Power generation element, and method of manufacturing power generation element

Abstract

To provide a power generation element which does not need to be charged with an external voltage and is capable of improving power generation efficiency despite compactness and light weight, and a method of manufacturing a power generation element.SOLUTION: In a power generation element 1, a substrate layer 10 containing moisture, a first charged layer 20 containing silicon dioxide and a first metal layer 40 containing a predetermined kind of metal on one face of the substrate layer 10 are successively laminated in a lamination direction, and a second charged layer 30 containing silicon dioxide and a second metal layer 50 containing a predetermined kind of metal of which the ionization tendency is smaller than that of the metal contained in the first metal layer 40 are successively laminated in the lamination direction on the other face of the substrate layer 10. Minus ions emitted from the first metal layer 40 are taken into the first charged layer 20 and the second charged layer 30 and a current can be extracted with electron movements from the first metal layer 40 the second metal layer 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power generating element and a method for manufacturing the power generating element. More specifically, the present invention relates to a power generating element that does not require charging with an external voltage, is small and lightweight, and yet can improve power generation efficiency, and a method for manufacturing the power generating element. [Background technology]

[0002] In recent years, demand for electrical devices, such as mobile phones, smartphones, and laptop personal computers, has been increasing rapidly, making this a field expected to see further growth in the future. Along with the widespread use of such electrical devices, research and development of power storage devices, which act as a driving source, has also been actively pursued. Furthermore, growing concerns about global environmental issues and petroleum resource issues have led to the rise of attention being paid to next-generation clean energy vehicles, such as hybrid electric vehicles (HEVs), electric vehicles (EVs), and plug-in hybrid electric vehicles (PHEVs). The importance of power storage devices will continue to grow in a variety of applications.

[0003] Generally, lead-acid batteries and nickel-cadmium batteries have been used as power storage devices up until now, but regulations on batteries containing such hazardous heavy metals are gradually becoming stricter due to the demands of an environmentally conscious society. Furthermore, with the widespread use of compact mobile information terminals, there is an increasing demand for higher energy density, higher voltage, higher output, longer life, smaller size and weight, and lower cost. As a result, new power storage devices such as lithium-ion batteries, electric double-layer capacitors, and lithium-ion capacitors have been developed and are becoming more widespread.

[0004] A lithium-ion battery generally comprises a positive electrode in which a positive electrode active material and the like are applied to both sides of a positive electrode current collector using a binder, and a negative electrode in which a negative electrode active material and the like are applied to both sides of a negative electrode current collector using a binder, the positive electrode and the negative electrode being connected via an electrolyte layer and housed in a battery exterior material. For example, Patent Document 1 describes a lithium-ion battery with a stacked structure in which 19 positive electrodes and 20 negative electrodes are alternately stacked with electrolyte layers between them.

[0005] Furthermore, Patent Document 2 discloses a power supply device that charges a secondary battery with electricity generated by a power generating element and uses it as auxiliary energy. Specifically, electricity generated by a piezoelectric element is charged into a secondary battery or a capacitor, and this electrical energy is used as auxiliary energy for the power supply battery of a mobile terminal, thereby realizing long-term use of the mobile terminal.

[0006] Lithium-ion batteries, which operate on a chemical reaction (Faraday reaction), have the drawbacks of high internal resistance and poor durability, despite their excellent energy density. Therefore, in devices using lithium-ion batteries, losses due to internal resistance are significant, making it difficult to efficiently charge the minute amounts of power generated by the power generation element. Furthermore, their poor durability in high-temperature environments and repeated charging and discharging requires maintenance, such as replacement every so often.

[0007] Furthermore, because capacitors operate not through chemical reactions but through the electrostatic adsorption of ions in an electrolyte, they have excellent internal resistance and durability. However, they also self-discharge quickly due to the diffusion of adsorbed ions, so the accumulated charge quickly disappears. Therefore, if power generation by the power generation element is intermittent and the power generation interval is long, there is a possibility that the discharge from the storage device will not function properly.

[0008] Furthermore, although the service life of the above-mentioned lithium-ion batteries and capacitors varies depending on the application and method of use, they will inevitably reach the end of their lifespan, and for example, lithium-ion batteries installed in hybrid vehicles and electric vehicles will eventually be discarded as used batteries. When disposing of these used lithium-ion batteries, valuable metals contained in each component are recovered and recycled as resources, but the reality is that most are discarded as industrial waste, which places a heavy burden on the environment. Therefore, in recent years, there has been a demand for the development of energy storage devices with a low environmental impact.

