Power generation system, power storage device, power generation device, and power generation method

Abstract

To provide a power generation system or a power generation method capable of extracting a large amount of electric energy even from a continuously supplied liquid.SOLUTION: A power generation system 1 includes a droplet forming unit 14 and a power generation layer 10 equipped with an electrode 11. The droplet forming unit is formed in contact with a power generation layer and supplies droplets formed by condensing a continuously supplied liquid to the power generation layer, and the power generation layer moves the droplets on the upper surface of the power generation layer to extract electrical energy from the electrode.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a power generation system, a power storage device, a power generation device, and a power generation method. [Background technology]

[0002] In recent years, there has been a demand to reduce greenhouse gas emissions to virtually zero, and solar power generation is a particularly promising technology. However, there is a demand for complementary technologies that utilize other renewable energy sources in order to obtain stable power regardless of weather changes.

[0003] In general, a triboelectric nano generator (TENG) is a device that converts external mechanical energy into electrical energy by combining the frictional charging effect and electrostatic induction. The movement of multiple discontinuous droplets or other liquid masses causes multiple electrostatic inductions, which transfer electric charge and thereby generate electrical energy. For example, Patent Document 1 describes a generator that obtains power from the sliding behavior of liquid droplets when they are dropped onto a layer of polytetrafluoroethylene (PTFE). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, when liquid is continuously supplied, after the initial electrostatic induction is induced, the charges are balanced and no electrostatic induction is induced thereafter. Therefore, unless liquid is supplied again after the continuous supply of liquid is stopped, no charge transfer occurs and a large amount of electricity cannot be generated from the continuously supplied liquid that is not in the form of droplets. An object of the present invention is to provide a power generation system and a power generation method capable of extracting a large amount of electrical energy even from a continuously supplied liquid. [Means for solving the problem]

[0005] In order to solve the above problems, one embodiment of the present invention comprises: A power generation system having a droplet forming unit and a power generation layer having an electrode, the droplet forming unit is formed in contact with the power generation layer, and supplies droplets obtained by forming a continuously supplied liquid into droplets to the power generation layer; The power generation layer provides a power generation system in which the droplets are moved on the upper surface of the power generation layer to extract electrical energy from the electrodes. Effect of the Invention

[0006] According to one embodiment of the present invention, it is possible to provide a power generation system capable of extracting a large amount of electrical energy even from a continuously supplied liquid. [Brief description of the drawings]

[0007] [Figure 1A] 1 is a schematic diagram of an example of a power generation system according to an embodiment of the present invention. [Figure 1B] FIG. 2 is a schematic diagram of another example of a power generation system according to an embodiment of the present invention. [Figure 1C] FIG. 2 is a schematic diagram of another example of a power generation system according to an embodiment of the present invention. [Diagram 2] 1 is an example of how a power generation layer is charged due to friction with droplets in a power generation system according to an embodiment of the present invention. [Diagram 3] 1 is an example of a flow of charge movement due to the movement of droplets in a power generation system according to an embodiment of the present invention. [Figure 4A] 1 is a schematic diagram of an example of a power generation system according to an embodiment of the present invention. [Figure 4B] 1 is a schematic diagram of an example of a power generation system according to an embodiment of the present invention. [Figure 5A] 1 is a photograph including an example of a material having a larger contact angle with a liquid formed in a droplet formation portion of a power generation system according to an embodiment of the present invention than the power generation layer. [Figure 5B]1 is a photograph showing an example of a material having a larger contact angle with a liquid than the power generation layer and a fine uneven structure formed in a droplet formation portion of a power generation system according to an embodiment of the present invention. [Figure 6A] 4 is a graph showing the state of power generation when liquid is continuously supplied to the power generation element produced in Example 1. [Figure 6B] 1 is a graph showing power generation when liquid is continuously supplied to the power generation element produced in Comparative Example 1. [Figure 7A] 4 is a schematic diagram showing an example of how a liquid is continuously supplied to the power generation element produced in Example 1. FIG. [Figure 7B] 1 is a schematic diagram showing an example of a partially enlarged view of a state in which liquid is continuously supplied to the power generation element produced in Example 2. FIG. [Figure 7C] 1 is a schematic diagram showing an example of how a liquid is continuously supplied to the power generation element produced in Comparative Example 1. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The embodiments of the present invention will be described in detail below.

[0009] (Power generation system and power generation method) The power generation system of the present invention comprises: A power generation system having a droplet forming unit and a power generation layer having an electrode, the droplet forming unit is formed in contact with the power generation layer, and supplies droplets obtained by forming a continuously supplied liquid into droplets to the power generation layer; The power generation layer is a power generation system that extracts electrical energy from the electrodes by moving the droplets on the upper surface of the power generation layer. The power generation system of the present invention is not particularly limited as long as it satisfies the above-mentioned configuration, and may be a power generation element that satisfies the configuration of the power generation system. The power generation system may further include other members as necessary. According to the power generation system of the present invention, a continuously supplied liquid is turned into droplets, and a large amount of electrical energy can be extracted.

