Power generation element and method for manufacturing power generation element

Abstract

[Problem] The purpose of the present invention is to provide a power generation element that does not need to be charged using an external voltage and can improve power generation efficiency while being reduced in size and weight, and a method for manufacturing a power generation element. [Solution] A power generation element 1 comprises: a base material layer 10 containing water; a first charging layer 20 containing silicon dioxide and a first metal layer 40 containing a predetermined type of metal laminated in the stated order in the lamination direction on one surface of the base material layer 10; and a second charging layer 30 containing silicon dioxide and a second metal layer 50 containing a predetermined type of metal having a lower ionization tendency than that of the metal contained in the first metal layer 40, said second charging layer 30 and said second metal layer 50 being laminated in the stated order in the lamination direction on the other surface of the base material layer 10. Negative ions emitted from the first metal layer 40 are drawn into the first charging layer 20 and the second charging layer 30, and a current can be taken out in association with electron transfer from the first metal layer 40 to the second metal layer 50.

Description

Power generating element and method for manufacturing the power generating element

[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.

[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 serve as driving sources, has also been actively pursued. Furthermore, growing interest in global environmental issues and petroleum resource issues has led to increased 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 due to environmental considerations, regulations on batteries containing such hazardous heavy metals are gradually becoming stricter. In addition, with the spread of small portable information terminals, there is an increasing demand for higher energy density, higher voltage, higher output, longer life, smaller size and weight, lower cost, etc., and 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] On the other hand, because the operating principle of lithium-ion batteries is based on a chemical reaction (Faraday reaction), although they have excellent energy density, they suffer from large losses due to internal resistance, making it difficult to efficiently charge the minute amounts of power generated by the power generation element, and they have problems such as low durability against repeated charge / discharge cycles and high-temperature operating environments.

[0005] 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.

[0006] 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.

[0007] For example, Patent Document 1 discloses a power generation element made from volcanic ash, which has a high static charge. Specifically, a static electricity generating member made from fine hollow spheres processed from volcanic ash, ore, and activated mineral water containing negative ions is filled into an insulating, airtight cylindrical container with conductive water-containing powder made from activated carbon, fullerenes, nanotubes, etc., and then an anode and cathode for extracting electricity are connected to both ends of the container, thereby realizing a large amount of electricity to be generated despite the compact size.

[0008] Furthermore, as shown in Patent Document 2, 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.

[0009] Special Publication No. 2005-502180 Publication Patent No. 6547082

[0010] According to the inventions disclosed in Patent Documents 1 and 2, the power generating element is made primarily from volcanic ash and shirasu, which does not require special disposal, resulting in a low environmental impact and a pollution-free, clean power generating element.

[0011] However, in the invention of Patent Document 1, 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.

[0012] 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.

[0013] 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.

[0014] In this regard, the invention of Patent Document 2 requires a certain amount of water to absorb negative ions into the balloon holes formed in the shirasu balloon layer, but the liquid 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.

[0015] On the other hand, the inventors of the present application have researched materials with even higher power generation efficiency, and as a result, have found silicon dioxide (SiO２ We have found that by using ZnO, it is possible to realize a power generation element with higher power generation efficiency.

[0016] 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.

[0017] In order to achieve the above-mentioned object, the power generating element of the present invention comprises a substrate layer containing moisture, a first electrostatic layer having a silicon dioxide purity of more than 20%, and a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more stacked in this order on one surface of the substrate layer, and a second electrostatic layer having a silicon dioxide purity of more than 20%, and a second metal layer containing a predetermined type of metal with a thickness of 20 nm or more stacked in this order on the other surface of the substrate layer.

[0018] Here, by providing a base layer, a power generating element made of a thin film can be formed by attaching a vapor deposition material to the base layer. Furthermore, since the base layer contains moisture, electrons can be efficiently transferred from the first metal layer to the second metal layer, which will be described later, thereby improving power generation efficiency.

[0019] Furthermore, a first charged layer having a silicon dioxide purity of more than 20% and a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more are stacked 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 charged layer while leaving electrons in the first metal layer.

[0020] In this case, since the first charging 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 improving power generation efficiency.

