Power generation device and power generation system using the same

Abstract

To provide a thermoelectric device having excellent power generation efficiency capable of generating current simply by irradiating with natural light or the like without artificial heating and / or cooling by applying external power and so on, and a generation system using the same.SOLUTION: A power generation device includes a light emitting layer that transmits visible light and near-infrared light and absorbs mid-infrared light, a light absorption layer that absorbs visible light and near-infrared light, and at least one thermoelectric power-generating element between the light emitting layer and the light absorption layer. At least one thermoelectric power-generating element includes a base material that transmits visible light and near-infrared light and a pair of thin films made of thermoelectric materials that are respectively provided on opposing main surfaces of the base material, transmit visible light and near-infrared light, and have different signs of Seebeck coefficients. At least one thermoelectric power-generating element is positioned such that a direction parallel to the planes of the pair of thin films is substantially perpendicular to a direction parallel to the planes of the light emitting layer and the light absorption layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power generation device and a power generation system using the same.

Background Art

[0002] In recent years, a thermoelectric conversion element has been developed that can obtain an electric current by simply irradiating light such as natural light without artificially heating and / or cooling by applying power or the like from the outside (for example, Patent Document 1). According to Patent Document 1, a light emission-spin current generation layer that transmits visible light and near-infrared light, absorbs mid-infrared light, and can generate a spin current, and a spin current-electric current conversion layer having a spin-orbit interaction and disposed in contact with at least a part of the light emission-spin current generation layer, and a light absorption layer that absorbs visible light and near-infrared light are provided in this order. A thermoelectric conversion element including a laminate is disclosed.

[0003] The thermoelectric conversion element described in Patent Document 1 enables power generation using the spin Seebeck effect by using a spin current generation layer, but further improvement in power generation efficiency is expected.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] From the above, an object of the present invention is to provide a thermoelectric device excellent in power generation efficiency that can obtain an electric current by simply irradiating light such as natural light without artificially heating and / or cooling by applying power or the like from the outside, and a power generation system using the same.

Means for Solving the Problems

[0006] The power generation device according to the present invention comprises a light emission layer that transmits visible light and near-infrared light and absorbs mid-infrared light, a light absorption layer that absorbs visible light and near-infrared light, and at least one thermoelectric power generation element between the light emission layer and the light absorption layer, wherein the at least one thermoelectric power generation element comprises a substrate that transmits visible light and near-infrared light, and a pair of thin films provided on opposing main surfaces of the substrate, each made of a thermoelectric material that transmits visible light and near-infrared light and has different signs of Seebeck coefficients, wherein the at least one thermoelectric power generation element is positioned such that the direction parallel to the plane of the pair of thin films is substantially perpendicular to the direction parallel to the plane of the light emission layer and the light absorption layer, thereby solving the above problem. The aforementioned light-emitting layer may have a transmittance of 70% or more for light in the wavelength range of 380 nm to 2.5 μm, and an absorptance of 70% or more for light in the wavelength range of greater than 2.5 μm and less than or equal to 20.0 μm. The aforementioned light-emitting layer may be made of a material selected from the group consisting of inorganic materials, organic materials, and combinations thereof. The light-emitting layer may have a thickness in the range of 200 μm to 1000 μm. The light-absorbing layer may have an absorption rate of 70% or more for light in the wavelength range of 380 nm to 2.5 μm. The light-absorbing layer may contain a black pigment. The black pigment may be selected from the group consisting of carbon pigments, metal oxide materials, and organic pigments. The light-absorbing layer may have a thickness in the range of 100 μm to 2 mm. The substrate may have a transmittance of 70% or more for light in the wavelength range of 380 nm to 2.5 μm. The substrate may be selected from the group consisting of inorganic materials, organic materials, and combinations thereof. The inorganic material may be a glass selected from the group consisting of soda-lime glass, borosilicate glass, alkali-barium silicate glass, aluminosilicate glass, quartz, and synthetic fused silica. The inorganic material may be a ceramic selected from the group consisting of sapphire, corundum, alumina, magnesium oxide, and yttrium aluminum garnet (YAG). The organic material may be a plastic selected from the group consisting of polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP / OPP), polyethylene naphthalate (PEN), polyvinyl chloride resin (PVC), polystyrene (PS / OPS), acrylic (PMMA), polycarbonate (PC), triacetate (TAC), cycloolefin polymer (COP), and polyimide (PI). The pair of thin films may be a combination of a p-type thermoelectric material and an n-type thermoelectric material. The p-type thermoelectric material may be selected from the group consisting of copper iodide (CuI) and Cu-based delafossite-type oxides (CuMO2, where M is selected from the group consisting of aluminum (Al), chromium (Cr), iron (Fe), and gallium (Ga)). The n-type thermoelectric material may be selected from the group consisting of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), fluorine-doped zinc oxide (FZO), and titanium nitride. The substrate may have a thickness in the thickness direction of 200 μm or more and 2000 μm or less, and a side length in the in-plane direction of 100 μm or more and 50 mm or less. Each of the pair of thin films may have a thickness in the range of 100 nm to 500 nm. The light-absorbing layer may include a solar cell. The at least one thermoelectric power generation element may be positioned such that the angle between the direction parallel to the plane of the pair of thin films and the direction parallel to the planes of the light-emitting layer and the light-absorbing layer is 70° or more and 90° or less. The power generation system according to the present invention comprises a power generation device and a storage device electrically connected to the power generation device and storing the electricity generated by the power generation device, thereby solving the above problems. [Effects of the Invention]