[0010] In the power generation system, it is preferable that electrical energy is extracted by electrostatic induction of the electrodes. It is preferable that the electrostatic induction is caused by moving a charged droplet on the upper surface of the power generation layer, causing the droplet, polarized by the charge on the upper surface side of the power generation layer, to come into contact with the electrode on the upper surface side.

[0011] The power generation method of the present invention comprises the steps of: A power generation method comprising: supplying droplets of a continuously supplied liquid to a power generation layer having electrodes; and moving the droplets on an upper surface of the power generation layer to extract electrical energy from the electrodes, the method comprising the steps of: The power generation method is such that the droplets are turned into droplets on the power generation layer. According to the power generation method of the present invention, a continuously supplied liquid is turned into droplets, and a large amount of electrical energy can be extracted.

[0012] In the power generating method, it is preferable that electrical energy is extracted by electrostatic induction of the electrodes. It is preferable that the electrostatic induction is caused by moving a charged droplet on the upper surface of the power generation layer, causing the droplet, polarized by the charge on the upper surface side of the power generation layer, to come into contact with the electrode on the upper surface side.

[0013] The power generation method further comprises: The power generation layer is provided with electrodes on both the upper and lower surfaces, and frictional charges are generated by moving charged droplets on the upper surface of the power generation layer, and electrical energy is extracted from the electrodes on the upper and lower surfaces, and it is preferable that the droplets are condensed onto the power generation layer.

[0014] The power generation method further comprises: The power generation layer is provided with electrodes on both the upper and lower surfaces, and by moving charged droplets on the upper surface of the power generation layer, the droplets polarized by the charge on the upper surface of the power generation layer come into contact with the electrode on the upper surface, thereby extracting electrical energy from the electrodes on the upper and lower surfaces, and it is preferable that the power generation method be such that the droplets are condensed on the power generation layer.

[0015] <Liquid> The liquid is not particularly limited, but from the viewpoint of practicality and ease of use in the renewable energy field, examples of the liquid include water, an aqueous solution, a colloidal solution, and oil.

[0016] The water includes rainwater, tap water, distilled water, ion-exchanged water, ultrafiltered water, reverse osmosis water, pure water, highly pure water, ultrapure water, etc., and these may be used alone or in combination of two or more types. Examples of the aqueous solution include NaCl solution, seawater, and sewage. Examples of the colloidal solution include milk and sewage.

[0017] The amount of liquid to be continuously supplied to the power generation system of the present invention is not particularly limited and can be appropriately selected depending on the purpose.

[0018] <Droplet> The droplets obtained by condensing the continuously supplied liquid into droplets are not particularly limited as long as they can extract electrical energy from the electrodes, and may be appropriately selected depending on the purpose, although the droplets are preferably 5 to 150 μl in shape, size, volume, and mass.

[0019] <Droplet formation section> The droplet forming section is a section formed in contact with the power generation layer and supplies the power generation layer with droplets obtained by converting a continuously supplied liquid into droplets. The droplet forming section may include a structure for converting the continuously supplied liquid into droplets, or may include a vicinity of the structure. The droplet forming portion is not particularly limited in shape, size and position as long as it does not impede the movement of the droplets through contact with the power generation layer, and can be appropriately selected depending on the purpose. The droplet former is located in contact with the power generation layer, and may be located on a portion of the top surface of the power generation layer, on a side surface of the power generation layer, or on any other suitable location. It is preferable that the droplet formation section is formed of a material having a larger contact angle with the liquid than the power generation layer, and forms the continuously supplied liquid into droplets by at least one of the following: vibrating the liquid, branching the continuous flow of the liquid using a convex body, and interrupting the continuous flow of the liquid using a convex body. The droplet forming unit as described above can easily and efficiently form the continuously supplied liquid into droplets. In the power generating method, "forming the continuously supplied liquid into droplets and supplying them to the power generating layer" can be suitably performed by the droplet forming unit.

[0020] <<Materials with a larger contact angle with liquid than the power generation layer>> As an embodiment in which a material having a larger contact angle with the liquid than the power generation layer is used, a preferable embodiment is one in which a droplet formation portion is formed by applying, attaching, or placing a material having a larger contact angle with the liquid than the power generation layer on a portion of the upper surface of the power generation layer, and the liquid continuously supplied in the droplet formation portion is converted into droplets. If a material having a larger contact angle with the liquid than that of the power generation layer is used for the droplet formation portion, the surface free energy of the liquid in contact with the material will be smaller and the liquid will have a stronger tendency to roll up due to surface tension, making it easier for the continuously supplied liquid to form droplets and also more likely to slow down the flow.

[0021] As a material having a larger contact angle with the liquid than the power generation layer, it is preferable that the ratio of the static contact angle between the liquid and the power generation layer to the static contact angle between the liquid and the material with the larger contact angle with the liquid, i.e., (static contact angle between the liquid and the power generation layer) / (static contact angle between the liquid and the material with the larger contact angle with the liquid), is 0.75 or less. If the value of the above ratio is 0.75 or less, even if the power generation layer contains a substance that has a small contact angle with the liquid, a sufficient contrast can be created between the static contact angle between the liquid and the power generation layer and the static contact angle between the liquid and a material that has a large contact angle with the liquid, making it easier to form droplets of the continuously supplied liquid.

