Hydrogen production system

Abstract

To provide a hydrogen production system capable of stably operating a hydrogen production device utilizing renewable energy even when weather or the like varies.SOLUTION: A hydrogen production system 1 includes: a continuous renewable energy device 10 capable of continuously generating electric power; a plurality of hydrogen production devices 20; and a power conversion device 80 that supplies electric power from the continuous renewable energy device 10 to the hydrogen production devices 20. The power conversion device 80 includes an interleaved power conversion device 81. The continuous renewable energy device 10 uses, as a main material, an electrolyte containing a substance that exists in nature while containing at least moisture, such as water or soil. A negative electrode made of a metal material having a negative standard electrode potential and a positive electrode made of a carbon-based material or the like are embedded in the electrolyte.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydrogen production system that utilizes renewable energy. [Background technology]

[0002] Towards a carbon-zero society, solar power generation and wind power generation are becoming more popular, replacing thermal power generation using fossil fuels. However, because the amount of power generated by solar power generation and wind power generation is subject to large fluctuations due to natural phenomena, it becomes necessary to store the electricity using storage batteries or to convert the electricity into hydrogen and store it. Devices that convert electricity into hydrogen and store it have been proposed, such as those described in Patent Documents 1, 2, and 3.

[0003] Patent document 1 discloses a system that includes a hydrogen production device that produces hydrogen using electricity from renewable energy sources and an absorbing alloy tank that stores hydrogen, and that uses the heat generated during hydrogen absorption and production to heat the absorbing alloy tank.

[0004] Patent Document 2 discloses a system that includes a power generation means for converting renewable energy into electricity, and multiple hydrogen production devices that produce hydrogen gas using the electricity, and a hydrogen gas backflow prevention mechanism in the piping that connects the multiple hydrogen production devices to a buffer tank.

[0005] Patent Document 3 discloses an energy management device that manages the supply of renewable energy power to an electrolyzer for producing hydrogen. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-23028 [Patent Document 2] JP 2013-49600 A [Patent Document 3] Japanese Patent Publication No. 2022-110287 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0007] As disclosed in Patent Documents 1, 2, and 3, renewable energy sources include solar power generation and wind power generation, but because they rely on nature, the amount of power generated fluctuates greatly. For example, solar power generation does not generate power at least at night, and its power generation capacity fluctuates depending on the weather. Furthermore, wind power generation does not generate power when there is no wind. Therefore, conventional technologies have the problem that hydrogen production devices that use renewable energy cannot be operated stably when the weather, etc. fluctuates.

[0008] In view of the above problems, the present invention aims to provide a hydrogen production system that can stably operate a hydrogen production device that uses renewable energy even when the weather, etc., changes. [Means for solving the problem]

[0009] (1) The hydrogen production system of the present invention is characterized by comprising: a continuous renewable energy device capable of continuously generating electricity using an electrolyte whose main material is a substance that exists in nature and contains at least water; a hydrogen production device; and a power conversion device that includes a plurality of power conversion circuits electrically connected in parallel and converts the electricity from the continuous renewable energy device using the plurality of power conversion circuits and supplies the electricity to the hydrogen production device.

[0010] In the present invention, the term "main material" in the term "electrolyte mainly made of a substance that exists in nature and contains at least water" means that the substance accounts for the highest proportion of the materials constituting the electrolyte.

[0011] Furthermore, the term "electrolyte" generally refers to a substance that ionizes into cations and anions when dissolved in a solvent, but in the present invention, the term "electrolyte" refers to a substance that is present between the negative electrode and the positive electrode in a battery, such as water containing ions or soil that retains water.

[0012] (2) In the present invention, the power conversion device is preferably an interleaved power conversion device that operates the plurality of power conversion circuits with a phase shift.

[0013] (3) In the present invention, it is preferable to provide a plurality of the hydrogen production devices.

[0014] (4) In the present invention, the continuous renewable energy device preferably includes a plurality of electrode units each consisting of a negative electrode and a positive electrode, at least a portion of which is disposed within the electrolyte, and the negative electrode is preferably made primarily of a first metal material having a negative standard electrode potential, and the positive electrode is preferably made primarily of a carbon-based material or a second metal material having a higher standard electrode potential than the first metal material.

[0015] In the present invention, "the negative electrode is mainly made of a first metal material having a negative standard electrode potential" means that the first metal material accounts for the largest proportion of the materials constituting the negative electrode. Also, in the present invention, "the positive electrode is mainly made of a carbon-based material or a second metal material having a higher standard electrode potential than the first metal material" means that the carbon-based material or the second metal material accounts for the largest proportion of the materials constituting the positive electrode.

[0016] The standard electrode potential is expressed with the potential of the standard hydrogen electrode as the reference (0 V). Therefore, the standard state electromotive force of a battery made by combining a standard hydrogen electrode and the electrode being measured is equal to the standard electrode potential of the electrode being measured.

[0017] (5) In the present invention, the first metallic material is preferably at least one of magnesium, aluminum, and zinc.

[0018] (6) In the present invention, it is preferable that a coating is formed on the first metal material, and the coating is a film formed from a conductive material, a film formed from an intercalation compound, a film formed from a semiconductor material, or a film formed from a resin containing at least one of a conductive material, an intercalation compound, and a semiconductor material.

[0019] (7) In the present invention, it is preferable that the conductive material is carbon, hard carbon, charcoal, a metal, or an anodic oxide of a metal, the intercalation compound is graphite or carbon graphite, and the semiconductor material is tin oxide, titanium oxide, or a photocatalytic material.

[0020] (8) In the present invention, the second metal material is preferably at least one of copper, silver, gold, platinum, and stainless steel.

[0021] (9) In the present invention, the substance is preferably soil.

[0022] (10) In the present invention, the substance is preferably water or seawater.

[0023] (11) In the present invention, the water is preferably river water, lake water, lake water, pond water, reservoir water, rainwater, groundwater, artificially treated tap water, or industrial water.

