Methane storage element, power generation device, and method for manufacturing a methane storage element

Abstract

The present invention provides a methane storage element that indirectly stores methane and generates it when needed, and a power generation device that utilizes this element. [Solution] The methane storage element 1a has a substrate 10, an aluminum film 11 laminated on the surface of the substrate 10, a carbon film 12 laminated on the surface of the aluminum film 11, and an Al4C3 layer 13 formed at the interface between the aluminum film 11 and the carbon film 12 by laser light irradiated from the side of the carbon film 12. When water that has permeated from the surface of the element 1a comes into contact with the Al4C3 layer 13, methane is generated. The methane that has come out of the element 1a from the Al4C3 layer 13 exposed on the outer end surfaces of the aluminum film 11 and the carbon film 12 is supplied to the fuel cell 3 to generate electricity (Figure 2).

Description

Technical Field

[0001] The present invention relates to an energy storage device that stores substances used as power generation energy in the form of compounds, a method for manufacturing the same, and a power generation device that applies this energy storage device. Specifically, it relates to a small methane storage device that stores methane, which is a substance that can be used as power generation energy, not in the form of methane itself but in the form of other compounds, and can generate and supply methane as needed, and a method for manufacturing the same. Furthermore, it relates to a power generation device that utilizes the methane storage device.

Background Art

[0002] We have entered the IoT (Internet of Things) era where everything is connected to the network, and digital data is being acquired everywhere by various sensors. Since a small amount of power is required to operate the sensors, research and development of power generation devices for generating this power and energy storage technologies for supplying energy to the power generation devices are currently being actively pursued. In the current situation of such technological development, the inventor of the present application came up with the idea of using an "indirect energy storage device" to supply power to a large number of small sensors. The indirect energy storage device used here is a term named by the inventor of the present application, and it means a device that does not store energy in its original form suitable for the purpose of use, but stores it in another stable form and can be returned to the original form and supplied as needed. In particular, energy storage for the purpose of power supply is an extremely important technology. For example, secondary batteries, electric double layer capacitors, hydrogen power storage, etc. are technologies required not only for power generation facilities that supply large-scale power but also for relatively small individual electronic devices.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The inventors of this invention considered methane to be a suitable energy source for a power generation device that supplies power to numerous small sensors used in IoT. Therefore, the inventors have been conducting multifaceted research on methane storage elements that can indirectly store methane, the energy source, in the form of a stable compound, and on means and methods for stably supplying power to sensors and wearable terminals using these elements, with the aim of supplying energy to a small power generation device. As a result, the inventors have come to believe that a power generation device combining a methane storage element that indirectly stores methane and can generate methane when needed, and a power generation element that can directly utilize methane, and furthermore, a power generation device combining the methane storage element, a hydrogen production element that produces hydrogen from methane, and a hydrogen power generation element that can utilize hydrogen, is useful for various applications and is a particularly promising technology for supplying power to numerous small sensors used in IoT. However, in this technical field, specific and practical solutions regarding the structure necessary to realize a small energy storage element that can stably store methane, and its manufacturing method, are not known, so the inventors have continued to conduct further research with great inclination.

[0004] This invention is based on the problems in the technical field described above and the knowledge and research results of the present inventor, and aims to provide a small methane storage element that indirectly stores methane and generates methane when needed, a method for manufacturing the same, a power generation device that combines the methane storage element and the methane power generation element, and a power generation device that combines the methane storage element, the hydrogen production element and the hydrogen power generation element. [Means for solving the problem]

[0005] The methane storage element described in claim 1 is characterized by generating methane by contacting an aluminum carbide compound with water.

[0006] The power generation device described in claim 2 is characterized by having a methane storage element described in claim 1 and a methane power generation element that generates electricity using methane.

[0007] The power generation device described in claim 3 is characterized by having a methane storage element as described in claim 1, a hydrogen production element that produces hydrogen from methane, and a hydrogen power generation element that generates electricity using hydrogen.

[0008] The methane storage element described in claim 4 is The device comprises a substrate, an aluminum film and a carbon film laminated in any order on one surface of the substrate, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film. It is characterized by generating methane by bringing water, which has permeated from at least one of the surfaces of the aluminum film or the carbon film on the side furthest from the substrate, and the other surface of the substrate, into contact with the aluminum carbide compound layer.

[0009] The methane storage element described in claim 5 is The device comprises a substrate, an aluminum film and a carbon film laminated in any order on one surface of the substrate, an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and a protective film formed on at least a portion of the surface of the aluminum film or the carbon film on the side furthest from the substrate to prevent moisture penetration. The device is characterized by generating methane by bringing water that has penetrated from at least one of the portion of the surface of the aluminum film or the carbon film on the side furthest from the substrate where the protective film is not formed, and the other surface of the substrate, into contact with the aluminum carbide compound layer.

[0010] The methane storage element described in claim 6 is The device comprises an aluminum film and a carbon film stacked in any order, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and is characterized by generating methane by bringing water that has permeated from the surface of the aluminum film or the carbon film into contact with the aluminum carbide compound layer.

[0011] The methane storage element described in claim 7 is The invention comprises an aluminum film and a carbon film stacked in any order, an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and a protective film formed on at least a portion of one surface of the aluminum film or the carbon film to prevent moisture penetration. The invention is characterized by generating methane by bringing water that has penetrated from at least one of the surfaces of the aluminum film or the carbon film, where the protective film is not formed, into contact with the aluminum carbide compound layer.

[0012] The power generation device described in claim 8 is The present invention is characterized by having a methane storage element according to any one of claims 4 to 7 and a methane power generation element that generates electricity using methane.

[0013] The power generation device described in claim 9 is The present invention is characterized by comprising a methane storage element according to any one of claims 4 to 7, a hydrogen production element for producing hydrogen from methane, and a hydrogen power generation element for generating electricity using hydrogen.

[0014] The methane storage element described in claim 10 is The methane storage element according to any one of claims 4 to 7 is characterized in that the aluminum carbide compound layer and the outside are connected by a hollow structure.