[0021] Furthermore, a second electrostatic layer having a silicon dioxide purity of more than 20% and a second metal layer having a thickness of 20 nm or more and 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 in the stacking direction 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 electrostatic layer and the second electrostatic layer. At this time, by conducting 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.

[0022] 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. Tuff has a large surface area due to the formation of many micropores, and can capture many negative ions into these micropores.

[0023] 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 stacking 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.

[0024] 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.

[0025] In order to achieve the above-mentioned object, the power generating element of the present invention comprises an electrostatically charged layer containing silicon dioxide, a first metal layer laminated on one side of the electrostatically charged layer and containing a predetermined type of metal with a thickness of 20 nm or more, a second metal layer laminated on the other side of the electrostatically charged layer and containing a predetermined type of metal with a lower ionization tendency than the metal contained in the first metal layer with a thickness of 20 nm or more, a first water retention layer laminated on the first metal layer and containing moisture, and a second water retention layer laminated on the second metal layer and containing moisture.

[0026] Here, by providing an electrostatically charged layer containing silicon dioxide, silicon dioxide forms a spherical surface, which has a large surface area and can charge a large amount of negative ions onto such a surface, thereby improving power generation efficiency.

[0027] Furthermore, by providing a first metal layer that is stacked on one side of the charged layer and contains a predetermined type of metal and has a thickness of 20 nm or more, and by 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.

[0028] Furthermore, by providing a second metal layer having a thickness of 20 nm or more and containing a predetermined type of metal with a lower ionization tendency than the metal contained in the first metal layer, which is laminated on the other surface of the charged layer, electrons are increased in the first metal layer by the amount of negative ions absorbed by the charged layer. At this time, by conducting 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.

[0029] Furthermore, by providing a first water-retaining layer that is laminated on the first metal layer and contains water, and a second water-retaining layer that is laminated on the second metal layer and contains water, electrons can efficiently move from the first metal layer to the second metal layer through the first water-retaining layer and the second water-retaining layer, thereby improving power generation efficiency.

[0030] 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, and power generation efficiency can be improved.

[0031] In order to achieve the above-mentioned object, the method for manufacturing a power generating element of the present invention includes the steps of: preparing a substrate layer containing moisture; depositing a first electrostatic layer having a silicon dioxide purity of more than 20% on one surface of the substrate layer; depositing a second electrostatic layer having a silicon dioxide purity of more than 20% on the other surface of the substrate layer; depositing a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more 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 thickness of 20 nm or more on the surface of the second electrostatic layer opposite to the surface facing the substrate layer.

[0032] 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.

[0033] Furthermore, by including a step of depositing a first electrostatic charge layer having a silicon dioxide purity of more than 20% on one surface of the base layer and a step of depositing a second electrostatic charge layer having a silicon dioxide purity of more than 20% on the other surface of the base layer, electrostatic charge layers can be stacked on both sides of the base layer. Because this electrostatic charge layer contains silicon dioxide, a large amount of negative ions can be charged onto the spherical surfaces of the silicon dioxide, thereby improving power generation efficiency.

[0034] The method further includes the steps of depositing a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more on the surface of the first electrostatic layer opposite the surface facing the substrate layer, and depositing a second metal layer containing a predetermined type of metal with a thickness of 20 nm or more on the surface of the second electrostatic layer opposite the surface facing the substrate layer, the second metal layer being a predetermined type of metal with a lower ionization tendency than the metal contained in the first metal layer. The first metal layer then generates electrons in proportion to the number of negative ions absorbed by the electrostatic layer. By electrically connecting the first and second metal layers, the electrons generated in the first metal layer migrate to the second metal layer, resulting in a current flowing between the first and second metal layers and generating an electromotive force.

[0035] Furthermore, when the step of depositing the first charged layer and the second charged layer onto the base layer includes a step 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, each of the tuff layer and the silicon dioxide layer can be charged with negative ions, thereby further improving power generation efficiency.

[0036] In order to achieve the above-mentioned object, the method for manufacturing a power generating element of the present invention includes the steps of: generating an electrostatically charged layer containing silicon dioxide; depositing a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more on one surface of the electrostatically charged layer; depositing a second metal layer containing a predetermined type of metal having a lower ionization tendency than the first metal layer and having a thickness of 20 nm or more on the other surface of the electrostatically charged layer; depositing 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 depositing 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.