[0024] "Industrial water" is water supplied for purposes such as cooling, boilers, and cleaning in industrial production processes; raw water has only been subjected to sedimentation treatment (primary treatment) and has not been sterilized or disinfected (secondary treatment). "Tap water" is water for human consumption; it is sterilized and disinfected in secondary treatment in addition to primary treatment, and its water quality standards and components are determined by the Water Supply Act. However, since both "tap water" and "industrial water" are simply water that has been partially modified from the properties of raw water that exists in nature, in this invention they are both included in "substances that exist in nature and contain at least water."

[0025] (12) In the present invention, it is preferable that plants grow in the soil.

[0026] (13) In the present invention, it is preferable that the soil is fertilized.

[0027] (14) In the present invention, it is preferable that at least one of an organic substance and an inorganic substance is dissolved in the water.

[0028] (15) In the present invention, it is preferable that the system further comprises a power storage device that stores power from the continuous renewable energy device, and an on-off control device that controls charging from the continuous renewable energy device to the power storage device and controlling the supply of power from the power storage device to the hydrogen production device.

[0029] (16) In the present invention, it is preferable that the power storage device stores the power from the continuous renewable energy device when the hydrogen production device is not operating or when surplus power is generated for the hydrogen production device.

[0030] (17) In the present invention, it is preferable that the power storage device supplies power to the hydrogen production device when the power supplied from the continuous renewable energy device is insufficient.

[0031] (18) In the present invention, the system further comprises a hydrogen storage tank for storing hydrogen produced by the hydrogen production device, a monitoring device for monitoring the amount of electricity generated by the continuous renewable energy device and the amount of electricity stored in the power storage device, and a control unit for controlling the supply of electricity to the hydrogen production device based on the monitoring results of the amount of electricity by the monitoring device, and it is preferable that both the electricity supplied to the hydrogen production device by the continuous renewable energy device and the electricity supplied to the hydrogen production device by the power storage device are supplied to the hydrogen production device via the power conversion device.

[0032] (19) In the present invention, it is preferable to provide a plurality of the continuous renewable energy devices.

[0033] (20) In the present invention, it is preferable that the plurality of continuous renewable energy devices include a plurality of series of continuous renewable energy devices that output power to the power conversion device for each series, and that the power conversion device includes a plurality of power conversion devices that convert the power output for each series from each of the plurality of series of continuous renewable energy devices for each series.

[0034] (21) In the present invention, it is preferable that the continuous renewable energy device further comprises a hydrogen gas recovery device that recovers hydrogen gas generated when the continuous renewable energy device generates electric power.

[0035] (22) In the present invention, it is preferable that the system further includes a hydrogen storage tank for storing hydrogen produced by the hydrogen production device, and that the hydrogen storage tank stores the hydrogen produced by the hydrogen production device and the hydrogen recovered by the hydrogen gas recovery device.

[0036] (23) In the present invention, it is preferable that the hydrogen gas recovery device further includes a power generation device that generates electric power using the recovered hydrogen, and the electric power generated by the power generation device is output to the power conversion device.

[0037] (24) In the present invention, it is preferable that the power generation system further comprises a control unit that controls the number of operating hydrogen production devices based on the amount of power supplied from the continuous renewable energy device.

[0038] (25) In the present invention, it is preferable to further include a means for transferring at least one of the heat generated when the hydrogen production device is operating and the heat generated when the power conversion device is operating to the soil in the continuous renewable energy device, thereby promoting the generation of electricity by the continuous renewable energy device. [Effects of the Invention]

[0039] In the present invention, the continuous renewable energy device can continuously supply power even when the weather, etc. fluctuates. Furthermore, the power from the continuous renewable energy device is stably supplied to the hydrogen production device via a power conversion device including multiple power conversion circuits electrically connected in parallel. Therefore, according to the present invention, a hydrogen production system can be provided that can stably operate the hydrogen production device that uses renewable energy, even when the weather, etc. fluctuates. [Brief explanation of the drawings]

[0040] [Figure 1] 1 is a block diagram showing the configuration of a hydrogen production system according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an explanatory diagram of the continuous renewable energy device shown in FIG. [Figure 3] FIG. 2 is an explanatory diagram showing an example of the power generation principle of the continuous renewable energy device shown in FIG. [Figure 4] FIG. 4 is an explanatory diagram showing a configuration example of the electrode unit shown in FIG. 3. [Figure 5] FIG. 4 is an explanatory diagram showing the principle of power generation when plants are grown in the continuous renewable energy device shown in FIG. [Figure 6] FIG. 6 is an explanatory diagram showing voltages and the like obtained when the electrolyte is changed in the continuous renewable energy devices shown in FIGS. 3 and 5. [Figure 7] FIG. 1 is a block diagram showing the configuration of a hydrogen production system according to a second embodiment of the present invention. [Figure 8] FIG. 10 is a block diagram showing the configuration of a hydrogen production system according to a third embodiment of the present invention. [Figure 9] FIG. 10 is a block diagram showing the configuration of a hydrogen production system according to a fourth embodiment of the present invention. [Figure 10] FIG. 10 is a block diagram showing the configuration of a hydrogen production system according to a fifth embodiment of the present invention. [Figure 11] FIG. 11 is an explanatory diagram of the hydrogen gas recovery device shown in FIG. [Figure 12] FIG. 10 is a block diagram showing the configuration of a hydrogen production system according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0042] [Embodiment 1] (Overall composition) Fig. 1 is a block diagram showing the configuration of a hydrogen production system 1 according to a first embodiment of the present invention. As shown in Fig. 1, the hydrogen production system 1 according to the first embodiment of the present invention includes a continuous renewable energy device 10 capable of generating and supplying electric power, and a hydrogen production device 20. The hydrogen production system 1 also includes a power conversion device 80 including a plurality of power conversion circuits 82 electrically connected in parallel.

[0043] The power conversion device 80 converts the power from the continuous renewable energy device 10 using a plurality of power conversion circuits 82 and supplies the converted power to the hydrogen production device 20. The continuous renewable energy device 10 can continuously generate power using an electrolyte whose main material is a substance that exists in nature and contains at least water.