[0015] The methane storage element described in claim 11 is The device is characterized by having a structure as a constituent unit, which comprises an aluminum film and a carbon film stacked in any order, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and by stacking a plurality of such constituent units, and by generating methane when water is brought into contact with the aluminum carbide compound layer.

[0016] The methane storage element described in claim 12 is The device comprises a substrate and particles of an aluminum carbide compound contained in the substrate, and is characterized by generating methane by bringing water that has permeated from the surface of the substrate into contact with the aluminum carbide compound layer.

[0017] The methane storage element described in claim 13 is The present invention comprises a methane storage film which is a methane storage element according to claim 12, a dispensing roll on which the methane storage film is wound, and a winding roll for winding up the methane storage film that has been dispensed from the dispensing roll, and is characterized in that water is brought into contact with the methane storage film that has been dispensed from the dispensing roll to generate methane.

[0018] The method for manufacturing a methane storage element described in claim 14 is a method for manufacturing a methane storage element described in claim 4, The aluminum carbide compound layer is formed by laminating the aluminum film and the carbon film in any order on one surface of the substrate, and irradiating the aluminum film and the carbon film with light that is transparent to them from the aluminum film and the carbon film side.

[0019] The method for manufacturing a methane storage element described in claim 15 is a method for manufacturing a methane storage element described in claim 5, The present invention is characterized by laminating the aluminum film and the carbon film in any order on one surface of the substrate, and irradiating the aluminum film and the carbon film with light of a wavelength of 200 nm or less that is transparent to the aluminum film and the carbon film from the aluminum film and the carbon film side to form the protective film and the aluminum carbide compound layer.

[0020] The method for manufacturing a methane storage element described in claim 16 is a method for manufacturing a methane storage element described in claim 6, A separation liquid having a vapor pressure lower than the reduced-pressure atmosphere when forming the aluminum film and the carbon film is applied to one surface of the substrate, and after forming the aluminum film and the carbon film on one surface of the substrate, an aluminum carbide compound layer is formed, and the substrate is removed from the laminated aluminum film and carbon film.

[0021] The method for manufacturing a methane storage element according to claim 17 is a manufacturing method for manufacturing the methane storage element according to claim 7, A separation liquid having a vapor pressure lower than the reduced-pressure atmosphere when forming the aluminum film and the carbon film is applied to one surface of the substrate, and after forming the aluminum film and the carbon film on one surface of the substrate, an aluminum carbide compound layer and a protective film are formed, and the substrate is removed from the laminated aluminum film and carbon film.

[0022] The method for manufacturing a methane storage element according to claim 18 is a manufacturing method for manufacturing the methane storage element according to any one of claims 4 to 7, An etching layer is formed at the interface so as to be exposed at the outer end surfaces of the aluminum film and the carbon film, an aluminum carbide compound layer is formed at the interface so as to contact the etching layer, and the etching layer is removed by etching to form the hollow structure that allows the aluminum carbide compound layer to communicate with the outside.

Advantages of the Invention

[0023] According to the methane storage element of the present invention described in claims 1 to 13, it can be miniaturized by utilizing a chemical reaction that generates methane upon contact between aluminum carbide and water, and can be used as a compact energy source for supplying energy to a power source (power generation device) such as a sensor, which is a small electronic element. Further, since water can be obtained relatively easily, various situations in which this methane storage element can be used as an energy source can be envisioned, and there are a wide variety of applicable examples. For example, when the methane storage element is used as an energy source for a small power supply for a wearable terminal, a person wearing the wearable terminal can utilize the sweat secreted from the skin to generate methane from aluminum carbide and supply it to the power generation device. Also, when the methane storage element is used as an energy source for a power generation device mounted on a sensor in order to arrange a large number of sensors in the environment to acquire data, methane can be generated by utilizing the moisture in the environment, so that data acquisition by the sensors can be continuously performed.

[0024] According to the power generation device described in claim 2, by combining the methane storage element described in claim 1 with a methane power generation element capable of directly utilizing methane, it can be used as a small power supply useful for a wearable terminal or the like.

[0025] According to the power generation device described in claim 3, by combining the methane storage element described in claim 1 with a hydrogen production element that produces hydrogen from methane and a hydrogen power generation element that generates electricity using hydrogen, it can be used as a small power supply useful for a wearable terminal or the like.

[0026] According to the methane storage element described in claim 4 and the method for manufacturing the methane storage element described in claim 14, a thin methane storage element can be realized having an aluminum film and a carbon film laminated in any order on one surface of a substrate, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film. Water can be supplied to the aluminum carbide compound layer from at least one of the surfaces of the aluminum film or carbon film on the side furthest from the substrate and the other surface of the substrate. Because it is thin, it can be configured as a film-like component, and since water can be supplied to the aluminum carbide compound layer from either the surface of the aluminum film or carbon film or the other surface of the substrate, when used as an energy source for a power generation device, there is a high degree of design freedom, including placement within the device, and a small, thin power generation device can be realized.

[0027] According to the methane storage element described in claim 5 and the method for manufacturing the methane storage element described in claim 15, a thin methane storage element can be realized having an aluminum film and a carbon film laminated in any order on one surface of a substrate, an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and a protective film formed on at least a portion of the surface of the aluminum film or carbon film on the side furthest from the substrate. Water can be supplied to the aluminum carbide compound layer from at least one of the portion of the surface of the aluminum film or carbon film on the side furthest from the substrate where the protective film is not formed, and the other surface of the substrate. Because it is thin, it can be configured as a film-like component, and since water can be supplied to the aluminum carbide compound layer from either the portion of the surface of the aluminum film or carbon film where the protective film is not formed or the other surface of the substrate, when used as an energy source for a power generation device, there is a high degree of design freedom, including placement within the device, and a small, thin power generation device can be realized.