[0037] 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 improving power generation efficiency.

[0038] Furthermore, by including a step of laminating a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more on one side of the charged layer, and a step of laminating a second metal layer containing a predetermined type of metal with a lower ionization tendency than the first metal layer and having a thickness of 20 nm or more on the other side of the charged layer, the first metal layer and the second metal layer can be laminated 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.

[0039] 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.

[0040] Furthermore, when 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.

[0041] 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.

[0042] It is a cross-sectional view that shows a schematic diagram of a power generating element according to a first embodiment of the present invention. It is a diagram showing an application example using the power generating element according to the first embodiment of the present invention. It is a cross-sectional view that shows a schematic diagram of a power generating element according to a second embodiment of the present invention.

[0043] Hereinafter, embodiments of the present invention will be described with reference to the drawings to facilitate understanding of the present invention.

[0044] 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 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 layer 10.

[0045] The first 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 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 charged layer 20 and the second charged layer 30 have the same configuration and are composed of a thickness of 20 nm or more.

[0046] 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 tuff layer 21 and the second tuff layer 31 may be collectively referred to as the "tuff layers," and the first silicon dioxide layer 22 and the second silicon dioxide layer 32 may be collectively referred to as the "silicon dioxide layers."

[0047] 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, increasing the overall surface area and making it possible to charge more negative ions.

[0048] Furthermore, deposition by sputtering is generally performed when forming a thin film of the power generating element 1. In this case, the material to be deposited on the base material layer 10 needs to be a relatively hard substance, and in this respect, heat-treated tuff, etc., has a certain degree of hardness and is an ideal material for deposition by sputtering.

[0049] The first silicon dioxide layer 22 and the second silicon dioxide layer 32 are primarily composed of silicon dioxide (preferably with a purity of 50% or higher). 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 as a thin film by vapor deposition onto the tuff layer using sputtering.

[0050] Here, the charged layer does not necessarily have to be composed of two layers, a tuff layer and a silicon dioxide layer. According to the inventor's research, 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 form a thin film of 20 nm or more, thereby forming a first silicon dioxide layer 22, and silicon dioxide is vapor-deposited on the other surface of the base layer 10 to form a thin film of 20 nm or more, thereby forming a second silicon dioxide layer 32.

[0051] 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, and may, for example, be stacked in the order of a silicon dioxide layer and a tuff layer, 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, as the material to be vapor-deposited onto the base layer 10.

[0052] 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, the inventors' repeated investigations 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.

[0053] On the other hand, it has been confirmed that a stable electromotive force can be generated when the total thickness of the charging layer is 40 nm or more. Therefore, the lower limit of the thickness of each of the first charging layer 20 and the second charging layer 30 is preferably 20 nm, and the upper limit can be changed appropriately depending on the size of the power generating element 1.

[0054] 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 to form a thin film of 20 nm or more.

[0055] Here, the type of the 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.

[0056] Furthermore, the thickness of the 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 the first metal layer 40 is less than 20 nm. This is thought to be because when the first metal layer 40 is a thin film with a thickness of less than 20 nm, fewer negative ions are generated in the first metal layer 40.

[0057] On the other hand, it has been confirmed that a stable electromotive force can be generated when the thickness of the first metal layer 40 is 20 nm or more. Therefore, the lower limit of the thickness of the first metal layer 40 is preferably 20 nm, and the upper limit can be changed as appropriate depending on the size of the power generating element 1.

[0058] 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 layer 30 by sputtering, resulting in a thin film of 20 nm or more.

[0059] Here, the type of the 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.

[0060] 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.

[0061] On the other hand, it has been confirmed that a stable electromotive force can be generated when the thickness of the second metal layer 50 is 20 nm or more. Therefore, the lower limit of the thickness of the second metal layer 50 is preferably 20 nm, and the upper limit can be changed as appropriate depending on the size of the power generating element 1.

[0062] The base layer 10 is approximately 20 nm thick and is made of a paper material capable of absorbing moisture from the atmosphere, and serves 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, the negative ions generated in 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.