[0007] The power generation device of the present invention comprises a light-emitting layer that transmits visible light and near-infrared light and absorbs mid-infrared light, a light-absorbing layer that absorbs visible light and near-infrared light, and at least one thermoelectric power generation element between them. With this configuration, a temperature gradient is generated in the thermoelectric power generation element by the simultaneous use of radiative cooling and solar heat during the day, and by radiative cooling at night, thereby enabling power generation. In particular, since at least one thermoelectric power generation element comprises a substrate that transmits visible light and near-infrared light, and a pair of thin films provided on opposing main surfaces of the substrate, each made of a thermoelectric material that transmits visible light and near-infrared light and has different signs of Seebeck coefficients, it is possible to utilize the Seebeck effect, which exhibits a higher power generation effect compared to the spin Seebeck effect. Furthermore, this thermoelectric power generation element is positioned such that the direction parallel to the plane of the pair of thin films is substantially perpendicular to the direction parallel to the plane of the light-emitting layer and the light-absorbing layer. As a result, a large temperature difference (temperature gradient) is generated in the in-plane direction of the pair of thin films between the light-emitting layer and the light-absorbing layer. As a result, power generation efficiency is further increased, allowing for the generation of more electricity. By combining such power generation and storage devices, a power generation system can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] Schematic diagram showing a power generation device according to the present invention [Figure 2] A schematic diagram showing another power generation device according to the present invention. [Figure 3] A schematic diagram showing yet another power generation device according to the present invention. [Figure 4] Schematic diagram showing the power generation system according to the present invention [Figure 5] A diagram showing the external appearance of the power generation device in Example 1. [Figure 6] This figure shows the change in thermoelectric power of the power generation device in Example 1 in an outdoor setting. [Figure 7]Figure showing the change in the thermoelectric power of the power generation device of Example 1 under each condition indoors [Figure 8] Figure showing the change in the thermoelectric power of the power generation device of Comparative Example 1 under each condition indoors [Figure 9] Figure showing the change in the thermoelectric power of the power generation device of Example 1 under another condition indoors

Mode for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same elements are denoted by the same numbers, and the description thereof will be omitted. (Embodiment 1) In Embodiment 1, the power generation device of the present invention and its manufacturing method will be described in detail.

[0010] FIG. 1 is a schematic diagram showing a power generation device according to the present invention.

[0011] The power generation device 100 of the present invention includes a light emitting layer 110 that transmits visible light and near infrared light and absorbs mid infrared light, a light absorbing layer 120 that absorbs visible light and near infrared light, and at least one thermoelectric power generation element 130 between them. The at least one thermoelectric power generation element 130 includes a base material 140 that transmits visible light and near infrared light, and a pair of thin films 150 and 160 that are provided on the opposing main surfaces of the base material 140, transmit visible light and near infrared light, and are made of thermoelectric materials having different signs of the Seebeck coefficient.

[0012] Here, the at least one thermoelectric power generation element 130 is positioned such that the direction parallel to the plane of the pair of thin films 150 and 160 (for example, arrow A) is substantially perpendicular to the direction parallel to the plane of the light emitting layer 110 and the light absorbing layer 120 (for example, arrow B). In the power generation device 100 of the present invention, the main surface of the light absorbing layer 120 faces the main surface of the light emitting layer 110. Therefore, since the directions parallel to these planes are substantially the same, it is shown as arrow B here. ​​The power generation device 100 of the present invention utilizes the Seebeck effect, which exhibits a high power generation effect, and therefore boasts excellent power generation efficiency. Furthermore, the power generation device 100 of the present invention generates a temperature gradient in the in-plane direction of the pair of thin films 150 and 160 between the light-emitting layer 110 and the light-absorbing layer 120, thereby further increasing power generation efficiency and enabling the generation of more electricity.

[0014] First, the power generation principle of this invention will be explained. Let's consider the case where the power generation device 100 of the present invention is placed outdoors. During the day, natural light hν is incident on the power generation device 100. The light emission layer 110 transmits visible light and near-infrared light from the natural light and absorbs mid-infrared light. It is generally known that natural light (sunlight observed at the Earth's surface, e.g., AM1.5G) contains almost no mid-infrared light. Since the light emission layer 110 transmits visible light and near-infrared light, which are the main components of natural light, and natural light contains almost no mid-infrared light, the temperature rise of the light emission layer 110 due to irradiation with natural light is almost negligible.

[0015] Visible light and near-infrared light transmitted through the light-emitting layer 110 reach the light-absorbing layer 120 and are absorbed by the light-absorbing layer 120. The light-absorbing layer 120, having absorbed visible light and near-infrared light, experiences a temperature increase due to photoheating. As a result, the light-emitting layer 110 becomes relatively cooler than the light-absorbing layer 120, creating a temperature gradient between the light-emitting layer 110 and the light-absorbing layer 120 along the thickness direction of the power generation device 100 (the temperature is higher on the light-absorbing layer 120 side and lower on the light-emitting layer 110 side).

[0016] Furthermore, the light-emitting layer 110 has a high absorption rate of mid-infrared light, meaning it has a high emissivity of mid-infrared light. As a result, thermal radiation easily occurs from the light-emitting layer 110 to a relatively cooler space (in this case, outer space). Consequently, the light-emitting layer 110 is cooled by radiative cooling even during the day. Consequently, the temperature of the light-emitting layer 110 becomes relatively lower compared to the light-absorbing layer 120, creating a temperature gradient between the light-emitting layer 110 and the light-absorbing layer 120.

[0017] This temperature gradient occurs in the in-plane direction of the thin films 150 and 160 of the thermoelectric power generation element 130, rather than in the thickness direction, resulting in a larger temperature gradient and potentially improving power generation efficiency. In addition, since natural light includes not only light transmitted through the light emission layer 110 but also light directly incident on the light absorption layer 120 (e.g., natural light hν'), a larger temperature gradient can be expected. Thus, during the daytime, thermoelectric power generation is possible by simultaneously utilizing light irradiation and radiative cooling.