[0022] Examples of the material having a larger contact angle with the liquid than the power generation layer include a water-repellent material and an ultra-water-repellent material.

[0023] -Water-repellent material- The water-repellent material is a material with a water droplet contact angle of 90° or more and less than 150°, and specific examples thereof include fluorine-based resins and silicone resins.

[0024] -Super water-repellent material- An "ultrawater-repellent material" is a material with a water droplet contact angle of 150° or more. Specific examples include materials that can form a fine uneven structure such as the surface of a lotus leaf, and materials into which functional groups have been introduced by chemical modification in order to reduce surface free energy. The super water repellent material may be any material having a contact angle with water of 150° or more, and specific examples thereof include nanosilica, nanowhisker mixtures, and the like. As the super water-repellent material, commercially available products such as water-repellent spray (Glaco Mirror Coat ZERO, manufactured by Soft99 Corporation) and Ultra Ever Dry Spray (manufactured by UltraTech International, Inc.) can be used.

[0025] If the material has a larger contact angle with the liquid than the power generation layer, particularly if it is a water-repellent material or an ultra-water-repellent material, the droplet formation portion can be formed more easily.

[0026] <<Vibrating the liquid>> Examples of the manner in which the liquid is vibrated include applying ultrasonic waves to the liquid using an ultrasonic generator, etc. Also, examples of the manner in which the liquid is vibrated include forming a droplet forming section in the vicinity of the ultrasonic generator, etc. by arranging the ultrasonic generator, etc. so as to be in contact with the power generation layer, and forming droplets of the continuously supplied liquid in the droplet forming section.

[0027] <<Branching a continuous liquid flow by a convex object>> A preferred embodiment of branching a continuous flow of liquid by a convex body is to arrange a convex body to form a droplet forming part, and to branch the moving liquid in the droplet forming part. With this embodiment, the droplet forming part can be easily formed. Examples of the convex bodies include projections, columnar structures, cone-shaped structures, needle-shaped bodies, and rod-shaped bodies. It is preferable that a plurality of convex bodies are arranged to form the droplet forming portion. When a plurality of convex bodies are arranged in the droplet forming portion, it becomes easier to increase the number of droplets formed from the liquid continuously supplied to the droplet forming portion, and it becomes easier to form droplets.

[0028] <> As an embodiment in which the continuous flow of the liquid is interrupted by a convex body, a preferred embodiment is one in which a convex body capable of interrupting the continuous flow of the liquid is disposed to form a droplet formation section, and the continuous flow is interrupted in the droplet formation section. Examples of the convex bodies include projections, columnar structures, cone-shaped structures, needle-shaped bodies, rod-shaped bodies, etc. The convex bodies are preferably taller because a continuous flow of liquid is more likely to be interrupted when passing over the convex bodies.

[0029] <Power generation layer> The power generation layer may be located within a range where droplets can come into contact with and move when the continuously supplied liquid is turned into droplets. The power generation layer is not particularly limited in terms of material, shape, size, thickness, or structure, so long as it is an insulator that is charged by friction with the liquid droplets, and can be appropriately selected depending on the purpose.

[0030] The droplet forming portion may be formed by combining two or more of the above configurations, for example, a combination of "a material having a larger contact angle with the liquid than the power generation layer" and "branching and / or dividing the continuous flow of liquid by a convex body", a combination of "a material having a larger contact angle with the liquid than the power generation layer" and "vibrating the liquid", a combination of "branching and / or dividing the continuous flow of liquid by a convex body" and "vibrating the liquid", etc.

[0031] Examples of the material for the power generation layer include polymer materials and rubber.

[0032] Examples of the polymeric material include polyethylene, polypropylene, polyethylene terephthalate, polyvinyl chloride, polyimide, polyamide, fluororesin, acrylic resin, polydimethylsiloxane, and cellulose.

[0033] Examples of the rubber include silicone rubber, acrylic rubber, chloroprene rubber, polysulfide rubber, urethane rubber, butyl rubber, natural rubber, ethylene-propylene rubber, nitrile rubber, fluororubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, ethylene-propylene-diene rubber, chlorosulfonated polyethylene rubber, and polyisobutylene.

[0034] The power generation layer is preferably made of an electret material. In the present invention, the electret material means a material that stably holds static electricity for a long period of time to provide an electric field to the surroundings. If the power generation layer is made of an electret material, it can retain electric charge semi-permanently, so there is no need to charge the power generation layer to a saturated state by friction with the droplets. Examples of the electret material include CYTOP (manufactured by AGC), fluorine-based resins such as polytetrafluoroethylene (PTFE), and porous polypropylene.

[0035] <Electrode> The electrodes need only be electrically conductive and capable of extracting electrical energy by moving droplets, and there are no particular limitations on their material, shape, size, structure, or position, and they can be appropriately selected depending on the purpose.

