Electrostatic charging device and electrostatic charging method

Abstract

In order to provide an electrostatic charging device that utilizes soil and is easy to use, this electrostatic charging device is provided with: a conductive section that comprises a first conductive section in which an electrically conductive substance is mixed into soil that includes ions and a second conductive section in which the amount of the electrically conductive substance mixed in is different from that of the first conductive section; a positive electrode disposed on the conductive section; a negative electrode disposed on the conductive section; and a separator disposed on the conductive section so as to insulate the positive electrode and the negative electrode from each other.

Description

Charging apparatus and charging method

[0001] The present invention relates to a charging device and charging method that can store electricity using soil.

[0002] In recent years, it has been proposed to incorporate electrically conductive nanoporous carbon into cement, form a network of nanoporous carbon using the fluidity of water, and use concrete as a capacitor (see, for example, Patent Document 1).

[0003] U.S. Publication No. 11512022

[0004] However, Patent Document 1 only proposed storing electricity in concrete to create a capacitor, and did not propose any other applications.

[0005] Therefore, the present invention aims to provide an easy-to-use electrostatic charging device and electrostatic charging method using soil.

[0006] The charging device according to claim 1 comprises a conduction section having a first conduction section in which an electrically conductive substance is mixed into soil containing ions, and a second conduction section in which the amount of the electrically conductive substance mixed in is different from that of the first conduction section, a positive electrode provided in the conduction section, a negative electrode provided in the conduction section, and a separator provided in the conduction section to insulate the positive electrode from the negative electrode. The charging method according to claim 11 is prepared by preparing a conduction section having a first conduction section in which an electrically conductive substance is mixed into soil containing ions, and a second conduction section in which the amount of the electrically conductive substance mixed in is different from that of the first conduction section, a positive electrode and a negative electrode are placed in the conduction section via a separator, and when a voltage is applied between the positive electrode and the negative electrode, anions are guided to the positive electrode and cations are guided to the negative electrode.

[0007] According to the charging device described in claim 1, since it comprises a first conduction section and a second conduction section in which the amount of electrically conductive material mixed in is different from that of the first conduction section, the charging efficiency can be improved. According to the charging method described in claim 11, the charging efficiency can be improved by using a first conduction section and a second conduction section in which the amount of electrically conductive material mixed in is different from that of the first conduction section.

[0008] This is a cross-sectional view showing a container filled with soil and two copper plates inserted into the soil. This is a cross-sectional view showing a container filled with a mixture of soil and carbon black and two copper plates inserted into the mixture. This is a schematic diagram showing the process of charging a capacitor using electrodes with an extendable portion. This is a diagram showing a first example in which the amount of electron-conductive material added to the soil is greater in some parts than in others. This is a diagram showing a second example in which the amount of electron-conductive material added to the soil is greater in some parts than in others. This is a diagram showing a third example in which the amount of electron-conductive material added to the soil is greater in some parts than in others. This is a schematic diagram showing a capacitor installed near a solar power generation device; Figure 7(a) is a schematic diagram showing the capacitor buried in the ground, and Figure 7(b) is a schematic diagram showing the capacitor installed near the foundation. This is a schematic diagram showing a drone port and capacitor installed near a solar power generation device. This is an enlarged cross-sectional view of the capacitors in Figures 7 and 8. This is a block diagram of a control device for controlling the charging and discharging of the capacitor in this second embodiment. This is a flowchart of this second embodiment.

[0009] (First Embodiment) The first embodiment will be described in detail below with reference to Figures 1 to 6. This first embodiment involves forming conductive soil by mixing an electrically conductive material with soil, and using this conductive soil to provide the capacitor 11 described later. In this first embodiment, the electrically conductive material is a material that has both electron conductivity, which moves electrons, and ionic conductivity, which moves ions. In this first embodiment, a combination of carbon black and binchotan charcoal is used as the electron conductive material, and soil 2 containing moisture is used as the ionic conductive material, but it is not limited to these. The vertical direction is shown as the Z direction, and the direction perpendicular to the Z direction in the left-right direction is shown as the X direction. In addition, although not shown, the direction perpendicular to the plane of the paper is the Y direction.

[0010] (Preliminary experiment to confirm the insulating properties of soil) Figure 1 is a cross-sectional view showing soil 2 in a glass container 1 with two copper plates 3 inserted into the soil 2. The soil 2 was collected in Tsukuba City, Ibaraki Prefecture, and was placed in container 1 after being sieved through a sieve with a mesh size of 4.75 mm. Note that a container 1 made of resin may be used instead of glass, and any material that has insulating properties may be used. Furthermore, even if the container 1 is made of a material that does not have insulating properties, it may be used in a state in which insulating properties have been given by coating or spraying, for example, an alkylalkoxysilane-based insulating agent or a silanesiloxane-based insulating agent.

[0011] When soil testing was performed on soil 2, the density of the soil particles was found to be 2.660 g / cm³. ３ The natural moisture content was 35.7%. The particle size distribution of soil 2 was 4.5% gravel, 39.5% sand, 42.0% silt, and 14.0% clay. As a result, soil 2 was classified as sandy silt.

[0012] Sandy silt contains calcium ions (Ca), which are electrolytes. ２＋ ) and magnesium ions (Mg ２＋ Since it contains ), soil 2 can be used as an electrolyte. If the electrolyte substance in soil 2 is insufficient, calcium ions (Ca ２＋ ), potassium ions (K ＋ ), magnesium ions (Mg ２＋ ), sodium ions (Na ＋ Positive ions with a high ionization tendency, such as those mentioned above, can be added to soil 2 as an electrolyte.

[0013] For example, cement contains calcium ions (Ca ２＋ Since it contains ), it can be mixed with soil 2 as soil cement.

[0014] When the test leads of the tester were touched to each of the two copper plates 3, no continuity was detected, indicating a non-conductive state. Therefore, no continuity was confirmed in soil 2.