[0018] On the other hand, at night, although there is no incident natural light, radiative cooling occurs from the light-emitting layer 110, so the temperature of the light-emitting layer 110 becomes relatively lower compared to the light-absorbing layer 120. As a result, a temperature gradient is created between the light-emitting layer 110 and the light-absorbing layer 120 even at night. Moreover, because the temperature of this gradient is higher on the light-absorbing layer 120 side and lower on the light-emitting layer 110 side, the sign (polarity) of the thermoelectric voltage extracted from the thermoelectric power generation element 130 remains the same regardless of whether or not light is irradiated.

[0019] Thus, in the power generation device 100 of the present invention, when light is irradiated from the light-emitting layer 110 side, light irradiation and radiative cooling act synergistically, creating a temperature gradient where the temperature on the light-emitting layer 110 side is low and the temperature on the light-absorbing layer 120 side is relatively high. Even when light is not irradiated, radiative cooling creates a temperature gradient in the same direction, so power can be obtained simply by irradiating with light such as natural light, without artificial heating and / or cooling by applying power from an external source. Furthermore, since this temperature gradient occurs in the in-plane direction of the thin films rather than in the thickness direction of the pair of thin films 150 and 160 of the thermoelectric power generation element 130, a larger temperature gradient can be achieved, and the power generation efficiency can be dramatically improved.

[0020] Next, we will explain each component in detail. The light-emitting layer 110 is not particularly limited as long as it is made of a material that transmits visible light and near-infrared light and absorbs mid-infrared light. Here, in this specification, visible light is light having a wavelength in the range of 380 nm to 780 nm, near-infrared light is light having a wavelength in the range of greater than 780 nm and less than or equal to 2.5 μm, and mid-infrared light is light having a wavelength in the range of greater than 2.5 μm and less than or equal to 20.0 μm.

[0021] The light-emitting layer 110 transmits visible light and near-infrared light if it is 200 μm thick and transmits 60% or more of the light having the above wavelengths. If it has a transmittance of 60% or more, the temperature of the light-absorbing layer 120 can be increased, so a temperature gradient can be created between the light-emitting layer 110 and the light-absorbing layer 120. From the viewpoint of power generation efficiency, the light-emitting layer 110 preferably transmits 70% or more, more preferably 80% or more, of visible light and near-infrared light in a thickness of 200 μm. The upper limit may be 100%.

[0022] The light-emitting layer 110 absorbs mid-infrared light, meaning that a 200 μm thick light-emitting layer 110 absorbs 60% or more of the light having the above wavelength. If the absorption rate is 60% or more, the light-emitting layer 110 emits heat, creating a temperature gradient between the light-emitting layer 110 and the light-absorbing layer 120. From the viewpoint of power generation efficiency, the light-emitting layer 110 preferably absorbs 70% or more, more preferably 80% or more, of mid-infrared light at a thickness of 200 μm. The upper limit may be 100%.

[0023] The transmittance of visible light and near-infrared light and the transmittance of mid-infrared light of the light-emitting layer 110 may be appropriately combined from the above ranges, but preferably, at a thickness of 200 μm, it has a transmittance of 70% or more for light in the wavelength range of 380 nm to 2.5 μm (visible light and near-infrared light) and an absorptive rate of 70% or more for light in the wavelength range of greater than 2.5 μm and 20.0 μm or less (mid-infrared light). More preferably, at a thickness of 200 μm, it has a transmittance of 80% or more for visible light and near-infrared light and an absorptive rate of 80% or more for mid-infrared light.

[0024] The light-emitting layer 110 is made of a material selected from the group consisting of inorganic materials, organic materials, and combinations thereof. An example of such a combination is a multilayer film of a thin film made of an inorganic material and a thin film made of an organic material.

[0025] The inorganic material is preferably a glass such as silica, and more preferably a glass selected from the group consisting of soda-lime glass, borosilicate glass, alkali barium silicate glass, aluminosilicate glass, quartz, and synthetic fused silica. These have transmittance and absorptance for the above wavelengths.

[0026] The inorganic material is preferably a ceramic, and more preferably a ceramic selected from the group consisting of sapphire, corundum, alumina, magnesium oxide, and yttrium aluminum garnet (YAG). These have transmittance and absorptance for the above wavelength.

[0027] The organic material is preferably a polymer such as plastic, and more preferably a plastic selected from the group consisting of polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP / OPP), polyethylene naphthalate (PEN), vinyl chloride resin (PVC), polystyrene (PS / OPS), acrylic (PMMA), polycarbonate (PC), triacetate (TAC), cycloolefin polymer (COP), and polyimide (PI). These have transmittance and absorptance at the above wavelength.

[0028] The thickness of the light-emitting layer 110 is not particularly limited, but exemplary it is in the range of 200 μm to 1000 μm. Within this range, the transmittance can be easily adjusted. More preferably, the thickness of the light-emitting layer 110 is in the range of 200 μm to 500 μm, and even more preferably, 200 μm to 300 μm. Within this range, it is possible to have high transmittance for visible light and near-infrared light, and high absorption for mid-infrared light.

[0029] The light-absorbing layer 120 is not particularly limited as long as it is made of a material that absorbs visible light and near-infrared light having the above wavelengths. The light-absorbing layer 120 absorbs visible light and near-infrared light if it absorbs 60% or more of the light having the above wavelengths. Absorption of 60% or more increases the temperature of the light-absorbing layer 120, creating a temperature gradient between the light-emitting layer 110 and the light-absorbing layer 120. From the viewpoint of power generation efficiency, the light-absorbing layer 120 preferably absorbs 70% or more, more preferably 80% or more, of visible light and near-infrared light at a thickness of 500 μm. The upper limit may be 100%.