[0036] The shape of the electrode may be, for example, a plate, a rod, a wire, a film, or a combination thereof.

[0037] The power generation system may include a single electrode or a plurality of electrodes. When there are a plurality of electrodes, the materials, shapes, sizes, and structures of the electrodes may be the same or different. In addition, when there is a single electrode, in order for the charge to move, an object equivalent to another electrode connected to the electrode is required, so the object at one end connected to the electrode can be considered as the other electrode, and the ground connected to the electrode can be considered as the other electrode.

[0038] The power generation system may have the electrodes on the upper and / or lower surfaces of the power generation layer, and from the viewpoint of extracting higher electric energy, it is preferable that the electrodes are provided on the upper and lower surfaces of the power generation layer. In addition, since it is preferable that the length of the lower electrode in the direction in which the water flows is approximately the same as the diameter of the droplets in order to obtain a large amount of power generation, it is preferable that the length of the lower electrode in the direction in which the water flows is 1 mm to 10 mm.

[0039] In the case where the power generation system has the electrodes only on the upper surface of the power generation layer, when a droplet comes into contact with the power generation layer, which is charged to a saturated state, the charge in the droplet is polarized. When the polarized droplet moves and comes into contact with the electrode on the upper surface of the power generation layer, the charge balance in the power generation system is disrupted, electrostatic induction is induced, and the charge is transferred via the ground or the like. When the droplet then flows down from the power generation layer, the charge balance in the power generation system is again disrupted, electrostatic induction is induced, and the charge is transferred via the electrode on the upper surface of the power generation layer.

[0040] In the case where the power generation system has the electrodes only on the lower surface of the power generation layer, when a droplet comes into contact with the power generation layer that is charged to a saturated state, the charge in the droplet is polarized, causing the charge balance in the power generation system to be disrupted, electrostatic induction to be induced, and charge to be transferred through the electrodes on the lower surface of the power generation layer. When the droplet then flows down from the power generation layer, the charge balance in the power generation system is disrupted, causing electrostatic induction to be induced, and charge to be transferred through the ground or the like.

[0041] In the case where the power generation system has the electrodes on the upper and lower surfaces of the power generation layer, when a droplet comes into contact with the power generation layer, which is charged to a saturated state, the charge in the droplet is polarized, causing the charge balance in the power generation system to be disrupted, electrostatic induction to be induced, and charge to be transferred through the electrode on the lower surface of the power generation layer. Next, when the polarized droplet moves and comes into contact with the electrode on the upper surface of the power generation layer, the charge balance in the power generation system is disrupted, electrostatic induction is induced, and charge is transferred through the ground or the like. After that, when the droplet flows down from the power generation layer, the charge balance in the power generation system is disrupted, electrostatic induction is induced, and charge is transferred through the electrode on the upper surface of the power generation layer.

[0042] Examples of materials for the electrodes include metals, conductive polymers, and conductive rubber compositions.

[0043] Examples of the metal include gold, silver, copper, aluminum, stainless steel, tantalum, nickel, phosphor bronze, and indium tin oxide.

[0044] Examples of the conductive polymer include polythiophene, polyacetylene, and polyaniline.

[0045] The conductive rubber composition may be, for example, a composition containing a conductive filler and rubber.

[0046] Examples of the conductive filler include carbon materials (e.g., ketjen black, acetylene black, graphite, carbon fibers, carbon nanofibers, carbon nanotubes, graphene, etc.), metals (e.g., gold, silver, platinum, copper, iron, aluminum, nickel, etc.), conductive polymers (e.g., at least any one of derivatives of polythiophene, polyacetylene, polyaniline, polypyrrole, polyparaphenylene, and polyparaphenylenevinylene, or derivatives of these derivatives to which a dopant typified by an anion or a cation has been added, etc.), and ionic liquids.

[0047] Examples of the rubber contained in the conductive rubber composition include silicone rubber, modified silicone rubber, acrylic rubber, chloroprene rubber, polysulfide rubber, urethane rubber, isobutyl rubber, fluorosilicone rubber, ethylene rubber, and natural rubber (latex).

[0048] <Other materials> Examples of the other members include a base material and an adhesive. The substrate may be any substrate that is insulating and capable of forming the power generation system. There are no particular limitations on the material, shape, size, thickness, or structure of the substrate, and the substrate may be appropriately selected depending on the purpose.

[0049] Examples of the material for the substrate include polymeric materials, rubber, paper, minerals, glass, ceramics, and combinations of these.

[0050] The shape of the substrate may be, for example, a plate, a rod, a wire, a film, or a combination thereof.

[0051] The adhesive may be, for example, a double-sided tape or a combination thereof.

[0052] (Power generation equipment) The power generating device of the present invention includes the power generating system and an electric circuit, and may further include other members as necessary.

[0053] <Electric circuit> The electric circuit in the power generating device of the present invention is not particularly limited as long as it is a circuit that extracts the electric power generated by the power generating system, and can be appropriately selected depending on the purpose.