[0015] (Mixing of soil and electrically conductive material) The aforementioned soil 2 was mixed with an electrically conductive material. As the electrically conductive material, a combination of carbon black and binchotan charcoal was used, but it is not limited to this, and for example, one type of carbon-derived material (for example, binchotan charcoal or activated carbon) may be used as the electrically conductive material. Carbon black is a suitable material for forming a carbon network and, when mixed with soil 2, lowers the internal resistance of soil 2 and increases the capacitance of soil 2. Binchotan charcoal is a suitable material for absorbing and releasing ions. In this first embodiment, acetylene black produced by the thermal decomposition of acetylene was used as the carbon black. However, registered trademark Ketjenblack, in which the primary particles have a hollow shell structure, may be used, or inexpensive activated carbon may be used. In this case, it is preferable to use activated carbon mainly composed of micropores or mesopores.

[0016] Binchotan charcoal, which is derived from carbon, may be used in crushed form or as commercially available powdered binchotan charcoal. Alternatively, oga charcoal (oga binchotan charcoal), which is made from oga briquettes (sawdust compressed under high pressure), may be used as binchotan charcoal. In addition, activated carbon with macropores may be used instead of binchotan charcoal.

[0017] Acetylene black and Binchotan charcoal are hydrophobic substances, but they become somewhat more compatible with water after being soaked in water for about a day. In this case, it is preferable to stir them for 10 to 30 minutes immediately after soaking them in water. In this first embodiment, acetylene black and Binchotan charcoal were each soaked in water before being mixed with soil 2. This improves the affinity between soil 2, acetylene black, and Binchotan charcoal. In this case, stirring acetylene black, Binchotan charcoal, and water together allows the acetylene black and Binchotan charcoal, which form a carbon network, to mix well, and also allows water molecules to be adsorbed into the pores of the Binchotan charcoal, enabling efficient ion storage and release. Alternatively, activated carbon, acetylene black, and water may be stirred together instead of Binchotan charcoal, or in addition to Binchotan charcoal. This allows water molecules to be adsorbed into the micropores and mesopores of the activated carbon.

[0018] The amount of acetylene black added is between 5% and less than 20% by weight of soil 2. If the amount of acetylene black added is 5% or more by weight of soil 2, a carbon network can be formed in soil 2. If the amount of acetylene black added is 20% or more by weight of soil 2, the resistance value of mixture 4, which will be described later, will be further reduced, but in this first embodiment, it is set to less than 20% considering the price and cost-effectiveness of acetylene black.

[0019] The amount of Binchotan charcoal added is set to be between 8% and less than 25% by weight of soil 2. If the amount of Binchotan charcoal added is 8% or more by weight of soil 2, charging using ions from soil 2 by the capacitor 11 described later becomes possible. The amount of Binchotan charcoal added may be 25% or more by weight of soil 2, but considering the price of Binchotan charcoal and cost-effectiveness, it is set to less than 25% in this first embodiment. Also, if activated carbon is used instead of Binchotan charcoal, the amount of activated carbon added should be between 8% and less than 25% by weight of soil 2.

[0020] The amount of binchotan charcoal to add will vary depending on the properties of soil 2, the amount of electrolytes contained in soil 2, and whether or not electrolytes are added, so the above amount should be used as a guideline. Furthermore, considering the performance of capacitor 11 (charge amount, charging time, etc.) described later, it is preferable that the amount of binchotan charcoal added be greater than the amount of acetylene black added. The amount of acetylene black added may also be determined by considering the internal resistance (several ohms to tens of ohms) when mixed with soil 2. Even when activated carbon is used instead of binchotan charcoal, it is preferable that the amount of activated carbon added be greater than the amount of acetylene black added. Furthermore, when both binchotan charcoal and activated carbon are used, it is preferable that the combined amount of binchotan charcoal and activated carbon added be greater than the amount of acetylene black added.

[0021] In this first embodiment, soil 2, acetylene black, and crushed binchotan charcoal were mixed in a mixer for several minutes (1 to 2 minutes) to create mixture 4.

[0022] (Experiment to confirm the conductivity of the mixture) Figure 2 is a cross-sectional view showing the mixture 4 in container 1 with two copper plates 3 inserted into the mixture 4.

[0023] When the test leads of the tester were touched to each of the two copper plates 3, the resistance was approximately 20 to 30 ohms, confirming the conductivity of the mixture 4. This confirmed that an electrical conductivity network was formed in the soil 2 by carbon black, a carbon-derived material.

[0024] The reason for the fluctuation of approximately 10 ohms in the resistance value is that gas (air) is mixed into mixture 4, making the contact state of the electrically conductive material unstable. Therefore, mixture 4 was manually compacted using a metal tamping rod to remove the gas, and the resistance value of mixture 4 was measured again.

[0025] After manual compaction, the resistance of mixture 4 was approximately 18-20 Ω, and it was confirmed that the resistance decreased and the fluctuation in resistance also decreased. Furthermore, this resistance can be reduced to a few Ω by increasing the amount of carbon black added to 10-15%.

[0026] In this first embodiment, the mixture 4 is a conductive part in which an electrically conductive carbon network is formed, and a capacitor 11 is realized as a charging device that utilizes ions from soil 2 using this conductive part.

[0027] (Experiment to confirm energy storage using a mixture) Figure 3 is a schematic diagram showing the charging of a capacitor 11 having the extension parts 6a and 7a described later, and is shown as a cross-sectional view except for the power supply 8. As shown in Figure 3, after attaching the separator 5 to the container 1, the mixture 4 is added, the positive electrode 6 and the negative electrode 7 are inserted into the mixture 4, and then the mixture 4 is compacted to form the capacitor 11 of this first embodiment. It is preferable to degas the mixture 4 after the positive electrode 6 and the negative electrode 7 have been inserted into the mixture 4. In this case, it is preferable to add the mixture 4 to the container 1 in several batches and degas it each time.

