Electrostatic charging device and electrostatic charging method

Abstract

In order to provide an electrostatic charging device that uses soil and is easy to use, this electrostatic charging device is obtained by providing, in the vicinity of a structure in which a frame is covered with a membrane, a capacitor that comprises: a conductive part obtained by adding an electrically conductive substance to the soil containing ions; a positive electrode provided to the conductive part; a negative electrode provided to the conductive part; and a separator provided to the conductive part so as to insulate the positive electrode and the negative electrode.

Description

Charging device and charging method

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

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

[0003] U.S. Pat. No. 1,512,022

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

[0005] Therefore, an object of the present invention is to provide a charging device and charging method that are easy to use and that use soil.

[0006] A charging device according to a first aspect of the present invention provides a capacitor provided near a structure in which a frame is covered with a membrane, the capacitor including: a conductive part in which an electrically conductive material is mixed in soil 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 method according to a twelfth aspect of the present invention provides a capacitor provided near a structure in which a frame is covered with a membrane, the capacitor including: a conductive part in which an electrically conductive material is mixed in soil 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.When a voltage is applied between the positive electrode and the negative electrode, anions are introduced to the positive electrode and cations are introduced to the negative electrode.

[0007] According to the charging device of claim 1, since the capacitor is provided near the structure, the power stored in the capacitor can be used within the structure. According to the charging method of claim 12, since the capacitor is provided near the structure, the power stored in the capacitor can be used within the structure.

[0008] 1 is a cross-sectional view showing a state in which soil is placed in a container and two copper plates are inserted into the soil; FIG. 2 is a cross-sectional view showing a state in which a mixture of soil and carbon black is placed in a container and two copper plates are inserted into the mixture; FIG. 3 is a schematic diagram showing the state of a capacitor during charging; FIG. 4 is a schematic diagram showing the state when a capacitor is charged using an electrode having an extension portion; FIG. 5 is a diagram showing an example in which a capacitor is installed near an agricultural greenhouse; FIG. 6 is a schematic diagram showing a capacitor 11 provided with a lid portion; FIG. 7 is a block diagram of a control device for controlling charging and discharging of a capacitor in the first embodiment; FIG. 8 is a flowchart executed by the control unit in the first embodiment; FIG. 9 is a diagram showing an example in which a capacitor is installed near a tent warehouse.

[0009] First Embodiment The first embodiment will be described in detail below with reference to FIGS. 1 to 8. In this first embodiment, an electrically conductive material is mixed into soil to form conductive soil, and this conductive soil is used to provide a capacitor 11, which will be described later. In this first embodiment, the electrically conductive material is a material that has electronic conductivity, which allows electrons to move, and ionic conductivity, which allows ions to move. In this first embodiment, a combination of carbon black and binchotan charcoal is used as the electronically conductive material, and soil 2 containing moisture is used as the ionic conductive material, but this is not limited to this. The vertical direction is illustrated as the Z direction, and the direction perpendicular to the Z direction and the left-right direction is illustrated as the X direction. Although not illustrated, the direction perpendicular to the paper surface is the Y direction.

[0010] (Preliminary experiment to confirm the insulating properties of soil) Figure 1 is a cross-sectional view showing soil 2 placed 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 the container 1 after being sieved through a 4.75 mm mesh sieve. Note that the container 1 may be made of resin instead of glass, and any material may be used as long as it has insulating properties. Furthermore, even if the container 1 is made of a material that does not have insulating properties, it may be made insulating by coating or spraying, for example, an alkylalkoxysilane-based insulating agent or a silanesiloxane-based insulating agent.

[0011] When soil 2 was subjected to a soil quality test, the density of the soil particles was found to be 2.660 g / cm ３ The natural water content was 35.7%. The particle size 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 ２＋ ) and magnesium ions (Mg ２＋ ), 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 ＋ ) or other cations with a high ionization tendency can be added to the soil 2 as an electrolyte substance.

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

[0014] When the test leads of the tester were brought into contact with each of the two copper plates 3, no continuity was confirmed, resulting in a non-conductive state. As a result, no continuity was confirmed in the soil 2.

[0015] (Mixing of Soil and Electrically Conductive Material) The aforementioned soil 2 was mixed with an electrically conductive material. The electrically conductive material used was a combination of carbon black and binchotan charcoal, but this is not limited thereto. For example, a single carbon-derived material (e.g., binchotan charcoal or activated carbon) may also be used as the electrically conductive material. Carbon black forms a carbon network and, when mixed with soil 2, is an ideal material for lowering the internal resistance of soil 2 and increasing the charge capacity of soil 2. Binchotan charcoal is an ideal 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, Ketjenblack, a registered trademark, whose primary particles have a hollow shell structure, may also be used, as may inexpensively available activated carbon. In this case, activated carbon primarily consisting of micropores or mesopores is preferred.