[0009] In this regard, Patent Document 3 discloses a power generating element that is manufactured from volcanic ash, which has a large amount of static electricity, and does not require disposal. Specifically, a static electricity generating member made of fine hollow spheres processed from volcanic ash, other minerals, and activated mineral water containing negative ions, as well as conductive water-containing powder made of activated carbon, fullerenes, nanotubes, etc., are filled into an insulating, airtight cylindrical container, and an anode electrode and a cathode electrode for extracting electricity are connected to both ends of the container, thereby realizing the generation of a large amount of electricity despite its small size.

[0010] Furthermore, as shown in Patent Document 4, the inventors of the present application discovered that shirasu balloons, which are made by baking shirasu, a volcanic ejecta, at a high temperature of approximately 1000°C to foam and expand them, have the property of absorbing a large amount of negative ions. Based on this knowledge, they developed a power generation element consisting of a laminated structure in which shirasu balloons are sandwiched between metals with different ionization tendencies, thereby realizing a technology that can stably extract current for long periods of time. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-272048 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-171341 [Patent Document 3] Special Publication No. 2005-502180 [Patent Document 4] Patent No. 6547082 Summary of the Invention [Problem to be solved by the invention]

[0012] According to the inventions disclosed in Patent Documents 3 and 4, the power generating element is made of volcanic ash and shirasu as its main materials, and therefore does not require special disposal, resulting in a low environmental impact and a pollution-free, clean power generating element.

[0013] However, in the invention of Patent Document 3, attention is focused on the ion exchange properties of allophane contained in volcanic ash, and the volcanic ash is impregnated with an aqueous solution of negative ions to form a static electricity generating member, and the static electricity generated by the static electricity generating member is extracted as electromotive force. Therefore, whenever the amount of accumulated static electricity decreases, it is necessary to add an aqueous solution of negative ions.

[0014] Furthermore, when generating a negative ion solution, for example, if tap water is used, it is necessary to reduce the molecular clusters contained in the tap water and turn them into negative ions. However, this generally requires the use of special substances such as ceramic chips or tourmaline, and the manufacturing process is also complicated, making it difficult to secure a sufficient amount of negative ion solution.

[0015] Furthermore, the inventor's research has revealed that volcanic ash contains elements such as silicon and aluminum, gas components such as halogen elements such as fluorine and chlorine, and sulfur, as well as trace metal elements such as copper, zinc, cadmium, and mercury. However, due to the presence of these impurities, although a large electromotive force can be generated temporarily, the effect is short-lived, necessitating the frequent addition of an aqueous solution of negative ions.

[0016] In this regard, the invention of Patent Document 4 requires a certain amount of water to absorb negative ions into the balloon holes formed in the shirasu balloon layer, but the aqueous solution used does not need to be specially processed, and any type of water, including tap water, can be used, which makes it more versatile and allows for stable extraction of current over long periods of time.

[0017] On the other hand, the inventors of the present application have researched materials with even higher power generation efficiency and have discovered that a power generation element with even higher power generation efficiency can be realized by using silicon dioxide (SiO2) as a material to replace the shirasu balloons disclosed in Patent Document 4.

[0018] The present invention has been devised in view of the above points, and aims to provide a power generation element that does not require charging with an external voltage, is small and lightweight, and yet can improve power generation efficiency, as well as a method for manufacturing the power generation element. [Means for solving the problem]

[0019] In order to achieve the above-mentioned object, the power generation element of the present invention comprises a substrate layer containing moisture, a first electrostatic layer containing silicon dioxide, and a first metal layer containing a predetermined type of metal stacked in this order on one surface of the substrate layer, and a second electrostatic layer containing silicon dioxide and a second metal layer containing a predetermined type of metal that has a lower ionization tendency than the metal contained in the first metal layer stacked in this order on the other surface of the substrate layer.

[0020] Here, by providing a base layer, a vapor deposition material can be attached to the base layer to form a power generating element made of a thin film. Furthermore, since the base layer contains moisture, electrons can be efficiently transferred from the first metal layer to the second metal layer (described later), thereby improving power generation efficiency.

[0021] Furthermore, by stacking a first electrostatic layer containing silicon dioxide and a first metal layer containing a predetermined type of metal in this order in the stacking direction on one side of the base material layer, for example, by using a metal with a relatively high ionization tendency as the first metal layer, it is possible to charge a large number of negative ions in the first electrostatic layer while leaving electrons in the first metal layer.

[0022] In this case, since the first charged layer contains silicon dioxide, silicon dioxide forms a spherical surface with a large surface area, and a large amount of negative ions can be charged onto this surface, thereby increasing the power generation efficiency.

[0023] Furthermore, a second electrostatic layer containing silicon dioxide and a second metal layer containing a predetermined type of metal with a lower ionization tendency than the metal contained in the first metal layer are stacked in this order on the other surface of the base layer, thereby generating an electromotive force. That is, in the first metal layer, electrons increase by the amount of negative ions absorbed by the first and second electrostatic layers. At this time, by conducting the first and second metal layers, the electrons generated in the first metal layer move to the second metal layer, resulting in a current flowing between the first and second metal layers and generating an electromotive force.