[0028] The applicant has found that when the aforementioned mixture 4 is compacted, the adhesion between the mixture 4 and the electrode improves, which in turn lowers the contact resistance between the mixture 4 (especially carbon black) and the electrode, improving the amount of charge stored in the capacitor 11. When compaction is performed along the arrow in Figure 3, a force is applied to the mixture 4 in the vertical Z direction, but a force in the X direction does not easily act on the electrode. For this reason, in this first embodiment, the shape of the electrode is made into an L-shape that intersects the vertical direction so that the vertical force applied to the electrode during compaction is applied to the electrode. Specifically, as shown in Figure 3, the lower end of the positive electrode 6 is bent to form an extended portion 6a, and the lower end of the negative electrode 7 is bent to form an extended portion 7a. In this way, the extended portions 6a and 7a extend in the X direction, which is the direction that intersects the Z direction in which the separator 5 is located. Here, the length of the extended portions 6a and 7a in the X direction can be set arbitrarily as long as they do not interfere with the separator 5. As a result, the adhesion between the extended portion 6a and the extended portion 7a and the mixture 4 is improved, which can increase the amount of energy stored in the capacitor 11, and consequently increase the charging energy of the capacitor 11. Here, charging energy is the product of power and charging time. It is preferable to provide extended portions on both the positive electrode 6 and the negative electrode 7, but the extended portion on either one may be omitted.

[0029] The separator 5 prevents direct contact and short-circuiting between the positive electrode 6 and the negative electrode 7, while allowing ions in the mixture 4 to pass through the formed carbon network. In this first embodiment, the separator 5 is arranged along the Z direction. In this first embodiment, the material of the separator 5 can be a polyolefin resin such as polyethylene or polypropylene, or a polyester resin such as polyethylene terephthalate or polybutylene terephthalate. Alternatively, the separator 5 can be a cellulose-derived nonwoven fabric or paper (e.g., Japanese paper or kitchen paper). The separator 5 may also be a composite material of a cellulose-derived nonwoven fabric or paper and polyethylene or glass fiber. The separator 5 is fixed to the container 1 with insulating tape. Alternatively, it may be placed in the container 1 sandwiched between insulating materials. Furthermore, it is preferable to use a hydrophilic material for the separator 5 to facilitate the passage of ions. The separator 5 may be fixed by forming a recess in the bottom of the container 1 and using this recess for fixing, by using insulating tape, or by other methods.

[0030] The positive electrode 6 can be made of a material that does not easily react with ionic substances contained in the soil 2, such as copper, aluminum, platinum, or carbon materials. In this first embodiment, a copper plate 3 was used. The positive electrode 6 is connected to a carbon network formed of acetylene black. An electrical double layer is formed near the surface of the binchotan charcoal connected to this carbon network, causing the positive electrode 6 to be charged by attracting anions with the opposite charge. Sheet-shaped carbon fibers may also be used as the carbon material for the positive electrode 6 and the negative electrode 7. Carbon fibers are lightweight and strong, making them easy to use electrodes. In this specification, the positive electrode 6 and the negative electrode 7 are sometimes collectively referred to as electrodes.

[0031] The negative electrode 7 can be made of a material that does not easily react with ionic substances contained in the soil 2, such as copper, aluminum, platinum, or carbon materials. In this first embodiment, a copper plate 3 was used. The negative electrode 7 is connected to a carbon network formed of acetylene black. An electrical double layer is formed near the surface of the binchotan charcoal connected to this carbon network, causing the negative electrode 7 to be charged by attracting cations with the opposite charge. Sheet-shaped carbon fibers may be used as the carbon material for the positive electrode 6 and the negative electrode 7. Carbon fibers are lightweight and strong, making them easy to use electrodes. Also, sheet-shaped carbon fibers are easier to bend than metal electrodes, making it easier to form the stretched portions 6a and 7a. After adding a mixture 4 of several mm to several cm in size to cover the stretched portions 6a and 7a, degassing by compaction is performed to improve the adhesion between the electrode and the mixture 4 and to remove gas from the mixture 4. It is also desirable to perform degassing by compaction when adding more mixture 4 to the container 1 afterward.

[0032] To improve the adhesion between the electrode and the mixture 4, the electrode shape may be made zigzag. By making the electrode shape zigzag, the surface area of ​​the electrode increases, and the contact area between the mixture 4 and the electrode increases, so that more carbon networks come into contact with the electrode, which can improve the amount of energy stored in the capacitor 11 and, consequently, increase the charging energy of the capacitor 11.

[0033] Furthermore, the electrodes may be positioned at an angle to the Z direction. By positioning the electrodes so as to intersect with respect to the Z direction, the length of the electrodes in the mixture 4 can be increased, thereby increasing the contact area between the mixture 4 and the electrodes. For this reason, positioning the electrodes so as to intersect with the Z direction allows more carbon networks to come into contact with the electrodes, thereby improving the amount of energy stored in the capacitor 11.

[0034] The power supply 8 is used when charging the capacitor 11, and a constant voltage power supply, a constant current power supply, etc. can be used. The charging of the capacitor 11 can be either constant voltage charging or constant current charging, but in this first embodiment, charging is performed by constant current charging from the perspective of charging efficiency.

[0035] One end of the wiring 9 is connected to the positive electrode 6, and the other end is connected to the + output terminal of the power supply 8. One end of the wiring 10 is connected to the negative electrode 7, and the other end is connected to the - output terminal of the power supply 8.

[0036] In this first embodiment, charging was performed at a voltage of 1 V to 3 V using a constant voltage power supply as the power supply 8. When the water content of the mixture 4 is high, charging is performed at 1.2 V or less to prevent hydrogen generation. When the water content of the mixture 4 is low, that is, when there is no influence of hydrogen generation, charging is performed at 3 V.