[0028] According to the methane storage element described in claim 6 and the method for manufacturing the methane storage element described in claim 16, a thin methane storage element can be realized having an aluminum film and a carbon film stacked in any order, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film. Water can be supplied to the aluminum carbide compound layer from either the surface of the aluminum film or the carbon film. Because it is thin and does not have a base film when forming the aluminum film or carbon film, it can be configured as a film-like component, and since water can be supplied to the aluminum carbide compound layer from either the surface of the aluminum film or the carbon film, when used as an energy source for a power generation device, there is a high degree of design freedom, including placement within the device, and a small, thin power generation device can be realized.

[0029] According to the methane storage element described in claim 7 and the method for manufacturing the methane storage element described in claim 17, a thin methane storage element can be realized having an aluminum film and a carbon film stacked in any order, an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and a protective film formed on at least a portion of one surface of the aluminum film or the carbon film. Water can be supplied to the aluminum carbide compound layer from at least one of the parts of the aluminum film or carbon film surface away from the substrate where the protective film is not formed, and the other surface of the aluminum film or carbon film. Because it is thin and does not have a base film for forming the aluminum film or carbon film, it can be configured as a film-like component, and because water can be supplied to the aluminum carbide compound layer from at least one of the parts of the aluminum film or carbon film surface where the protective film is not formed and the other surface of the aluminum film or carbon film, when used as an energy source for a power generation device, there is a high degree of design freedom, including placement within the device, and a small, thin power generation device can be realized.

[0030] According to the power generation device described in claim 8, the methane storage element described in claims 4 to 7 can be combined with a methane power generation element that can directly utilize methane, thereby enabling its use as a small power source useful for wearable devices and the like.

[0031] According to the power generation device described in claim 9, by combining the methane storage element described in claims 4 to 7, the hydrogen production element that produces hydrogen from methane, and the hydrogen power generation element that generates electricity using hydrogen, it can be used as a small power source useful for wearable devices and the like.

[0032] According to the methane storage element described in claim 10, in the methane storage element described in claims 4 to 7, the aluminum carbide compound layer at the interface between the aluminum film and the carbon film is in communication with the outside of the element through a hollow structure, so that the generated methane can be guided through the hollow structure and collected at a required location on the outside for use.

[0033] According to the methane storage element described in claim 11, since it is constructed by stacking multiple structural units, each of which has an aluminum carbide compound layer at the interface between stacked aluminum films and carbon films, the amount of methane generated is greater than in the case of a single structural unit, or if the amount generated is the same, the generation time can be extended. Therefore, when used as an energy source for a power generation device, the power generation time can be extended.

[0034] The methane storage element described in claim 12 can be constructed simply by placing commercially available aluminum carbide compound particles (or particles processed from commercially available aluminum carbide compounds) in a water-permeable substrate. Aluminum carbide compounds can be generated at the interface between two films by stacking an aluminum film and a carbon film and irradiating them with electromagnetic waves of a predetermined energy, but the methane storage element described in claim 12 does not require such an expensive process to generate aluminum carbide compounds, and can be manufactured at a lower cost.

[0035] According to the methane storage element described in claim 13, a methane storage film made by forming the methane storage element described in claim 12 into a film is wound onto a dispensing roll, and this is pulled out and wound onto a winding roll. Methane can be generated by bringing the dispensed methane storage film into contact with water. When methane generation stops, the old methane storage film is wound up while a new methane storage film is dispensed and reacted with water, thereby continuously generating an amount of methane corresponding to the amount of methane storage film initially wound onto the dispensing roll.

[0036] According to the method for manufacturing a methane storage element described in claim 18, the hollow structure of the methane storage element described in claim 10 can be manufactured precisely, quickly, and in any design by using etching technology. [Brief explanation of the drawing]

[0037] [Figure 1] This figure schematically shows the configuration of a methane storage element according to the first embodiment. [Figure 2] This figure schematically shows the configuration of a methane power generation device utilizing a methane storage element according to the first embodiment. [Figure 3] This diagram schematically shows the configuration of a hydrogen power generation device utilizing a methane storage element according to the first embodiment. [Figure 4] This figure schematically shows the configuration and manufacturing method of a methane storage element according to the second embodiment. [Figure 5] This figure schematically shows the configuration and manufacturing method of a methane storage element according to the third embodiment. [Figure 6] This figure schematically shows the configuration of a methane power generation device utilizing a methane storage element according to the second and third embodiments. [Figure 7] This figure schematically shows the configuration of a hydrogen power generation device utilizing a methane storage element according to the second and third embodiments. [Figure 8] This figure schematically shows the configuration and manufacturing method of a methane storage element according to the fourth embodiment. [Figure 9] This figure schematically shows the configuration and manufacturing method of a methane storage element according to the fifth embodiment. [Figure 10] This figure schematically shows the configuration of a methane storage element according to the sixth embodiment. [Figure 11] This is a schematic, partially enlarged cross-sectional view showing the configuration of the main part of the methane storage element according to the seventh embodiment. [Figure 12] This figure schematically shows the overall configuration of the methane storage element according to the seventh embodiment. [Modes for carrying out the invention]

[0038] A first embodiment of the present invention will be described with reference to Figures 1 to 3. The first embodiment relates to a methane storage element (Figure 1) and two types of power generation devices (Figures 2 and 3) that utilize it as an energy source.

[0039] Figure 1 schematically shows the basic structure and operation of the methane storage element 1 of the first embodiment. The methane storage element 1 does not store methane itself, but rather contains an Al4C3 compound (hereinafter simply referred to as Al4C3 in this specification), which is an example of an aluminum carbide compound. Although Al4C3 is a stable compound, when it comes into contact with water, methane is generated by the chemical reaction shown in the following equation (1). Al4C3+12H2O→3CH4+4Al(OH)3… (1) The generated methane can be used in a power generation device, as will be explained later with reference to Figures 2 and 3.