[0024] Furthermore, when the first and second electrostatically charged layers are formed by stacking a tuff layer made of tuff or welded tuff and a silicon dioxide layer made of silicon dioxide from the base layer in the stacking direction, the tuff layer can be charged with negative ions in addition to the silicon dioxide layer. Furthermore, tuff has a large surface area due to the formation of many micropores, and can capture many negative ions into these micropores.

[0025] Furthermore, when the first metal layer is a layer made of at least one metal selected from the group consisting of aluminum, titanium, zinc, chromium, iron, nickel, and lead, by placing a metal with a relatively high ionization tendency as the first metal layer, more negative ions can be absorbed into the charged layer, thereby improving power generation efficiency.

[0026] Furthermore, when the second metal layer is a layer made of at least one metal selected from the group consisting of gold, silver, copper, and platinum, a greater electromotive force can be generated by stacking a metal having a lower ionization tendency than the first metal layer as the second metal layer.

[0027] In order to achieve the above object, the power generating element of the present invention comprises an electrostatic charging layer containing silicon dioxide; The electrostatic charging device comprises a first metal layer laminated on one side of the electrostatic charging layer and containing a predetermined type of metal, a second metal layer laminated on the other side of the electrostatic charging layer and containing a predetermined type of metal that has a lower ionization tendency than the metal contained in the first metal layer, a first water-retaining layer laminated on the first metal layer and containing moisture, and a second water-retaining layer laminated on the second metal layer and containing moisture.

[0028] Here, by providing an electrostatically charged layer containing silicon dioxide, silicon dioxide forms a spherical surface with a large surface area, and a large amount of negative ions can be charged onto this surface, thereby increasing the power generation efficiency.

[0029] Furthermore, by providing a first metal layer containing a predetermined type of metal laminated on one side of the charged layer, and using a metal with a relatively high ionization tendency as the first metal layer, it is possible to charge the charged layer with many negative ions while leaving electrons in the first metal layer.

[0030] Furthermore, by providing a second metal layer, which is laminated on the other surface of the charged layer and contains a specific type of metal with a lower ionization tendency than the metal contained in the first metal layer, electrons increase in the first metal layer by the amount of negative ions absorbed by the charged layer. At this time, by conducting the first and second metal layers together, the electrons generated in the first metal layer move to the second metal layer, causing a current to flow between the first and second metal layers and generating an electromotive force.

[0031] In addition, by providing a first water-retaining layer that is laminated on the first metal layer and contains moisture, and a second water-retaining layer that is laminated on the second metal layer and contains moisture, electrons can efficiently move from the first metal layer to the second metal layer via the first water-retaining layer and the second water-retaining layer, thereby improving power generation efficiency.

[0032] Furthermore, when the electrostatic layer contains tuff or welded tuff in a weight ratio of 0.25 to 0.5 for every 1 weight ratio of silicon dioxide, the mixture ratio of silicon dioxide to tuff or welded tuff becomes appropriate, thereby improving power generation efficiency.

[0033] In order to achieve the above-mentioned object, the manufacturing method of the power generation element of the present invention includes the steps of preparing a substrate layer containing moisture, depositing a first electrostatic layer containing silicon dioxide on one surface of the substrate layer, depositing a second electrostatic layer containing silicon dioxide on the other surface of the substrate layer, depositing a first metal layer containing a predetermined type of metal on the surface of the first electrostatic layer opposite to the surface facing the substrate layer, and depositing a second metal layer containing a predetermined type of metal having a lower ionization tendency than the metal contained in the first metal layer on the surface of the second electrostatic layer opposite to the surface facing the substrate layer.

[0034] Here, by providing a step of preparing a substrate layer containing moisture, it is possible to produce a power generating element made of a thin film by depositing the charging layer and the substrate layer described below on both sides of the substrate layer.

[0035] Furthermore, by including a step of depositing a first charged layer containing silicon dioxide on one surface of the base layer and a step of depositing a second charged layer containing silicon dioxide on the other surface of the base layer, charged layers can be stacked on both sides of the base layer. Because this charged layer contains silicon dioxide, a large amount of negative ions can be charged onto the spherical surface of the silicon dioxide, thereby improving power generation efficiency.

[0036] Furthermore, the method includes a step of depositing a first metal layer containing a predetermined type of metal on the surface of the first electrostatic layer opposite the surface facing the substrate layer, and a step of depositing a second metal layer containing a predetermined type of metal with a lower ionization tendency than the metal contained in the first metal layer on the surface of the second electrostatic layer opposite the surface facing the substrate layer, thereby enabling the first metal layer and the second metal layer to be laminated. The first metal layer then gains electrons by the amount of negative ions absorbed by the electrostatic layer. By electrically connecting the first metal layer and the second metal layer, the electrons generated in the first metal layer move to the second metal layer, resulting in a current flowing between the first metal layer and the second metal layer, generating an electromotive force.