[0030] There are no particular restrictions on the components of the light-absorbing layer 120, but it is preferable that it contains a black pigment. The black pigment may be selected from the group consisting of carbon pigments, metal oxide materials, and organic pigments. Carbon pigments are carbon materials such as activated carbon and carbon black. Metal oxide materials are metal oxides such as chromium (Cr), cobalt (Co), nickel (Ni), iron (Fe), manganese (Mn), and copper (Cu). Organic pigments are organic materials such as aniline black, lactam black, and perylene black.

[0031] The black pigment may be a surface-treated pigment that has been surface-treated with silicon compounds, aluminum compounds, organic substances, etc. Examples of surface treatments include (meth)acrylsilane treatment, alkylation treatment, trimethylsilylation treatment, silicone treatment, and treatment with coupling agents.

[0032] While not particularly limited, the light-absorbing layer 120 is preferably a coating film obtained from a black paint containing a black pigment and a resin. The resin contained in the black paint is not particularly limited and includes known resins such as (meth)acrylic resins, polyester resins, polyamide resins, vinyl resins, and epoxy resins. Such a black paint may be applied to various substrates such as glass substrates, plastic substrates, semiconductor substrates, ceramic substrates, and metal substrates. This makes it easier to handle the power generation device 100.

[0033] In addition to the above, black paint may also contain hardeners, surfactants, solvents, pigments, dyes, fillers, etc.

[0034] The thickness of the light-absorbing layer 120 is not particularly limited, but exemplary it is in the range of 100 μm to 2 mm. Within this range, the absorption rate can be easily adjusted. More preferably, the thickness of the light-absorbing layer 120 is in the range of 300 μm to 1.5 mm, and even more preferably, 500 μm to 1.2 mm. Within this range, it is possible to have a high absorption rate for visible light and near-infrared light. If the light-absorbing layer 120 is made of a substrate coated with a black paint film, the thickness of the light-absorbing layer 120 may be the combined thickness of the paint film and the substrate.

[0035] The substrate 140 of the thermoelectric power generation element 130 is not limited as long as it is capable of forming a thin film on its main surface, but preferably it is made of a material that transmits visible light and near-infrared light. As a result the substrate 140 transmits natural light, the temperature of the light absorption layer 120 can be further increased. Consequently, a larger temperature gradient is created between the light emission layer 110 and the light absorption layer 120.

[0036] The substrate 140, like the light-emitting layer 110, can be made of a material with a thickness of 200 μm that has a transmittance of 60% or more for light in the wavelength range of 380 nm to 2.5 μm (visible light and near-infrared light). More preferably, the substrate 140 has a transmittance of 70% or more for visible light and near-infrared light, and even more preferably, 80% or more. The upper limit may be 100%.

[0037] The material of the substrate 140 can be the same as the material of the light-emitting layer 110 described above, and consists of materials selected from the group consisting of inorganic materials, organic materials, and combinations thereof. An example of such a combination is a multilayer film of a thin film made of an inorganic material and a thin film made of an organic material.

[0038] The inorganic material is preferably a glass such as silica, and more preferably a glass selected from the group consisting of soda-lime glass, borosilicate glass, alkali barium silicate glass, aluminosilicate glass, quartz, and synthetic fused silica. These have transmittance for the above wavelength.

[0039] The inorganic material is preferably a ceramic, and more preferably a ceramic selected from the group consisting of sapphire, corundum, alumina, magnesium oxide, and yttrium aluminum garnet (YAG). These have transmittance to the above wavelength.

[0040] The organic material is preferably a polymer such as plastic, and more preferably a plastic selected from the group consisting of polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP / OPP), polyethylene naphthalate (PEN), vinyl chloride resin (PVC), polystyrene (PS / OPS), acrylic (PMMA), polycarbonate (PC), triacetate (TAC), cycloolefin polymer (COP), and polyimide (PI). These have transmittance to the above wavelength.

[0041] There are no particular restrictions on the size of the substrate 140, but exemplary, it has a thickness in the thickness direction of 200 μm to 2 mm and a side length in the in-plane direction of 100 μm to 50 mm. Within this range, handling is easy and the formation of a thin film on the main surface is also easy. Preferably, the substrate 140 has a thickness in the thickness direction of 500 μm to 1 mm and a side length in the in-plane direction of 5 mm to 15 mm. This allows for the generation of a larger temperature gradient in the in-plane direction of the thin films 150 and 160.

[0042] The thin films 150 and 160 are not particularly limited as long as they are a pair of thin films made of thermoelectric materials that transmit visible light and near-infrared light and have different signs of Seebeck coefficients. Here, as with the substrate 140, the thin films 150 and 160 can be those that have a transmittance of 60% or more for light in the wavelength range of 380 nm to 2.5 μm (visible light and near-infrared light) at a thickness of 100 nm. More preferably, the thin films 150 and 160 have a transmittance of 70% or more for visible light and near-infrared light, and even more preferably, 80% or more. This allows the thermoelectric power generation element 130 to transmit natural light and further increase the temperature of the light absorption layer 120. As a result, a larger temperature gradient is created between the light emission layer 110 and the light absorption layer 120. The upper limit may be 100%.

[0043] The sign of the Seebeck coefficients of a pair of thin films 150 and 160 being different means that thin films 150 and 160 are thermoelectric materials of different conduction types, a combination of a p-type thermoelectric material (Seebeck coefficient: positive value) and an n-type thermoelectric material (Seebeck coefficient: negative value). For example, if thin film 150 is made of a p-type thermoelectric material and thin film 160 is made of an n-type thermoelectric material, current flows in the order of thin film 150, conductive material 170, and thin film 160. In detail, holes in thin film 150 gain thermal energy from the high-temperature side light-absorbing layer 120, move to the conductive material 170 in contact with the low-temperature side light-emitting layer 110, and release thermal energy, and then electrons in thin film 160 gain thermal energy from the high-temperature side. If the conduction types of thin films 150 and 160 are reversed, current flows in the opposite direction.