[0040] There are no particular limitations on the shape of the Al4C3 in this methane storage element 1 or the holding structure within the element; in Figure 1, the methane storage element 1 is schematically shown as a square shape. However, this methane storage element 1 needs to have the function of generating methane as an energy source by reacting Al4C3 with water and supplying it to a predetermined location outside the element. Therefore, in order to realize such a function, at least a holding structure that confines and holds Al4C3 inside the element, a water-permeable structure (or material) that allows water to penetrate from the outside of the holding structure into the inside and come into contact with the Al4C3, or a supply means for supplying water to the Al4C3, and a guide supply structure that leads the generated methane to a predetermined location outside the holding structure are necessary.

[0041] As shown in Figure 1, the water that reacts with the Al4C3 in the methane storage element 1 may be a gas, liquid, or solid containing water (H2O) as a component, or it may be water itself. The water supplied to the methane storage element 1, and the gas, liquid, or solid containing water, may be obtained from the environment, or it may originate from the person wearing it (e.g., sweat).

[0042] Figure 2 schematically shows a first power generation device 2 that utilizes the methane storage element 1 of the first embodiment shown in Figure 1 as an energy supply source. Water or a gas, liquid, or solid containing water is supplied to the methane storage element 1, and Al4C3 reacts with the water to generate methane that can be used for power generation. This methane is then supplied to a fuel cell 3, which is a methane power generation element that can directly utilize methane, to generate electricity and obtain power.

[0043] Figure 3 schematically shows a second power generation device 4 that utilizes the methane storage element 1 of the first embodiment shown in Figure 1 as an energy supply source. Water or a gas, liquid, or solid containing water is supplied to the methane storage element 1, and Al4C3 reacts with water to generate methane that can be used for power generation. This methane is supplied to a hydrogen production device 5, which is a hydrogen production element that produces hydrogen from methane, and the hydrogen produced by the hydrogen production device 5 is supplied to a fuel cell, which is a hydrogen power generation element that can generate electricity using hydrogen, thereby generating electricity and obtaining power.

[0044] As shown in Figure 1, the methane storage element 1 generates methane through a chemical reaction between aluminum carbide and water, eliminating the need for complex chemical reactors, mechanical devices, and control electronic circuits, thus enabling miniaturization. Furthermore, the first power generation device 2 shown in Figure 2 generates electricity using a fuel cell 3 that directly utilizes methane, allowing for a compact overall configuration. Similarly, the second power generation device 4 shown in Figure 3 generates electricity using a fuel cell 6 that utilizes hydrogen produced from methane, allowing for a compact overall configuration.

[0045] Therefore, the power generation devices 2 and 4 shown in Figures 2 and 3 can be used as compact power generation devices to supply power to small sensors. In particular, since water is a common substance and can be obtained relatively easily, electronic devices such as sensors equipped with these power generation devices 2 and 4 can be suitably used in a variety of situations. For example, if these power generation devices 2 and 4 are used as a power source for a wearable terminal, methane can be generated from aluminum carbide using the moisture from sweat secreted from the skin of the person wearing the wearable terminal, and power can be supplied to the electronic devices of the wearable terminal. Furthermore, if these power generation devices 2 and 4 are mounted on sensors in order to acquire data by placing many sensors in the environment, methane can be generated using moisture in the environment, so that data acquisition by the sensors can be performed continuously.

[0046] The effects obtained from the methane storage element 1 in Figure 1 and the power generation devices 2 and 4 in Figures 2 and 3, as described above, can be similarly obtained in other embodiments described below.

[0047] A second embodiment of the present invention will be described with reference to Figure 4. The methane storage element 1a of the second embodiment is a more concrete example of the methane storage element 1 of the first embodiment (Figure 1).

[0048] As shown in Figure 4(a), a carbon film 11 is formed on one surface of the substrate 10 (the upper surface shown), and an aluminum film 12 is formed on top of it. In the third to sixth embodiments described later, the layering order of the carbon film 11 and the aluminum film 12 is the same as in the second embodiment, but conversely, the aluminum film 12 may be formed on one surface of the substrate 10, and the carbon film 11 may be formed on top of it. In other words, the layering order of the carbon film 11 and the aluminum film 12 is arbitrary.

[0049] As shown in Figure 4(a), laser light is irradiated onto the stacked carbon film 11 and aluminum film 12 from the side of the upper aluminum film 12, into the light irradiation area indicated by the two vertical dashed lines, using light that is transparent to these films. In this step, if the laser light is also transparent to the substrate 10, the laser light may be irradiated from the other surface of the substrate 10 (the lower surface shown in the figure).

[0050] As shown in Figure 4(b), when laser light is irradiated, an Al4C3 layer 13 is formed in the light-irradiated region at the interface between the carbon film 11 and the aluminum film 12. After the Al4C3 layer 13 is formed, as indicated by the downward arrow at the top of Figure 4(b), if water or a gas or liquid containing water is allowed to penetrate from the surface of the aluminum film 12, the chemical reaction shown in formula (1) occurs within the Al4C3 layer 13, generating methane. Methane can be generated when needed. Furthermore, if the substrate 10 is a material that water or a gas or liquid containing water can penetrate (for example, a porous material exhibiting hydrophilicity), then as indicated by the upward arrow at the bottom of Figure 4(b), water or a gas or liquid containing water can be allowed to penetrate from the other surface of the substrate 10 (the lower surface shown), generating methane when needed.

[0051] In this embodiment, the Al4C3 layer 13 is formed such that at least a portion of it reaches the outer end surfaces of the carbon film 11 and the aluminum film 12. Therefore, methane generated in the Al4C3 layer 13 can be guided outside the device and used as an energy source for power generation. That is, in the light irradiation region shown by the two vertical dashed lines in Figure 4(a), both the left and right ends are located inward from the outer end surfaces of the carbon film 11 and the aluminum film 12. Although the Al4C3 layer 13 appears to be confined between the carbon film 11 and the aluminum film 12, in the depth direction of the figure, the Al4C3 layer 13 reaches the outer end surfaces of the carbon film 11 and the aluminum film 12. The outer end surface of the Al4C3 layer 13 in the depth direction of the figure is exposed to the outside of the device from between the outer end surfaces of the carbon film 11 and the aluminum film 12. Therefore, methane generated in the Al4C3 layer 13 can be released outside the device. The methane storage elements of other embodiments described below also have the same "exposed structure" as described above, but the methane storage element 1d of the fifth embodiment (see Figure 9), which has a hollow structure, does not necessarily require the "exposed structure".

