Charging apparatus and charging method

Abstract

The present invention provides a charging device and charging method that can store a larger capacitance using soil particles. [Solution] The charging device comprises a capacitor having a conductive part in which an electrically conductive material is mixed with soil particles containing ions, a positive electrode provided in the conductive part, a negative electrode provided in the conductive part, and a separator provided in the conductive part to insulate the positive electrode from the negative electrode, a charging device that charges the capacitor with electricity generated by a power generation device provided in a body of water, and a maintenance device that performs maintenance on the capacitor using water from the body of water.

Description

[Technical Field]

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

[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). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent Publication No. 11512022 [Overview of the Initiative] [Problems that the invention aims to solve]

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

[0005] Therefore, the present invention aims to provide an easy-to-use charging device and charging method using soil particles. [Means for solving the problem]

[0006] The charging device according to claim 1 comprises a capacitor having a conductive part in which an electrically conductive material is mixed with soil particles containing ions, a positive electrode provided in the conductive part, a negative electrode provided in the conductive part, and a separator provided in the conductive part to insulate the positive electrode from the negative electrode, a charging device for charging the capacitor with electricity generated by a power generation device provided in a body of water, and a maintenance device for performing maintenance on the capacitor using water from the body of water. The charging method according to claim 18 is to mix an electrically conductive substance into soil particles containing ions to form a conduction part, and provide a positive electrode, a negative electrode, and a separator to the conduction part to form a capacitor. The power generated by a power generation device provided in a water area is used to charge the capacitor, and the capacitor is maintained using the water in the water area.

Advantages of the Invention

[0007] According to the charging device of claim 1, since the maintenance device uses the water in the water area to maintain the capacitor, a user-friendly charging device can be realized. According to the charging method of claim 18, since the capacitor is maintained using the water in the water area, a user-friendly charging method can be realized.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a state where sand is put into a container and two copper plates are inserted into the sand. [Figure 2] FIG. 2 is a cross-sectional view showing a state where a mixture of sand and carbon black is put into a container and two copper plates are inserted into the mixture. [Figure 3] FIG. 3 is a schematic view showing the configuration of a capacitor and the state when the capacitor is charged. [Figure 4] FIG. 4 is a view taken along the line A - A of FIG. 3. [Figure 5] FIG. 5 is a schematic view showing an example in which a lid member and a maintenance member are provided to the capacitor of FIG. 3. [Figure 6] FIG. 6 is a schematic view showing an example in which a water supply member is provided to the capacitor of FIG. 5. [Figure 7] FIG. 7 is a schematic view showing an example in which a capacitor is provided to a floodgate. [Figure 8] FIG. 8 is a block diagram of a control device for controlling charging and discharging of the capacitor of the present embodiment. [Figure 9] FIG. 9 is a flowchart of the present embodiment.

Mode for Carrying Out the Invention

[0009] (Embodiment) Hereinafter, embodiments will be described in detail based on FIGS. 1 to 9. In this embodiment, by mixing an electrically conductive substance into soil particles, conductive soil particles are formed, and a capacitor 11 described later is configured using these conductive soil particles. The power generated by a power generation device described later provided in a water area is used to charge the capacitor 11, and the capacitor 11 is maintained using the water in the water area.

[0010] In this embodiment, the electrically conductive substance is a substance having both electronic conductivity for moving electrons and ionic conductivity for moving ions. In this embodiment, a combination of carbon black and activated carbon is adopted as the electron-conductive substance, and soil particles containing moisture are adopted as the ion-conductive substance, but it is not limited thereto. The vertical direction is illustrated as the Z direction, and the direction orthogonal to the left-right direction in this Z direction is illustrated as the X direction. Also, the direction perpendicular to the plane of FIG. 1 is the Y direction (see FIG. 4).

[0011] (Preliminary Experiment for Confirming Insulation of Soil) FIG. 1 is a cross-sectional view showing a state in which sand 2 as soil particles is placed in a glass container 1 and two copper plates 3 are inserted into the sand 2. The sand 2 was collected from the coast of Ito City, Shizuoka Prefecture. Note that a container 1 using resin instead of glass may be used, and any material may be used as long as it has insulation. Also, even if the container 1 is made of a non-insulating material, for example, it may be used in a state where an alkylalkoxysilane-based insulating agent or a silanesiloxane-based insulating agent is applied or sprayed to give it insulation.

[0012] When a soil quality test of this sand 2 was conducted, the density of the soil particles was 2.915 g / cm 3 and the natural water content ratio was 2.1%. Also, the particle size of the sand 2 was 1.6% gravel, 97.6% sand, and 0.8% clay.

[0013] A component analysis of this sand 2 revealed that it contained silicon dioxide 44.28%, iron oxide 20.79%, aluminum oxide 13.5%, calcium oxide 9.23%, magnesium oxide 5.83%, sodium oxide 1.77%, etc. Therefore, calcium ions (Ca), which are electrolytes with a high ionization tendency, were found to be present. 2+ ) and magnesium ions (Mg 2+ ) and sodium ions (Na + It was found that ) can be used. Furthermore, if the electrolyte substance in sand 2 is insufficient, calcium ions (Ca 2+ ), potassium ions (K + ), magnesium ions (Mg 2+ ), sodium ions (Na + Cations with a high ionization tendency, such as ), can be added to sand 2 as an electrolyte. When adding an electrolyte to sand 2, it is preferable to add it as an electrolyte solution obtained by dissolving the electrolyte in water. The ions mentioned above are also found in the water of rivers and canals, which will be described later. In this embodiment, the sand containing ions includes not only the ions originally contained in the sand but also the ions that were added later.

[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, conductivity was not confirmed in the sand 2 of this embodiment.