[0016] The carbon-derived binchotan may be crushed or commercially available powdered binchotan. Alternatively, sawdust charcoal (sawdust binchotan), which is made from sawdust compressed under high pressure, may be used. Instead of binchotan, activated carbon with macropores may be used.

[0017] Although acetylene black and binchotan charcoal are hydrophobic substances, they become somewhat more compatible with water after soaking in water for about a day. In this case, it is preferable to stir them for 10 to 30 minutes immediately after soaking. In this first embodiment, acetylene black and binchotan charcoal were 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 the acetylene black, binchotan charcoal, and water together thoroughly mixes the acetylene black and binchotan charcoal, which form a carbon network, and allows water molecules to be adsorbed into the binchotan charcoal's pores, enabling efficient ion absorption and desorption. Alternatively, activated carbon, acetylene black, and water may be stirred together instead of or in addition to the 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 5% to 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 within 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, the amount is set to less than 20% in consideration of the price and cost-effectiveness of acetylene black.

[0019] The amount of binchotan charcoal added is 8% or more 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 of soil 2 by capacitor 11, which will be described later, becomes possible. The amount of binchotan charcoal added may be 25% or more by weight of soil 2, but in this first embodiment, it is less than 25% in consideration of the price and cost-effectiveness of binchotan charcoal. Furthermore, when activated carbon is used instead of binchotan charcoal, the amount of activated carbon added may be 8% or more and less than 25% by weight of soil 2.

[0020] The amount of binchotan charcoal added varies depending on the properties of the soil 2, the amount of electrolyte contained in the soil 2, and whether or not an electrolyte is added, so the above amount should be used as a guideline. Furthermore, considering the performance of the capacitor 11 (charge amount, charging time, etc.) described below, 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 taking into account the internal resistance (several ohms to tens of ohms) when mixed with the 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 the first embodiment, the mixture 4 was prepared by mixing the soil 2, acetylene black, and crushed binchotan charcoal for several minutes (1 to 2 minutes) using a mixer.

[0022] (Experiment to Confirm the Conductivity of the Mixture) FIG. 2 is a cross-sectional view showing a state in which a mixture 4 is placed in a container 1 and two copper plates 3 are inserted into the mixture 4. As shown in FIG.

[0023] When the test leads of a tester were brought into contact with each of the two copper plates 3, the resistance value was about 20 to 30 Ω, confirming the conductivity of the mixture 4. This confirmed that an electrically conductive network had been formed in the soil 2 by carbon black, a carbon-derived material.

[0024] The reason why the resistance value fluctuates by about 10 Ω is because gas (air) gets mixed into the mixture 4, making the contact state of the electrically conductive material unstable. For this reason, the mixture 4 was manually degassed by compacting it with a metal tamping rod, and the resistance value of the mixture 4 was measured again.

[0025] After manual compaction, the resistance of Mixture 4 was about 18-20 Ω, and it was confirmed that the resistance decreased and the fluctuations in the resistance also decreased. Note that 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 portion in which an electrically conductive carbon network is formed, and this conductive portion is used to realize a capacitor 11 as a charging device that utilizes the ions of the soil 2.

[0027] (Experiment to confirm power storage using mixture) Figure 3 shows the state of capacitor 11 during charging, and is shown as a cross-sectional view excluding power source 8. As shown in Figure 3, after a separator 5 is attached to container 1, mixture 4 is placed therein, and a positive electrode 6 and a negative electrode 7 are inserted into this mixture 4, thereby forming capacitor 11 of the first embodiment. The degassing of mixture 4 described above is preferably performed after the positive electrode 6 and the negative electrode 7 have been inserted into mixture 4. In this case, it is preferable to place mixture 4 in container 1 in several batches, and degas each time.

[0028] The separator 5 prevents direct contact between the positive electrode 6 and the negative electrode 7 and short-circuits, while allowing ions in the mixture 4 to pass through the formed carbon network. In the first embodiment, the separator 5 can be made of a polyolefin resin such as polyethylene or polypropylene, or a polyester resin such as polyethylene terephthalate or polybutylene terephthalate. The separator 5 can also be made of a cellulose-derived nonwoven fabric or paper (e.g., Japanese paper or kitchen paper). The separator 5 may also be made of a composite material of a cellulose-derived nonwoven fabric or paper with polyethylene or glass fiber. The separator 5 is fixed to the container 1 with insulating tape. Alternatively, the separator 5 may be sandwiched between insulating materials and placed in the container 1. It is preferable to use a hydrophilic material for the separator 5 to facilitate the passage of ions. The separator 5 can be fixed by forming a recess in the bottom of the container 1 and using this recess, by using insulating tape, or by other methods.

[0029] The positive electrode 6 can be made of a material that does not easily react chemically with the ionic substances contained in the soil 2, such as copper, aluminum, platinum, or a carbon material. In this first embodiment, a copper plate 3 is used. The positive electrode 6 is connected to a carbon network formed from acetylene black. An electric double layer is formed near the surface of the binchotan charcoal connected to this carbon network, and the positive electrode 6 is charged by attracting anions with the opposite charge.