[0037] Furthermore, if the process of depositing the first and second charged layers onto the base layer includes a process of depositing a tuff layer made of tuff or welded tuff and a silicon dioxide layer made of silicon dioxide from the base layer in the stacking direction, the tuff layer and the silicon dioxide layer can each be charged with negative ions, thereby further improving power generation efficiency.

[0038] In order to achieve the above-mentioned object, the manufacturing method of the power generation element of the present invention includes the steps of: generating an electrostatically charged layer containing silicon dioxide; stacking a first metal layer on one side of the electrostatically charged layer; stacking a second metal layer having a lower ionization tendency than the first metal layer on the other side of the electrostatically charged layer; stacking a first moisture-retaining layer capable of absorbing moisture on either the surface of the first metal layer facing the electrostatic layer or the surface opposite to the surface facing the electrostatic layer; and stacking a second moisture-retaining layer capable of absorbing moisture on either the surface of the second metal layer facing the electrostatic layer or the surface opposite to the surface facing the electrostatic layer.

[0039] Here, by including a step of generating a charged layer containing silicon dioxide, the charged layer contains silicon dioxide, and therefore a large amount of negative ions can be charged onto the spherical surface of the silicon dioxide, thereby making it possible to increase power generation efficiency.

[0040] Furthermore, by including a step of stacking a first metal layer on one side of the charged layer and a step of stacking a second metal layer, which has a lower ionization tendency than the first metal layer, on the other side of the charged layer, the first metal layer and the second metal layer can be stacked on either side of the charged layer. The first metal layer then gains electrons by the amount of negative ions absorbed by the charged layer. By electrically connecting the first metal layer and the second metal layer, the electrons generated in the first metal layer move to the second metal layer, resulting in a current flowing between the first metal layer and the second metal layer, generating an electromotive force.

[0041] In addition, by laminating a first moisture-absorbing layer on either the surface of the first metal layer facing the charged layer or the surface opposite to the surface facing the charged layer, and by providing a second moisture-absorbing layer on either the surface of the second metal layer facing the charged layer or the surface opposite to the surface facing the charged layer, electrons can efficiently move from the first metal layer to the second metal layer via the first moisture-retaining layer and the second moisture-retaining layer, thereby improving power generation efficiency.

[0042] Furthermore, if the process of generating the electrocharged layer includes a process of mixing tuff or welded tuff in a weight ratio of 0.25 to 0.5 with silicon dioxide in a weight ratio of 1, the mixing ratio of silicon dioxide to tuff or welded tuff becomes appropriate, and power generation efficiency can be improved. [Effects of the Invention]

[0043] The power generating element and the method for manufacturing the power generating element according to the present invention do not require charging with an external voltage, and are small and lightweight, yet can increase power generation efficiency. [Brief explanation of the drawings]

[0044] [Figure 1] 1 is a cross-sectional view schematically showing a power generating element according to a first embodiment of the present invention. [Figure 2] 1A to 1C are diagrams illustrating an application example using the power generating element according to the first embodiment of the present invention. [Figure 3] FIG. 4 is a cross-sectional view schematically showing a power generating element according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0045] Hereinafter, embodiments of the present invention will be described with reference to the drawings to facilitate understanding of the present invention.

[0046] [First embodiment] First, the configuration of a power generating element 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. As shown in Fig. 1, the power generating element 1 is in the form of a thin film sheet in which a first electrostatic layer 20 and a first metal layer 40 made of a metal with a high ionization tendency are stacked in the stacking direction on one surface of a base material layer 10, and a second electrostatic layer 30 and a second metal layer 50 made of a metal with a low ionization tendency are stacked in the stacking direction on the other surface of the base material layer 10.

[0047] The first electrostatically charged layer 20 is made of tuff or welded tuff (hereinafter referred to as "tuff, etc.") and is composed of a first tuff layer 21 having a thickness of 10 nm or more, and a first silicon dioxide layer 22 having a thickness of 10 nm or more and composed primarily of silicon dioxide. The second electrostatically charged layer 30 is made of tuff, etc. and is composed of a second tuff layer 31 having a thickness of 10 nm or more, and a second silicon dioxide layer 32 having a thickness of 10 nm or more and composed primarily of silicon dioxide. In other words, the first electrostatically charged layer 20 and the second electrostatically charged layer 30 have the same configuration and are composed of a thickness of 20 nm or more.