[0015] (A mixture of sand and an electrically conductive material) The aforementioned sand 2 was mixed with an electrically conductive material. While a combination of carbon black and activated carbon was used as the electrically conductive material, it is not limited to this; for example, a single carbon-derived material (e.g., Binchotan charcoal or activated carbon) may be used. The granular carbon black forms a carbon network and, when mixed with sand 2, is suitable for reducing the internal resistance of sand 2 and increasing its capacitance. Activated carbon is suitable for adsorbing and releasing ions. In this embodiment, acetylene black, produced by the thermal decomposition of acetylene, was used as the carbon black. However, registered trademark Ketjenblack, whose 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] Activated carbon can be coarse, fine, or coconut shell activated carbon, but in this embodiment, fine activated carbon or coconut shell activated carbon will be used from the viewpoint of ion storage and release properties.

[0017] Acetylene black and activated carbon 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 embodiment, acetylene black and activated carbon were each soaked in water before being mixed with sand 2. This improves the affinity between sand 2, acetylene black, and activated carbon.

[0018] In this case, stirring acetylene black, activated carbon, and water together ensures that the acetylene black and activated carbon, which form a carbon network, are thoroughly mixed. Furthermore, water molecules can be adsorbed into the pores of the activated carbon, allowing for efficient ion storage and release. Alternatively, binchotan charcoal, acetylene black, and water can be stirred together instead of, or in addition to, the activated carbon.

[0019] The amount of acetylene black added is between 5% and less than 20% by weight of sand 2. If the amount of acetylene black added is 5% or more by weight of sand 2, a carbon network can be formed in sand 2. If the amount of acetylene black added is 20% or more by weight of sand 2, the resistance value of mixture 4, which will be described later, will be further reduced, but in this embodiment, considering the price and cost-effectiveness of acetylene black, it is kept below 20%.

[0020] The amount of activated carbon added is set to be between 8% and less than 25% by weight of sand 2. If the amount of activated carbon added is 8% or more by weight of sand 2, charging using ions from sand 2 by the capacitor 11 described later becomes possible. The amount of activated carbon added may be 25% or more by weight of sand 2, but in this embodiment, it is set to less than 25% considering the price of activated carbon and cost-effectiveness. Also, when using binchotan charcoal instead of activated carbon, the amount of binchotan charcoal added should be between 8% and less than 25% by weight of sand 2. When using both activated carbon and binchotan charcoal, the combined weight of both activated carbon and binchotan charcoal should be between 8% and less than 25% by weight of sand 2.

[0021] The amount of activated carbon to be added will vary depending on the properties of sand 2, the amount of electrolytes contained in sand 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 activated carbon 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 sand 2. Even when using binchotan charcoal instead of activated carbon, it is preferable that the amount of binchotan charcoal added be greater than the amount of acetylene black added. Furthermore, when using both binchotan charcoal and activated carbon, it is preferable that the combined amount of binchotan charcoal and activated carbon added be greater than the amount of acetylene black added.

[0022] In this embodiment, sand 2, acetylene black, and activated carbon were mixed in a mixer for several minutes (1 to 2 minutes), and then water and an electrolyte solution were added to create mixture 4. Depending on the amount of electrolyte solution, the addition of water may be omitted.

[0023] (Experiment to confirm the conductivity of a mixture) Figure 2 is a cross-sectional view showing a container 1 containing a mixture 4, with two copper plates 3 inserted into the mixture 4.

[0024] When the test leads of the tester were touched to each of the two copper plates 3, the resistance was approximately 20-30Ω, confirming the conductivity of the mixture 4. This confirmed that an electrical conductivity network was formed in the sand 2 by carbon black, a carbon-derived material.

[0025] The reason for the fluctuation of approximately 10Ω in the resistance value is that gas (air) is mixed into mixture 4, making the contact state of the electrically conductive material unstable. Therefore, the mixture 4 was manually compacted and degassed using a metal tamping rod, and the resistance value of mixture 4 was measured again.

[0026] 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%.

[0027] In this 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 the sand 2 using this conductive part. The sand 2 is not limited to sea sand; it may be natural silica sand such as mountain sand or artificial silica sand, as long as it contains silicon dioxide as its main component. Furthermore, the soil particles are not limited to sand 2; for example, the sand 2 may contain gravel, silt, or clay, and their particle size distribution is not particularly limited.

[0028] (Capacitor configuration) Figure 3 is a schematic diagram showing the configuration of capacitor 11 and the charging process of capacitor 11, and is shown as a cross-sectional view except for the power supply 8. Figure 4 is a view taken along the line A-A in Figure 3. Note that wiring 9 and wiring 10 are omitted from the illustration in Figure 4.

[0029] As shown in Figures 3 and 4, in this embodiment, the positive electrode is composed of a first positive electrode 6 and a second positive electrode 12, and the negative electrode is composed of a first negative electrode 7 and a second negative electrode 13. The positive electrode may be composed of three or more electrodes, and the negative electrode may be composed of three or more electrodes. In this embodiment, the first positive electrode 6, the second positive electrode 12, the first negative electrode 7, and the second negative electrode 13 are collectively referred to as electrodes.

[0030] The first positive electrode 6 is positioned closer to the separator 5 than the second positive electrode 12. In this embodiment, the first positive electrode 6 has a portion that extends in the Z direction so as to face the separator 5, and an extended portion 6a that extends along the -X direction.