[0037] Depending on the state of the mixture 4, after charging for several minutes or about 5 to 10 minutes, when the wiring 9 and the wiring 10 were connected to a rotation motor (not shown), the rotation motor (not shown) rotated. As a result, it was confirmed that a carbon network of acetylene black was formed in the soil 2 and that the occlusion and release of ions by the binchotan, which is an ion adsorption substance, were occurring. That is, it was confirmed that power storage was possible using the mixture 4. Note that the charging time becomes longer as the volume of the container 1 increases, that is, as the amount of the mixture 4 increases, and may be several hours or more.

[0038] Also, the mixture 4 was newly created at the aforementioned weight ratio, and sodium ions (Na ＋ ) were added. Specifically, several hundred cc of 5% saline solution was added. Then, in the same manner as described above, charging was performed at a voltage of 1.2 V for the same time (several minutes or about 5 to 10 minutes). After that, when the wiring 9 and the wiring 10 were connected to the rotation motor, the rotation motor rotated longer compared to the mixture 4 to which no sodium ions (Na ＋ ) were added.

[0039] Thus, by adding cations, the charge amount of the capacitor 11 increases, so it can supply a large amount of power. Therefore, according to the amount of ions in the mixture 4, the addition amount of binchotan charcoal or activated carbon that stores and releases these ions may be determined. In addition, the applicant of the present application has found that when the mixture 4 dries, the power storage performance of the capacitor 11 deteriorates. Therefore, it is preferable that the mixture 4 is installed in an environment where humidity is easily maintained, or that a liquid such as water is supplied when it dries. Thereby, deterioration of the power storage performance of the capacitor 11 can be prevented, or the capacitor 11 with deteriorated power storage performance can be recovered.

[0040] The applicant of the present application repeatedly conducted charging experiments of the capacitor 11 and discharge experiments with a load such as resistance connected by appropriately combining the above conditions. As a result, compared with the case where an electronically conductive substance is uniformly added to the soil 2, by making the addition amount of the electronically conductive substance to the soil 2 larger in a part than in the other part, the internal resistance of the capacitor 11 can be reduced, so it was found that the charging efficiency can be improved. The charging efficiency is the ratio of the energy actually stored in the capacitor 11 to the energy supplied to the capacitor 11.

[0041] FIG. 4 is a diagram showing a first example in which the addition amount of the electronically conductive substance to the soil 2 is made larger in a part than in the other part. The same components as those in FIG. 3 are denoted by the same reference numerals and their description is omitted. The mixture 4 shown in FIG. 4 has a first mixing portion 4a in which the addition amount of the electronically conductive substance is the same as that of the mixture 4 in FIG. 3, and a second mixing portion 4b in which the addition amount of the electronically conductive substance is larger than that of the first mixing portion 4a.

[0042] In the first mixing portion 4a, for example, the addition amount of acetylene black is 10% by weight of the soil, and the addition amount of binchotan charcoal or activated carbon is 15% by weight of the soil. On the other hand, in the second mixing portion 4b, for example, the addition amount of acetylene black is 15% by weight of the soil, and the addition amount of binchotan charcoal or activated carbon is 20% by weight of the soil.

[0043] In this first embodiment, since the extension portions 6a and 7a are provided so as to be in contact with the upper surface of the second mixing portion 4b, ion conductivity is improved and the charging energy can be increased. Also, since the amount of acetylene black, binchotan charcoal, and activated carbon used is less compared to making the entire mixture 4 into the second mixing portion 4b, the cost of manufacturing the mixture 4 can be reduced. In this first embodiment, in order to reduce the cost of manufacturing the mixture 4, the area occupied by the second mixing portion 4b is smaller than the area occupied by the first mixing portion 4a. In addition, the weight of the second mixing portion 4b is lighter than the weight of the first mixing portion 4a.

[0044] As described above, the area occupied by the second mixing section 4b is smaller than the area occupied by the first mixing section 4a, so the amount of acetylene black added may exceed 20% by weight of the soil, and the amount of binchotan charcoal or activated carbon added may exceed 25% by weight of the soil. In this case as well, from the viewpoint of cost, it is preferable that the amount of acetylene black added be about 30% by weight of the soil, and the amount of binchotan charcoal or activated carbon added be about 35% by weight of the soil.

[0045] Furthermore, the second mixing section 4b may be composed of acetylene black and at least one of binchotan charcoal and activated carbon, without using soil 2. In this case, as described above, by adding water to the acetylene black and stirring, the acetylene black will coagulate in the water and change from a powder to a lumpy (clumpy) state. The second mixing section 4b can then be formed by adding at least one of binchotan charcoal and activated carbon to the lumpy (clumpy) acetylene black. It is also preferable to degas the lumpy (clumpy) acetylene black even when soil 2 is not used. Additionally, since the density of acetylene black is much lower than that of soil 2, the weight of the second mixing section 4b can be made lighter when soil 2 is not used.

[0046] The second mixing section 4b contains potassium ions (K) whether soil is used or not. ＋ ) and sodium ions (Na ＋ It is preferable to add cations with a high ionization tendency, such as ), as an electrolyte substance. Also, potassium ions (K) are also added in the first mixing section 4a.＋ ) and sodium ions (Na ＋ It is preferable to add cations with a high ionization tendency, such as ), as an electrolyte substance.

[0047] Figure 5 shows a second example in which the amount of electron-conductive material added to the soil 2 is greater in one part than in other parts. Note that the same reference numerals are used for components that are the same as in Figures 3 and 4, and their explanations are omitted. The mixture 4 shown in Figure 5 has multiple first mixing sections 4a and multiple second mixing sections 4b. The number of first mixing sections 4a and second mixing sections 4b is not limited to two, but may be three or more. Also, the position of the second mixing section 4b in the container 1 is not limited to the bottom and middle of the container 1, but may be located at the top. Furthermore, in Figures 4 and 5, the first mixing section 4a and the second mixing section 4b are arranged along the X direction, but this is not limited to that. Also, the second mixing section 4b may be configured without soil 2.