[0063] Here, the thickness of the substrate 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 substrate 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 lower limit of the thickness of the substrate layer 10 is 20 nm or more, and the upper limit can be changed appropriately depending on the size of the power generation element 1.

[0064] Furthermore, as described above, the base layer 10 can absorb moisture from the atmosphere, but a predetermined liquid 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 liquid, including tap water, can be used.

[0065] As described above, by using the base layer 10 as a base material and depositing each layer by sputtering to form a thin film, it is possible to obtain a power generating element 1 with excellent power generation capacity. Furthermore, the power generating element 1 configured in this manner is small and lightweight, and can therefore be used as a thin battery for electronic devices such as mobile phones, smartphones, and notebook personal computers.

[0066] 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.

[0067] 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.

[0068] 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, because the layers constituting the power generating element 100 are formed by adhesive lamination or the like.

[0069] As shown in FIG. 3 , the power generating element 100 according to 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 surface of the first metal layer 120 opposite to the surface facing the electrostatic layer 110, and a second water retention layer 150 laminated on the surface of the second metal layer 130 opposite to the surface facing the electrostatic layer 110.

[0070] The material of the charging 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. 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.

[0071] Furthermore, as a result of investigations by the inventors, it is preferable that the particle size of the powdered silicon dioxide, tuff, etc. that make up the charged layer 110 be set to approximately 500 μm as the upper limit. In other words, if the particle size of the silicon dioxide, tuff, etc. that make up the charged layer 110 exceeds 500 μm, the gaps between adjacent particles become large, reducing the amount of negative ions that charge the charged layer 110, which may result in a deterioration in the power generation efficiency of the power generating element 100.

[0072] A first metal layer 120 and a second metal layer 130 are respectively laminated by adhesive on one surface and the other surface of the charging layer 110. In the 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.

[0073] 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.

[0074] 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 (i.e., a metal having a lower ionization tendency than the metal material selected for the first metal layer 120).

[0075] Here, the type of the 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.

[0076] The first water retention layer 140 and the second water retention layer 150 are each made of a paper material capable of absorbing moisture from the atmosphere, and the moisture absorbed by the first water retention layer 140 and the second water retention layer 150 is supplied to the power generation element 100, so that the inside of the power generation element 100 always contains a certain amount of moisture. Then, negative ions generated from the first metal layer 120 can be charged to the charged layer 110 via the water molecules absorbed by the first water retention layer 140 and the second water retention layer 150.

[0077] Furthermore, even if the moisture content of the power generating element 100 decreases, since the first moisture retention layer 140 and the second moisture retention layer 150 are adhesively laminated around the power generating element 100, it is easy to supply a specified liquid as needed using a dropper or the like.

[0078] 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.

[0079] As described above, by forming each layer by adhesive lamination, it is possible to easily manufacture the power generating element 1 having 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.

[0080] [Example] Next, an example of a power generating element of the present invention will be described. The power generating element used in the example 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 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. A second tuff layer 31 and a second silicon dioxide layer 32 were vapor-deposited on the other surface of the base layer 10, to form a second electrostatic layer 30. The first tuff layer 21 and the first silicon dioxide layer 22 were each formed to a thickness of 10 nm, and the second tuff layer 31 and the second silicon dioxide layer 32 were each formed to a thickness of 10 nm.

[0081] The first tuff layer 21 and the second tuff layer 31 were made from powder of tuff that had been foamed by heating at approximately 1300°C, and the silicon dioxide layers consisting of the first silicon dioxide layer 22 and the second silicon dioxide layer 32 were classified into Example 1 (purity 100%), Example 2 (purity 50%), and Comparative Example (purity 20%) according to the purity of the silicon dioxide.

[0082] Here, the silicon dioxide layer with 100% silicon dioxide purity in Example 1 was produced using glass or quartz glass used in solar panel covers, which contain high-purity silicon dioxide, as raw materials. Furthermore, the silicon dioxide layers with 50% or 20% silicon dioxide purity in Example 2 and Comparative Example 1 were produced by mixing glass materials such as window glass, cups, and bottles, and adjusting the purity while measuring the silicon dioxide purity with an X-ray fluorescence analyzer (XRF). The silicon dioxide layers in Example 2 and Comparative Example 1 also contained components other than silicon dioxide, such as boric acid, alumina, lead oxide, sodium oxide, potassium oxide, and calcium oxide.