[0031] The second positive electrode 12 is positioned further away from the separator 5 than the first positive electrode 6. In this embodiment, the second positive electrode 12 has a portion extending in the Z direction so as to face the separator 5, and an extended portion 12a extending along the -X direction. As shown in Figure 4, in this embodiment, the dimension of the second positive electrode 12 in the Y direction (width dimension) is larger than the dimension of the first positive electrode 6 in the Y direction (width dimension). However, the dimension of the first positive electrode 6 in the Y direction may be larger than the dimension of the second positive electrode 12 in the Y direction. In this embodiment, in either case, the area of ​​the first positive electrode 6 in the mixture 4 is larger than the area of ​​the second positive electrode 12.

[0032] The first negative electrode 7 is positioned closer to the separator 5 than the second negative electrode 13. In this embodiment, the first negative electrode 7 has a portion that extends in the Z direction so as to face the separator 5, and an extended portion 7a that extends along the +X direction.

[0033] The second negative electrode 13 is positioned further away from the separator 5 than the first negative electrode 7. In this embodiment, the second negative electrode 13 has a portion extending in the Z direction so as to face the separator 5, and an extended portion 13a extending along the +X direction. As shown in Figure 4, in this embodiment, the dimension of the second negative electrode 13 in the Y direction (width dimension) is larger than the dimension of the first negative electrode 7 in the Y direction (width dimension). However, the dimension of the first negative electrode 7 in the Y direction may be larger than the dimension of the second negative electrode 13 in the Y direction. In this embodiment, in either case, the area of ​​the first negative electrode 7 in the mixture 4 is larger than the area of ​​the second negative electrode 13.

[0034] The positive electrode connection portion 23 is conductive and is electrically connected to the first positive electrode 6 and the second positive electrode 12. When charging the capacitor 11, the wiring 9 from the power supply 8 is connected to the positive electrode connection portion 23. In this embodiment, the positive electrode connection portion 23 is connected to the first positive electrode 6 and the second positive electrode 12 above the mixture 4.

[0035] The negative electrode connection section 24 is conductive and is electrically connected to the first negative electrode 7 and the second negative electrode 13. When charging the capacitor 11, the wiring 10 from the power supply 8 is connected to the negative electrode connection section 24. In this embodiment, the negative electrode connection section 24 is connected to the first negative electrode 7 and the second negative electrode 13 above the mixture 4.

[0036] After attaching the separator 5 to the container 1, a certain amount of the mixture 4 is added and compacted. The extendable portion 6a of the first positive electrode 6 is then placed in the mixture 4, and a certain amount of more mixture 4 is added and compacted to fix the extendable portion 6a in the mixture 4. After this, the extendable portion 12a of the second positive electrode 12 is then placed in the mixture 4, and a certain amount of mixture 4 is added and compacted to fix the extendable portion 12a in the mixture 4. In this way, the first positive electrode 6 and the second positive electrode 12 can be provided in the mixture 4. As is clear from Figure 3, the first positive electrode 6 and the second positive electrode 12 are not in contact in the mixture 4, and the extendable portion 12a is located above the extendable portion 6a.

[0037] Similarly, a certain amount of mixture 4 is added and compacted, the extendable portion 7a of the first negative electrode 7 is placed in this mixture 4, and a certain amount of mixture 4 is added and compacted to fix the extendable portion 7a in the mixture 4. After this, the extendable portion 13a of the second negative electrode 13 is placed in this mixture 4, and a certain amount of mixture 4 is added and compacted to fix the extendable portion 13a in the mixture 4. In this way, the first negative electrode 7 and the second negative electrode 13 can be provided in the mixture 4. As is clear from Figure 3, the first negative electrode 7 and the second negative electrode 13 are not in contact in the mixture 4, and the extendable portion 13a is located above the extendable portion 7a.

[0038] In this embodiment, since the capacitor 11 is equipped with multiple electrodes, the contact area between the mixture 4 and the electrodes increases, allowing more ions to be adsorbed onto the electrode surface during charging of the capacitor 11. This increases the capacitance and thus the amount of energy that the capacitor 11 can store. Furthermore, since the area of ​​the first positive electrode 6 located near the capacitor 11 is larger than the area of ​​the second positive electrode 12, the distance that anions must travel to the first positive electrode 6 during charging is shortened, and more anions can be stored in the first positive electrode 6. Similarly, since the area of ​​the first negative electrode 7 located near the capacitor 11 is larger than the area of ​​the second negative electrode 13, the distance that cations must travel to the first negative electrode 7 during charging is shortened, and more cations can be stored in the first negative electrode 7.

[0039] Furthermore, although it depends on the charging conditions described later, when the current values ​​of each electrode were measured during the discharge of the capacitor 11, a current of several tens of mA could be measured from the second positive electrode 12 and the second negative electrode 13. Therefore, by providing the second positive electrode 12 and the second negative electrode 13, the capacitor 11 as a whole can store more charge.

[0040] 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 along the vertical Z direction is applied to the mixture 4, but a force along the X direction is less likely to act on the electrode. For this reason, in this 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.

[0041] Here, the lengths of the extension portions 6a, 7a, 12a, and 13a in the X direction can be arbitrarily set as long as they do not interfere with the separator 5. This improves the adhesion between the extension portions 6a, 7a, 12a, and 13a and the mixture 4, thereby improving the amount of charge stored in the capacitor 11 and, consequently, increasing the charging energy of the capacitor 11. Here, charging energy is the product of power and charging time. Note that either the extension portion 12a or the extension portion 13a may be omitted, or all of the extension portions 6a, 7a, 12a, and 13a may be omitted. Also, there do not necessarily have to be multiple electrodes, and the second positive electrode 12 and the second negative electrode 13 may be omitted.