[0048] Figure 6 shows a third example in which the amount of electron-conductive material added to soil 2 is greater in one part than in other parts. In Figure 6, the first mixing section 4a and the second mixing section 4b are provided along the Z direction. By providing two second mixing sections 4b so as to sandwich the separator 5, the movement of ions through the separator 5 becomes smoother, which improves charging efficiency and also increases the amount of stored energy.

[0049] Furthermore, by providing the second mixing section 4b so as to be in contact with the positive electrode 6 along the Z direction, the reduction reaction of the positive electrode 6 can be carried out efficiently. Similarly, by providing the second mixing section 4b so as to be in contact with the negative electrode 7 along the Z direction, the oxidation reaction of the negative electrode 7 can be carried out efficiently.

[0050] Furthermore, the two second mixing sections 4b that sandwich the separator 5, the second mixing section 4b that contacts the positive electrode 6, and the second mixing section 4b that contacts the negative electrode 7 are not necessarily required, and at least one may be omitted depending on the cost-effectiveness. Also, the second mixing section 4b may be configured without soil 2.

[0051] In civil engineering and construction, soil has played a role as ground and foundation, but according to this first embodiment, in addition to these roles, soil also plays a role in energy storage, making it possible to realize an electric double-layer capacitor using soil. When the capacitor 11 shown in Figures 3 to 6 is used outdoors, a waterproof sheet can be placed on top of the capacitor 11 or a cover can be placed over the capacitor 11 to prevent rain, snow, etc. from penetrating the capacitor 11. As the waterproof sheet, a vinyl chloride sheet or a high-density polyethylene sheet can be used.

[0052] (Second Embodiment) The second embodiment will be described below with reference to Figures 7 to 11. Components identical to those in the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted or simplified. The second embodiment will describe the case in which the capacitor 11 is used outdoors.

[0053] (Installation of a capacitor near a solar power generation device) The following explanation will continue with an example of using the capacitor 11 outdoors, specifically when it is installed near a solar power generation device 30 that generates renewable energy. However, a wind power generation device may also be used as the device that generates renewable energy.

[0054] Figure 7 is a schematic diagram showing a capacitor 11 installed near the solar power generation device 30. Figure 7(a) is a schematic diagram showing a capacitor 11 buried in the ground 36. Figure 7(b) is a schematic diagram showing a capacitor 11 installed near the foundation 35. In Figure 7(b), the capacitors 11 are stacked on top of each other via a support member 37. As is clear from Figure 7(a), the capacitor 11 is positioned to avoid being directly beneath the foundation 35 in order to prevent the foundation 35 from sinking. Also, as is clear from Figure 7(b), the capacitor 11 is installed between two foundations 35. The number of capacitors 11 can be set arbitrarily.

[0055] The solar power generation system 30 comprises a solar panel 31, a mounting frame 34 having panel support sections 32 and support columns 33, and a concrete foundation 35. Multiple foundations 35 are installed on the ground 36. The mounting frame 34 is placed on these foundations 35. The solar panel 31 is supported by this mounting frame 34. The mounting frame 34 can be of any shape as long as it can support the solar panel 31, and the number of support columns 33 can be as few as one.

[0056] Furthermore, in this second embodiment, the concrete foundation 35 may be embedded in the ground 36, or the foundation 35 may be omitted and the support columns 33 may be driven into the ground 36. If the capacitor 11 is placed below the solar power generation device 30, the solar power generation device 30 acts as an umbrella, preventing the capacitor 11 from being exposed to rain, snow, or sunlight.

[0057] Figure 8 is a schematic diagram showing a drone port 50 and a capacitor 11 provided near the solar power generation device 30. In this second embodiment, as shown in Figure 8, a capacitor 11 is provided inside the drone port 50, and power is supplied to the drone 51 via a power supply device 48c (see Figure 10) using the capacitor 11.

[0058] In this second embodiment, the drone port 50 is configured to be sealed, thereby preventing rain, snow, and other elements from penetrating the capacitor 11. Furthermore, in this second embodiment, a power supply device 48c is provided on the upper surface of the drone port 50, allowing for wireless or contact-type power supply. Wireless power supply is a method of supplying power to the power receiving device 103 without contact, and methods such as magnetic resonance and electromagnetic induction are known.

[0059] In this second embodiment, the imaging device provided on the drone 51 can detect dirt on the solar panel 31. Furthermore, by equipping the drone 51 with cleaning fluid and supplying this fluid to the solar panel 31 using a pump (not shown), the solar panel 31 can be cleaned. In this way, by storing the electricity generated by the solar panel 31 in the capacitor 11 and using it for the maintenance of the solar panel 31, the electricity generated by the solar panel 31 can be efficiently utilized even when there is a request for output control. Moreover, by producing and consuming electricity locally in this way, equipment for supplying electricity over long distances becomes unnecessary.

[0060] Figure 9 is an enlarged cross-sectional view of the capacitor 11 shown in Figures 7 and 8. In particular, the capacitor 11 in Figure 7 is for outdoor use, and therefore has a cover and maintenance components added to the capacitor 11 in Figure 4. Note that in Figures 7 to 10, some wiring 9, wiring 10, and piping 19 are omitted to avoid making the drawings too complex. Also, although the capacitor 11 shown in Figure 9 uses the L-shaped electrodes shown in Figure 4, straight electrodes with the extensions 6a and 7a omitted may be used, zigzag electrodes may be used, or the electrodes may be arranged at an angle with respect to the Z direction. Furthermore, cover and maintenance components may be added to the capacitor 11 in Figures 5 and 6.