[0054] <<Other materials>> Examples of the other components in the power generating device of the present invention include a ground, a resistor, a rectifier circuit, and the like.

[0055] (Electricity storage device) The electricity storage device of the present invention includes the power generation system, and may further include other members as necessary.

[0056] <Other materials> Examples of the other components in the electricity storage device of the present invention include an electric circuit for extracting the electricity generated from the power generation system, an electric circuit for storing the extracted electricity, and the like.

[0057] <<Electric circuits>> The electric circuit in the electricity storage device of the present invention is not particularly limited as long as it is a circuit for extracting or storing the electric power generated by the power generation system, and can be appropriately selected depending on the purpose.

[0058] (Sensor) The power generation system can be used as a sensor by extracting, as an electrical signal, the movement of charges caused by contact between the droplets and the electrodes or the movement of the droplets on the upper surface of the power generation layer. Examples of the sensor include a water level sensor, a flow meter, a water leakage sensor, and a rain gauge.

[0059] The fields in which the power generation device, the power storage device, and the sensor are used are not particularly limited as long as they are fields that use a configuration in which droplets are brought into contact with a power generation layer and / or an electrode when extracting electrical energy, and can be selected appropriately depending on the purpose. However, it is preferable to use them in fields that utilize renewable energy, and it is more preferable to use them in fields that generate electricity using natural energy such as solar, wave, hydroelectric, and wind power, or a combination of these, and it is even more preferable to use them as a complement to these power generation methods.

[0060] Here, an example of the power generation system of the present invention will be described with reference to FIGS. 1A to 1C. In addition, in each drawing, the same components are denoted by the same reference numerals, and duplicated explanations may be omitted. Furthermore, the number, position, shape, etc. of the following components are not limited to these embodiments, and may be the number, position, shape, etc. that are preferable for implementing the present invention.

[0061] Fig. 1A is a schematic diagram of an example of a power generation system according to an embodiment of the present invention. The power generation system 1 in Fig. 1A has an electrode 11 and a droplet forming part 14 on a part of the upper surface of a power generation layer 10, and is connected to a ground 15 from the electrode 11 via a resistor 13. The ground 15 is one end connected to the electrode 11, and since electric charge moves through the ground 15, in the power generation system 1 in Fig. 1A, the ground 15 can be regarded as another electrode connected to the electrode 11.

[0062] FIG. 1B is a schematic diagram of another example of a power generation system according to an embodiment of the present invention. 1B has a droplet forming part 14 on a part of the upper surface of the power generation layer 10, has an electrode 12 on the lower surface of the power generation layer 10, and is connected to ground 15 from the electrode 12 via resistor 13. Ground 15 is one end connected to electrode 12, and since charge moves through ground 15, in the power generation system 1 of FIG. 1B, ground 15 can be regarded as another electrode connected to electrode 12.

[0063] FIG. 1C is a schematic diagram of another example of a power generation system according to an embodiment of the present invention. 1C has an electrode 11 and a droplet forming part 14 on a part of the upper surface of a power generation layer 10, and an electrode 12 on the lower surface, with the electrodes 11 and 12 connected to a ground 15 via a resistor 13. The ground 15 is one end connected to the electrodes 11 and 12, and since charge moves through the ground 15, in the power generation system 1 of FIG.

[0064] Next, an example of the power generation method of the present invention will be described with reference to FIGS.

[0065] FIG. 2 shows an example of how the power generation layer is charged by friction with droplets in a power generation system according to an embodiment of the present invention.

[0066] The droplet 21 initially falls onto the uncharged upper surface of the power generation layer 10 (FIG. 2(a)), and as it comes into contact with and moves onto the upper surface of the power generation layer 10, friction is generated, and a negative charge is transferred from the droplet 21 to the upper surface of the power generation layer 10 (FIG. 2(b)). At this time, the electrode 12 on the lower surface of the power generation layer 10 is positively charged due to electrostatic induction.

[0067] A second droplet 21 falls onto the upper surface of the power generation layer 10, to which a negative charge has been transferred due to the fall of the first droplet 21 (FIG. 2(c)), and moves in contact with the upper surface of the power generation layer 10, generating friction, and a negative charge is transferred from the droplet 21 to the upper surface of the power generation layer 10 (FIG. 2(d)). At this time, the electrode 12 on the lower surface of the power generation layer 10 is further charged with a positive charge due to electrostatic induction.

[0068] The third droplet 21 falls on the upper surface of the power generation layer 10 (FIG. 2(e)), and similarly to the case where the second droplet 21 falls, a negative charge is transferred from the droplet 21 to the upper surface of the power generation layer 10. At this time, the electrode 12 on the lower surface of the power generation layer 10 is further charged with a positive charge due to electrostatic induction, similarly to the case where the second droplet 21 falls.

[0069] The droplets 21 continue to fall onto the upper surface of the power generation layer 10, repeating the cycle of (c) and (d) in FIG.