[0030] The negative electrode 7 can be made of a material that is unlikely to react chemically with the ionic substances contained in the soil 2, such as copper, aluminum, platinum, or a carbon material. In this first embodiment, a copper plate 3 is used. The negative electrode 7 is connected to a carbon network formed from acetylene black. An electric double layer is formed near the surface of the binchotan charcoal connected to this carbon network, and the negative electrode 7 is charged by attracting cations with opposite charges. Sheet-shaped carbon fiber may also be used as the carbon material for the positive electrode 6 and the negative electrode 7. Carbon fiber is lightweight and strong, making it an easy-to-use electrode. In this specification, the positive electrode 6 and the negative electrode 7 may be collectively referred to as electrodes.

[0031] The present applicant discovered that compacting the mixture 4 improves the adhesion between the mixture 4 and the electrodes, thereby reducing the contact resistance between the mixture 4 (especially carbon black) and the electrodes and improving the charge storage capacity of the capacitor 11. Compacting along the arrows in Figure 3 applies a force to the mixture 4 in the vertical Z direction, but the force in the X direction is less likely to act on the electrodes. Figure 4 is a schematic diagram showing the charging of a capacitor using electrodes with extensions 6a and 7a. As shown in Figure 4, the electrodes are L-shaped, intersecting the vertical direction, so that the vertical force applied during compaction is applied to the electrodes. Specifically, the lower end of the positive electrode 6 is bent to form the extension 6a, and the lower end of the negative electrode 7 is bent to form the extension 7a. The lengths of the extensions 6a and 7a in the X direction can be set as desired as long as they do not interfere with the separator 5. This improves the adhesion between the extension portions 6 a and 7 a and the mixture 4, thereby improving the charge storage capacity of the capacitor 11. It is preferable to provide an extension portion on each of the positive electrode 6 and the negative electrode 7, but one of the extension portions may be omitted.

[0032] If a sheet of carbon fiber is used for the electrode of the first embodiment, the extensions 6 a and 7 a can be easily formed because the sheet of carbon fiber is easier to bend than a metal electrode. After pouring a few millimeters to a few centimeters of mixture 4 to cover the extensions 6 a and 7 a, compaction to degas the mixture can improve adhesion between the electrode and the mixture 4 and remove gas from the mixture 4. It is also desirable to subsequently compact and degas the mixture 4 when adding the mixture 4 to the container 1.

[0033] The electrode may be formed in a zigzag shape to improve adhesion between the electrode and the mixture 4. By forming the electrode in a zigzag shape, the surface area of ​​the electrode increases, and the contact area between the mixture 4 and the electrode increases, so that more of the carbon network comes into contact with the electrode, thereby improving the amount of electricity stored in the capacitor 11.

[0034] The electrodes may also be provided at an angle with respect to the Z direction. If the electrodes are provided so as to intersect with 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. Therefore, if the electrodes are provided so as to intersect with the Z direction, more of the carbon network comes into contact with the electrodes, thereby improving the amount of electricity stored in the capacitor 11.

[0035] The power supply 8 is used to charge the capacitor 11, and may be a constant voltage power supply, a constant current power supply, etc. The capacitor 11 may be charged by either constant voltage charging or constant current charging, but in the first embodiment, constant current charging is used from the viewpoint of charging efficiency.

[0036] One end of the wire 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 wire 10 is connected to the negative electrode 7, and the other end is connected to the − output terminal of the power supply 8.

[0037] In the first embodiment, a constant voltage power supply was used as the power supply 8, and charging was performed at a voltage of 1 V to 3 V. When the water content of the mixture 4 was high, charging was performed at 1.2 V or less to prevent hydrogen generation, and when the water content of the mixture 4 was low, i.e., when hydrogen generation was low, charging was performed at 3 V.

[0038] After charging for several minutes or 5 to 10 minutes (depending on the state of the mixture 4), when wires 9 and 10 were connected to a rotary motor (not shown), the rotary motor rotated. This confirmed that a carbon network was formed in the soil 2 using acetylene black, and that ions were being absorbed and released by the binchotan charcoal, an ion-absorbing material. In other words, it was confirmed that electricity could be stored using the mixture 4.

[0039] In addition, a mixture 4 was newly prepared in the above weight ratio, and sodium ions (Na ＋ ) was added. Specifically, several hundred cc of 5% concentration saline solution was added. Then, as in the case of the above, it was charged at a voltage of 1.2 V for the same time (several minutes or about 5 to 10 minutes). After that, when the wires 9 and 10 were connected to the rotary motor, the rotary motor generated sodium ions (Na ＋ Mixture 4 rotated longer than Mixture 4 without the addition of .