[0044] In Figure 1, the thin films 150 and 160 are electrically connected by a conductive material 170, and current flows, for example, from thin film 150 to thin film 160. Such a conductive material 170 may be a conventional electrode material such as aluminum (Al), nickel (Ni), copper (Cu), or silver (Ag), or it may be a transparent conductive film such as indium tin oxide (ITO) or fluorine-doped tin oxide (FTO).

[0045] p-type thermoelectric materials are preferably selected from the group consisting of copper iodide (CuI) and Cu-based delafossite-type oxides (CuMO2, where M is selected from the group consisting of aluminum (Al), chromium (Cr), iron (Fe), and gallium (Ga)). These are known to be thermoelectric materials that transmit visible and near-infrared light, have a p-type conductivity, and have a positive Seebeck coefficient.

[0046] n-type thermoelectric materials are preferably selected from the group consisting of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), fluorine-doped zinc oxide (FZO), and titanium nitride. These are known to be thermoelectric materials that transmit visible and near-infrared light, have an n-type conductivity, and have a negative Seebeck coefficient.

[0047] The thin films 150 and 160 preferably have a thickness in the range of 100 nm to 500 nm. Within this range, a film of excellent quality is obtained, and it has excellent transmittance to visible light and near-infrared light. The thin films 150 and 160 are more preferably in the range of 100 nm to 300 nm. The thicknesses of the thin films 150 and 160 may be the same or different.

[0048] As shown in Figure 1, the thermoelectric power generation element 130 is characterized in that the direction parallel to the plane of the pair of thin films (arrow A) is positioned approximately perpendicular to the direction parallel to the plane of the light emission layer 110 and the light absorption layer 120 (arrow B). This creates a temperature gradient in the in-plane direction of the thin films 150 and 160 of the thermoelectric power generation element 130 between the light emission layer 110 and the light absorption layer 120. This temperature gradient is dramatically larger than the temperature gradient of the thin film in the thermoelectric power generation element shown in Figure 8 (i.e., when the direction parallel to the plane of the thin film made of thermoelectric material is the same as the direction parallel to the plane of the light emission layer and the light absorption layer) (in this case, it occurs in the thickness direction of the thin film). As a result, a large thermoelectric voltage can be obtained.

[0049] Positioning them so that they are nearly perpendicular means that the angle (acute angle) between arrow A and arrow B is 70° or more and 90° or less. Within this range, a temperature gradient can be efficiently generated in the in-plane direction of the thin films 150 and 160. More preferably, the angle (acute angle) between arrow A and arrow B is 80° or more and 90° or less. Within this range, a larger temperature gradient can be efficiently generated in the in-plane direction of the thin films 150 and 160, and the thermoelectric power generation element 130 can be easily fixed.

[0050] From the viewpoint of power generation efficiency and the stability of the thermoelectric power generation element, it is preferable that the direction parallel to the plane of the pair of thin films 150 and 160 is approximately perpendicular to the direction parallel to the plane of the light emission layer 110 and the light absorption layer 120. However, as long as the in-plane direction of the thin films and the in-plane directions of the light emission layer and the light absorption layer are not parallel, the power generation efficiency will be improved compared to the thermoelectric power generation element shown in Figure 8. For example, a power generation device may be realized in which the thermoelectric power generation element is arranged between the light emission layer and the light absorption layer such that the angle (acute angle) between the in-plane direction of the thin films and the in-plane directions of the light emission layer and the light absorption layer is greater than 0° and less than 70°.

[0051] The manufacturing method of the power generation device 100 of the present invention is not particularly limited and may be manufactured by known methods. For example, first, a light-emitting layer 110 and a light-absorbing layer 120 are prepared. Next, a pair of thin films 150 and 160 made of thermoelectric material are deposited on each of the main surfaces of the substrate 140 by physical vapor deposition, chemical vapor deposition, etc., to manufacture a thermoelectric power generation element 130. Next, the thermoelectric power generation element 130 is arranged such that the direction parallel to the plane of the thin films 150 and 160 is substantially perpendicular to the direction parallel to the plane of the light-absorbing layer 120. Next, the pair of thin films 150 and 160 are electrically connected with a conductive material, and the light-emitting layer 110 is placed on top of them such that the direction parallel to the plane of the thin films 150 and 160 is substantially perpendicular to the direction parallel to the plane of the light-emitting layer 110.

[0052] Figure 2 is a schematic diagram showing another power generation device according to the present invention.

[0053] Another power generation device 200 of the present invention is the same as the power generation device 100 in Figure 1, except that three thermoelectric power generation elements 130 are alternately connected in series via a conductive material 210, so redundant explanations are omitted. By connecting multiple thermoelectric power generation elements 130 in this way, the thermoelectric voltage can be increased. Figure 2 shows three thermoelectric power generation elements 130, but the number of thermoelectric power generation elements is not limited to three.

[0054] Figure 3 is a schematic diagram showing yet another power generation device according to the present invention.

[0055] Another power generation device 300 of the present invention is the same as the power generation device 100 in Figure 1, except that the light absorption layer 120 is equipped with a solar cell 310, so redundant explanations are omitted. The solar cell 310 is not particularly limited as long as it performs photoelectric conversion, and may be any solar cell module or solar cell panel.

[0056] By placing the solar cell 310 on the light-absorbing layer 120, the thermoelectric power during the day can be increased. Of the natural light (sunlight), the light that the solar cell 310 does not use to convert into electricity is absorbed by the solar cell 310, and the solar cell 310 itself can function as a light-absorbing layer. As a result, a larger temperature gradient is created between the light-emitting layer 110 and the solar cell 310 and light-absorbing layer 120, so a larger thermoelectric power can be obtained.