[0070] The droplets 21 are allowed to fall until no more negative charge is transferred to the upper surface of the power generation layer 10 as the droplets 21 fall, and the cycle of (c) and (d) in Figure 2 is repeated to charge the power generation layer 10 to a saturated state, whereby the subsequent fall of the droplets 21 will result in a stable output due to charge transfer.

[0071] In addition, since the droplet 21 is liquid, the actual contact area with the object it comes into contact with is large, so that the power generation layer 10 can be charged to a saturated state quickly. When the power generation layer 10 is charged by friction of the droplets 21 in the power generation system 1, the droplets 21 act as a frictional charging partner to the power generation layer 10, exchanging charges with the power generation layer 10.

[0072] When the power generation layer 10 is made of an electret material, the power generation layer 10 can retain an electric charge semi-permanently. Therefore, as shown in FIG. 2, it is not necessary to charge the power generation layer 10 by dropping, contacting, and moving a liquid droplet 21 onto the upper surface of the power generation layer 10, which is initially uncharged, and then causing friction to cause the power generation layer 10 to be charged.

[0073] FIG. 3 shows an example of a flow of charge movement due to the movement of droplets in a power generation system according to an embodiment of the present invention.

[0074] A droplet 21 falls onto the upper surface of the power generation layer 10 of the power generation system 1, which is sufficiently negatively charged and in a charge-balanced state (FIG. 3(a)).

[0075] When the fallen droplet 21 comes into contact with the upper surface of the power generation layer 10 and moves, the positive charge of the droplet 21 is attracted to the side of the power generation layer 10 because the upper surface of the power generation layer 10 is negatively charged, and the negative charge of the droplet 21 is induced to the opposite side of the power generation layer 10, resulting in a polarized state (FIG. 3(b)). At this time, since the droplet 21 and the power generation system 1 are in contact with each other, the power generation system 1 in contact with the droplet 21 loses its charge balance, and releases excess positive charge from the positively charged electrode 12 (FIG. 3(b)).

[0076] When the polarized liquid droplet 21 moves over the upper surface of the power generation layer 10 and comes into contact with the electrode 11, the negative charge polarized in the liquid droplet 21 moves to the interface with the electrode 11 (FIG. 3(c)).

[0077] In the power generation system 1, the charge balance state is lost, so electrostatic induction is caused to form an electric double layer with the negative charge of the droplet 21 that has moved to the interface with the electrode 11, and a positive charge moves from the ground 15 through the resistor 13 to the interface with the electrode 11 (Figure 3 (d)).

[0078] When a positive charge is electrostatically induced in the electrode 11, the power generation system 1 in contact with the droplet 21 is brought into a charge-balanced state (FIG. 3(e)), and the transfer of charge stops.

[0079] Thereafter, when the droplet 21 flows down beyond the electrode 11, the amount of liquid in the droplet 21 decreases, and therefore the amount of negative charge in the droplet 21 also decreases, causing the charge balance in the power generation system 1 in contact with the droplet 21 to be lost, and the excess positive charge is released from the electrode 11 by electrostatic induction (Figure 3 (f)). Since the charge moves due to this electrostatic induction, electrical energy can be extracted by the droplets 21 flowing down from the power generation system 1. The direction in which the charge moves at this time is opposite to the direction in which the charge moves when a positive charge is electrostatically induced from the ground 15 through the resistor 13 to the electrode 11 as shown in (d) of FIG.

[0080] By continuing to drop the droplets 21 and repeating the cycle from (a) to (f) in Figure 3, electrostatic induction is induced many times, and a charge transfer occurs each time, making it possible to efficiently extract electrical energy.

[0081] When a droplet 21 is dropped onto the upper surface of the power generation layer 10 of the power generation system 1 in which the power generation layer 10 is sufficiently charged close to a saturated state and the charges are balanced, and the droplet 21 comes into contact with the upper surface of the power generation layer 10 and travels to and contacts the electrode 11 to extract electrical energy, the droplet 21 acts as a dielectric to bridge the power generation layer 10 and the electrode 11 to form a closed circuit. EXAMPLES

[0082] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0083] Example 1 <Power generation system with droplet formation section made of ultra-water-repellent material> A power generating element for the power generating system was fabricated by the following method, by stacking the components in the order shown in FIG. 4A to obtain a power generating system as shown in FIG. 4B. On top of the acrylic plate (Kanaselite, Kanase Corporation: 80 mm x 150 mm x 5 mm thick) serving as the base material, a copper foil tape (CU-35C, 3M Corporation) serving as the electrode, a polytetrafluoroethylene (PTFE) tape (Scotch5480, 3M Corporation: 80 mm x 50 mm) serving as the power generation layer, and another copper foil tape (CU-35C, 3M Corporation) serving as the electrode were layered in that order. Finally, a droplet formation area was formed in the center of the PTFE tape using a superwater-repellent material using the following method.