[0040] In this way, the addition of cations increases the charge of capacitor 11, allowing it to supply more power. Therefore, the amount of binchotan charcoal or activated carbon that absorbs and releases ions may be determined based on the amount of ions in mixture 4. The applicant of the present application also discovered that the electricity storage performance of capacitor 11 deteriorates when mixture 4 dries. Therefore, it is preferable to store mixture 4 in an environment where humidity is easily maintained, or to supply a liquid such as water to mixture 4 when it dries. This can prevent deterioration of the electricity storage performance of capacitor 11 or restore a capacitor 11 whose electricity storage performance has deteriorated.

[0041] Furthermore, in civil engineering and construction, soil has played a role as the ground and foundation, but according to the first embodiment, in addition to these roles, soil also plays a role in storing electricity, making it possible to realize an electric double layer capacitor using soil. When the capacitor 11 shown in Figures 3 and 4 is used outdoors, a waterproof sheet may be placed on top of the capacitor 11 or a lid may be placed on the capacitor 11 to prevent rain, snow, and the like from penetrating the capacitor 11. Examples of the waterproof sheet that can be used include a vinyl chloride sheet and a high-density polyethylene sheet.

[0042] (Installation of Capacitor Near an Agricultural Greenhouse) The following continues the explanation of the case where the above-mentioned capacitor 11 is installed near an agricultural green house 12.

[0043] 5 is a diagram showing an example in which a capacitor is installed near an agricultural greenhouse 12. The agricultural greenhouse 12 has a frame (not shown) covered with a membrane material (not shown), and has a ceiling 13, left and right side surfaces 14, and front and rear end surfaces 15.

[0044] In the first embodiment, perovskite solar cells 16 that generate renewable energy are provided on the ceiling 13 and front and rear end panels 15 of the agricultural greenhouse 12. The perovskite solar cells 16 may also be provided on the side panels 14. The perovskite solar cells 16 are film-like solar cells that use a compound with a crystalline structure called perovskite, and can be manufactured by, for example, printing technology. When providing perovskite solar cells 16 in the agricultural greenhouse 12, it is preferable to provide them discretely on the ceiling 13 and side panels 14 so as to minimize blocking of sunlight. The perovskite solar cells 16 may also be provided on the end panels 15 rather than on the ceiling 13 and side panels 14 so as not to block sunlight.

[0045] In the first embodiment, the capacitor 11 is charged with power generated by the perovskite solar cell 16. The capacitor 11 may also be charged with power generated by a solar power generation device (not shown) provided near the agricultural greenhouse 12. In this case, the perovskite solar cell 16 provided in the agricultural greenhouse 12 may be omitted.

[0046] In the first embodiment, the power stored in the capacitor 11 is used by the equipment in the agricultural greenhouse 12. Specifically, the power stored in the capacitor 11 is supplied to an air conditioning system that controls the temperature of the agricultural greenhouse 12, a ventilation system that ventilates the agricultural greenhouse 12, and a supply system that supplies water and fertilizer to agricultural crops. In this way, power generated near the agricultural greenhouse 12 is stored near the agricultural greenhouse 12 and used near the agricultural greenhouse 12, eliminating the need for a power transmission and distribution system for supplying power to distant locations. Therefore, according to the first embodiment, power can be used inexpensively and efficiently.

[0047] As described above, the capacitor 11 may be installed inside the agricultural greenhouse 12 or outside near the agricultural greenhouse 12. The capacitor 11 may also be buried in the ground inside or outside the agricultural greenhouse 12. By burying the capacitor 11 in the ground, the ground can be used effectively. Furthermore, if the mixture 4 is made using soil dug up from the ground, the cost of transporting the soil can be saved. The number of capacitors 11 installed near the agricultural greenhouse 12 can be set as desired.

[0048] Furthermore, in hydroponic cultivation, nutriculture, and potted plant cultivation, an elevated cultivation bench is provided in the agricultural greenhouse 12. This elevated cultivation bench has a space below it, so by placing the capacitor 11 below this elevated cultivation bench, the dead space below the elevated cultivation bench can be effectively utilized.

[0049] It is preferable to provide a lid on the container 1 to prevent the capacitor 11 from drying out, to bury the capacitor 11, and to perform maintenance on the capacitor 11. Fig. 6 is a schematic diagram showing the capacitor 11 provided with a lid.

[0050] The first lid member 17 is a lid that covers the container 1, and in the first embodiment, a circular resin member is used. For example, if the container 1 is 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 first lid member 17 can cover the container 1 by screwing the male thread and the female thread together. Alternatively, the first lid member 17 may be shaped to cover the container 1 from above, and the container 1 and the first lid member 17 may be fastened together by fastening members such as bolts. When fastening members such as bolts are used, the container 1 and the first lid member 17 may be any shape, such as rectangular.

[0051] The first cover member 17 is provided with communication hole members 18 that communicate with the outside. In the first 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 present invention is not limited to this.

[0052] The communication hole member 18a is a hole for performing maintenance on the separator 5, and in the first embodiment, a pipe 19 passes through the communication hole member 18a to supply water (e.g., distilled water such as pure water) to the separator 5. In the first embodiment, water is supplied to the separator 5 because ions become less likely to move when the separator 5 dries.