[0061] The first lid member 17 is a lid that covers the container 1, and in this second embodiment, a circular resin is used. For example, if the container 1 is made of circular resin, a female thread can be formed on the inner surface of the container 1, and a male thread can be formed on the outer surface of the first lid member 17, so that the container 1 can be covered by the first lid member 17 by screwing the male and female threads together. Alternatively, the shape of the first lid member 17 may be such that it covers the container 1 from above, and the container 1 and the first lid member 17 may be fastened together with fastening members such as bolts. When fastening members such as bolts are used, the container 1 and the first lid member 17 can be any shape, such as a rectangle.

[0062] The first lid member 17 is provided with a communication hole member 18 that communicates with the outside. In this second embodiment, three communication hole members 18a, 18b, and 18c are formed so as to face the separator 5, the positive electrode 6, and the negative electrode 7, respectively, but the embodiment is not limited to this.

[0063] The communication hole member 18a is a hole for maintaining the separator 5, and in this second embodiment, a pipe 19 for supplying water (for example, distilled water such as pure water) to the separator 5 passes through it. In this second embodiment, water is supplied to the separator 5 because ions become less mobile when the separator 5 dries out.

[0064] The connecting hole member 18b is a hole for passing the first pipe member 20 through which the wiring 9 from the positive electrode 6 passes. The connecting hole member 18c is a hole for passing the second pipe member 21 through which the wiring 10 from the negative electrode 7 passes. PF (Plastic Flexible) pipes can be used as the first pipe member 20 and the second pipe member 21. The lengths of the first pipe member 20 and the second pipe member 21 can be set arbitrarily.

[0065] The second cover member 22 is a cover member provided in correspondence with the communication hole member 18. The second cover member 22a covers the communication hole member 18a and has an opening for the pipe 19 that supplies water (for example, distilled water such as pure water) to the separator 5 to pass through. If it is necessary to prevent rain from seeping in through this opening, the area around the opening can be wrapped with sealing tape or a clay material can be provided.

[0066] The second cover member 22b covers the communication hole member 18b and has an opening for the first pipe member 20 to pass through for the wiring 9 from the positive electrode 6. If it is necessary to prevent rain from seeping in through this opening, the area around the opening can be wrapped with sealing tape or a clay-like material can be provided.

[0067] The second cover member 22c covers the communication hole member 18c and has an opening for the second pipe member 21 to pass through for the wiring 10 from the negative electrode 7. If it is necessary to prevent rain from seeping in through this opening, the area around the opening can be wrapped with sealing tape or a clay material can be provided.

[0068] In this second embodiment, the communication hole member 18 is provided with a female thread, and the second lid member 22 is provided with a male thread that screws into this female thread, thereby engaging the second lid member 22 with the communication hole member 18. If it is necessary to replace at least one of the separator 5, the positive electrode 6, and the negative electrode 7, this can be done with the first lid member 17 removed. At this time, the mixture 4 may also be replaced, or an electrolyte substance may be supplied to the mixture 4.

[0069] Furthermore, by providing opposing recesses in the bottom of the container 1 and the top of the first lid member 17, and fitting the support member 37 into these recesses, multiple capacitors 11 can be arranged along the Z direction. The height dimension (Z direction) of the support member 37 should be set considering the connection and maintenance of the piping 19.

[0070] It is preferable to supply the electrolyte in solution form, for example, by dissolving it in water. This prevents deterioration of the energy storage performance of the capacitor 11 and allows for the recovery of a capacitor 11 whose energy storage performance has deteriorated. If the first lid member 17 is engaged with the container 1, the electrolyte may be supplied to the mixture 4 using the communication hole members 18a, 18b, and 18c.

[0071] As shown in Figure 7(a), by burying the capacitor 11 in the ground 36, previously unused space in the ground 36 can be utilized. Furthermore, by digging deeper into the ground 36 and stacking the capacitors 11 via support members 37, or by arranging the capacitors 11 perpendicular to the plane of the paper, more capacitors 11 can be installed in the ground. In addition, by using the soil excavated from the ground 36 to make the mixture 4, the cost of transporting the soil can be saved.

[0072] As shown in Figure 7(b), by installing the capacitor 11 near the foundation 35 or the support column 33, the previously unused space below the solar panel 31 can be utilized. Furthermore, by stacking the capacitors 11 via the support member 37, or by arranging the capacitors 11 vertically in the plane of the paper, more capacitors 11 can be installed below the solar panel 31. In this second embodiment, multiple capacitors 11 may be installed both underground and above ground.

[0073] Figure 10 is a block diagram of a control device 40 for controlling the charging and discharging of the capacitor 11 in this second embodiment. In this second embodiment, the capacitor 11 is charged using electricity generated by the photovoltaic power generation device 30, but it is not limited to this. Furthermore, a perovskite solar cell may be used as the photovoltaic power generation device 30.

[0074] The control device 40 includes a voltage conversion unit 41, a charging switch 42, a discharge power conditioner 43, a discharge switch 44, a memory 45, a communication unit 46, and a control unit 47.

[0075] The voltage conversion unit 41 converts the voltage of the DC current output from the solar power generation device 30 to a voltage suitable for charging the capacitor 11 (for example, from 1V to 2V) and outputs it to the charging switch 42.

[0076] The charging switch 42 is an on / off switch. When the switch is on, the solar power generation device 30 charges the capacitor 11, and when the switch is off, the solar power generation device 30 does not charge the capacitor 11. The charging switch 42 is turned off by the control unit 47 when it is necessary to prevent overcharging of the capacitor 11.

[0077] The discharge power conditioner 43 has an inverter that converts the DC current output from the capacitor 11 into AC current. The discharge power conditioner 43 also has a function to adjust the output voltage in order to supply power to the load equipment 48.

[0078] The discharge switch 44 is an on / off switch; when the switch is on, discharge and charging occur to the load device 48, and when the switch is off, no discharge occurs to the load device 48.