[0083] 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.

[0084] 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 the voltage (V) for 20 days from the start of measurement.

[0085]

[0086] As shown in Table 1, it was confirmed that the higher the purity of 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 deterioration of the power generation element was accelerated. From the above examples and comparative examples, the superiority of the power generation element 1 according to the present invention can be confirmed.

[0087] 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.

[0088] 1, 100 Power generating element 10 Base material layer 20 First charged layer 21 First tuff layer 22 First silicon dioxide layer 30 Second charged layer 31 Second tuff layer 32 Second silicon dioxide layer 40, 120 First metal layer 50, 130 Second metal layer 60 Insulating layer 110 Charged layer 140 First water retention layer 150 Second water retention layer W Conductive wire T Terminal

Claims

1. A power generating element comprising: a substrate layer containing moisture; a first charged layer having a silicon dioxide purity of over 20% and a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more, stacked in this order on one side of the substrate layer; and a second charged layer having a silicon dioxide purity of over 20% and a second metal layer containing a predetermined type of metal with a thickness of 20 nm or more, stacked in this order on the other side of the substrate layer.

2. A power generating element as described in claim 1, wherein the first charged layer is formed by laminating a first tuff layer made of tuff or welded tuff and a first silicon dioxide layer made of silicon dioxide on one surface of the base material layer, and the second charged layer is formed by laminating a second tuff layer made of tuff or welded tuff and a second silicon dioxide layer made of silicon dioxide on the other surface of the base material layer.

3. A power generating element according to claim 1 or claim 2, wherein 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, and the second metal layer is made of at least one metal selected from the group consisting of gold, silver, copper, and platinum.

4. A power generating element comprising: an electrostatic layer containing silicon dioxide; a first metal layer laminated on one surface of the electrostatic layer, the first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more; a second metal layer laminated on the other surface of the electrostatic layer, the second metal layer containing a predetermined type of metal that has a lower ionization tendency than the metal contained in the first metal layer and having a thickness of 20 nm or more; a first moisture retention layer laminated on the first metal layer and containing moisture; and a second moisture retention layer laminated on the second metal layer and containing moisture.

5. The power generating element according to claim 4, wherein the charging layer contains tuff or welded tuff in a weight ratio of 0.25 to 0.5 for every 1 weight ratio of silicon dioxide.

6. A method for manufacturing a power generating element, comprising the steps of: preparing a substrate layer containing moisture; vapor-depositing a first electrostatic layer having a silicon dioxide purity of more than 20% on one surface of the substrate layer; vapor-depositing a second electrostatic layer having a silicon dioxide purity of more than 20% on the other surface of the substrate layer; vapor-depositing a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more on the surface of the first electrostatic layer opposite to the surface facing the substrate layer; and vapor-depositing a second metal layer containing a predetermined type of metal having a thickness of 20 nm or more on the surface of the second electrostatic layer opposite to the surface facing the substrate layer.

7. A method for manufacturing a power generating element as described in claim 6, wherein the step of depositing the first electrostatic layer on the base material layer comprises a step of depositing, from the base material layer in the stacking direction, a first tuff layer made of tuff or welded tuff, and a first silicon dioxide layer made of silicon dioxide, and the step of depositing the second electrostatic layer on the base material layer comprises a step of depositing, from the base material layer in the stacking direction, a second tuff layer made of tuff or welded tuff, and a second silicon dioxide layer made of silicon dioxide.

8. A method for manufacturing a power generating element, comprising the steps of: forming a charged layer containing silicon dioxide; laminating a first metal layer containing a predetermined type of metal and having a thickness of 20 nm or more on one surface of the charged layer; laminating a second metal layer containing a predetermined type of metal having a lower ionization tendency than the first metal layer and having a thickness of 20 nm or more on the other surface of the charged layer; laminating a first moisture-retaining layer capable of absorbing moisture 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 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.

9. The method for manufacturing a power generating element according to claim 8, wherein the step of generating the electrostatic layer includes a step of 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.

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