[0048] In the following description, the first charged layer 20 and the second charged layer 30 may be collectively referred to as the "charged layers," the first silicon dioxide layer 22 and the second silicon dioxide layer 32 may be collectively referred to as the "silicon dioxide layers," and the first tuff layer 21 and the second tuff layer 31 may be collectively referred to as the "tuff layers."

[0049] The first tuff layer 21 and the second tuff layer 31 are formed by foaming tuff or the like by heating it at a high temperature of approximately 1000 to 1500°C, and then forming thin films on one and the other surfaces of the base material layer 10. When tuff or the like is foamed by heating it at a high temperature, many bubbles are formed, which increases the overall surface area and makes it possible to charge it with more negative ions.

[0050] Furthermore, when forming the power generating element 1 into a thin film, deposition by sputtering is generally performed, but the material to be deposited on the base material layer 10 must be a relatively hard substance. In this regard, heat-treated tuff, etc., has a certain degree of hardness and is an ideal material for deposition by sputtering.

[0051] The first silicon dioxide layer 22 and the second silicon dioxide layer 32 are composed primarily of silicon dioxide (with a purity of 50% or more). Because the surface of silicon dioxide is spherical, it has a large surface area and can be charged with a larger number of negative ions. Like the tuff layer, the silicon dioxide layer is also formed into a thin film by vapor deposition onto the tuff layer using sputtering.

[0052] Here, the charged layer does not necessarily have to be composed of two layers, a tuff layer and a silicon dioxide layer. The inventors' investigations revealed that a silicon dioxide layer has a higher ability to charge negative ions than a tuff layer, so the charged layer may be composed of only a silicon dioxide layer. When the charged layer is composed of only a silicon dioxide layer, silicon dioxide is vapor-deposited on one surface of the base layer 10 to a thickness of 20 nm or more to form a first silicon dioxide layer 22, and silicon dioxide is vapor-deposited on the other surface of the base layer 10 to a thickness of 20 nm or more to form a second silicon dioxide layer 32.

[0053] Furthermore, the electrostatically charged layer does not necessarily have to have a tuff layer and a silicon dioxide layer stacked in this order in the stacking direction; for example, the silicon dioxide layer and the tuff layer may be stacked in this order, starting from the base layer 10. However, as described above, when forming a thin film on the base layer 10 by sputtering, it is preferable to vapor-deposit a material with as high a hardness as possible onto the base layer 10. Therefore, it is preferable to vapor-deposit a tuff layer, which is a material with a higher hardness, onto the base layer 10.

[0054] Furthermore, the thickness of each of the first charged layer 20 and the second charged layer 30 is not limited to 20 nm or more. However, repeated investigations by the inventors have revealed that if the total thickness of the charged layer is less than 40 nm, the surface area becomes relatively small and it is not possible to absorb all of the negative ions emitted from the first metal layer 40, which may result in a failure to generate a stable electromotive force.

[0055] On the other hand, it was confirmed that when the total thickness of the charged layer is 40 nm or more, a stable electromotive force is generated, and that even if the thickness is changed within a range of, for example, 40 nm or more, there is no significant difference in the generated electromotive force. Therefore, the lower limit of the thickness of each of the first charged layer 20 and the second charged layer 30 is preferably 20 nm, and the upper limit of the thickness of each of the first charged layer 20 and the second charged layer 30 is preferably about 700 nm from the viewpoint of size and weight reduction.

[0056] In this embodiment of the present invention, aluminum is selected as the first metal layer 40 because it has a higher ionization energy than hydrogen and is easily immersed in water or acid. The first metal layer 40 is formed by depositing aluminum on the first charged layer 20 by sputtering, resulting in a thin film of 20 nm or more.

[0057] Here, the type of first metal layer 40 does not necessarily have to be aluminum. As described above, any type of metal may be used as long as it has a higher ionization energy than hydrogen and is easily corroded by water or acid, and may be at least one metal selected from, for example, titanium, zinc, chromium, iron, nickel, lead, etc.

[0058] Furthermore, the thickness of first metal layer 40 does not necessarily need to be approximately 20 nm, but the inventors' repeated investigations have shown that a stable electromotive force cannot be generated when the thickness of first metal layer 40 is less than 20 nm. This is thought to be because when first metal layer 40 is a thin film less than 20 nm, fewer negative ions are generated in first metal layer 40.

[0059] On the other hand, when the thickness of the first metal layer 40 is 20 nm or more, it was confirmed that a stable electromotive force is generated, and that even if the film thickness of the first metal layer 40 is changed within a range of, for example, 20 nm or more, there is no significant difference in the amount of electromotive force generated. Therefore, the lower limit of the film thickness of the first metal layer 40 is preferably 20 nm, and the upper limit of the film thickness of the first metal layer 40 is preferably about 700 nm from the viewpoint of size and weight reduction.