[0084] [Droplet formation using super-water-repellent material] The area other than the 20 mm × 50 mm area shown as droplet formation area 14 in Figure 4B was masked with polyimide tape, and then a water-repellent spray (Glaco Mirror Coat ZERO, manufactured by Soft99 Corporation) was sprayed near the center of the top surface of the PTFE tape to apply a superwater-repellent material to the area of ​​droplet formation area 14 in Figure 4B, and by drying it, a silica film with a fine uneven structure and a thickness of tens to hundreds of nm was formed on the top surface of the PTFE tape as a droplet formation area.

[0085] [Water repellency evaluation] Using water droplets as droplets, a contact angle meter DropMaster DM500 (Kyowa Interface) was used to measure the static contact angle of the water droplet on the PTFE tape (power generation layer) and the static contact angle on the silica film (droplet formation part) formed with a water repellent spray (Glaco Mirror Coat ZERO, Soft99 Corporation) under the following measurement conditions. Note that ion-exchanged water droplets were used for the measurements. <Measurement conditions> Droplet volume: 1 [μL] Liquid volume increase rate: 1.23 [μL / s] Discharge level: 2000 <Measurement results> Static contact angle of PTFE tape (power generation layer): 106° Static contact angle of nanosilica film (droplet formation area): 151° (Static contact angle on PTFE tape) / (Static contact angle on nanosilica film): 0.70

[0086] [Observation of the microscopic uneven structure of super-water-repellent materials] The fine uneven structure of a silica film having a thickness of several tens to several hundreds of nm and formed from the same material as that used to form the droplet forming portion in Example 1 was observed by the following method. First, a composite material (Alpet 30-100, Panac Corporation) made by bonding polyester film (PET) and aluminum foil was used as the substrate, and a water-repellent spray (Glaco Mirror Coat ZERO, Soft99 Corporation) was sprayed onto the aluminum surface of this substrate to form a nanosilica film with a thickness of tens to hundreds of nm. Next, the substrate that has been treated as above is 2 The specimen was cut out, coated with osmium (Os) for electrical conductivity, and observed and photographed under the following observation conditions using the scanning electron microscope and equipment described below. The photographs are shown in Figures 5A and 5B.

[0087] Scanning electron microscope: Carl Zeiss (SII) FIB / SEM cross beam device NVision 40 <Observation conditions> Acceleration voltage: 0.8 kV Aperture Size: 10μm WD: 3.0mm High Current:On Detector: InLens+SE2 Sample tilt: 0° EsB Grid:0V

[0088] It was confirmed that the aluminum surface 23 to which no water-repellent spray was applied was nearly smooth, whereas the silica film 22 formed by applying the water-repellent spray was not smooth (FIG. 5A). Moreover, when the silica film formed by applying the water-repellent spray was photographed in a magnified manner, it was confirmed that the film had a nano-level fine uneven structure 24 (FIG. 5B).

[0089] Example 2 <Power generation system having a droplet forming section with a convex body> A power generating element was produced in the same manner as in Example 1, except that the droplet forming portion in Example 1 was changed from a droplet forming portion made of an ultrawater-repellent material to a droplet forming portion having the convex bodies described below.

[0090] [Formation of droplet forming part having a convex body] A small piece (50 μm thick) of austenitic stainless steel SUS304 was folded to create a triangular prism with a side length of 5 mm and a height of 5 mm to form the convex body contained in the droplet formation part. Three of the triangular prisms thus created were attached with double-sided tape near the center of the top surface of the PTFE tape, which was the power generation layer, so that the centers of the triangles of each triangular prism were spaced approximately 10 mm apart, forming a droplet formation part with multiple convex bodies.

[0091] Comparative Example 1 <Power generation system without droplet formation section> A power generating element was produced in the same manner as in Example 1, except that no droplet forming portion was provided.

[0092] The power generating elements of Examples 1 and 2 and Comparative Example 1 were tilted at 45°, and water was continuously supplied as a liquid. In addition, the number of times electricity was generated in 2 seconds when water was continuously supplied under the following measurement conditions was measured. The results of the number of times electricity was generated are shown in Table 1, and graphs showing the power generation in Example 1 and Comparative Example 1 are shown in Figures 6A and 6B. Ion-exchanged water was used as the water to be continuously supplied. <Measurement conditions> Measuring device: Oscilloscope WaveSurfer3024 (manufactured by LeCroy) Probe resistance: 10MΩ Load resistance: 1 [MΩ] Recording time: 2 seconds Sampling rate: 50[kHz] Water nozzle diameter: φ1.6 [mm] Water flow rate: 0.3 [ml / s]

[0093] [Table 1]

[0094] When water was continuously supplied to the power generation element of Example 1, the water continuously supplied to the droplet formation section turned into droplets as shown in Figure 7A, which resulted in a large number of power generation cycles and a sufficient amount of power generation.

[0095] When water was continuously supplied to the power generation element of Example 2, the water continuously supplied to the droplet formation section branched and turned into droplets, as shown in Figure 7B, which demonstrated that the number of power generation was high and a sufficient amount of power generation was obtained.

[0096] Because the power generating element of Comparative Example 1 did not have a droplet forming portion, as shown in FIG. 7C, even when water was continuously supplied to the power generating element of Comparative Example 1, the water did not turn into droplets but simply flowed, and power generation was only performed once, resulting in insufficient power generation.