[0057] Naturally, the power generation device 300 in Figure 3 may be combined with the multiple thermoelectric power generation elements 130 of the power generation device 200 in Figure 2, and such modifications are also part of the present invention.

[0058] In Figures 1 to 3, the pair of thin films 150 and 160 have been described as being made of thermoelectric materials with different signs of Seebeck coefficients from the viewpoint of power generation efficiency. However, even if the signs of the Seebeck coefficients are the same, the pair of thin films 150 and 160 can convert thermal energy into electricity if there is a difference in the absolute values ​​of the Seebeck coefficients. Such modifications are also part of the present invention.

[0059] (Embodiment 2) Embodiment 2 describes a power generation system using the power generation device of the present invention described in Embodiment 1.

[0060] Figure 4 is a schematic diagram showing the power generation system according to the present invention.

[0061] The power generation system of the present invention comprises a power generation device 410 and a storage device 420 electrically connected to the power generation device 410 and storing the electricity generated by the power generation device 410. The power generation device 410 is the power generation devices 100, 200, and 300 of the present invention described with reference to Figures 1 to 3, so its description is omitted. In Figure 4, the power generation device 410 is located on the roof of a building, but it is not limited to this as long as it is in an environment where natural light can be shone on it.

[0062] The storage device 420 is not particularly limited as long as it can store electricity, but examples include secondary batteries such as lead-acid batteries and alkaline batteries, and capacitors such as ceramic capacitors and film capacitors.

[0063] The power generation device 410 generates a thermoelectric voltage of the same sign during the day through light irradiation and radiative cooling, and at night through radiative cooling, and stores the generated electricity in the storage device 420. This provides a power generation system that can supply electricity using light such as natural light without artificially heating and / or cooling by applying electricity from an external source.

[0064] The present invention will now be described in detail using specific examples, but please note that the present invention is not limited to these examples. [Examples]

[0065] [Example 1] In Example 1, a power generation device was manufactured using a PET sheet as the light-emitting layer, an acrylic plate coated with black paint as the light-absorbing layer, and a glass substrate having IGZO and CuI on opposite main surfaces as thermoelectric power generation elements.

[0066] A black coating (TA410KS, manufactured by Ichinen TASCO Co., Ltd.) was applied to the surface of a cleaned acrylic sheet (Hikari Co., Ltd., A960-2M, 18mm x 18mm x 1mm) to form a film. The thickness of the film was approximately 20 μm. The transmission spectrum of the coated acrylic sheet (wavelength range from 380 nm to 2.5 μm) was measured using an ultraviolet-visible-near-infrared spectrophotometer (V-570, manufactured by JASCO Corporation), and the coated acrylic sheet had an absorption rate of 90% or more in the above wavelength range.

[0067] A CuI thin film was deposited on one main surface of a cleaned borosilicate glass substrate (SCHOTT, D263Teco, 10mm x 10mm x 0.7mm), and an IGZO thin film was deposited on the opposite main surface. The transmission spectrum of the glass substrate (wavelength range from 380nm to 2.5μm) was measured, and the glass substrate exhibited a transmittance of over 90% in the above wavelength range. Furthermore, when converted to a thickness of 200μm, the transmittance was found to be over 90%.

[0068] A CuI thin film (200 nm) was deposited as follows: A Cu film (40 nm) was deposited on one main surface of a glass substrate by EB deposition, and then the Cu film was iodized. Iodization was performed by exposing the Cu film to iodine gas under atmospheric pressure for 2 hours. When the transmission spectrum of the CuI thin film (wavelength range from 380 nm to 2.5 μm) was measured, the CuI thin film had a transmittance of 80% or more in the above wavelength range. At this time, the transmission spectrum of the glass substrate was removed as background. Furthermore, when converted to a thickness of 100 nm, it was found that the transmittance was 90% or more.

[0069] The IGZO thin film (150 nm) was deposited as follows: The IGZO film was deposited by sputtering on the other main surface of a glass substrate on which a CuI film had been formed. The sputtering conditions were as follows: Targets: Indium oxide (In2O3) target, gallium oxide (Ga2O3) target, zinc oxide (ZnO) target, Pressure: 0.01 Pa DC output: 200W Temperature: room temperature (25℃), Sputtering gases: Argon gas (flow rate 19.6 sccm) and oxygen gas (flow rate 0.4 sccm) Distance between substrate and target: 10 cm

[0070] When the transmission spectrum of the IGZO thin film (wavelength range from 380 nm to 2.5 μm) was measured, the IGZO thin film had a transmittance of 80% or more in the above wavelength range. At this time, the transmission spectra of the CuI thin film and glass substrate were removed as background. Furthermore, when converted to a thickness of 100 nm, the transmittance was found to be 85% or more.

[0071] Next, aluminum foil was attached to the side of the substrate on which the IGZO thin film and CuI thin film had been deposited using silver paste (Fujikura Chemical Co., Ltd., D-500), thereby electrically connecting the IGZO thin film and the CuI thin film. In this way, a thermoelectric power generation element was formed.

[0072] A thermoelectric power generation device was obtained by placing a thermoelectric power generation element on an acrylic plate coated with black paint, and then placing a PET sheet (Toray Industries, Ltd., Lumirror T60, 25mm x 25mm x 0.25mm) on top of it. When the transmission spectrum of the PET sheet (wavelength range from 380nm to 2.5μm) was measured, the PET sheet had a transmittance of 80% or more in the above wavelength range. When converted to a thickness of 200μm, it was found that the transmittance was 85% or more. In addition, when another transmission spectrum of the PET sheet (range greater than 2.5μm and less than or equal to 20.0μm) was measured using a Fourier transform infrared spectrometer (Thermo Fisher Scientific Inc., iS50R), the PET sheet had an absorptive rate of 80% or more in the above wavelength range. When converted to a thickness of 200μm, it was found that the absorptive rate was 75% or more.