[0044] In the first embodiment, the hydrogen production system 1 is provided with a plurality of hydrogen production devices 20. Therefore, the hydrogen production system 1 has a high hydrogen production capacity. Although four hydrogen production devices 20 are shown in FIG. 1 as the plurality of hydrogen production devices 20, the number is not limited to four. Furthermore, although four power conversion circuits 82 are shown in FIG. 1 as the plurality of power conversion circuits 82, the number is not limited to four.

[0045] There are two main types of hydrogen production device 20: alkaline water electrolysis devices and solid polymer water electrolysis devices, but either type is acceptable. An alkaline water electrolysis device uses an alkaline solution as an electrolyte and operates at a high temperature (approximately 70°C). Green hydrogen can be produced by using inexpensive raw materials and electricity from renewable energy sources. A solid polymer water electrolysis device uses a solid polymer (PEM / Polymer Electrolyte Membrane) as an electrolyte and operates at a low temperature (approximately 60°C).

[0046] (Configuration of power conversion device 80) In the hydrogen production system 1 of the first embodiment, the power conversion device 80 is an interleaved power conversion device 81 that operates a plurality of power conversion circuits 82 electrically connected in parallel with a phase shift. The interleaved power conversion device 81 is, for example, an interleaved DC / DC converter or an interleaved DC / AC inverter. In the first embodiment, the interleaved power conversion device 81 is an interleaved DC / DC converter.

[0047] In a typical DC / DC converter, one power conversion circuit (power section) converts the input voltage to the output voltage, so in high-power applications, a single power conversion circuit may not be able to perform sufficient power conversion.

[0048] In contrast, in an interleaved power conversion device 81, a plurality of power conversion circuits 82 are electrically connected in parallel and operated with a phase shift between them. This causes a phase shift in the ripple currents flowing through input and output capacitors (not shown) that are generated when the power conversion circuits 82 are turned on and off.

[0049] Therefore, the interleaved power conversion device 81 can reduce the burden on the capacitor compared to when multiple power conversion circuits 82 are simply electrically connected in parallel. Therefore, even if a large amount of power is required due to the multiple hydrogen production devices 20, the interleaved power conversion device 81 can supply power stably.

[0050] 2 and other figures, the continuous renewable energy device 10 uses a substance found in nature as an electrolyte, so the output from the continuous renewable energy device 10 has a lot of noise and ripple, but in the interleaved system, multiple stages operate alternately, so the output noise and power ripple can be reduced, making it possible to provide a stable output voltage and current.

[0051] (Main effects of the embodiment) In the hydrogen production system 1 according to the first embodiment, the continuous renewable energy device 10 can continuously supply power even when the weather and other conditions change, as will be described later with reference to Figures 2 to 6. Furthermore, the power from the continuous renewable energy device 10 is stably supplied to the hydrogen production device 20 via a power conversion device 80 including a plurality of power conversion circuits 82 electrically connected in parallel. Therefore, according to the hydrogen production system 1 according to the first embodiment, the hydrogen production device 20 that uses renewable energy can be stably operated even when the weather and other conditions change.

[0052] Furthermore, since the power conversion device 80 is an interleaved power conversion device 81, the multiple power conversion circuits 82 operate at different phases. Therefore, the phases of the ripple currents flowing through the input and output capacitors (not shown) provided in the power conversion device 80 are shifted, thereby reducing the load on the capacitors. Therefore, according to the first embodiment, it is possible to stably supply power to the multiple hydrogen production devices 20.

[0053] (Configuration of continuous renewable energy device 10) Figure 2 is an explanatory diagram of the continuous renewable energy device 10 shown in Figure 1. As shown in Figure 2, the continuous renewable energy device 10 is a power generation device that can generate electricity continuously, day and night, regardless of the weather, using an electrolyte 13 whose main material is a substance that exists in nature and contains at least water.

[0054] Therefore, the continuous renewable energy device 10 includes an electrode unit 15 composed of a negative electrode 11 and a positive electrode 12, at least a portion of which is installed inside the electrolyte 13. In the first embodiment, the continuous renewable energy device 10 includes a plurality of electrode units 15. A negative electrode lead wire 110 is connected to the negative electrode 11, and a positive electrode lead wire 120 is connected to the positive electrode 12.

[0055] Examples of the electrolyte 13 that exists in nature and contains at least water include water, seawater, and soil. Because water, seawater, and soil are widely and commonly found in nature, there are few restrictions on the location where the continuous renewable energy device 10 can be installed. In particular, if soil is used as the electrolyte 13, it is possible to generate electricity using the microorganisms contained in the soil, based on the same principle as a microbial fuel cell. Furthermore, because soil allows plants to grow, it is possible to generate electricity based on the same principle as a plant battery.

[0056] Furthermore, when water is used for the electrolyte 13, the water may be river water, lake water, lake water, pond water, reservoir water, rainwater, groundwater, artificially treated tap water, or industrial water. This configuration eliminates the need to use pure water, making it possible to supply water inexpensively and easily. Furthermore, when water is used for the electrolyte 13, plants can easily grow there, making it possible to generate electricity using the same principle as a plant battery.

[0057] The negative electrode 11 is mainly made of a first metal material 111 having a negative standard electrode potential. The positive electrode 12 is mainly made of a carbon-based material 121 or a second metal material 122 having a higher standard electrode potential than the first metal material 111. Therefore, the continuous renewable energy device 10 operates as a battery, and is capable of generating a voltage due to the difference in electrode potential between the negative electrode 11 and the positive electrode 12.

[0058] The first metal material 111 used for the negative electrode 11 is, for example, at least one of magnesium, aluminum, and zinc. The standard electrode potential of magnesium is −2.34 V, the standard electrode potential of aluminum is −1.68 V, and the standard electrode potential of zinc is −0.76 V. With this configuration, the negative electrode 11 can be made of a relatively inexpensive metal material.