[0097] From the above, it has been demonstrated that a power generation system satisfying the configuration of the present invention can convert a continuously supplied liquid into droplets and extract a large amount of electrical energy.

[0098] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to such specific embodiments, and various modifications and changes are possible within the scope of the spirit of the present invention described in the claims, unless otherwise specifically limited in the above description. The effects described in the embodiments of the present invention are merely examples of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments of the present invention.

[0099] For example, aspects of the present invention are as follows. <1> A power generation system having a droplet formation unit and a power generation layer equipped with electrodes, wherein the droplet formation unit is formed in contact with the power generation layer and supplies droplets formed by liquefying a continuously supplied liquid to the power generation layer, and the power generation layer moves the droplets on an upper surface of the power generation layer to extract electrical energy from the electrodes. <2> The droplet forming unit includes: The power generation layer is made of a material having a larger contact angle with the liquid than the power generation layer. The power generation layer is formed into droplets by at least one of vibrating the liquid, branching a continuous flow of the liquid with a convex body, and interrupting a continuous flow of the liquid with a convex body. <1> The power generation system according to claim 1. <3> The liquid is water, an aqueous solution, a colloidal solution, or an oil. <1> or <2> The power generation system according to claim 1. <4> The material having a larger contact angle with the liquid than the power generation layer is a super water-repellent material. <2> or <3> The power generation system according to claim 1. <5> the droplet forming portion is formed of a material having a contact angle with the liquid larger than that of the power generation layer, and a value of (static contact angle between the liquid and the power generation layer) / (static contact angle between the liquid and a material having a contact angle with the liquid larger than that of the power generation layer) is 0.75 or less; <1> from <4> The power generation system according to any one of claims 1 to 5. <6> The electrode is provided on the upper and / or lower surfaces of the power generation layer. <1> from <5> The power generation system according to any one of claims 1 to 5. <7> The above <1> from <6> 2. A power storage device comprising the power generation system according to claim 1 . <8> The above <1> from <6> A power generation device comprising the power generation system according to any one of claims 1 to 4. <9> A method of generating electricity in which droplets of a continuously supplied liquid are supplied to a power generation layer equipped with electrodes, and the droplets are moved over an upper surface of the power generation layer to extract electrical energy from the electrodes, wherein the droplets are condensed onto the power generation layer. <10> The power generation layer is provided with the electrodes on the upper surface and / or the lower surface. <9> The power generation method according to claim 1.

[0100] the above <1> from <6> Any of the power generation systems listed above. <7> The storage device <8> The power generating device, <9> or <10> According to this power generation method, the conventional problems can be solved and the object of the present invention can be achieved. [Explanation of symbols]

[0101] 1. Power generation system 10 Power generation layer 11 electrodes 12 electrodes 13 Resistance 14 Droplet formation part 15 Grand 16 Base material 17 Convex body 20 Continuously supplied liquid 21 droplets 22 Silica membrane 23 Aluminum Surface 24 Fine uneven structure [Prior art documents] [Patent documents]

[0102] [Patent Document 1] U.S. Patent No. 11,239,768

Claims

1. A power generation system having a droplet forming unit and a power generation layer having an electrode, the droplet forming unit is formed in contact with the power generation layer, and supplies droplets obtained by forming a continuously supplied liquid into droplets to the power generation layer; The power generation layer moves the droplets on an upper surface of the power generation layer to extract electrical energy from the electrodes.

2. The droplet forming unit includes: The power generation system of claim 1, wherein the power generation layer is made of a material having a larger contact angle with the liquid than the power generation layer, and the liquid is turned into droplets by at least one of the following: vibrating the liquid; branching a continuous flow of the liquid with a convex body; and interrupting the continuous flow of the liquid with a convex body.

3. The power generation system according to claim 1 or 2, wherein the liquid is water, an aqueous solution, a colloidal solution, or an oil.

4. The power generation system according to claim 2 , wherein the material having a larger contact angle with the liquid than the power generation layer is a super water-repellent material.

5. the droplet forming portion is formed of a material having a larger contact angle with the liquid than the power generation layer, The power generation system according to claim 1 , wherein the value of (static contact angle between the liquid and the power generation layer) / (static contact angle between the liquid and a material having a larger contact angle with the liquid than the power generation layer) is 0.75 or less.

6. The power generation system according to claim 1 or 2, further comprising the electrode on an upper surface and / or a lower surface of the power generation layer.

7. A power storage device comprising the power generation system according to claim 1 or 2.

8. A power generation device comprising the power generation system according to claim 1 or 2.

9. A power generation method comprising: supplying droplets of a continuously supplied liquid to a power generation layer having electrodes; and moving the droplets on an upper surface of the power generation layer to extract electrical energy from the electrodes, the method comprising the steps of: The power generating method, wherein the droplets are condensed on the power generating layer.

10. The power generating method according to claim 9 , wherein the power generating layer has the electrode on an upper surface and / or a lower surface.

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