[0052] A third embodiment of the present invention will be described with reference to Figure 5. The methane storage element 1b of the third embodiment is another specific example of the methane storage element 1 of the first embodiment (Figure 1).

[0053] As shown in Figure 5(a), a carbon film 11 is formed on one surface of the substrate 10 (the upper surface shown in the figure), and an aluminum film 12 is formed on top of it.

[0054] In Figure 5(a), when laser light with a wavelength of 200 nm or less is irradiated onto the light irradiation area indicated by the two vertical dashed lines, an Al4C3 layer 13 is formed in the light irradiation area at the interface between the carbon film 11 and the aluminum film 12, as shown in Figure 5(b). At the same time, a protective film 14 that can continuously suppress the penetration of water or a gas or liquid containing water is photochemically formed on the light irradiation area of ​​the surface of the aluminum film 12. After the Al4C3 layer 13 and the protective film 14 are formed, as indicated by the downward arrow at the top of Figure 5(b), even if water or a gas or liquid containing water is attempted to penetrate from the surface of the aluminum film 12, the protective film 14 prevents the water from entering, and the water does not reach the Al4C3 layer 13. In this embodiment, the substrate 10 is formed of a material that allows water or a water-containing gas or liquid to penetrate (for example, a hydrophilic porous material). When supplying water or the like to the Al4C3 layer 13, as indicated by the upward-pointing arrow at the bottom of Figure 5(b), water or the like is allowed to penetrate from the other surface of the substrate 10 (the lower surface shown in the figure), and when necessary, the chemical reaction shown in formula (1) can be caused within the Al4C3 layer 13 to generate methane. The structure for guiding the methane generated in the Al4C3 layer 13 to the outside of the element is the same as that of the methane storage element 1a of the second embodiment described with reference to Figure 4.

[0055] The protective film 14 is formed by using a fluorine laser with a wavelength of 157 nm, with a single pulse fluence of 10 mJ / cm². 2 This is carried out by irradiation under conditions of a pulse repetition frequency of 10 Hz and an irradiation time of 15 to 90 min. As a result, a transparent Al2O3 protective film 14 with a thickness of approximately 10 nm is formed on the surface of the aluminum film 12. If the aluminum film 12 is formed on one surface of the substrate 10 and an amorphous carbon film 11 is formed on top of it as a carbon film 11, a transparent diamond-like carbon protective film 14 with a thickness of approximately 10 nm is formed by the same process.

[0056] Figure 6 schematically shows a first power generation device 2a that utilizes the methane storage element 1a of the second embodiment shown in Figure 4 or the methane storage element 1b of the third embodiment shown in Figure 5 as an energy supply source. Water or a gas, liquid, or solid containing water is supplied to the methane storage element 1a or 1b, and Al4C3 reacts with the water to generate methane that can be used for power generation. This methane is then supplied to a fuel cell 3, which is a methane power generation element that can directly utilize methane, to generate electricity and obtain power.

[0057] Figure 7 schematically shows a second power generation device 4a that utilizes the methane storage element 1a of the second embodiment shown in Figure 4 or the methane storage element 1b of the third embodiment shown in Figure 5 as an energy supply source. Water or a gas, liquid, or solid containing water is supplied to the methane storage element 1a or 1b, and Al4C3 reacts with water to generate methane that can be used for power generation. This methane is supplied to a hydrogen production device 5, which is a hydrogen production element that produces hydrogen from methane, and the hydrogen produced by the hydrogen production device 5 is supplied to a fuel cell 6, which is a hydrogen power generation element that can generate electricity using hydrogen, thereby generating electricity and obtaining power.

[0058] A fourth embodiment of the present invention will be described with reference to Figure 8. The methane storage element 1c of the fourth embodiment is another specific example of the methane storage element 1 of the first embodiment (Figure 1).

[0059] As shown in Figure 8(a), a very thin layer of silicone oil or ionic liquid with a low vapor pressure is pre-applied to one surface of the substrate 10 (the upper surface shown) to form a sacrificial layer (not shown). A carbon film 11 is then formed on this sacrificial layer, and an aluminum film 12 is formed on the carbon film 11. The formation of the carbon film 11 and aluminum film 12 is often carried out under reduced pressure, but the silicone oil or ionic liquid in the sacrificial layer remains without evaporating even under reduced pressure because of its low vapor pressure.

[0060] As shown in Figure 8(a), laser light is irradiated from the aluminum film 12 side to the light irradiation area indicated by the two vertical dashed lines, with light that is transparent to both the aluminum film 12 and the carbon film 11. In this step, if the laser light is also transparent to the substrate 10, the laser light may be irradiated from the other surface of the substrate 10 (the lower surface shown in the figure).

[0061] As shown in Figure 8(b), when laser light is irradiated, an Al4C3 layer 13 is formed in the light-irradiated region at the interface between the carbon film 11 and the aluminum film 12.

[0062] As shown in Figure 8(c), the stacked carbon film 11 and aluminum film 12 are separated from the substrate 10. Since there is a sacrificial layer between the carbon film 11 and aluminum film 12 and the substrate 10, separation can be easily performed, thereby realizing a methane storage element 1c1 without a substrate 10.

[0063] As indicated by the downward arrow at the top of Figure 8(d), water or a gas or liquid containing water can be permeated from the surface of the aluminum film 12, causing the chemical reaction shown in formula (1) within the Al4C3 layer 13, thereby generating methane when needed. Also, as indicated by the upward arrow at the bottom of Figure 8(d), methane can be generated when needed by permeating water or a gas or liquid containing water from the surface of the carbon film 11. The structure for guiding the methane generated in the Al4C3 layer 13 to the outside of the element is the same as that of the methane storage element 1a of the second embodiment described with reference to Figure 4.