[0053] The communication hole member 18b is a hole for passing a first pipe member 20 through which the wiring 9 from the positive electrode 6 is passed. The communication hole member 18c is a hole for passing a second pipe member 21 through which the wiring 10 from the negative electrode 7 is passed. 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 as desired.

[0054] The second cover member 22 is a cover member provided corresponding to the communication hole member 18. The second cover member 22a covers the communication hole member 18a and has an opening through which a pipe 19 passes that supplies water (e.g., distilled water such as pure water) to the separator 5. If it is necessary to prevent rain from seeping in through this opening, sealing tape may be wrapped around the periphery of the opening, or a clay material or the like may be provided.

[0055] The second cover member 22b covers the communication hole member 18b and has an opening through which the first pipe member 20 passes to pass the wiring 9 from the positive electrode 6. If it is necessary to prevent rain from seeping in through this opening, sealing tape may be wrapped around the opening or a clay material or the like may be provided.

[0056] The second cover member 22c covers the communication hole member 18c and has an opening through which the second pipe member 21 passes to pass the wiring 10 from the negative electrode 7. If it is necessary to prevent rain from seeping in through this opening, sealing tape may be wrapped around the opening or a clay material or the like may be provided.

[0057] In the first embodiment, a female thread is provided in the communicating hole member 18, and a male thread that screws into the female thread is provided in the second lid member 22, thereby engaging the second lid member 22 with the communicating 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 be replaced, or an electrolyte material may be supplied to the mixture 4.

[0058] The electrolyte material is preferably supplied in the form of a solution, for example, by dissolving it in water. This makes it possible to prevent deterioration of the electricity storage performance of capacitor 11 and to recover capacitor 11 whose electricity storage performance has deteriorated. When first lid member 17 is engaged with container 1, the electrolyte material may be supplied to mixture 4 using communication hole members 18a, 18b, and 18c.

[0059] 7 is a block diagram of a control device 23 for controlling the charging and discharging of the capacitor 11 in the first embodiment. In the first embodiment, the capacitor 11 is charged with power generated by the perovskite solar cell 16 described above, but the present invention is not limited to this.

[0060] The control device 23 includes a voltage conversion unit 24 , a charging switch 25 , a discharging power conditioner 26 , a discharging switch 27 , a memory 28 , a communication unit 29 , and a control unit 30 .

[0061] The voltage conversion unit 24 converts the voltage of the direct current output from the perovskite solar cell 16 into a voltage suitable for charging the capacitor 11 (for example, 1 V to 2 V), and outputs it to the charging switch 25.

[0062] Charging switch 25 is an on / off switch, and when the switch is on, the perovskite solar cell 16 charges capacitor 11, and when the switch is off, the perovskite solar cell 16 does not charge capacitor 11. Charging switch 25 is turned off under the control of control unit 30 when it is necessary to prevent overcharging of capacitor 11, for example.

[0063] Discharge power conditioner 26 has an inverter that converts the direct current output from capacitor 11 into alternating current. Discharge power conditioner 26 also has a function of adjusting the output voltage in order to supply power to load device 31.

[0064] The discharge switch 27 is an on / off switch, and when the switch is on, the load device 31 is discharged and charged, and when the switch is off, the load device 31 is not discharged.

[0065] The memory 28 is a non-volatile memory (e.g., flash memory) that stores a program for controlling the charging and discharging of the capacitor 11, a program for controlling the perovskite solar cell 16, and the like. The memory 28 also stores the daily charge and discharge amounts of the capacitor 11 in addition to the daily power generation amount of the perovskite solar cell 16. The memory 28 may also store the charge and discharge amounts by hour. The memory 28 may also store a program for growing plants cultivated in the agricultural greenhouse 12 (e.g., the timing of supplying water and fertilizer, the required hours of sunlight, etc.).

[0066] The communication unit 29 is a wireless communication unit that accesses a wide area network such as the Internet. The communication unit 29 may also use wired communication. In the first embodiment, the communication unit 29 communicates with a host computer that is located remotely.

[0067] The communication unit 29 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 31d (described later). In this case, the host computer may determine whether to perform maintenance based on parameters such as weather conditions (e.g., sunny or rainy), seasonal conditions (e.g., summer or winter), the time elapsed since the capacitor 11 was installed, and the time elapsed since the last maintenance. Note that maintenance includes at least one of supplying water to the separator 5 constituting the capacitor 11 and supplying water or an electrolyte substance to the mixture 4.

[0068] The control unit 30 is equipped with a CPU, and controls the perovskite solar cell 16 as well as the charging and discharging of the capacitor 11. In the first embodiment, the control unit 30 monitors the voltage of the capacitor 11, and if the voltage becomes lower than a lower threshold, controls the discharge switch 27 to prevent discharging. Furthermore, if the voltage becomes higher than an upper threshold, the control unit 30 may control the charge switch 25 to turn off so as not to charge the capacitor 11. Note that the control unit 30 also controls maintenance of the capacitor 11, as will be described in detail later.