[0059] In the first embodiment, the first metal material 111 is coated with a coating 14. The coating 14 is, for example, a film formed of a conductive material, a film formed of an intercalation compound, or a film formed of a semiconductor material. The coating 14 is formed, for example, by vapor deposition. The coating 14 may also be a film formed of a resin containing at least one of a conductive material, an intercalation compound, and a semiconductor material. In this case, the conductive material, the intercalation compound, and the semiconductor material are blended into the resin to a level that causes the coating 14 to exhibit conductivity.

[0060] When a conductive material is used for the coating 14, the conductive material is, for example, carbon, hard carbon, charcoal, metal, metal, or anodic oxide of a metal. When an intercalation compound is used for the coating 14, the intercalation compound is, for example, graphite or carbon graphite. When a semiconductor material is used for the coating 14, the semiconductor material is, for example, tin oxide, titanium oxide, or a photocatalytic material. With this configuration, the first metal material 111 used for the negative electrode 11 is protected from corrosion and the like by the coating 14, thereby improving durability. Even in this case, electrons can pass through the coating 14, so operation as a battery is not impaired.

[0061] Furthermore, when the first metal material 111 of the negative electrode 11 is magnesium or aluminum, durability may be improved by forming an oxide film by anodizing.

[0062] In addition, when photocatalytic materials as semiconductor materials are irradiated with light (mainly ultraviolet light), electrons are excited from the valence band to the conduction band, but it has been experimentally demonstrated that current flows even in the absence of light, such as in soil. This is thought to be because the application of a voltage between the electrodes excites electrons, which then move from the conduction band to magnesium, causing current to flow. Titanium oxide is a material that is widely used as a photocatalyst. Tin oxide is also a type of semiconductor material, and its properties can be improved by doping it with impurities, allowing current to flow.

[0063] In the positive electrode 12, the second metal material 122 is, for example, at least one of copper, silver, gold, platinum, and stainless steel. The standard electrode potential of copper is +0.34 V, the standard electrode potential of silver is +0.80 V, the standard electrode potential of gold is +1.52 V, and the standard electrode potential of platinum is +1.19 V. Therefore, the standard electrode potentials of copper, silver, gold, and platinum are positive values, and the standard electrode potential is sufficiently higher than that of the first metal material 111. Therefore, the difference in electrode potential between the negative electrode 11 and the positive electrode 12 can be increased.

[0064] When a carbon-based material such as carbon, hard carbon, carbon graphite, carbon nanotubes, or charcoal is used for the positive electrode 12, the carbon-based material has a standard electrode potential of approximately 0V.

[0065] Among the second metal materials 122 used for the positive electrode 12, silver, gold, platinum, and stainless steel are resistant to corrosion and can be used without treatment. In contrast, copper is prone to corrosion. Therefore, when copper is used for the positive electrode 12, it is preferable to coat it with a conductive material such as carbon, hard carbon, graphite, or carbon graphite, as with the negative electrode 11.

[0066] 3 and 5, it is preferable that at least one of organic matter and inorganic matter is dissolved in the water or soil of the electrolyte 13. With this configuration, electrons generated when the organic matter and inorganic matter decompose contribute to power generation, thereby increasing the amount of power generation.

[0067] As will be described later with reference to Figure 5, it is preferable that plants grow in the soil. With this configuration, the amount of organic matter increases due to the sugars produced by the plants, and the amount of electrons generated when the organic matter decomposes increases, thereby increasing the amount of power generated.

[0068] (Configuration example of continuous renewable energy device 10) FIG. 3 is an explanatory diagram showing an example of the power generation principle of the continuous renewable energy device 10 shown in FIG.

[0069] In the continuous renewable energy device 10 shown in Figure 3, soil is used for the electrolyte 13, and binchotan charcoal is used for the positive electrode 12. For the negative electrode 11, a first metal material 111 such as lithium, magnesium, aluminum, or zinc can be used, but magnesium is used in consideration of safety and standard electrode potential. Therefore, the continuous renewable energy device 10 has the same characteristics as a magnesium battery in that it is possible to generate voltage due to the difference in electrode potential between the negative electrode 11 and the positive electrode 12.

[0070] However, magnesium is a metal that corrodes easily and quickly forms an insulating film when placed in soil. However, in embodiment 1, a coating 14 made of a carbon-based conductive material or a semiconductor material such as titanium oxide is formed on the surface of the magnesium in the negative electrode 11. Furthermore, a magnesium oxide film is formed on the negative electrode 11 by anodization treatment below the coating 14. Therefore, the formation of an insulating film due to corrosion is suppressed on the surface of the negative electrode 11.

[0071] Furthermore, the continuous renewable energy device 10 electrolyzes the water, inorganic matter, and organic matter contained in the soil used as the electrolyte 13 using a voltage generated by the difference in standard electrode potential between the negative electrode 11 and the positive electrode 12. The electrons generated during this process are collected by the negative electrode 11, and these electrons are transferred to the positive electrode 12 through an external circuit, generating electricity. Therefore, the continuous renewable energy device 10 realizes a power generation principle in which the generation of voltage and current are separated.

[0072] If magnesium is used for the negative electrode 11, the standard electrode potential is -2.3 V. If binchotan charcoal is used for the positive electrode 12, theoretically the voltage difference due to the standard electrode potential would be 2.3 V, but in reality losses occur and the voltage difference is around 1.5 V. The current value is determined by the size of the electrode, and the larger the electrode area, the greater the current. If binchotan charcoal is used for the positive electrode 12, the number of pieces will need to be increased.

[0073] (Configuration example of electrode unit 15) Fig. 4 is an explanatory diagram showing an example of the configuration of the electrode unit 15 shown in Fig. 3. In Fig. 4, Fig. 4(A) is an explanatory diagram showing an example of the configuration of the electrode unit 140 using one flat plate-shaped negative electrode 11, and Fig. 4(B) is an explanatory diagram showing an example of the configuration of the electrode unit 140 using two plate-shaped negative electrodes 11 curved into semicircular shapes.