[0079] Memory 45 is a non-volatile memory (for example, flash memory) and stores programs for controlling the charging and discharging of the capacitor 11, and programs for controlling the solar power generation device 30. In addition, memory 45 stores the daily power generation amount of the solar power generation device 30, as well as the daily charge and discharge amounts of the capacitor 11. Memory 45 may also store the charge and discharge amounts on an hourly basis. Furthermore, memory 45 may store programs for supplying power to load devices 48 (for example, a program for supplying water, or a program for charging the drone 51).

[0080] The communication unit 46 is a wireless communication unit that accesses a wide-area network such as the Internet. The communication unit 46 may also use wired communication. In this second embodiment, the communication unit 46 communicates with a host computer located remotely.

[0081] The communication unit 46 communicates, for example, the daily charge and discharge amounts of the capacitor 11 to the host computer. The host computer may issue an instruction to perform maintenance on the capacitor 11 when there is a decrease in the charge amount or when there is a change in the environment due to the detection results of the environmental sensor 48a, which will be described later. In this case, the host computer may use parameters such as weather conditions such as sunny or rainy days, seasonal conditions such as summer or winter, the time elapsed since the capacitor 11 was installed, and the time elapsed since the last maintenance to determine whether or not to perform maintenance. Maintenance includes at least one of supplying water to the separator 5 that constitutes the capacitor 11 and supplying water or an electrolyte substance to the mixture 4.

[0082] The control unit 47 is equipped with a CPU and controls the solar power generation device 30, as well as the charging and discharging of the capacitor 11. In this second embodiment, the control unit 47 monitors the voltage of the capacitor 11, and if the voltage falls below a lower threshold, it controls the discharge switch 44 to prevent discharge. Alternatively, if the voltage rises above an upper threshold, the control unit 47 may turn off the charge switch 42 to prevent charging of the capacitor 11. As will be described in detail later, the control unit 47 also controls maintenance of the capacitor 11.

[0083] The load device 48 is a device driven by the power stored in the capacitor 11. In this second embodiment, it is a device used for maintenance of the capacitor 11 and a power supply device 48c that supplies power to the drone 51. The capacitor 11 may be configured to supply power to the load device 48 at night.

[0084] Equipment used for maintenance of the capacitor 11 includes an environmental sensor 48a for detecting the environment of the capacitor 11, and a supply device 48b for supplying water to the separator 5 and supplying at least one of water and an electrolyte substance to the mixture 4.

[0085] The environmental sensor 48a is a sensor that detects at least one of the temperature, humidity, moisture content, and electrical conductivity of the mixture 4. In this second embodiment, the environmental sensor 48a uses a sensor capable of measuring the temperature, moisture content, and electrical conductivity of the mixture 4. The environmental sensor 48a can measure the temperature, moisture content, and electrical conductivity of the mixture 4 by inserting the probe of the environmental sensor 48a into the mixture 4.

[0086] The supply device 48b has a pump (not shown) and supplies water (for example, distilled water such as pure water) to the separator 5 via the piping 19. By supplying water to the separator 5, this water is also supplied to the mixture 4, which helps to prevent the mixture 4 from drying out. In order to supply water to the mixture 4, a spray nozzle may be provided on the piping 19, or multiple pipes 19 may be provided. The supply device 48b may also be used to supply an electrolyte substance to the mixture 4.

[0087] The control of the capacitor 11 and the photovoltaic power generation device 30 by the control unit 47 of this second embodiment, configured as described above, will now be explained. Figure 11 is a flowchart executed by the control unit 47 of this second embodiment. This flowchart is executed when the photovoltaic power generation device 30 is capable of generating power and the capacitor 11 is not being charged.

[0088] (Flowchart) The control unit 47 determines whether it is possible to charge the capacitor 11 (step S1). If maintenance of the capacitor 11 and power supply to the drone 51 are not required, and the voltage of the capacitor 11 indicates that the capacitor 11 is not in an overcharged state, the control unit 47 determines Yes in step S1 and proceeds to step S2. If the capacitor 11 is overcharged, the control unit 47 determines No in step S1 and repeats the determination in step S1 until the overcharge of the capacitor 11 is resolved.

[0089] Here, we continue the explanation assuming that the control unit 47 is capable of charging the capacitor 11 and that the process proceeds to step S2.

[0090] The control unit 47 switches the charging switch 42 to ON and starts charging the capacitor 11 (step S2).

[0091] As mentioned above, the capacitor 11 can be charged using either constant voltage charging or constant current charging, but constant current charging is preferable considering charging efficiency. When using constant current charging, a current control circuit can be added to supply a constant current between the voltage conversion unit 41 and the capacitor 11. In both cases, charging is performed by applying voltage from the solar power generation device 30.

[0092] The control unit 47 determines whether charging of the capacitor 11 is complete (step S3). When charging of the capacitor 11 is complete, the voltage of the capacitor 11 becomes maximum, while the current flowing through the capacitor 11 becomes minimum (almost zero). Therefore, the control unit 47 can determine whether charging of the capacitor 11 is complete by detecting the voltage of the capacitor 11 or the current flowing through the capacitor 11.

[0093] The control unit 47 continues charging until the capacitor 11 is fully charged, and proceeds to step S4 once the capacitor 11 is fully charged. Here, we assume that the capacitor 11 is fully charged and proceed to step S4. When charging is complete, the control unit 47 switches the charging switch 42 to the OFF position.

[0094] The control unit 47 determines whether power supply to the load device 48 is necessary (step S4). If power supply to the load device 48 is not necessary, the control unit 47 terminates this flowchart; if power supply to the load device 48 is necessary, it proceeds to step S5. Here, we will assume that power supply to the load device 48 is necessary and proceed to step S5.

[0095] The control unit 47 supplies power (discharges) to the load equipment 48 using the capacitor 11 (step S5). The control unit 47 controls the discharge power conditioner 43 and the discharge switch 44 to supply power (discharge) to the load equipment 48 using the capacitor 11.