[0069] The load devices 31 are devices that are driven by the power stored in the capacitor 11, and include devices used in the agricultural greenhouse 12 and devices used for maintenance of the capacitor 11. Note that the power supply to the load devices 31 does not have to be entirely provided by the capacitor 11, and it is sufficient if part of the power supply to the load devices 31 is provided by the power stored in the capacitor 11. Furthermore, the capacitor 11 may be configured to supply power to the load devices 31 at night.

[0070] In the first embodiment, the equipment used in the agricultural greenhouse 12 includes an air conditioning system 31a that controls the temperature of the agricultural greenhouse 12, a ventilation system 31b that ventilates the agricultural greenhouse 12, and a first supplying device 31c that supplies water and fertilizer to the crops. Furthermore, the power stored in the capacitor 11 may be supplied to an LED (not shown) that illuminates the interior of the agricultural greenhouse 12. On the other hand, the equipment used for maintenance of the capacitor 11 includes an environmental sensor 31d that detects the environment of the capacitor 11, and a second supplying device 31e that supplies water to the separator 5 and at least one of water and an electrolyte material to the mixture 4.

[0071] The environmental sensor 31d is a sensor that detects at least one of the temperature, humidity, moisture content, and electrical conductivity of the mixture 4. In the first embodiment, the environmental sensor 31d uses a sensor that can measure the temperature, moisture content, and electrical conductivity of the mixture 4. Note that the environmental sensor 31d can measure the temperature, moisture content, and electrical conductivity of the mixture 4 by inserting the probe of the environmental sensor 31d into the mixture 4.

[0072] The second supply device 31e has a pump (not shown) and supplies water (e.g., distilled water such as pure water) to the separator 5 via the pipe 19. By supplying water to the separator 5, the water is also transferred to the mixture 4, which can prevent the mixture 4 from drying out. In order to supply water to the mixture 4, a spray nozzle may be provided on the pipe 19, or a plurality of pipes 19 may be provided. The second supply device 31e may also be used to supply an electrolyte material to the mixture 4.

[0073] The control by the control unit 30 of the capacitor 11 and perovskite solar cell 16 of the first embodiment configured as described above will now be described. This flowchart is executed by the control unit 30 when the perovskite solar cell 16 is capable of generating power. Figure 8 is a flowchart executed by the control unit 30 of the first embodiment.

[0074] (Flowchart) The control unit 30 determines whether or not it is possible to charge the capacitor 11 (step S1). When the maintenance of the capacitor 11 is not required and the voltage of the capacitor 11 indicates that the capacitor 11 is not in an overcharged state, the control unit 30 determines Yes in step S1 and proceeds to step S2. If the capacitor 11 is overcharged, the control unit 30 determines No in step S1 and proceeds to step S10, and repeats the determinations of steps S1 and S10 until the overcharge of the capacitor 11 is resolved.

[0075] Furthermore, if the output of the environment sensor 31d indicates that maintenance of the capacitor 11 is necessary, the control unit 30 determines No in step S1 and proceeds to step S10.

[0076] Here, the explanation will be continued assuming that control unit 30 determines that capacitor 11 cannot be charged and proceeds to step S10. In the first embodiment, when capacitor 11 cannot be charged, this indicates the above-described overcharge state and a state requiring maintenance.

[0077] The control unit 30 determines whether or not maintenance of the capacitor 11 is required based on the output of the environment sensor 31d (step S10). In this example, it is assumed that maintenance of the capacitor 11 is required, and the process proceeds to step S11.

[0078] The control unit 30 performs maintenance of the capacitor 11 by supplying water to the separator 5 and supplying water or an electrolyte material to the mixture 4 using the second supply device 31e (step S11). The control unit 30 monitors the output of the environment sensor 31d and drives the second supply device 31e until a predetermined moisture content or a predetermined electrical conductivity is achieved.

[0079] In this way, if the control unit 30 performs maintenance on the capacitor 11 in accordance with the output of the environmental sensor 31d, it is possible to automate the maintenance of the capacitor 11. Note that the control of the automated maintenance may be performed by a host computer.

[0080] When the maintenance in step S11 is completed, the control unit 30 returns to step S1. Note that a predetermined time elapses due to the determination in step S10 or the determination in step S10 and the execution of step S11, and by making the determination in step S1 using this predetermined time, it is possible to determine whether the overcharged state of capacitor 11 has been resolved. Note that the control unit 30 may end this flowchart if the overcharged state of capacitor 11 is not resolved within a predetermined time (e.g., several tens of minutes to several hours).

[0081] The control unit 30 turns on the charging switch 25 to start charging the capacitor 11 (step S2).