[0064] Furthermore, although the methane storage element 1c of the fourth embodiment was a type without a substrate 10 and a protective film 14, if the substrate 10 is removed in the same manner as in the fourth embodiment during the manufacturing process of the methane storage element 1b of the third embodiment, which has a substrate 10 and a protective film 14 as described with reference to Figure 5, a methane storage element without a substrate 10 and with a protective film 14 can be obtained.

[0065] Furthermore, by using the methane storage element 1c of the fourth embodiment, which lacks the substrate 10 and protective film 14, and the methane storage element having a protective film 14 but lacking the substrate 10, as energy sources, a first power generation device 2a and a second power generation device 4a can be constructed as shown in Figures 6 and 7.

[0066] A fifth embodiment of the present invention will be described with reference to Figure 9. The methane storage element 1d of the fifth embodiment is another specific example of the methane storage element 1 of the first embodiment (Figure 1).

[0067] In Figure 9(a), a very thin sacrificial layer (not shown) consisting of a silicone oil or ionic liquid with a low vapor pressure is pre-applied to one surface of the substrate 10 (the upper surface shown), and a carbon film 11 is formed on this sacrificial layer. A silica glass (SiO2) film 15 is formed on a portion of the surface of the carbon film 11 at a predetermined position and in a predetermined shape, with a thickness of approximately 10 to 30 nm. After forming the silica glass film 15, an aluminum film 12 is formed on the silica glass film 15 and the carbon film 11.

[0068] The silica glass film 15 is removed in a later etching process, becoming a cavity that serves as a supply channel for methane generated from the Al4C3 layer 13 formed in a later process, guiding it to the outside of the device (see Figures 9(b), (c), and (d)). Therefore, the position and shape of the silica glass film 15 to be formed are, for example, as follows: At a position between the outer end surface of the Al4C3 layer 13 formed by laser light at the interface between the aluminum film 12 and the carbon film 11 in a later process, and the outer end surfaces of the aluminum film 12 and the carbon film 11, at least a portion of the outer end surface of the Al4C3 layer 13 must be formed in a shape (or pattern) that connects it to the outer end surfaces of the carbon film 11 and the aluminum film 12. In other words, when the Al4C3 layer 13 is formed in a later process, the Al4C3 layer 13 and the silica glass film 15 must be in contact, and the cavity created when the silica glass film 15 is removed must open to the outer end surface of the device.

[0069] Each figure in Figure 9 is a cross-sectional view taken with the line of sight in the depth direction (direction perpendicular to the paper) which is perpendicular to the thickness direction (vertical direction parallel to the paper) of the carbon film 11 and aluminum film 12. In Figure 9(a), the silica glass film 15 appears as a horizontally elongated line, but when the line of sight is parallel to the paper, the shape of the silica glass film 15 is assumed to be the same linear pattern as the silica glass film 15 shown in Figure 9(a), either one or multiple lines arranged side by side. That is, the silica glass film 15 is one or multiple thin lines arranged side by side when viewed from directly above the element. However, it may be any shape in which the dimension in the direction perpendicular to the paper (depth dimension) is larger than the dimension in the direction parallel to the paper (thickness). That is, the silica glass film 15 may be a planar pattern with a certain extent when viewed from directly above the element.

[0070] As shown in Figure 9(a), laser light is irradiated from the aluminum film 12 side to the light irradiation area indicated by the two vertical dashed lines, with light that is transparent to both the aluminum film 12 and the carbon film 11. One outer end of the light irradiation area is in contact with the inner end of the silica glass film 15, but since the silica glass film 15 is not affected by the irradiation of the laser light, it is sufficient if the laser light only slightly irradiates the edge of the silica glass film 15. In this process, if the laser light is also transparent to the substrate 10, the laser light may be irradiated from the other surface of the substrate 10 (the lower surface shown in the figure).

[0071] As shown in Figure 9(b), when laser light is irradiated, an Al4C3 layer 13 is formed in the light-irradiated region at the interface between the carbon film 11 and the aluminum film 12. As a result, a structure is obtained in which the outer end surface of the formed Al4C3 layer 13 and the outer end surfaces of the carbon film 11 and the aluminum film 12 are connected by a silica glass film 15. Subsequently, by exposing the outer end surfaces of the carbon film 11 and the aluminum film 12 to hydrogen fluoride gas or hydrofluoric acid and chemically etching and removing only the silica glass film 15, a hollow structure 16 with a shape and pattern similar to the originally existing silica glass film 15 can be obtained. In Figure 9(b), both the silica glass film 15 and the hollow structure 16 are denoted by reference numerals at the corresponding locations. In this embodiment, the silica glass film 15 was chemically etched with hydrogen fluoride gas, etc., but the principle or method of etching and the materials used therein are arbitrary.

[0072] In this embodiment, the outer end surface of the Al4C3 layer 13 and the outer end surfaces of the carbon film 11 and aluminum film 12 are connected by a hollow structure 16 formed between the carbon film 11 and aluminum film 12, and at least a portion of the outer end surface of the Al4C3 layer 13 is exposed to the outside of the element via the hollow structure 16. Therefore, methane generated in the Al4C3 layer 13 can be led out of the element via the hollow structure 16. Accordingly, in this embodiment, it is not necessary to adopt a structure in which at least a portion of the Al4C3 layer 13 reaches the outer end surfaces of the carbon film 11 and aluminum film 12 and is exposed to the outside of the element, as in the methane storage element 1a of the second embodiment described earlier with reference to Figure 4, but this does not prevent the creation of the "exposed structure" in a location other than the part in which the hollow structure 16 is formed.