[0074] 4(A) and (B) uses a round rod of binchotan charcoal as the positive electrode 12, and a magnesium plate (first metal material 111) coated with a coating 14 and covered with a water-permeable insulating sheet 115 (protective film) as the negative electrode 11. Therefore, even if the electrode unit 15 is placed in soil or water and the negative electrode 11 and positive electrode 12 are in contact with each other, the water-permeable insulating sheet 115 can prevent a short circuit.

[0075] In the first embodiment, the negative electrode 11 and the positive electrode 12 are integrated by bundling them with a binding band 150. A negative electrode lead wire 110 is connected to the negative electrode 11, and a positive electrode lead wire 120 is connected to the positive electrode 12.

[0076] 4(A) uses one flat plate-shaped negative electrode 11, and one positive electrode 12 is arranged on each side so as to face each other. In the electrode unit 15 shown in FIG. 4(B), two semicircular curved plate-shaped negative electrodes 11 surround one positive electrode 12, and multiple positive electrodes 12 are arranged so as to surround the negative electrode 11 from the outside.

[0077] Such an integrated electrode unit 15 is easy to handle. Therefore, when soil is used as the electrolyte 13, it has the advantage that it can be simply buried in the soil. When water is used as the electrolyte 13, it has the advantage that it can be simply immersed in water.

[0078] (Example of a suitable configuration of the continuous renewable energy device 10) FIG. 5 is an explanatory diagram showing the principle of power generation when plants are grown in the continuous renewable energy device 10 shown in FIG.

[0079] Similar to the continuous renewable energy system 10 described with reference to Fig. 3, the continuous renewable energy system 10 shown in Fig. 5 has a negative electrode 11 made of magnesium with a coating 14 formed thereon and a positive electrode 12 made of binchotan charcoal embedded in an electrolyte 13 made of soil. In the continuous renewable energy system 10 shown in Fig. 5, plants grow in the soil.

[0080] Such a continuous renewable energy device 10 generates electricity based on the same principle as a magnesium battery. Furthermore, since plants grow in the soil, sugars produced by plant photosynthesis and excreted from the roots can be used. Therefore, the continuous renewable energy device 10 can also generate electricity based on the same principle as a microbial fuel cell or plant-based power generation.

[0081] More specifically, sugars decomposed by current-generating bacteria (such as Shewanella and Geobacter) in the soil release electrons. So-called microbial fuel cells extract these electrons using carbon felt.

[0082] In contrast, the continuous renewable energy device 10 applies a voltage that utilizes the difference in standard electrode potential between the electrodes, so in addition to the electrons released by the sugars produced by the current-producing bacteria, electrons are also released as a result of the electrolysis of organic matter containing sugars in the soil. As a result, in the continuous renewable energy device 10, many electrons flow through the negative electrode 11 to the positive electrode 12, making it possible to extract a large amount of power.

[0083] Moreover, because photosynthesis absorbs carbon dioxide from the atmosphere, it is possible to generate clean electricity.

[0084] Fertilizer is also applied to the soil, so electricity can be generated from the fertilizer components, increasing the amount of electricity that can be generated.

[0085] Furthermore, even when electrons are released during the process of decomposition of water or components (inorganic substances) of chemical fertilizer, the electrons flow to positive electrode 12 through negative electrode 11, and electricity can be extracted.

[0086] In this way, in a microbial fuel cell, the only energy source is the electrons generated by the current-generating bacteria, whereas in the continuous renewable energy device 10, organic matter, water, and inorganic matter other than sugars can also be used as energy sources, making it possible to extract large amounts of electricity.

[0087] Needless to say, plant-based power generation is power generation using plants, but the plants themselves do not generate the power. How to use them to obtain electricity is important. For this reason, it is necessary to understand how plants grow.

[0088] Plants absorb water and nutrients through their roots, and use sunlight through their leaves to convert carbon dioxide from the air and water absorbed through their roots into sugars such as starch through photosynthesis. 12 O6) and release oxygen into the air. Sugars are transported throughout the plant as nutrients by the phloem, helping the plant grow. Photosynthesis is a reaction process that converts light energy into chemical energy to produce the nutrients needed by plants.

[0089] The sugars produced by photosynthesis in plants are starch and other substances, but not all of them are used for plant growth; it is said that about 70% is left over and excreted from the roots. Mycorrhizal fungi that exist around the roots extend their hyphae widely from the roots into the soil, absorbing nutrients from the soil, especially phosphorus, and supplying them to the plant.

[0090] In addition, the roots supply the mycorrhizal fungi with carbon compounds such as sugars, which are products of plant photosynthesis. Mycorrhizal fungi and plants have a symbiotic relationship. Mycorrhizal fungi contain current-generating bacteria (Shewanella, Geobacter, etc.), which break down and ionize sugars. In this way, using plants has the advantage of constantly supplying a new source of electricity (sugars).

[0091] (Relationship between Electrolyte 13 and Electricity) Fig. 6 is an explanatory diagram showing the voltage and other data obtained when the electrolyte 13 is changed in the continuous renewable energy device 10 shown in Fig. 3 and Fig. 5. Note that Fig. 6 is data demonstrating that electrical energy can be obtained even when the electrolyte 13 is changed when the electrode unit 15 shown in Fig. 4 is used, and is not data comparing the magnitude of electrical energy when the electrolyte 13 is changed.

[0092] As shown in FIG. 6, when the electrolyte 13 is water (tap water), the open circuit voltage is 1.47 V and the short circuit current is 3.57 mA / cm 2 When chemical fertilizer (nitrogen, phosphoric acid, potassium) was dissolved in this tap water to make a chemical fertilizer solution, the open circuit voltage was 1.73 V and the short circuit current was 15.39 mA / cm. 2 Obtained.

[0093] The same experiment was also conducted when chemical fertilizer was mixed into the soil. In this case, the open circuit voltage was 1.47 V and the short circuit current was 5.84 mA / cm. 2 At this time, the soil was sufficiently moist. Furthermore, after planting the plants in the soil, the power obtained after one week was 1.62V open circuit voltage and 4.11mA / cm short circuit current. 2The reason for leaving it for a week was to store the sugars released from the roots during plant photosynthesis and to verify its effectiveness.