[0073] Here, the thermoelectric power generation elements were positioned so that the direction parallel to the plane of the IGZO thin film and CuI thin film was approximately perpendicular (at an angle of 90°) to the direction parallel to the plane of the black-painted plastic. For stability, cuts were made in the surface of the black-painted plastic, and the thermoelectric power generation elements were inserted and fixed in place. Then, wires were attached to the lower ends of the IGZO thin film and CuI thin film to make electrical contacts, and a PET sheet was placed on top of these wires so that it was parallel to the direction parallel to the plane of the black-painted plastic. In this way, the power generation device of Example 1 was obtained. The appearance of the power generation device of Example 1 is shown in Figure 5.

[0074] The change in thermoelectric power outdoors (May 25-26, 2022) was measured using the power generation device of Example 1. The results are shown in Figure 6. The change in thermoelectric power indoors (temperature 25°C, relative humidity 45%) was measured using the power generation device of Example 1. To reproduce the same environment indoors as outdoors, a Peltier module (VIX Corporation, LVPU-40) with its surface coated with the aforementioned blackbody paint was used instead of space, and a solar simulator (simulated sunlight irradiation device; Peccel Corporation, PEC-L01) was used instead of the sun. The Peltier module was positioned approximately 6 cm away from the power generation device and adjusted to cool to 0 degrees Celsius. The simulated sunlight irradiation device irradiated the power generation device with a simulated sunlight intensity of 333 mW / cm². 2 The settings were adjusted accordingly. The results are shown in Figure 7. Next, without using a solar simulator, the change in thermoelectric power was measured when the Peltier module temperature was varied from -10°C to 60°C. The results are shown in Figure 9.

[0075] [Comparative Example 1] In Comparative Example 1, a power generation device was manufactured using a glass substrate coated with an ITO thin film as the light-emitting layer and black paint as the light-absorbing layer, with IGZO and CuI as thermoelectric power generation elements.

[0076] A black coating was applied to the surface of a cleaned glass substrate to form a film. The thickness of the film was 20 μm. On the other main surface of the glass substrate, a transparent electrode (ITO thin film, 100 nm) was formed in the same manner as in Example 1, and a CuI thin film (300 nm) and an IGZO thin film (300 nm) were formed in parallel on top of it, and these CuI and IGZO thin films were connected by the transparent electrode (ITO thin film, 100 nm). A metal mask was used to limit the area in which each thin film was formed. In this way, the power generation device of Comparative Example 1 was obtained.

[0077] Using the power generation device of Comparative Example 1, the simulated sunlight intensity was set to 500 mW / cm². 2 Except for the above, the thermoelectric power in the indoor environment was measured in the same manner as in Example 1. The results are shown in Figure 8.

[0078] The above results will be summarized and explained below. Figure 5 shows the external appearance of the power generation device of Example 1.

[0079] As shown in Figure 5, the power generation device of Example 1 comprises a light-emitting layer (PET sheet), a light-absorbing layer (acrylic plate coated with black paint), and a thermoelectric power generation element having a thin film made of a transparent thermoelectric material on the opposing main surfaces of a glass substrate. It can be seen that the direction parallel to the plane of the thin film is approximately perpendicular to the direction parallel to the plane of the PET sheet and the acrylic plate.

[0080] The temperature difference (ΔT) generated in the thermoelectric power generation element, i.e., the temperature gradient (temperature difference (ΔT)) between the light-emitting layer and the light-absorbing layer, was numerically calculated using the power generation device of Example 1 (Figure 5) and the power generation device of Comparative Example 1 (schematic diagram in Figure 8). The setting conditions were a solar intensity of 333 mW / cm². 2 The temperature was set to 25°C. For numerical calculations, COMSOL Multiphysics, a simulation software based on the finite element method, was used. As a result, it was found that ΔT exceeded 1K for the power generation device of Example 1. On the other hand, for the power generation device of Comparative Example 1, ΔT was 1mK or less. This suggests that the power generation efficiency of the power generation device of the present invention is high.

[0081] Figure 6 shows the change in thermoelectric power of the power generation device of Example 1 in an outdoor setting.

[0082] As shown in Figure 6, the power generation device of Example 1 generated a thermoelectric voltage in the range of 1 mV, and it was confirmed that the sign of the thermoelectric voltage did not reverse between day and night. This indicates that a temperature difference is generated in the same direction across the thermoelectric power generation element throughout the day and night, and that a current of the same polarity can be extracted.

[0083] Figure 6 shows the results for a power generation device equipped with only one thermoelectric element, but it goes without saying that the thermoelectric voltage can be increased by connecting multiple thermoelectric elements in series. Furthermore, the thermoelectric voltage during the day can also be increased by placing a solar cell on a light-absorbing layer. Solar cells do not convert all wavelengths of sunlight into electricity; the wavelengths not used for photoelectric conversion heat the solar cell and, consequently, the area beneath the element, thus functioning as a light-absorbing layer. In this case, the power obtained from the thermoelectric element and the solar cell can be used in combination, or these can be stored in a storage device.

[0084] Figure 7 shows the change in thermoelectric power of the power generation device of Example 1 under various indoor conditions. Figure 8 shows the change in thermoelectric power of the power generation device of Comparative Example 1 under various indoor conditions.