[0060] In the embodiment of the present invention, copper is selected for the second metal layer 50 as a metal having a lower ionization energy than hydrogen (i.e., a metal having a lower ionization tendency than the metal material selected for the first metal layer 40). The second metal layer 50 is formed by depositing copper on the second electrostatic charging layer 30 by sputtering, resulting in a thin film of 20 nm or more.

[0061] Here, the type of second metal layer 50 does not necessarily have to be copper. As described above, any type of metal may be used as long as it has a lower ionization energy than hydrogen, and for example, in addition to copper, it may be at least one metal selected from gold, silver, copper, platinum, etc.

[0062] Furthermore, the thickness of the second metal layer 50 does not necessarily need to be approximately 20 nm, but the inventors' repeated investigations have shown that a stable electromotive force cannot be generated when the film thickness of the second metal layer 50 is less than 20 nm. This is thought to be because when the second metal layer 50 is a thin film less than 20 nm, the amount of electrons received from the first metal layer 40 decreases.

[0063] On the other hand, when the thickness of the second metal layer 50 is 20 nm or more, it has been confirmed that a stable electromotive force is generated, and that even if the film thickness of the second metal layer 50 is changed within a range of, for example, 20 nm or more, there is no significant difference in the amount of electromotive force generated. Therefore, the lower limit of the film thickness of the second metal layer 50 is preferably 20 nm, and the upper limit of the film thickness of the second metal layer 50 is preferably about 700 nm from the viewpoint of reducing size and weight.

[0064] The base layer 10 is thin, approximately 20 nm thick, and is made of a paper material capable of absorbing moisture from the atmosphere, serving as the base material when each layer is deposited by sputtering. Because the base layer 10 is made of a material capable of absorbing moisture from the atmosphere, it always contains a certain amount of moisture. Then, negative ions generated from the first metal layer 40 can be used as a medium to charge the charging layer via the water molecules absorbed in the base layer 10.

[0065] Here, the thickness of the base material layer 10 does not need to be 20 nm, but if the thickness is less than 20 nm, the amount of moisture absorbed by the base material layer 10 will be small, which may result in a relative decrease in negative ions that charge the charging layer from the first metal layer 40, resulting in a risk of a decrease in power generation capacity. Therefore, it is preferable to ensure that the thickness of the base material layer 10 is 20 nm or more, and from the perspective of reducing size and weight, the upper limit of the thickness is preferably around 700 nm.

[0066] Furthermore, as described above, the base layer 10 can absorb moisture from the atmosphere, but a predetermined aqueous solution may also be supplied using a dropper, etc. Note that, as long as the base layer 10 can contain a certain amount of moisture, any aqueous solution, including tap water, can be used.

[0067] As described above, by using the base layer 10 as the base material and depositing each layer by sputtering to form a thin film, a power generating element 1 can be obtained that is small and lightweight yet has excellent power generating capacity, and can therefore be used, for example, as a thin battery for mobile devices.

[0068] 2 is a diagram showing an application example using the power generating element 1 according to the first embodiment. Two power generating elements 1a and 1b are prepared and connected in series via an insulating layer 60, thereby enabling an increase in capacity.

[0069] That is, the second metal layer 50a, which is the positive electrode of the power generating element 1a, and the first metal layer 40b, which is the negative electrode of the power generating element 1b, are connected by a conductor W. Furthermore, a terminal T for taking out electricity is connected to the first metal layer 40a, which is the negative electrode of the power generating element 1a, and the second metal layer 50b, which is the positive electrode of the power generating element 1b, respectively. This makes it possible to achieve twice the power generation performance compared to a single power generating element 1. Note that, to further improve the power generation performance, it is also possible to connect three or more power generating elements in series.

[0070] [Second embodiment] Next, a power generating element 100 according to a second embodiment will be described. Note that descriptions that overlap with those of the first embodiment will be omitted. The power generating element 100 according to the second embodiment is easier to manufacture than the first embodiment in which thin films are formed by vapor deposition using sputtering, since each layer constituting the power generating element 100 is formed by adhesive lamination or the like.

[0071] As shown in Figure 3, the power generation element 100 of the second embodiment is composed of an electrostatic layer 110, a first metal layer 120 laminated on one side of the electrostatic layer 110, a second metal layer 130 laminated on the other side of the electrostatic layer 110, a first water retention layer 140 laminated on the side of the first metal layer 120 opposite to the side facing the electrostatic layer 110, and a second water retention layer 150 laminated on the side of the second metal layer 130 opposite to the side facing the electrostatic layer 110.