[0042] The separator 5 prevents the first positive electrode 6 and the second positive electrode 12 from directly contacting and short-circuiting the first negative electrode 7 and the second negative electrode 13, while allowing ions in the mixture 4 to pass through the formed carbon network. In this embodiment, the separator 5 is arranged along the Z direction. In this 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. In addition, the separator 5 can be made of cellulose-derived nonwoven fabric or paper (for example, Japanese paper or kitchen paper).

[0043] Furthermore, the separator 5 may be made of a composite material of 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 installed in the container 1 sandwiched between insulating materials. It is also 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 fixing it using this recess, by using insulating tape, or by other methods.

[0044] Furthermore, the electrodes can be made of materials that do not easily react with ionic substances contained in the sand 2, such as copper, aluminum, platinum, or carbon materials. In this embodiment, a copper plate 3 was used. The first positive electrode 6 and the second positive electrode 12 are connected to a carbon network formed of acetylene black. An electrical double layer is formed near the surface of the activated carbon connected to this carbon network, causing the first positive electrode 6 and the second positive electrode 12 to be charged by attracting anions with the opposite charge. Similarly, the first negative electrode 7 and the second negative electrode 13 are charged by attracting cations with the opposite charge.

[0045] Furthermore, sheet-shaped carbon fibers may be used as the carbon material for the electrodes. Because carbon fibers are lightweight and strong, they can be used to create easy-to-use electrodes. Also, since sheet-shaped carbon fibers are easier to bend than metal electrodes, it is easier to form stretched portions 6a, 7a, 12a, and 13a.

[0046] Furthermore, the electrode shape may be made zigzag in order to improve the adhesion between the electrode and the mixture 4. 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, and thus the amount of energy stored in the capacitor 11 can be improved.

[0047] Power supply 8 is used to charge the capacitor 11, and can be a constant voltage power supply or a constant current power supply. Charging the capacitor 11 can be done by either constant voltage charging or constant current charging, but in this embodiment, charging is performed by constant current charging from the viewpoint of charging efficiency.

[0048] Wiring 9 has one end connected to the positive terminal connector 23 and the other end connected to the + output terminal of the power supply 8. Wiring 10 has one end connected to the negative terminal connector 24 and the other end connected to the - output terminal of the power supply 8.

[0049] (Charging and discharging experiment) In this embodiment, constant current charging was performed using a constant voltage power supply equipped with a current control circuit as the power supply 8. The current value for constant current charging was set between several tens of mA and several hundred mA. The voltage value was set to 1.2V or less to prevent hydrogen generation when the water content of the mixture 4 was high, and to 3V or less when the water content of the mixture 4 was low, i.e., when there was no effect of hydrogen generation. Note that the above settings are just examples and are not limited thereto.

[0050] Depending on the state of Mixture 4, after charging for several minutes or about 5 to 10 minutes, when Wiring 9 and Wiring 10 were connected to a rotating motor (not shown), the rotating motor (not shown) rotated. As a result, it was confirmed that a carbon network was formed on the sand 2 with acetylene black, and that the storage and release of ions by the activated carbon, which is an ion adsorbing substance, were occurring. That is, it was confirmed that power storage was possible using Mixture 4.

[0051] Also, Mixture 4 was newly created with the aforementioned weight ratio, and sodium ions (Na + ) were added as an electrolyte. Specifically, several hundred cc of 5% saline solution was added. Then, charging was performed for the same time under the same conditions using Mixture 4 to which sodium ions (Na + ) were added. After that, when Wiring 9 and Wiring 10 were connected to the rotating motor, the rotating motor rotated longer compared to Mixture 4 to which no sodium ions (Na + ) were added.

[0052] As the electrolyte, cations with a high ionization tendency such as calcium ions (Ca 2+ ), potassium ions (K + ), magnesium ions (Mg 2+ ), and sodium ions (Na + ) can be used. In this embodiment, the aforementioned sodium ions (Na + ) or potassium ions (K + ) shall be used.

[0053] Depending on the composition and amount of Mixture 4, and the distance between the electrodes and the area of the electrodes, after adding sodium ions (Na + ) or potassium ions (K + ) and performing constant current charging for about 30 minutes to several hours, a resistance of several Ω to a dozen or so Ω was connected, and the voltage value and current value at each time during discharge were measured to obtain a capacitance of 900 F to 1800 F.

[0054] Also, sodium ions (Na +Compared to adding potassium ions (K + Adding potassium ions (K) reduced the internal resistance of mixture 4. + Depending on conditions such as the amount of sodium ions (Na) added, + Compared to adding potassium ions (K + Adding ) resulted in an increase in the capacitance when charging capacitor 11.

[0055] This is sodium ion (Na + The radius of the potassium ion (K + Since it is smaller than the radius of the sodium ion (Na + This is because it is adsorbed by the silicon dioxide on the surface of sand 2.

[0056] In this way, the capacitor 11 can supply more power because its charge increases by adding positive ions. For this reason, the amount of binchotan charcoal or activated carbon added to absorb and release these ions may be determined according to the amount of ions in the mixture 4.

[0057] Furthermore, the applicant has found that the energy storage performance of the capacitor 11 deteriorates when the mixture 4 dries out. The drying of the mixture 4 is predominantly due to natural drying, with a portion due to the thermal energy generated during the charging of the capacitor 11. For this reason, it is preferable to install the mixture 4 in an environment where humidity is easily maintained, or to supply a liquid such as water if it dries out. This can prevent deterioration of the energy storage performance of the capacitor 11 or recover the energy storage performance of a capacitor 11 that has deteriorated.