[0094] When soil is used as an electrolyte, the effectiveness naturally depends on the properties of the soil, so fertilizer can be either chemical or organic, such as chicken manure. The power required also varies depending on the type of plant. Therefore, the data shown in Figure 6 is merely an example showing that both inorganic chemical fertilizers and organic fertilizers are effective.

[0095] The power output depends on the size and number of electrodes, and large power can be obtained by increasing the size and number of electrodes. Therefore, it is clear that the continuous renewable energy device 10 according to the first embodiment can be used as a power source for the hydrogen production device 20. Moreover, the continuous renewable energy device 10 can generate power continuously, day and night, even in case of weather changes.

[0096] [Embodiment 2] 7 is a block diagram showing the configuration of a hydrogen production system 1 according to embodiment 2 of the present invention. In embodiment 2 and embodiments 3, 4, 5, and 6 described below, the configurations of the continuous renewable energy device 10, the hydrogen production device 20, the power conversion device 80 (interleaved power conversion device 81), etc. are the same as those of the hydrogen production system 1 according to embodiment 1, and therefore, description thereof will be omitted.

[0097] 7, similar to the first embodiment, the hydrogen production system 1 according to the second embodiment also includes a continuous renewable energy device 10 capable of continuously generating electric power, a plurality of hydrogen production devices 20, and a power conversion device 80 (interleaved power conversion device 81) that supplies electric power from the continuous renewable energy device 10 to the hydrogen production device 20. The interleaved power conversion device 81 is, for example, an interleaved DC / DC converter or an interleaved DC / AC inverter.

[0098] The hydrogen production system 1 according to the second embodiment further includes a power storage device 30 that stores power from the continuous renewable energy device 10, and an on-off control device 60 that controls charging from the continuous renewable energy device 10 to the power storage device 30 and controlling power supply from the power storage device 30 to the hydrogen production device 20. The power storage device 30 stores power using a secondary battery, a capacitor, or the like.

[0099] The hydrogen production system 1 according to the second embodiment also includes a hydrogen storage tank 70 that stores hydrogen produced by the hydrogen production device 20, a monitoring device 50 that monitors the amount of power generated by the continuous renewable energy device 10 and the amount of power charged to the power storage device 30, and a control unit 40 that controls the power supply to the hydrogen production device 20 based on the results of monitoring the amount of power by the monitoring device 50. The control unit 40 controls the on / off control device 60 via the monitoring device 50, thereby controlling the power supply to the hydrogen production device 20.

[0100] The monitoring device 50 monitors the amount of power by detecting the voltage and current output from the continuous renewable energy device 10, and monitors the amount of power by the voltage between the output terminals of the power storage device 30. The control unit 40 can be configured by a control circuit that operates in a predetermined order based on an input signal, or can be configured using a CPU or the like that performs processing based on programs stored in various recording media or storage devices.

[0101] In the second embodiment, the control unit 40 controls the on-off control device 60 via the monitoring device 50, but it is also possible to adopt a configuration in which the control unit 40 directly controls the on-off control device 60.

[0102] In the hydrogen production system 1 configured in this manner, under the control of the control unit 40 and the on / off control device 60, the power storage device 30 is charged with power from the continuous renewable energy device 10 when the hydrogen production device 20 is not operating or when surplus power is generated for the hydrogen production device 20. Therefore, even when the continuous renewable energy device 10 is used as a power source, power is less likely to be wasted.

[0103] Furthermore, under the control of the control unit 40 and the on-off control device 60, the power stored in the power storage device 30 is supplied to the hydrogen production device 20 when the power supplied from the continuous renewable energy device 10 to the hydrogen production device is insufficient. Therefore, a stable and efficient power supply to the hydrogen production device 20 is possible, and hydrogen can be efficiently stored in the hydrogen storage tank 70.

[0104] Furthermore, both the power supplied from the continuous renewable energy device 10 to the hydrogen production device 20 and the power supplied from the power storage device 30 to the hydrogen production device 20 are supplied to the hydrogen production device 20 via a power conversion device 80 such as an interleaved power conversion device 81. Therefore, even when a large amount of power is supplied from a common power source, it is possible to avoid situations in which the input / output ripple becomes large or the power supply operation becomes unstable.

[0105] [Embodiment 3] Fig. 8 is a block diagram showing the configuration of a hydrogen production system 1 according to a third embodiment of the present invention. In the third embodiment and a fourth embodiment described below, "plurality" of continuous renewable energy devices 10 means that there are a plurality of devices that each output power independently, and even if a plurality of electrode units as shown in Fig. 3 etc. are provided, they are considered to be one continuous renewable energy device 10 when power is output collectively.

[0106] As shown in FIG. 8, the hydrogen production system 1 of the third embodiment includes a plurality of continuous renewable energy devices 10, and the electricity generated by the plurality of continuous renewable energy devices 10 is all output to a common power conversion device 80.

[0107] This makes it possible to increase the amount of power supplied to the hydrogen production device 20. Furthermore, since the continuous renewable energy device 10 uses renewable energy, the amount of power generated is prone to fluctuate depending on environmental conditions such as temperature, and in particular, the amount of power generated by the continuous renewable energy device 10 described with reference to Fig. 3 varies greatly depending on the amount of moisture in the soil, etc.

[0108] Therefore, by providing a plurality of continuous renewable energy devices 10 as in the third embodiment, it is possible to suppress fluctuations in the total power output from the plurality of continuous renewable energy devices 10. This stabilizes the power supplied to the power conversion device 80 and the hydrogen production device 20, allowing the power conversion device 80 and the hydrogen production device 20 to operate stably.

[0109] [Embodiment 4] Fig. 9 is a block diagram showing the configuration of a hydrogen production system 1 according to embodiment 4 of the present invention. As shown in Fig. 9, the hydrogen production system 1 of embodiment 4 includes a plurality of continuous renewable energy devices 10, which include multiple series of continuous renewable energy devices 10A, 10B, 10C, and 10D that output electric power to a power conversion device 80 for each series.

