed (proton reduction) to generate hydrogen, which flows out with the aqueous solution. After passing through the compressor, the gas-liquid separation device and the hydrogen purification device 63, the hydrogen is supplied to hydrogen users.

[0107] A heat exchanger 39 is provided on the pipeline for allowing the hydrazine solution to flow from the first chamber 15 to the first storage tank 17 and / or the pipeline for allowing the aqueous solution to flow from the second chamber 16 to the second storage tank 18. The pipeline for allowing the positive electrode electrolyte to flow from the third storage tank 27 to the third chamber 25 and the pipeline for allowing the negative electrode electrolyte to flow from the fourth storage tank 28 to the fourth chamber 26 are both connected to the heat exchanger 39 to exchange heat between the positive electrode electrolyte and the negative electrode electrolyte flowing to the battery stack 21.

[0108] That is, in the hydrazine oxidation hydrogen production system 1, the electrolysis reaction heat in the electrolyzer 11 is transmitted to the heat exchanger 39 by the hydrazine solution flowing from the first chamber 15 to the first storage tank 17 and / or the aqueous solution flowing from the second chamber 16 to the second storage tank 18, and the positive electrode electrolyte flowing from the third storage tank 27 to the third chamber 25 and the negative electrode electrolyte flowing from the fourth storage tank 28 to the fourth chamber 26 in the liquid flow battery 2 are heated, the reaction rate of the liquid flow battery 2 is increased, and the reaction heat of the electrolyzer 11 is recycled. The electrolysis reaction heat can be transferred through the heat exchanger 39 for heating the positive and negative electrolytes of the Ce-based liquid flow battery, the reaction rate of the Ce-based liquid flow battery is increased, and the reaction heat of the electrolyzer 11 is recycled.

[0109] The positive electrode of the electrolyzer 11 uses the hydrazine oxidation reaction (HzOR) to replace the water decomposition positive electrode reaction, i.e., the oxygen evolution reaction (OER), in the traditional water electrolysis hydrogen production process. Due to the slow reaction kinetics and high energy barrier of the oxygen evolution reaction, the water electrolysis hydrogen production has high voltage, high power consumption, and low efficiency. The overpotential of the hydrazine oxidation reaction (HzOR) is lower than that of the oxygen evolution reaction (OER). Therefore, the voltage and power consumption required for the electrolyzer 11 using the hydrazine oxidation reaction (HzOR) at the positive electrode are reduced, and efficient water electrolysis can be achieved. The positive electrode hydrazine of the electrolyzer 11 is oxidized and converted into nitrogen and water, which is environmentally friendly.

[0110] The renewable energy hydrogen production system of the embodiment of the present invention can improve the stability of renewable energy hydrogen production power supply through the joint operation of the liquid flow battery 2 and the hydrazine oxidation hydrogen production system 1, reduce the voltage and power consumption required for the hydrazine oxidation reaction, achieve efficient water electrolysis, and the converted nitrogen and water will not pollute the environment, thereby reducing system costs and increasing the proportion of green electricity.

[0111] In the embodiment of the present invention, according to the needs of hydrogen users, the hydrogen generator 5 and the hydrazine oxidation hydrogen production system 1 can be operated simultaneously, which increases the response rate and hydrogen production. At the same time, the renewable energy power generation power supply and the Ce-based liquid flow battery jointly ensure stable power supply.

[0112] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0113] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0114] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0115] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0116] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0117] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A renewable energy hydrogen production system, characterized in that: include: A liquid flow battery, wherein the liquid flow battery is used to be connected to a renewable energy system so as to charge and store energy through the renewable energy system; A hydrazine oxidation hydrogen production system, wherein the hydrazine oxidation hydrogen production system is connected to a renewable energy system and the liquid flow battery, so as to supply power to the hydrazine oxidation hydrogen production system through the renewable energy system or the liquid flow battery; The hydrazine oxidation hydrogen production system comprises: An electrolytic cell, wherein the electrolytic cell has a first positive electrode, a first negative electrode and a first ion exchange membrane, wherein the first ion exchange membrane divides the electrolytic cell into a first chamber for arranging the first positive electrode and a second chamber for arranging the first negative electrode; a first storage tank storing a hydrazine solution, wherein the first storage tank is connected to the first chamber and forms a circulation loop so that the hydrazine solution circulates in the first storage tank and the first chamber; A second storage tank storing an aqueous solution is connected to the second chamber to form a circulation loop so that the aqueous solution circulates in the second storage tank and the second chamber, and the aqueous solution is electrolyzed in the second chamber to generate hydrogen.

2. The renewable energy hydrogen production system according to claim 1, characterized in that: The hydrazine oxidation hydrogen production system further includes a first pump and a second pump, wherein the first pump is provided on a circulation loop between the first storage tank and the first chamber, and the second pump is provided on a circulation loop between the second storage tank and the second chamber; And / or, the first storage tank has a first feed inlet, the first feed inlet is used to add hydrazine solution to the first storage tank, and the second storage tank has a second feed inlet, the second feed inlet is used to add aqueous solution to the second storage tank.