[0058] The effect of degradation on the drying of mixture 4 is also due to potassium ions (K + ) is better, sodium ions (Na + It was found to be less than potassium ions (K + The mobility of sodium ions (Na) +This is due to the fact that it is higher than the mobility of potassium ions (K). For this reason, the frequency and amount of liquid supplied to mixture 4 are + ) is better for sodium ions (Na + It can be less than )

[0059] Figure 5 is a schematic diagram showing an example in which a cover member and a maintenance member are provided to the capacitor 11 in Figure 3. Since the capacitor 11 is installed outdoors, such as in the sluice gate 40 described later, it may be exposed to rain and snow. For this reason, in this embodiment, a cover member is provided to the capacitor 11. Also, as mentioned above, in order to prevent the mixture 4 from drying out, a maintenance member is provided in this embodiment. Note that in Figure 5, in order to avoid making the drawing complex, the power supply 8 is not shown, and the wiring 9, wiring 10, and the piping 19 described later are partially omitted from the illustration.

[0060] The first lid member 17 is a lid that covers the container 1, and in this 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, and 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 shapes of the container 1 and the first lid member 17 can be any shape, such as a rectangle. By providing the first lid member 17, the drying of the mixture 4 can be suppressed.

[0061] The first lid member 17 is provided with a communication hole member 18 that communicates with the outside. In this embodiment, three communication hole members 18a, 18b, and 18c are formed so as to face the separator 5, the positive electrode connection portion 23, and the negative electrode connection portion 24, respectively, but the embodiment is not limited to this.

[0062] The connecting hole member 18a is a hole for maintaining the separator 5, and in this embodiment, it passes through a pipe 19 that supplies water to the separator 5. The pipe 19 is connected to a pump (not shown), and water from rivers, canals, etc., is supplied to the pipe 19 by the pump (not shown). In this embodiment, it is preferable to provide a filter (not shown) upstream of the pump to remove foreign matter from rivers, canals, etc. In this embodiment, water is supplied to the separator 5 because ions become less mobile when the separator 5 dries out.

[0063] The connecting hole member 18b is a hole for passing the wiring 9 from the positive electrode connection part 23 through the first pipe member 20. The connecting hole member 18c is a hole for passing the wiring 10 from the negative electrode connection part 24 through the second pipe member 21. PF (Plastic Flexible) pipes can be used for 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.

[0064] 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.

[0065] 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 connection part 23. 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 installed.

[0066] The second cover member 22c covers the communication hole member 18c and has an opening through which the second pipe member 21 passes for the wiring 10 from the negative electrode connection part 24. 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 installed.

[0067] In this 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 and the electrodes, 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.

[0068] Furthermore, 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.

[0069] Figure 6 is a schematic diagram showing an example in which a water supply member 14 is provided on the capacitor 11 of Figure 5. In Figure 6, the water supply member 14 is provided on the upper surface of the mixture 4 of Figure 5. The water supply member 14 is also provided near the upper end of the separator 5 so that water can be supplied to the separator 5 as well. In this case, it is preferable to position the water supply member 14 so that it is in contact with the separator 5.

[0070] The water supply component 14 is a superabsorbent polymer with water retention and drainage properties, capable of absorbing and holding several hundred to a thousand times its own weight in water. This superabsorbent polymer gradually releases its moisture as the soil dries, so it can supply moisture to the mixture 4 when it dries out. In this way, by using a superabsorbent polymer with drying responsiveness, the drying of the mixture 4 can be prevented.

[0071] Furthermore, some superabsorbent polymers are temperature-responsive, pH-responsive, or ion-responsive, so you should select the appropriate polymer based on the required responsiveness.

[0072] Alternatively, potassium chloride (KCl) or sodium chloride (NaCl) may be dissolved in water to form an electrolyte solution, and this electrolyte solution may be absorbed by the water supply member 14. This allows the electrolyte solution to be supplied to the mixture 4 and the separator 5.

[0073] Since acetylene black is a hydrophobic substance, if the amount of acetylene black added is high, water and electrolyte solutions may not penetrate the mixture 4 easily. Therefore, it takes time for water and electrolyte solutions from the water supply member 14 located on the upper surface of the mixture 4 to penetrate downwards (in the -Z direction) of the mixture 4.

[0074] Therefore, in Figure 6, holes 15 are formed in the mixture 4, and a water supply member 14 is also provided in these holes 15. This shortens the time it takes for water or electrolyte solution from the water supply member 14 to penetrate downwards (in the -Z direction) of the mixture 4. In this embodiment, since two holes 15 are formed on either side of the separator 5, the water supply member 14 prevents the separator 5 from drying out and facilitates the movement of ions.

[0075] The number of holes 15 can be set to one or more as desired, and their location can also be set as desired. Furthermore, the direction in which the holes 15 are formed can be diagonally downward. In this case, if the holes 15 are formed toward the separator 5 embedded in the mixture 4, water and electrolyte solution can be quickly supplied to the portion of the separator 5 embedded in the mixture 4. In this embodiment, the holes 15 may be omitted.

[0076] Alternatively, the water supply member 14 may be mixed into the mixture 4. Note that the water supply member 14 may be provided in a capacitor 11 that does not have the first lid member 17 shown in Figure 3, or a hole 15 may be formed to provide the water supply member 14.

[0077] As described above, by supplying water or electrolyte solution to the mixture 4 and separator 5 from the water supply member 14, it is possible to prevent the mixture 4 and separator 5 from drying out, and by supplying electrolyte solution to the mixture 4 and separator 5, it is possible to prevent performance degradation of the capacitor 11. It is preferable to periodically supply water or electrolyte solution to the water supply member 14. Whether to supply water or electrolyte solution should be determined based on the performance change of the capacitor 11. For example, if the capacitance of the capacitor 11 tends to decrease with each charge, it is preferable to supply electrolyte solution to the water supply member 14. The liquid to the water supply member 14 may be supplied using the piping 19.