[0082] As described above, the capacitor 11 can be charged by either constant voltage charging or constant current charging, but constant current charging is preferable in consideration of charging efficiency. When constant current charging is performed, a current control circuit for supplying a constant current between the voltage conversion unit 24 and the capacitor 11 can be added. In either case of constant voltage charging or constant current charging, charging is performed by applying a voltage from the perovskite solar cell 16.

[0083] The control unit 30 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 30 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.

[0084] The control unit 30 continues charging until the charging of the capacitor 11 is completed, and proceeds to step S4 when the charging of the capacitor 11 is completed. Here, it is assumed that the charging of the capacitor 11 is completed, and the process proceeds to step S4. When the charging is completed, the control unit 30 switches the charging switch 25 off.

[0085] The control unit 30 determines whether or not power supply to the load device 31 is necessary (step S4). If power supply to the load device 31 is not necessary, the control unit 30 ends this flowchart, and if power supply to the load device 31 is necessary, the control unit 30 proceeds to step S5. Here, it is assumed that power supply to the load device 31 is necessary, and the control unit 30 proceeds to step S5.

[0086] The control unit 30 causes the capacitor 11 to supply (discharge) power to the load device 31 (step S5). The control unit 30 controls the discharging power conditioner 26 and the discharge switch 27 to cause the capacitor 11 to supply (discharge) power to the load device 31. The control unit 30 supplies the power stored in the capacitor 11 to an air conditioning system 31a that controls the temperature of the agricultural greenhouse 12, a ventilation system 31b that ventilates the greenhouse, and a first supply device 31c that supplies water and fertilizer to the crops. By placing the capacitor 11 in the agricultural greenhouse 12 that is air-conditioned by the air conditioning system 31a, the mixture 4 and the separator 5 can be prevented from drying out, thereby reducing the frequency of maintenance of the capacitor 11.

[0087] The control unit 30 determines whether the power supply (discharge) from the capacitor 11 to the load device 31 can be continued (step S6). The control unit 30 can determine whether the power supply (discharge) to the load device 31 can be continued by monitoring the voltage and current when the capacitor 11 is discharging, or by monitoring the amount of energy consumed relative to the capacitance stored in the capacitor 11.

[0088] In order to avoid interruption of the power supply (discharge) to the load device 31, the control unit 30 sets a threshold value (the above-mentioned voltage value, current value, or amount of consumed energy) for the end of discharge of the capacitor 11, and provides a switching circuit so that when this threshold is exceeded, the power supply (discharge) to the load device 31 is switched to that from another capacitor 11.

[0089] Furthermore, when the control unit 30 is unable to continue supplying (discharging) power from the capacitor 11 to the load device 31, the control unit 30 returns to step S1 and determines whether or not to recharge the capacitor 11 that is no longer able to supply (discharge) power. In this case, it is assumed that the power supply can be continued, and the process proceeds to step S7.

[0090] The control unit 30 determines whether or not it is necessary for the capacitor 11 to supply (discharge) power to the load device 31 (step S7). If it is necessary to supply (discharge) power to the load device 31, the control unit 30 proceeds to step S5 and continues supplying power.

[0091] On the other hand, if the environment detection by the environment sensor 31d is not required or if it is morning and the LED illumination is no longer required, the control unit 30 determines that power supply (discharge) is not required and ends this flowchart.

[0092] As described above, according to the first embodiment, the power stored in the capacitor 11 can be used to control the temperature of the agricultural greenhouse 12, ventilate the greenhouse, and supply water and fertilizer to the crops, thereby realizing a user-friendly agricultural greenhouse 12 and reducing the labor required for agriculture. Note that some of the multiple perovskite solar cells 16 may supply power to the load devices 31 from a power conditioner (not shown) without passing through the capacitor 11. The power generated by the remaining perovskite solar cells 16 may be stored in the capacitor 11 and used as nighttime power or emergency power. Compaction of the mixture 4 may be performed while applying vibrations such as ultrasonic waves, or may be performed using a liquid such as water. In this case, the amount of water may be determined while measuring the electrical conductivity of the mixture 4.

[0093] Second Embodiment A second embodiment will be described below with reference to Fig. 9. The same components as those in the first embodiment are denoted by the same reference numerals, and their description will be omitted or simplified. Fig. 9 is a diagram showing an example in which a capacitor 11 is installed near a tent warehouse 32.

[0094] The tent warehouse 32 is a warehouse with a lightweight steel framework covered with a sheet membrane. In the second embodiment, perovskite solar cells 16 are provided on the sheet membrane. The tent warehouse 32 is used for storing parts, products, etc., and for performing machine maintenance work, so there is no need to guide sunlight into the tent warehouse 32, as opposed to agricultural greenhouses.

[0095] For this reason, in the second embodiment, perovskite solar cells 16 are provided on the ceiling portion 13 and side portion 14 of the tent warehouse 32, but this is not limited to this, and perovskite solar cells 16 may also be provided on the gable surface portion 15.