[0110] The power converter 80 includes a plurality of power converters 80A, 80B, 80C, and 80D that convert the power output from each of the plurality of series of continuous renewable energy devices 10A, 10B, 10C, and 10D for each series.

[0111] Therefore, similar to the third embodiment, by providing a plurality of continuous renewable energy devices 10, it is possible to increase the amount of power supplied to the hydrogen production device 20. Furthermore, by providing a plurality of continuous renewable energy devices 10, it is possible to suppress fluctuations in the total power output from the plurality of continuous renewable energy devices 10. Therefore, the power supplied to the hydrogen production device 20 is stabilized, and the hydrogen production device 20 can be operated stably.

[0112] Furthermore, even if a malfunction occurs in any of the power conversion devices 80A, 80B, 80C, and 80D, the operation of the hydrogen production device 20 will not be stopped, and the hydrogen production device 20 can be operated stably. The number of systems is not limited to four systems.

[0113] [Embodiment 5] Fig. 10 is a block diagram showing the configuration of a hydrogen production system 1 according to a fourth embodiment of the present invention. Fig. 11 is an explanatory diagram of a hydrogen gas recovery device 91 shown in Fig. 10. In the hydrogen production system 1 of the fourth embodiment, the continuous renewable energy device 10 generates hydrogen gas on the side of the positive electrode 12 shown in Fig. 2 etc. when generating electric power.

[0114] 10 and 11, the hydrogen production system 1 is provided with a hydrogen gas recovery device 91 equipped with a hood 910 and the like for recovering hydrogen gas generated by the continuous renewable energy device 10. In the fifth embodiment, hydrogen gas is recovered in the atmosphere, but if the electrolyte 13 shown in FIG. 2 and the like is water, hydrogen gas may be recovered in water.

[0115] In addition, the hydrogen gas recovered by the hydrogen gas recovery device 91 may be stored in the hydrogen storage tank 70, but in the hydrogen production system 1 of embodiment 5, a hydrogen storage device 92 that stores the hydrogen gas recovered by the hydrogen gas recovery device 91 is provided separately from the hydrogen storage tank 70.

[0116] According to this configuration, the hydrogen gas recovered by the hydrogen gas recovery device 91 can be used as a power source for operating the hydrogen production system 1. Furthermore, even if the hydrogen production device is stopped due to a malfunction or maintenance, hydrogen supply can be continued.

[0117] [Embodiment 6] 12 is a block diagram showing the configuration of a hydrogen production system 1 according to a sixth embodiment of the present invention. Similar to the fifth embodiment, the hydrogen production system 1 of the sixth embodiment is provided with a hydrogen gas recovery device 91 including a hood 910 for recovering hydrogen gas generated by the continuous renewable energy device 10.

[0118] However, in the hydrogen production system 1 of embodiment 6, the hydrogen storage tank 70 stores the hydrogen produced by the hydrogen production device 20 and the hydrogen recovered by the hydrogen gas recovery device 91. The hydrogen production system 1 of embodiment 6 also includes a power generation device 93 that generates electricity using the hydrogen recovered by the hydrogen gas recovery device 91, and the electricity generated by the power generation device 93 is output to the power conversion device 80. Therefore, the electricity generated by the power generation device 93 is used to operate the hydrogen production device 20.

[0119] To achieve this configuration, the hydrogen production system 1 of the sixth embodiment is provided with a hydrogen storage device 92 that stores the hydrogen gas recovered by the hydrogen gas recovery device 91, separate from the hydrogen storage tank 70. Therefore, the hydrogen recovered by the hydrogen gas recovery device 91 is supplied to the hydrogen storage tank 70 and the power generation device 93 via the hydrogen storage device 92.

[0120] Here, three-way valves 94 are provided in the flow path from the hydrogen storage device 92 to the hydrogen storage tank 70 and in the flow path from the hydrogen storage device 92 to the power generation device 93. Therefore, it is possible to control the supply of hydrogen from the hydrogen storage device 92 to the hydrogen storage tank 70, the supply of hydrogen from the hydrogen storage tank 70 to the hydrogen storage device 92, the supply of hydrogen from the hydrogen storage device 92 to the power generation device 93, and the supply of hydrogen from the hydrogen storage tank 70 to the power generation device 93. Such control can be performed by operation by an operator or by commands from the control unit 40.

[0121] In the sixth embodiment, the storage of hydrogen recovered by the hydrogen gas recovery device 91 in the hydrogen storage tank 70 and the output of electricity generated by the power generation device 93 to the power conversion device 80 are carried out not only during maintenance of the continuous renewable energy device 10, but also when the continuous renewable energy device 10 is operating normally. This has the effect of improving the hydrogen production efficiency in the hydrogen production system 1.

[0122] [Embodiment 7] Although not shown in the figures, in the hydrogen production system according to the seventh embodiment of the present invention, when a control unit 40 is provided as in the second embodiment and multiple hydrogen production devices 20 are provided, it is preferable that the control unit 40 controls the number of operating hydrogen production devices 20 based on the amount of power supplied from the continuous renewable energy device 10. With this configuration, even if the power output from the power conversion device 80 decreases, it is possible to operate the hydrogen production devices 20 corresponding to the amount of power supply, so that hydrogen production can continue.

[0123] [Embodiment 8] A hydrogen production system (not shown) according to an eighth embodiment of the present invention has a configuration basically similar to that of any one of the hydrogen production systems 1 according to the first to sixth embodiments. However, the hydrogen production system 1 according to the eighth embodiment further includes a means for transferring at least one of the heat generated when the hydrogen production device 20 operates and the heat generated when the power conversion device 80 operates to the soil (see FIG. 3 ) in the continuous renewable energy devices 10, 10A, 10B, and 10D to promote power generation by the continuous renewable energy devices 10, 10A, 10B, and 10D. The hydrogen production system according to the eighth embodiment activates current-producing bacteria living in the soil near the negative electrode 11 and the positive electrode, thereby promoting power generation by the continuous renewable energy devices 10, 10A, 10B, and 10D.