[0078] Furthermore, the water supply component 14 is not limited to superabsorbent polymers; natural materials such as vermiculite, which possesses both water retention and drainage properties, or coco peat may also be used. In addition, the liquid contained in the water supply component 14 may be a liquid other than water.

[0079] A drying prevention material may be used instead of, or in combination with, the water supply member 14. Examples of drying prevention materials include polyethylene, polypropylene, and polylactic acid.

[0080] Furthermore, burying the capacitor 11 in the ground near the sluice gate 40 allows us to utilize previously unused ground space. Also, if the ground is sandy, such as a beach, we can save on sand transportation costs by using sand excavated from the ground to make the mixture 4.

[0081] As described above, in this embodiment, the power generated by the solar power generation device 25 and hydroelectric power generation device 46, which are installed in the water body, is used to charge the capacitor 11, and the water from the water body is used to maintain the capacitor 11. Figure 7 is a schematic diagram showing an example in which the capacitor 11 is installed in the sluice gate 40. In this embodiment, the sluice gate 40 is assumed to be installed in a river or canal, but it is not limited to this.

[0082] As shown in Figure 7, the sluice gate 40 includes a block 41, a beam member 42, a gate 43, a support section 44, a gate drive unit 45, and a hydroelectric power generation device 46. The gate drive unit 45 may be driven using electricity stored in the capacitor 11.

[0083] In this embodiment, block 41 is a U-shaped block and is made of concrete, but may be made of metal. In this embodiment, block 41 is U-shaped in order to hold the hydroelectric power generation device 46 at the bottom, but is not limited to this.

[0084] The beam member 42 is fixed to the upper part of the block 41. The beam member 42 is made of concrete, but may also be made of metal. Multiple capacitors 11 are provided on the beam member 42. Note that the capacitors 11 may be provided near the sluice gate 40, and do not necessarily have to be installed on the sluice gate 40.

[0085] The gate 43 is positioned between the blocks 41 so that it can move in the vertical direction, the Z direction. When the gate 43 moves in the Z direction by the gate drive unit 45, river water flows in and generates electricity with the hydroelectric power generator 46.

[0086] The support portion 44 is fixed to the beam member 42 and is a member that supports the photovoltaic power generation device 25 above the beam member 42. In this embodiment, the capacitor 11 is charged with electricity generated by the photovoltaic power generation device 25 and the hydroelectric power generation device 46. Alternatively, a perovskite solar cell may be used as the photovoltaic power generation device 25. By using the hydroelectric power generation device 46, the capacitor 11 can be charged even at night when the photovoltaic power generation device 25 is not generating electricity. The photovoltaic power generation device 25 may be installed near the sluice gate 40 and does not necessarily have to be installed on the sluice gate 40. The photovoltaic power generation device 25 may also be omitted.

[0087] The gate drive unit 45 drives the gate 43 in the Z direction and includes a servo motor 47, an output shaft 48, a coupling 49, a screw shaft 50, and a ball nut 51.

[0088] In this embodiment, the servo motor 47 is an AC motor with a built-in encoder and is fixed to the beam member 42. Compared to DC motors, AC motors have higher torque, superior durability and maintainability, and are suitable for driving the gate 43. The output shaft 48 of the servo motor 47 is connected to a screw shaft 50 via a coupling 49. This screw shaft 50 is screwed into a ball nut 51 provided on the upper part of the gate 43.

[0089] The hydroelectric power generation device 46 comprises a water turbine 52, a rotating shaft 53, a pair of brackets 54, and a generator 55. The hydroelectric power generation device 46 can be of any type depending on the conditions of the water body (e.g., elevation difference).

[0090] The turbine 52 rotates due to the water flow passing through the sluice gate 40. The rotating shaft 53 has one end connected to the turbine 52 and the other end connected to the generator 55, and rotates in conjunction with the rotation of the turbine 52 to drive the generator 55. The pair of brackets 54 support the turbine 52 so that it can rotate.

[0091] Figure 8 is a block diagram of the control device 30 for controlling the charging and discharging of the capacitor 11 in this embodiment. The following description of the control device 30 will continue using Figure 8.

[0092] The control device 30 includes a power conditioner 31 for power generation, a voltage conversion unit 32, a charge switch 33, a power conditioner 34 for discharge, a discharge side switching unit 35, a memory 36, a communication unit 37, and a control unit 38.

[0093] The power conditioner 3 for power generation includes a rectifier 31a, a changeover switch 31b, and an inverter 31c. The power conditioner 31 receives DC power generated by the solar power generation device 25 and AC power generated by the hydroelectric power generation device 46 as input.

[0094] The rectifier 31a converts AC power from the hydroelectric power generator 46 into DC power.

[0095] The changeover switch 31b is a switching unit that switches between sending the DC power generated by the solar power generation device 25 and the DC power converted by the rectifier 31a back into the power grid or charging the capacitor 11.

[0096] The inverter 31c converts the DC power generated by the solar power generation device 25 and the DC power converted by the rectifier 31a into AC power, and then feeds it back into the power grid.

[0097] Furthermore, the power conditioner 31 for power generation has a function to adjust the output voltage in order to reverse power flow to the power grid, and a function to disconnect from the power grid in the event of an abnormality such as an earthquake.

[0098] The voltage conversion unit 32 converts the voltage of the DC current output from the solar power generation device 25 to a voltage suitable for charging the capacitor 11 (for example, from 1V to 1.2V) and outputs it to the charging switch 33.

[0099] The charging switch 33 is an on / off switch; when the switch is on, the capacitor 11 is charged, and when the switch is off, the capacitor 11 is not charged. The charging switch 33 is turned off by the control unit 38 when it is necessary to prevent overcharging of the capacitor 11.