[0096] The control unit 47 determines whether the power supply (discharge) to the load device 48 by the capacitor 11 can be continued (step S6). The control unit 47 can determine whether the power supply (discharge) to the load device 48 can be continued by monitoring the voltage and current during the discharge of the capacitor 11, or by monitoring the amount of energy consumed relative to the capacitance stored in the capacitor 11.

[0097] To avoid interruption of power supply (discharge) to the load device 48, the control unit 47 can set a threshold for the termination of the discharge of the capacitor 11 (the voltage value, current value, and energy consumption amount mentioned above), and provide a switching circuit so that when this threshold is not met, it can switch to supplying power (discharging) to the load device 48 with another capacitor 11.

[0098] Furthermore, if the capacitor 11 is unable to continue supplying power (discharging) to the load device 48, the control unit 47 returns to step S1 and determines whether to recharge the capacitor 11 that can no longer supply power (discharge). Here, it is assumed that power supply can be continued, and the process proceeds to step S7.

[0099] The control unit 47 determines whether it is necessary to supply power (discharge) to the load device 48 by the capacitor 11 (step S7). If it is necessary to supply power (discharge) to the load device 48, the control unit 47 proceeds to step S5 and continues to supply power.

[0100] On the other hand, the control unit 47 determines that power supply (discharge) is unnecessary when environmental detection by the environmental sensor 48a is not required, and terminates this flowchart.

[0101] As described above, according to this flowchart, the electricity generated by the solar power generation device 30 can be used to charge the capacitor 11 and also supplied to the load equipment 48. Therefore, even when there is a request to control the output of the solar power generation device 30, the electricity generated by the solar power generation device 30 can be used effectively.

[0102] Furthermore, while U.S. Patent No. 1,151,2022, listed in the prior art section, discloses the storage of electricity in concrete, it does not disclose how to insulate the reinforcing bars when they are present in the concrete. In contrast, in the first and second embodiments of this invention, the container 1 is made insulating, so there is no problem even if there are metal structures around the container 1.

[0103] The embodiments described above are preferred examples of the present invention. However, the invention is not limited thereto, and various modifications are possible without departing from the spirit of the invention. For example, an electronically conductive polymer may be used as the electronically conductive material. A conductive polymer can be used as the conductive polymer. In this case, the conductive polymer may be dissolved in a solvent to liquefy it, or an additive may be added to the conductive polymer to liquefy it.

[0104] 2...Soil 3...Copper plate 4...Mixture 4a...First mixing section 4b...Second mixing section 5...Separator 6...Positive electrode 6a...Extended section 7...Negative electrode 7a...Extended section 11...Capacitor 30...Solar power generation device 34...Mounting frame 35...Foundation 40...Control device 42...Charging switch 43...Discharge power conditioner 47...Control unit 48...Load equipment 48a...Environmental sensor 48b...Supply device 48c...Power supply device 50...Drone port 51...Drone

Claims

1. A charging device comprising: a conduction section having a first conduction section in which an electrically conductive substance is mixed into soil containing ions, and a second conduction section in which the amount of the electrically conductive substance mixed in is different from that of the first conduction section; a positive electrode provided in the conduction section; a negative electrode provided in the conduction section; and a separator provided in the conduction section to insulate the positive electrode from the negative electrode.

2. The charging device according to claim 1, wherein the second conductive part is provided so as to be in contact with the positive electrode and the negative electrode.

3. The charging device according to claim 1, wherein a plurality of second conductive parts are provided so as to sandwich the first conductive part.

4. The charging device according to claim 1, wherein the second conductive part is provided so as to sandwich the separator.

5. The charging device according to claim 1, wherein the second conduction part contains a larger proportion of the electrically conductive material than the first conduction part, and the second conduction part is configured such that the weight of the second conduction part is lighter than the weight of the first conduction part.

6. The charging device according to claim 1, wherein the electrically conductive material comprises a first member that forms a carbon network and a second member that absorbs and releases ions, and the weight ratio of the second member to the soil is greater than the weight ratio of the first member to the soil.

7. The charging device according to claim 6, wherein the first member is carbon black, and the second member is at least one of binchotan charcoal and activated carbon.

8. The charging device according to claim 1, wherein at least one of the positive electrode and the negative electrode has an extendable portion that extends in a direction intersecting the direction in which the separator is arranged.

9. The charging device according to claim 1, further comprising an environmental sensor for measuring the environment of the conductive part.

10. The charging device according to claim 1, further comprising a liquid supply device for supplying liquid to at least one of the conductive part and the separator.

11. A charging method comprising: preparing a conduction section having a first conduction section in which an electrically conductive substance is mixed into soil containing ions, and a second conduction section in which the amount of the electrically conductive substance mixed in is different from that of the first conduction section; arranging a positive electrode and a negative electrode in the conduction section via a separator; and applying a voltage between the positive electrode and the negative electrode to guide anions to the positive electrode and cations to the negative electrode.

12. The charging method according to claim 11, wherein the first conduction part and the second conduction part are degassed.

13. The charging method according to claim 11, wherein the second conductive part is in contact with the positive electrode and the negative electrode.

14. The charging method according to claim 11, wherein a plurality of second conductive parts are provided so as to sandwich the first conductive part.

15. The charging method according to claim 11, wherein the second conductive portion is provided so as to sandwich the separator.

16. The charging method according to claim 11, wherein the second conduction part contains a larger proportion of the electrically conductive material than the first conduction part, and the weight of the second conduction part is lighter than the weight of the first conduction part.

17. The charging method according to claim 11, further comprising the step of measuring the environment of the conductive part.

18. The charging method according to claim 11, wherein liquid is supplied to at least one of the conductive part and the separator.

19. The charging method according to claim 11, further comprising the step of stirring the electrically conductive substance and water.

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