[0124] [Other embodiments] The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications and applications are possible within the scope of the invention as defined in the claims. [Explanation of symbols]

[0125] 1 Hydrogen production system, 10, 10A, 10B, 10C, 10D Continuous renewable energy device, 11 Negative electrode, 12 Positive electrode, 13 Electrolyte, 14 Coating, 15 Electrode unit, 20 Hydrogen production device, 30 Power storage device, 40 Control unit, 50 Monitoring device, 60 On-off control device, 70 Hydrogen storage tank, 80, 80A, 80B, 80C, 80D Power conversion device, 81 Interleaved power conversion device, 82 Power conversion circuit, 91 Hydrogen gas recovery device, 92 Hydrogen storage device, 93 Power generation device, 94 Three-way valve, 110 Negative electrode lead wire, 111 First metal material, 115 Water-permeable insulating sheet, 120 Positive electrode lead wire, 121 Carbon-based material, 122 Second metal material, 150 Cable tie, 910 Hood

Claims

1. A continuous renewable energy device capable of continuously generating electricity using an electrolyte whose main material is a substance that exists in nature and contains at least water; A hydrogen production device; a power conversion device including a plurality of power conversion circuits electrically connected in parallel, which converts electric power from the continuous renewable energy device by the plurality of power conversion circuits and supplies the converted electric power to the hydrogen production device; A hydrogen production system comprising:

2. 2. The hydrogen production system according to claim 1, wherein the power conversion device is an interleaved power conversion device that operates the plurality of power conversion circuits with a phase shift.

3. 2. The hydrogen production system according to claim 1, comprising a plurality of the hydrogen production devices.

4. The continuous renewable energy device includes a plurality of electrode units each including a negative electrode and a positive electrode, at least a portion of which is disposed within the electrolyte; the negative electrode is mainly made of a first metal material having a negative standard electrode potential, 2. The hydrogen production system according to claim 1, wherein the positive electrode is mainly made of a carbon-based material or a second metal material having a standard electrode potential higher than that of the first metal material.

5. 5. The hydrogen production system according to claim 4, wherein the first metal material is at least one of magnesium, aluminum, and zinc.

6. the first metallic material has a coating formed thereon; 6. The hydrogen production system according to claim 5, wherein the coating is a film formed of a conductive material, a film formed of an intercalation compound, a film formed of a semiconductor material, or a film formed of a resin containing at least one of a conductive material, an intercalation compound, and a semiconductor material.

7. the conductive material is carbon, hard carbon, charcoal, metal, or anodic oxide of metal; the intercalation compound is graphite or carbon graphite, 7. The hydrogen production system according to claim 6, wherein the semiconductor material is tin oxide, titanium oxide, or a photocatalytic material.

8. 5. The hydrogen production system according to claim 4, wherein the second metal material is at least one of copper, silver, gold, platinum, and stainless steel.

9. 9. The hydrogen production system according to claim 1, wherein the material is soil.

10. 9. The hydrogen production system according to claim 1, wherein the substance is water or seawater.

11. 11. The hydrogen production system according to claim 10, wherein the water is river water, lake water, lake water, pond water, reservoir water, rainwater, groundwater, artificially treated tap water, or industrial water.

12. 10. The hydrogen production system according to claim 9, wherein plants are growing in the soil.

13. 10. The hydrogen production system according to claim 9, wherein the soil is fertilized.

14. 12. The hydrogen production system according to claim 11, wherein at least one of an organic substance and an inorganic substance is dissolved in the water.

15. a power storage device that stores power from the continuous renewable energy device; an on / off control device that controls charging from the continuous renewable energy device to the power storage device and power supply from the power storage device to the hydrogen production device; The hydrogen production system according to claim 1, further comprising:

16. 16. The hydrogen production system according to claim 15, wherein the power storage device stores the electricity from the continuous renewable energy device when the hydrogen production device is not operating or when surplus electricity is generated for the hydrogen production device.

17. 16. The hydrogen production system according to claim 15, wherein the power storage device supplies power to the hydrogen production device when the power supplied from the continuous renewable energy device is insufficient.

18. a hydrogen storage tank for storing hydrogen produced by the hydrogen production device; a monitoring device that monitors the amount of power generated by the continuous renewable energy device and the amount of power stored in the power storage device; a control unit that controls the supply of power to the hydrogen production device based on the monitoring result of the power amount by the monitoring device; Furthermore, 18. The hydrogen production system according to claim 15, wherein the power supplied from the continuous renewable energy device to the hydrogen production device and the power supplied from the power storage device to the hydrogen production device are both supplied to the hydrogen production device via the power conversion device.

19. The hydrogen production system according to claim 1, characterized in that it comprises a plurality of the continuous renewable energy devices.

20. The plurality of continuous renewable energy devices include a plurality of series of continuous renewable energy devices that output electric power to the power conversion device for each series, 20. The hydrogen production system according to claim 19, wherein the power conversion device includes a plurality of power conversion devices that convert the power output from each of the plurality of series of continuous renewable energy devices for each series.

21. 2. The hydrogen production system according to claim 1, further comprising a hydrogen gas recovery device that recovers hydrogen gas generated when the continuous renewable energy device generates electric power.

22. The hydrogen generating system further includes a hydrogen storage tank for storing hydrogen generated by the hydrogen generating device, 22. The hydrogen production system according to claim 21, wherein the hydrogen storage tank stores the hydrogen produced by the hydrogen production device and the hydrogen recovered by the hydrogen gas recovery device.

23. a power generation device that generates electricity using the hydrogen recovered by the hydrogen gas recovery device, 22. The hydrogen production system according to claim 21, wherein the electric power generated by the power generation device is output to the power conversion device.

24. The hydrogen production system according to claim 3 , further comprising a control unit that controls the number of operating hydrogen production devices based on the amount of power supplied from the continuous renewable energy device.

25. 10. The hydrogen production system according to claim 9, further comprising a means for transferring at least one of heat generated when the hydrogen production device is operating and heat generated when the power conversion device is operating to the soil in the continuous renewable energy device, thereby promoting power generation by the continuous renewable energy device.

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