[0100] The discharge power conditioner 34 has an inverter that converts the DC current output from the capacitor 11 into AC current. The discharge power conditioner 34 also has a function to adjust the output voltage for reverse power flow to the power grid or to supply power to the load equipment 39, and a function to disconnect from the power grid in the event of an abnormality such as an earthquake. The function to disconnect from the power grid in the event of an abnormality may also be performed by the discharge side switching unit 35.

[0101] The discharge-side switching unit 35 is connectable to both the power grid and the load equipment 39, and is a switching unit that switches between flowing the power generated by the capacitor 11 back into the power grid or supplying it to the load equipment 39. The discharge-side switching unit 35 may also be configured to supply the power generated by the capacitor 11 to both the power grid and the load equipment 39.

[0102] Memory 36 is a non-volatile memory (e.g., flash memory) and stores programs for controlling the charging and discharging of the capacitor 11, as well as programs for controlling the solar power generation device 25 and the hydroelectric power generation device 46. Memory 36 also stores the daily power generation amounts of the solar power generation device 25 and the hydroelectric power generation device 46, as well as the daily charge and discharge amounts of the capacitor 11. Memory 36 may also store the charge and discharge amounts on an hourly basis. Furthermore, memory 36 may store programs for supplying power to the load equipment 39 (e.g., a program for supplying water).

[0103] The communication unit 37 is a wireless communication unit that accesses a wide-area network such as the Internet. The communication unit 37 may also use wired communication. In this embodiment, the communication unit 37 communicates with a host computer located remotely.

[0104] The communication unit 37 communicates, for example, the daily charge and discharge amounts of the capacitor 11 to the host computer. The host computer may also issue an instruction to perform maintenance on the capacitor 11 when the charge of the capacitor 11 decreases or when drying of the mixture 4 is detected by a sensor (not shown).

[0105] In this case, the host computer may use parameters such as weather conditions (sunny or rainy), seasons (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.

[0106] The control unit 38 is equipped with a CPU and controls the solar power generation device 25 and the hydroelectric power generation device 46, as well as the charging and discharging of the capacitor 11. In this embodiment, the control unit 38 monitors the voltage of the capacitor 11 using a voltmeter (not shown), and if the voltage falls below a lower threshold, it controls the discharge power conditioner 34 to prevent discharge. Alternatively, if the voltage rises above an upper threshold, the control unit 38 may turn off the charge switch 33 to prevent charging of the capacitor 11. As will be described in detail later, the control unit 38 also controls maintenance of the capacitor 11.

[0107] The load equipment 39 is equipment that is driven by the power stored in the capacitor 11. In this embodiment, this includes equipment used for maintenance of the capacitor 11, and various lighting equipment. The capacitor 11 may also be configured to supply power to the load equipment 39 at night.

[0108] Equipment used for maintenance of the capacitor 11 includes a sensor (not shown) that detects the drying of the mixture 4, and equipment (hereinafter referred to as a supply device) that supplies water to the separator 5 and supplies at least one of water and the electrolytic solution to the mixture 4. Multiple pipes 19 may be provided, designated as water supply pipes and electrolytic solution pipes. Spray nozzles may also be provided at the ends of the pipes 19.

[0109] The control of the capacitor 11 in this embodiment, configured as described above, by the control unit 38 will now be explained. Figure 9 shows a flowchart executed by the control unit 38 of this embodiment. This flowchart is executed when the solar power generation device 25 and the hydroelectric power generation device 46 are capable of generating power and the capacitor 11 is not being charged.

[0110] (flowchart) The control unit 38 determines whether it is possible to charge the capacitor 11 (step S1). If the capacitor 11 does not require maintenance and the voltage of the capacitor 11 indicates that the capacitor 11 is not in an overcharged state, the control unit 38 determines Yes in step S1 and proceeds to step S2. If the capacitor 11 is overcharged, the control unit 38 determines No in step S1 and repeats the determination in step S1 until the overcharge of the capacitor 11 is resolved.

[0111] Here, we continue the explanation assuming that the control unit 38 determines that the capacitor 11 requires maintenance and proceeds to step S10.

[0112] In step S10, the control unit 38 performs maintenance on the capacitor 11, which is the implementation of the procedure (step S10). The control unit 38 controls the discharge power conditioner 34 and the discharge-side switching unit 35 to discharge to the load equipment 39. The control unit 38 also uses a supply device, which is one of the load equipment 39, to supply water to the separator 5 and to the mixture 4 with water and the electrolyte solution. Then, the control unit 38 returns to step S1. When returning to step S1, the control unit 38 controls the discharge power conditioner 34 and the discharge-side switching unit 35 to stop the discharge to the load equipment 39.

[0113] The control unit 38 makes another determination as to whether it is possible to charge the capacitor 11 (step S1). Since maintenance of the capacitor 11 was performed in step S10, the control unit 38 determines that it is possible to charge the capacitor 11 and proceeds to step S2.

[0114] The control unit 38 switches the changeover switch 31b to charge the capacitor 11 and also switches the charging switch 33 to ON to start charging the capacitor 11 (step S2).

[0115] As mentioned above, the capacitor 11 can be charged using either constant voltage 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 32 and the capacitor 11.

[0116] In this embodiment, since the capacitor 11 is equipped with multiple electrodes, the contact area between the mixture 4 and the electrodes increases, and the ion migration distance is shortened at the first positive electrode 6 and the first negative electrode 7, so that a large amount of charge can be efficiently stored in the capacitor 11.

[0117] The control unit 38 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 38 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.