[0072] The material of the charged layer 110 is primarily powdered silicon dioxide, which may be mixed with powdered tuff or the like that has been foamed by heat treatment at a high temperature of approximately 1000 to 1500°C, as needed. The optimum power generation efficiency is achieved by mixing silicon dioxide and tuff or the like at a weight ratio of 1 part silicon dioxide to 0.25 to 0.5 parts tuff or the like.

[0073] Furthermore, as a result of investigations by the inventors, it is preferable to set the upper limit of the particle size of the powdered silicon dioxide, tuff, etc. that make up the charged layer 110 to about 500 μm. In other words, if the particle size of the silicon dioxide, tuff, etc. that make up the charged layer 110 is larger than 500 μm, the gaps between adjacent particles will become larger, and the amount of negative ions that charge the charged layer 110 will decrease, which may result in a deterioration in the power generation efficiency of the power generating element 100.

[0074] A first metal layer 120 and a second metal layer 130 are respectively laminated and adhesively attached to one surface and the other surface of the charging layer 110. In this embodiment of the present invention, the first metal layer 120 is selected to be aluminum, which has a higher ionization energy than hydrogen and is easily immersed in water or acid.

[0075] Here, the type of first metal layer 120 does not necessarily have to be aluminum. As described above, any type of metal may be used as long as it has a higher ionization energy than hydrogen and is easily corroded by water or acid, and may be, for example, aluminum or at least one metal selected from magnesium, titanium, zinc, chromium, iron, nickel, lead, etc.

[0076] In the embodiment of the present invention, copper is selected for the second metal layer 130 as a metal having an ionization energy lower than that of hydrogen (that is, a metal having a lower ionization tendency than the metal material selected for the first metal layer 120).

[0077] Here, the type of second metal layer 130 does not necessarily have to be copper. As described above, any type of metal may be used as long as it has a lower ionization energy than hydrogen, and for example, in addition to copper, it may be at least one metal selected from gold, silver, copper, platinum, etc.

[0078] First water retention layer 140 and second water retention layer 150 are each made of a paper material that can absorb moisture, and because these are materials that can absorb moisture from the atmosphere, a certain amount of moisture is always contained in power generation element 100. Then, negative ions generated from first metal layer 120 can be charged onto charged layer 110 via the water molecules absorbed by first water retention layer 140 and second water retention layer 150.

[0079] Furthermore, even if the moisture content of the power generating element 100 decreases, since the first water retention layer 140 and the second water retention layer 150 are adhesively laminated around the power generating element 100, it is easy to supply a specified aqueous solution as needed using a dropper or the like.

[0080] Here, the first water retention layer 140 and the second water retention layer 150 are not necessarily limited to the arrangement described above, and the first water retention layer 140 may be laminated on either side of the first metal layer 120, and the second water retention layer 150 may be laminated on either side of the second metal layer 130.

[0081] As described above, by forming each layer by adhesive lamination, it is possible to easily manufacture a power generating element 1 with excellent power generation capacity. Furthermore, since the power generating element 100 is larger than the power generating element 1 according to the first embodiment, it can be used as a large-capacity battery, such as a battery for an automobile.

[0082] [Example] Next, examples of the power generating element of the present invention will be described. The power generating element used in the examples was formed into a thin film by vapor deposition using sputtering, as shown in the power generating element 1 of the first embodiment of the present invention. A first tuff layer 21 and a first silicon dioxide layer 22 were each vapor-deposited on one surface of a base layer 10 having a thickness of 20 nm and containing a predetermined amount of water (approximately 2 to 5 drops with a dropper) to form a first electrostatic layer 20. The first tuff layer 21 and the first silicon dioxide layer 22 were each formed to a film thickness of 10 nm. A second tuff layer 31 and a second silicon dioxide layer 32 were each vapor-deposited on the other surface of the base layer 10 to form a second electrostatic layer 30. The second tuff layer 31 and the second silicon dioxide layer 32 were each formed to a film thickness of 10 nm.

[0083] The first tuff layer 21 and the second tuff layer 31 use powder made by heating and foaming tuff at approximately 1300°C. The silicon dioxide layers made up of the first silicon dioxide layer 22 and the second silicon dioxide layer 32 are classified into Example 1 (purity 100%), Example 2 (purity 50%), and Comparative Example (purity 20%) according to the purity of the silicon dioxide.

[0084] In addition, a first metal layer 40 made of aluminum was laminated to a thickness of 20 nm on the surface of the first silicon dioxide layer 22 opposite to the surface facing the first tuff layer 21, and a second metal layer 50 made of copper was laminated to a thickness of 20 nm on the surface of the second silicon dioxide layer 32 opposite to the surface facing the second tuff layer 31.

[0085] For the power generating elements 1 according to the above-described Example 1, Example 2, and Comparative Example, a resistor of a predetermined size was connected between the first metal layer 40 and the second metal layer 50 to measure the voltage. Table 1 shows time-series data of the measurement results of voltage (V) for 20 days from the start of measurement.