[0073] * In this embodiment, the hollow structure 16 is formed in the shape of a thin wire, but by using one wire or a number small compared to the amount of methane generated, the concentration of methane supplied outside the element can be increased even if the amount of methane generated is small. Furthermore, the shape of the portion of the thin wire-shaped hollow structure 16 that opens outside the element, and the position of the opening on the outer end face of the element, can be set according to the arrangement of the power generation element (fuel cell, etc.) to which the methane is supplied, as well as the size and shape of the fuel supply port.

[0074] As shown in Figure 9(c), the stacked carbon film 11 and aluminum film 12 are separated from the substrate 10. Since there is a sacrificial layer between the carbon film 11 and aluminum film 12 and the substrate 10, separation can be easily performed, thereby realizing a methane storage element 1 that has a hollow structure 16 without a substrate 10.

[0075] As indicated by the downward arrow at the top of Figure 9(d), water or a gas or liquid containing water can be permeated from the surface of the aluminum film 12, causing the chemical reaction shown in formula (1) within the Al4C3 layer 13, thereby generating methane when needed. Also, as indicated by the upward arrow at the bottom of Figure 9(b), methane can be generated when needed by permeating water or a gas or liquid containing water from the surface of the carbon film 11.

[0076] As indicated by the rightward arrow on the right side of Figure 9(d), the methane generated in the Al4C3 layer 13 is guided out of the element through the hollow structure 16 and can be used as energy for power generation. The structure of the power generation device using the methane storage element 1d of the fifth embodiment as an energy source is the same as that of the first power generation device 2a shown in Figure 6 and the second power generation device 4a shown in Figure 7.

[0077] A sixth embodiment of the present invention will be described with reference to Figure 10. The methane storage element 1e of the sixth embodiment is another specific example of the methane storage element 1 of the first embodiment (Figure 1).

[0078] The methane storage element 1e of the sixth embodiment has three layers of film structures consisting of a carbon film 11 and an aluminum film 12 stacked on one surface (the upper surface in the figure) of a substrate 10, with an Al4C3 layer 13 formed at the interface of each layer. Therefore, it has three Al4C3 layers 13, which are sources of methane. If the material and dimensions of the film structure are the same, the methane storage element 1 of the sixth embodiment can be expected to have three times the methane generation capacity compared to the methane storage element 1a of the second embodiment shown in Figure 4. Therefore, when used as an energy source for a power generation device, the power generation duration will be three times longer under the same conditions. Note that the number of layers in the film structure is not limited to three; it may be two layers or four or more layers depending on the purpose. In any case, using multiple layers can extend the methane generation lifetime compared to the case of a single layer.

[0079] The methane storage element 1e of the sixth embodiment is manufactured as follows. First, a carbon film 11 is formed on one surface of the substrate 10 (the upper surface shown in the figure), and an aluminum film 12 is formed on top of it. This process is repeated three times to form a three-layer laminated film structure of carbon film 11 and aluminum film 12. Then, a laser beam that is transparent to these three film structures is irradiated from the upper surface of the topmost aluminum film 12 into a predetermined light irradiation area to form an Al4C3 layer 13 at the interface of each film structure. The method for generating methane from the Al4C3 layer 13 using water or the like, and the structure and method for guiding the methane generated from the Al4C3 layer 13 outside the element and using it as energy for a power generation device, are the same as in the other embodiments described above.

[0080] A seventh embodiment of the present invention will be described with reference to Figures 11 and 12. The methane storage element 1e of the seventh embodiment is a more concrete example of the methane storage element 1 of the first embodiment (Figure 1).

[0081] The Al4C3 layer 13 in the methane storage elements 1a, 1b, 1c, 1d, and 1e of the second to sixth embodiments was a layered material formed at the interface by irradiating a stacked carbon film 11 and aluminum film 12 with laser light. However, the aluminum carbide compound of the present invention does not need to be manufactured by such a method and does not form layers. As shown in the enlarged cross-sectional view in Figure 11, the methane storage element of the seventh embodiment is a methane storage film 1f in which commercially available Al4C3 particles or Al4C3 particles 20 obtained by processing commercially available Al4C3 are dispersed inside a film-like and continuous strip-shaped substrate 10f. To manufacture such a methane storage film 1f, an appropriate amount of Al4C3 particles 20 can be added to a substrate 10f material having appropriate viscosity to create the raw material, which can then be processed into a continuous strip-shaped film and solidified. However, the substrate 10f material must have the property of permeating moisture after solidifying into a film.

[0082] As shown by the two arrows in Figure 11, water or a water-containing gas or liquid is allowed to permeate both surfaces (top and bottom) or one of the surfaces of the methane storage film 1f, causing the chemical reaction shown in formula (1) in the Al4C3 particles 20, thereby generating methane when needed.

[0083] Figure 12 is a schematic diagram illustrating a specific example of how the methane storage film 1f shown in Figure 11 can be used. The methane storage element 1f is wound onto a dispensing roll 21, and the methane storage film 1f unwound from the dispensing roll 21 is wound onto a winding roll 22. When the winding roll 22 is driven by a driving means (not shown), the methane storage film 1f is pulled out from the dispensing roll 21 in the direction of the arrow and wound onto the winding roll 22. When water or the like is brought into contact with the pulled-out methane storage film 1f using a hydration means (not shown), the Al4C3 particles 20 contained in the methane storage film 1f undergo the chemical reaction shown in formula (1), and methane can be generated when needed.

[0084] Furthermore, by using the methane storage element 1 with the methane storage film of the seventh embodiment as an energy supply source, a power generation device similar to the first power generation device 2a and the second power generation device 4a shown in Figures 6 and 7 can be constructed.

[0085] According to the methane storage film 1f of the seventh embodiment, there is no need for an apparatus to form an aluminum film 12 and a carbon film 11 on a substrate 10 under a reduced pressure environment, nor an apparatus to irradiate with laser light. It can be manufactured at low cost by using commercially available, inexpensive aluminum carbide compounds. Furthermore, when methane generation stops, the old methane storage film 1f is wound up while a new methane storage film 1f is unwound and reacted with water, thereby continuously generating methane until the methane storage film 1f initially wound on the unwinding roll 21 is used up.