3. The renewable energy hydrogen production system according to claim 1, characterized in that: The flow battery comprises: A battery stack, wherein the inner cavity of the battery stack has a second positive electrode, a second negative electrode and a second ion exchange membrane, and the second ion exchange membrane divides the inner cavity of the battery stack into a third chamber for arranging the second positive electrode and a fourth chamber for arranging the second negative electrode; A third storage tank storing a positive electrode electrolyte, wherein the third storage tank is connected to the third chamber to form a circulation loop so that the positive electrode electrolyte circulates between the third storage tank and the third chamber; a fourth tank storing a negative electrode electrolyte, the fourth tank being connected to the fourth chamber to form a circulation loop so that the negative electrode electrolyte circulates between the fourth tank and the fourth chamber; A heat exchanger is provided on the pipeline for allowing the hydrazine solution to flow from the first chamber to the first storage tank, and / or on the pipeline for allowing the aqueous solution to flow from the second chamber to the second storage tank. The pipeline for allowing the positive electrode electrolyte to flow from the third storage tank to the third chamber and the pipeline for allowing the negative electrode electrolyte to flow from the fourth storage tank to the fourth chamber are both connected to the heat exchanger to perform heat exchange on the positive electrode electrolyte and the negative electrode electrolyte flowing to the battery stack.

4. The renewable energy hydrogen production system according to claim 3, characterized in that: The flow battery is a Ce-based flow battery. In the initial state, the positive electrode electrolyte and the negative electrode electrolyte in the flow battery are the same and both include a supporting electrolyte and Ce. 3+ ion.

5. The renewable energy hydrogen production system according to claim 4, characterized in that: The positive electrolyte and the negative electrolyte in the liquid flow battery in the initial state both include Cr 3+ Ion, V 3+ Any of the ions; And / or, the supporting electrolyte is an acidic medium, and the supporting electrolyte comprises at least methanesulfonic acid; And / or, the second positive electrode is a carbon-based electrode with a TiC / TiO2 coating synthesized by chemical vapor deposition, or a carbon-based electrode with a boron-doped titanium dioxide coating; And / or, the liquid flow battery includes a third pump and a fourth pump, the third pump is arranged on the circulation loop between the third storage tank and the third chamber, and the fourth pump is arranged on the circulation loop between the fourth storage tank and the fourth chamber.

6. The renewable energy hydrogen production system according to claim 4, characterized in that: The battery stack comprises a plurality of battery cells, a positive current collector plate and a negative current collector plate, each of the battery cells comprises the second positive electrode, the second negative electrode and the second ion exchange membrane, and the positive current collector plate and the negative current collector plate connect the plurality of battery cells in series to form the battery stack.

7. The renewable energy hydrogen production system according to any one of claims 3 to 6, characterized in that: Also includes: An oxygen generator, the oxygen generator having an oxygen-generating catalytic layer and a third feed port, the third feed port being used to replenish the aqueous solution into the oxygen generator, the oxygen generator being connected to the third storage tank to form a circulation loop, the positive electrode electrolyte being regenerated in the oxygen generator and generating oxygen in the oxygen generator; A hydrogen generator, the hydrogen generator having a hydrogen production catalytic layer and a fourth feed port, the fourth feed port is used to add aqueous solution to the hydrogen generator, the hydrogen generator is connected to the fourth storage tank and forms a circulation loop, the negative electrode electrolyte is regenerated in the hydrogen generator and hydrogen is generated in the hydrogen generator.

8. The renewable energy hydrogen production system according to claim 7, characterized in that: The oxygen generator further comprises a first circulation pump, a first heater and a first agitator, and the hydrogen generator further comprises a second circulation pump, a second heater and a second agitator; And / or, the oxygen generator is connected to a first pressure gauge and a first compressor, and the hydrogen generator is connected to a second pressure gauge and a second compressor.

9. The renewable energy hydrogen production system according to claim 7, characterized in that: The oxygen-generating catalytic layer comprises a first substrate layer and first catalytic particles, wherein the first substrate layer is any one of carbon felt, graphite felt, titanium mesh, and a fixed bed of SiO2 particles, and the first catalytic particles are IrO2 or RuO2 particles; The hydrogen production catalytic layer comprises a second substrate layer and second catalytic particles, the second substrate layer is any one of carbon felt, graphite felt, titanium mesh, and a fixed bed of SiO2 particles, and the second catalytic particles are MoS2 or Mo2C particles.

10. The renewable energy hydrogen production system according to claim 7, characterized in that: It also includes a drier, a gas-liquid separator and a hydrogen purification device. The drier is connected to the hydrogen outlet of the hydrogen generator, and the gas-liquid separator and the hydrogen purification device are connected to the hydrogen outlet of the second storage tank.

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