[0086] [Table 1]

[0087] As shown in Table 1, it was confirmed that the higher the purity of the silicon dioxide, the more stable the power generation over the long term. In particular, in Example 1 (silicon dioxide purity 100%), the power generation capacity did not deteriorate significantly even after 20 days had passed since the start of measurement. On the other hand, in the case of the comparative example (silicon dioxide purity less than 20%), the power generation capacity was reduced to about half after 5 days had passed since the start of measurement, confirming that the power generation element deteriorated more quickly. From the above examples and comparative examples, the superiority of the power generation element 1 according to the present invention can be confirmed.

[0088] As described above, the power generating element and the method for manufacturing the power generating element according to the present invention do not require charging with an external voltage, and can improve power generation efficiency while being small and lightweight. [Explanation of symbols]

[0089] 1,100 power generating element 10 Base material layer 20 First charged layer 21 First Tuff Layer 22 First silicon dioxide layer 30 Second charging layer 31 Second Tuff Layer 32 Second silicon dioxide layer 40, 120 1st metal layer 50, 130 second metal layer 60 insulating layer 110 Charged layer 140 First Water Retaining Layer 150 Second Water Retaining Layer W Conductive Wire T terminal

Claims

1. a substrate layer containing moisture; a first electrostatic layer including silicon dioxide and a first metal layer including a predetermined type of metal are stacked in this order in a stacking direction on one surface of the base material layer; A second electrostatic layer containing silicon dioxide and a second metal layer containing a predetermined type of metal having a lower ionization tendency than the metal contained in the first metal layer are stacked in this order in a stacking direction on the other surface of the base material layer. Power generating element.

2. The first electrostatic layer is A first tuff layer made of tuff or welded tuff and a first silicon dioxide layer made of silicon dioxide are laminated on one surface of the base layer, The second electrostatic layer is A second tuff layer made of tuff or welded tuff and a second silicon dioxide layer made of silicon dioxide are laminated on the other surface of the base layer. The power generating element according to claim 1 .

3. the first metal layer is made of at least one metal selected from the group consisting of aluminum, titanium, zinc, chromium, iron, nickel, and lead; The second metal layer is made of at least one metal selected from the group consisting of gold, silver, copper, and platinum. The power generating element according to claim 1 or 2.

4. an antistatic layer comprising silicon dioxide; a first metal layer laminated on one surface of the charging layer and containing a predetermined type of metal; a second metal layer laminated on the other surface of the charging layer and containing a predetermined type of metal having a lower ionization tendency than the metal contained in the first metal layer; a first water retention layer laminated on the first metal layer and containing moisture; a second water retention layer laminated on the second metal layer and containing moisture; Power generating element.

5. The charging layer is The weight ratio of the silicon dioxide to the tuff or welded tuff is 0.25 to 0.

5. The power generating element according to claim 4 .

6. providing a substrate layer containing moisture; depositing a first electrostatic layer comprising silicon dioxide on one surface of the substrate layer; depositing a second electrostatic layer comprising silicon dioxide on the other side of the substrate layer; a step of depositing a first metal layer containing a predetermined type of metal on a surface of the first electrostatic layer opposite to a surface facing the base material layer; and depositing a second metal layer containing a predetermined type of metal having a lower ionization tendency than the metal contained in the first metal layer on a surface of the second electrostatic layer opposite to the surface facing the base material layer. Manufacturing method of power generating element.

7. The step of depositing the first electrostatic layer on the substrate layer includes: The method includes a step of depositing a first tuff layer made of tuff or welded tuff and a first silicon dioxide layer made of silicon dioxide from the base layer in a stacking direction, The step of depositing the second electrostatic layer on the substrate layer comprises: a step of depositing a second tuff layer made of tuff or welded tuff and a second silicon dioxide layer made of silicon dioxide from the base layer in the stacking direction. The method for manufacturing the power generating element according to claim 6 .

8. forming an electrostatic layer comprising silicon dioxide; laminating a first metal layer on one surface of the charging layer; a step of stacking a second metal layer having a lower ionization tendency than the first metal layer on the other surface of the charging layer; a step of laminating a first moisture-retaining layer capable of absorbing moisture on either a surface of the first metal layer facing the electrostatic layer or a surface opposite to the surface facing the electrostatic layer; and laminating a second moisture-retaining layer capable of absorbing moisture on either the surface of the second metal layer facing the charged layer or the surface opposite to the surface facing the charged layer. Manufacturing method of power generating element.

9. The step of forming the charged layer comprises: and mixing tuff or welded tuff in a weight ratio of 0.25 to 0.5 with respect to a weight ratio of 1 of the silicon dioxide. The method for manufacturing a power generating element according to claim 8 .

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