[0086] In the embodiments described above, Al4C3 was shown as the aluminum carbide compound, but this is merely an example. Other aluminum carbide compounds with different numbers of Al and C atoms can also be used as the aluminum carbide compound of the present invention to generate methane. [Explanation of symbols]

[0087] 1, 1a, 1b, 1c, 1d, 1e... Methane storage elements 1f... Methane storage film as a methane storage element 2,2a...First power generation device 3. Fuel cells as methane power generation elements 4,4a...Second power generation device 5. Hydrogen production equipment as a hydrogen production element. 6. Fuel cells as hydrogen power generation elements 10...Base 11…Carbon film 12…Aluminum film 13…Al4C3 layer 14...Protective film 15…Silica glass film 16...Hollow structure 20…Al4C3 particles 21... Dispensing Roll 22... Reel roll

Claims

1. A methane storage element characterized by generating methane by contacting an aluminum carbide compound with water.

2. A power generation device characterized by having a methane storage element according to claim 1 and a methane power generation element that generates electricity using methane.

3. A power generation device characterized by comprising a methane storage element according to claim 1, a hydrogen production element for producing hydrogen from methane, and a hydrogen power generation element for generating electricity using hydrogen.

4. A methane storage element comprising a substrate, an aluminum film and a carbon film laminated in any order on one surface of the substrate, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, wherein methane is generated by bringing water that has permeated from at least one of the surfaces of the aluminum film or the carbon film on the side furthest from the substrate and the other surface of the substrate into contact with the aluminum carbide compound layer.

5. A methane storage element comprising a substrate, an aluminum film and a carbon film laminated in any order on one surface of the substrate, an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and a protective film formed on at least a portion of the surface of the aluminum film or the carbon film on the side furthest from the substrate to prevent moisture penetration, wherein water that has penetrated from at least one of the portion of the surface of the aluminum film or the carbon film on the side furthest from the substrate where the protective film is not formed and the other surface of the substrate are brought into contact with the aluminum carbide compound layer to generate methane.

6. A methane storage element comprising an aluminum film and a carbon film stacked in any order, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, characterized in that methane is generated by bringing water that has permeated from the surface of the aluminum film or the carbon film into contact with the aluminum carbide compound layer.

7. A methane storage element comprising an aluminum film and a carbon film stacked in any order, an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, and a protective film formed on at least a portion of one surface of the aluminum film or the carbon film to prevent moisture penetration, wherein methane is generated by bringing water that has penetrated from at least one of the surfaces of the aluminum film or the carbon film and the aluminum carbide compound layer into contact with the portion of one surface of the aluminum film or the carbon film where the protective film is not formed.

8. A power generation device characterized by having a methane storage element according to any one of claims 4 to 7 and a methane power generation element that generates electricity using methane.

9. A power generation device characterized by having a methane storage element according to any one of claims 4 to 7, a hydrogen production element for producing hydrogen from methane, and a hydrogen power generation element for generating electricity using hydrogen.

10. A methane storage element according to any one of claims 4 to 7, characterized in that the aluminum carbide compound layer and the outside are connected by a hollow structure.

11. A methane storage element characterized by having a structure as a constituent unit, comprising an aluminum film and a carbon film stacked in any order, and an aluminum carbide compound layer formed at the interface between the aluminum film and the carbon film, wherein a plurality of such constituent units are stacked, and methane is generated by bringing water into contact with the aluminum carbide compound layer.

12. A methane storage element comprising a substrate and particles of an aluminum carbide compound contained in the substrate, characterized in that methane is generated by bringing water that has permeated from the surface of the substrate into contact with the aluminum carbide compound layer.

13. A methane storage element comprising a methane storage film which is a methane storage element according to claim 12, a dispensing roll on which the methane storage film is wound, and a winding roll for winding up the methane storage film dispensed from the dispensing roll, wherein methane is generated by bringing water into contact with the methane storage film dispensed from the dispensing roll.

14. A method for manufacturing a methane storage element according to claim 4, characterized in that the aluminum film and the carbon film are laminated on one surface of the substrate in any order, and the aluminum carbide compound layer is formed by irradiating the aluminum film and the carbon film with light that is transparent to the aluminum film and the carbon film from the aluminum film and the carbon film side.

15. A method for manufacturing a methane storage element according to claim 5, characterized in that the aluminum film and the carbon film are laminated on one surface of the substrate in any order, and the protective film and the aluminum carbide compound layer are formed by irradiating the aluminum film and the carbon film with light of a wavelength of 200 nm or less that is transparent to the aluminum film and the carbon film from the aluminum film and the carbon film side.

16. A method for manufacturing a methane storage element according to claim 6, characterized by applying a separation liquid with a vapor pressure lower than that of the reduced-pressure atmosphere used when forming the aluminum film and the carbon film to one side of the substrate, forming the aluminum film and the carbon film on one side of the substrate, forming the aluminum carbide compound layer, and then removing the substrate from the laminated aluminum film and the carbon film.

17. A method for manufacturing a methane storage element according to claim 7, characterized in that a separation liquid having a vapor pressure lower than that of the reduced-pressure atmosphere used when forming the aluminum film and the carbon film is applied to one surface of the substrate, the aluminum film and the carbon film are formed on one surface of the substrate, the aluminum carbide compound layer and the protective film are formed, and the substrate is removed from the laminated aluminum film and the carbon film.

18. A method for manufacturing a methane storage element according to any one of claims 4 to 7, characterized in that an etchable layer is formed at the interface so as to be exposed on the outer end surface of the aluminum film and the carbon film, an aluminum carbide compound layer is formed at the interface so as to be in contact with the etchable layer, and the etchable layer is removed by etching to form the hollow structure that connects the aluminum carbide compound layer to the outside.

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