[0096] Furthermore, as shown in FIG. 9, in the second embodiment, the capacitor 11 is buried in the ground, but the capacitor 11 may be placed inside or outside the tent warehouse 32. A belt conveyor with a space formed below may be installed in the tent warehouse 32, and parts, products, etc. may be transported by this belt conveyor. In this case, by placing the capacitor 11 below the belt conveyor, the dead space below the belt conveyor can be effectively utilized. The belt conveyor may also be driven by the power stored in the capacitor 11.

[0097] In the second embodiment, the electricity generated by the perovskite solar cell 16 is stored in the capacitor 11 and can be used to light the tent warehouse 32 and for the air conditioning equipment 31a. This makes it possible to realize a user-friendly tent warehouse 32. By placing the capacitor 11 inside the tent warehouse 32 that is air-conditioned by the air conditioning equipment 31a, the mixture 4 and the separator 5 can be prevented from drying out, thereby reducing the frequency of maintenance of the capacitor 11.

[0098] Furthermore, when capacitor 11 is buried, container 1 can be made of concrete, and the inner surface of the concrete containing mixture 4 can be made insulating by coating or spraying an insulating agent such as an alkylalkoxysilane or silanesiloxane. This allows the size of concrete container 1 to be set as desired, so that a large capacitor 11 can be realized by increasing the volume of capacitor 11.

[0099] Although U.S. Patent No. 11,512,022 listed in the prior art discloses storing electricity in concrete, it does not disclose how to insulate the reinforcing bars that may be placed in the concrete. In contrast, in the first and second embodiments, the container 1 is made insulating, so that the presence of metal structures around the container 1 does not pose a problem.

[0100] The above-described embodiment is a preferred example of the present invention. However, the present invention is not limited to this, and various modifications are possible within the scope of the gist of the present invention. For example, an electron-conductive conductive polymer may be used as the electron-conductive substance. A conductive polymer may be used as the conductive polymer. In this case, the conductive polymer may be liquefied by dissolving it in a solvent, or by adding an additive to the conductive polymer.

[0101] DESCRIPTION OF SYMBOLS 1: Container 2: Soil 3: Copper plate 4: Mixture 5: Separator 6: Positive electrode 7: Negative electrode 11: Capacitor 12: Agricultural greenhouse 16: Perovskite solar cell 17: First lid member 23: Control device 30: Control unit 31: Load device 32: Tent warehouse

Claims

1. A charging device in which a capacitor is provided near a structure with a frame covered with a membrane, the capacitor comprising a conductive part in which an electrically conductive substance has been mixed into soil 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.

2. The charging device according to claim 1, wherein the capacitor is embedded in the vicinity of the structure.

3. The charging device according to claim 1, wherein a platform having a space below it is provided within the structure, and the capacitor is disposed below the platform.

4. A charging device according to claim 1, wherein the electrically conductive material has 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.

5. The charging device according to claim 4, wherein the first member is carbon black, and the second member is at least one of binchotan charcoal and activated carbon.

6. The charging device according to claim 1, wherein at least one of said positive electrode and said negative electrode has an extension portion that extends in a direction intersecting the compaction direction when said conductive portion is compacted.

7. The charging device according to claim 1, further comprising a control device that charges the capacitor with power from a generating device that generates renewable energy.

8. The charging device according to claim 7, wherein the generating device is provided in the vicinity of the structure or on the structure.

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

10. The charging device according to claim 9, wherein said environment sensor has an electrical conductivity sensor for measuring the electrical conductivity of said conductive portion.

11. The charging device according to claim 1 or claim 9, further comprising a liquid supply device for supplying liquid to at least one of the conductive portion and the separator.

12. A charging method in which a capacitor is provided near a structure having a frame covered with a membrane, the capacitor comprising a conductive part in which an electrically conductive substance has been mixed into soil 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 so as to insulate the positive electrode from the negative electrode, and when a voltage is applied between the positive electrode and the negative electrode, an anion is introduced to the positive electrode and a cation is introduced to the negative electrode.

13. The charging method according to claim 12, wherein the capacitor is buried near the structure.

14. The charging method according to claim 12, wherein a platform having a space below it is provided within the structure, and the capacitor is disposed below the platform.

15. A charging method according to claim 12, wherein the electrically conductive material has a first member forming 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.

16. The charging method according to claim 15, wherein the first member is carbon black, and the second member is at least one of binchotan charcoal and activated carbon.

17. The method of claim 12, further comprising the step of soaking the electrically conductive material in water before the electrically conductive material is mixed with the soil.

18. The charging method according to claim 17, further comprising the step of stirring the electrically conductive material and the water.

19. The charging method according to claim 12, further comprising the step of removing gas contained in the soil after mixing the soil with the electrically conductive material.

20. The charging method according to claim 12, further comprising the step of measuring the environment of said conductive portion.

21. The charging method according to claim 12, wherein a liquid is supplied to at least one of the conductive portion and the separator.

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