[0118] The control unit 38 charges the capacitor 11 until charging is complete, and proceeds to step S4 once charging of the capacitor 11 is complete. Here, we assume that charging of the capacitor 11 is complete and proceed to step S4. When charging is complete, the control unit 38 switches the changeover switch 31b to allow reverse power flow to the power system and switches the charging switch 33 to the OFF position.

[0119] The control unit 38 determines whether power supply to the load device 39 is necessary (step S4). If power supply to the load device 39 is not necessary, the control unit 38 terminates this flowchart; if power supply to the load device 39 is necessary, it proceeds to step S5. Here, we will assume that power supply to the load device 39 is necessary and proceed to step S5.

[0120] The control unit 38 supplies power (discharges) to the load equipment 39 using the capacitor 11 (step S5). The control unit 38 controls the discharge power conditioner 34 and the discharge side switching unit 35 to supply power (discharge) to the load equipment 39 using the capacitor 11.

[0121] The control unit 38 determines whether the power supply (discharge) to the load device 39 by the capacitor 11 can be continued (step S6). The control unit 38 can determine whether the power supply (discharge) to the load device 39 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.

[0122] To avoid interruption of power supply (discharge) to the load device 39, the control unit 38 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 39 by another capacitor 11.

[0123] Furthermore, if the capacitor 11 is unable to continue supplying power (discharging) to the load device 39, the control unit 38 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.

[0124] The control unit 38 determines whether power supply (discharge) to the load device 39 by the capacitor 11 is necessary (step S7). If power supply (discharge) to the load device 39 is necessary, the control unit 38 proceeds to step S5 and continues supplying power. On the other hand, if power supply (discharge) to the load device 39 is unnecessary, the control unit 38 terminates this flowchart.

[0125] As described above, according to this flowchart, the electricity generated by the solar power generation device 25 and the hydroelectric power generation device 46 can be used to charge the capacitor 11 located at or near the sluice gate 40, which is a facility in the water body, and can also be supplied to the load equipment 39. Therefore, even when there is a request to control the output of the solar power generation device 25, the electricity generated by the solar power generation device 25 can be used effectively. In addition, the electricity generated by the hydroelectric power generation device 46 can be used to charge the capacitor 11 even on rainy days or at night.

[0126] 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 this embodiment, since the container 1 is made insulating, there is no problem even if there are metal structures around the container 1.

[0127] 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. Furthermore, 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. [Explanation of Symbols]

[0128] 1...Container 2...Sand 4...Mixture 5...Separator 6...First positive electrode 6a...Stretched section 7...First negative electrode 7a...Stretched section 11. Capacitor 12. Second positive electrode 12a...Stretched section 13...Second negative electrode 13a...Stretched section 14. Water supply component 15. Hole 17. First lid component 22...Second cover member 25...Solar power generation device 30...Control device 38...Control Unit 40...Water Gate 46...Hydroelectric Power Plant

Claims

1. A capacitor comprising: a conductive part in which an electrically conductive material is mixed with soil particles containing ions; a positive electrode provided in the conductive part; a negative electrode provided in the conductive part; and a separator provided in the conductive part to insulate the positive electrode from the negative electrode. A charging device that charges the capacitor with electricity generated by a power generation device installed in a body of water, A charging device comprising a maintenance device for performing maintenance on the capacitor using water from the aforementioned body of water.

2. The charging device according to claim 1, wherein the soil surrounding the water body is used as the soil particles.

3. The charging device according to claim 1, wherein the soil particles contain sand.

4. The charging device according to claim 1, wherein the maintenance device supplies ions contained in the water body to the conductive part.

5. The charging device according to claim 1, wherein the maintenance device supplies water from the water body to the separator.

6. The power generation apparatus comprises a first power generation apparatus that utilizes water from the body of water, and a second power generation apparatus different from the first power generation apparatus. The charging device according to claim 1, wherein the charging device charges the capacitor with the power generated by the first power generation device and the power generated by the second power generation device.

7. The charging device according to claim 1, wherein the electrically conductive material comprises a first carbon material and a second carbon material different from the first carbon material.

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

9. The charging device according to claim 1, wherein the capacitor is installed in the sluice gate of the water body.

10. The charging device according to claim 9, wherein the capacitor has a power supply unit that supplies power to the sluice gate.

11. The charging device according to claim 1, wherein the positive electrode comprises a first positive electrode and a second positive electrode, and the first positive electrode is positioned on the separator side relative to the second positive electrode.

12. The charging device according to claim 11, wherein the area of ​​the first positive electrode is larger than the area of ​​the second positive electrode.

13. The charging device according to claim 11, wherein the first positive electrode and the second positive electrode are not in contact within the conductive portion.

14. The charging device according to claim 1, wherein the negative electrode comprises a first negative electrode and a second negative electrode, and the first negative electrode is positioned on the separator side relative to the second negative electrode.

15. The charging device according to claim 14, wherein the area of ​​the first negative electrode is larger than the area of ​​the second negative electrode.

16. The charging device according to claim 14, wherein the first negative electrode and the second negative electrode are not in contact within the conductive portion.

17. The aforementioned electrically conductive material comprises a first carbon material in powder form and a second carbon material different from the first carbon material. The charging device according to claim 1, wherein the weight ratio of the second carbon material to the soil particles is greater than the weight ratio of the first carbon material to the soil particles.

18. By mixing an electrically conductive material into soil particles containing ions, a conductive part is created. A capacitor is configured by providing a positive electrode, a negative electrode, and a separator in the conductive part. The power generated by the power generation device installed in the water body charges the capacitor, A method for charging the capacitor using water from the aforementioned body of water for maintenance.

19. The charging method according to claim 18, wherein the soil surrounding the water body is used as the soil particles.

20. The charging method according to claim 18, wherein the soil particles contain sand.

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