[0085] Figures 7 and 8 show, from left to right, the thermoelectric voltages under the conditions of "radiative cooling only," "pseudo-sunlight only," and "simultaneous use of radiative cooling and pseudo-sunlight." According to Figure 7, the power generation device of Example 1 generated thermoelectric voltages of the same sign in all cases, and it was found that the thermoelectric voltage (0.8mV) increased particularly with the simultaneous use of radiative cooling and pseudo-sunlight. This value was equal to the sum of the thermoelectric voltages under "radiative cooling only" and "pseudo-sunlight only."

[0086] On the other hand, as shown in Figure 8, the power generation device of Comparative Example 1 generates a thermoelectric voltage of the same sign in all cases, but even with the simultaneous use of radiative cooling and simulated sunlight, the thermoelectric voltage is only about 0.08 mV, which is more than an order of magnitude lower than that of Example 1.

[0087] This demonstrates that, as in the power generation device of the present invention, a large temperature difference is generated in the in-plane direction of the pair of thin films (IGZO thin film and CuI thin film) when the direction parallel to the plane of the pair of thin films is positioned approximately perpendicular to the direction parallel to the plane of the light-emitting layer (PET sheet) and the light-absorbing layer (acrylic substrate with black paint).

[0088] Figure 9 shows the change in thermoelectric power of the power generation device of Example 1 under different indoor conditions.

[0089] Figure 9 shows the change in thermoelectric voltage of the power generation device in Example 1 when the Peltier module temperature was varied from -10°C to 60°C without using a solar simulator. Figure 9 shows that thermoelectric voltages of different signs are generated between radiative cooling and radiative heating. From this, it was confirmed that the light-emitting layer is cooled by radiative cooling and heated by radiative heating. [Industrial applicability]

[0090] The power generation device of the present invention can generate electricity from the environment simply by being installed outdoors and exposed to natural light or radiative cooling, without the need for artificial heating and / or cooling by applying electricity from an external source. Because it boasts excellent power generation efficiency, it can be applied to power supply applications such as off-grid sensors. Furthermore, by combining the power generation device of the present invention with a storage device, a power generation system can be provided. [Explanation of Symbols]

[0091] 100, 200, 300, 410 power generation equipment 110 Light-emitting layer 120 Light-absorbing layer 130 Thermoelectric power generation element 140 Base material 150, 160 thin film 170, 210 Conductive substances 310 Solar Cells 420 Storage equipment

Claims

1. A light-emitting layer that transmits visible light and near-infrared light and absorbs mid-infrared light, A light-absorbing layer that absorbs visible light and near-infrared light, The optical radiation layer and the optical absorption layer are provided with at least one thermoelectric power generation element, The at least one thermoelectric power generation element is A substrate that transmits visible light and near-infrared light, The substrate comprises a pair of thin films provided on opposing main surfaces of the substrate, each made of a thermoelectric material that transmits visible light and near-infrared light and has a Seebeck coefficient with a sign different from the other. The at least one thermoelectric power generation element is positioned such that the direction parallel to the plane of the pair of thin films is substantially perpendicular to the direction parallel to the plane of the light-emitting layer and the light-absorbing layer, The light-absorbing layer includes a solar cell, which is provided except in the area where the thermoelectric power generation element is installed, and generates electricity using visible light and near-infrared light that directly passes through the light-emitting layer without going through the substrate. The light-absorbing layer is located on the high-temperature side of the thermoelectric power generation element, and the light-emitting layer is located on the low-temperature side of the thermoelectric power generation element. A power generator.

2. The power generation apparatus according to claim 1, wherein the light-emitting layer has a transmittance of 70% or more for light in the wavelength range of 380 nm to 2.5 μm, and an absorption rate of 70% or more for light in the wavelength range of greater than 2.5 μm and 20.0 μm or less.

3. The power generation apparatus according to claim 2, wherein the light-emitting layer is made of a material selected from the group consisting of inorganic materials, organic materials, and combinations thereof.

4. The power generation apparatus according to claim 1, wherein the light-emitting layer has a thickness in the range of 200 μm to 1000 μm.

5. The power generation apparatus according to claim 1, wherein the light-absorbing layer has an absorption rate of 70% or more for light in the wavelength range of 380 nm to 2.5 μm.

6. The power generation apparatus according to claim 1, wherein the light-absorbing layer contains a black pigment.

7. The power generation apparatus according to claim 6, wherein the black pigment is selected from the group consisting of carbon pigments, metal oxide materials, and organic pigments.

8. The power generation apparatus according to claim 1, wherein the light-absorbing layer has a thickness in the range of 100 μm to 2 mm.

9. The power generation apparatus according to claim 1, wherein the substrate has a transmittance of 70% or more to light in the wavelength range of 380 nm to 2.5 μm.

10. The power generation apparatus according to claim 1, wherein the substrate is selected from the group consisting of inorganic materials, organic materials, and combinations thereof.

11. The power generation apparatus according to claim 10, wherein the inorganic material is a glass selected from the group consisting of soda-lime glass, borosilicate glass, alkali barium silicate glass, aluminosilicate glass, quartz, and synthetic fused silica.

12. The power generation apparatus according to claim 10, wherein the inorganic material is a ceramic selected from the group consisting of sapphire, corundum, alumina, magnesium oxide, and yttrium aluminum garnet (YAG).

13. The power generation apparatus according to claim 10, wherein the organic material is a plastic selected from the group consisting of polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP / OPP), polyethylene naphthalate (PEN), vinyl chloride resin (PVC), polystyrene (PS / OPS), acrylic (PMMA), polycarbonate (PC), triacetate (TAC), cycloolefin polymer (COP), and polyimide (PI).

14. The power generation apparatus according to claim 1, wherein the pair of thin films is a combination of a p-type thermoelectric material and an n-type thermoelectric material.

15. The aforementioned p-type thermoelectric material is copper iodide (CuI) and Cu-based delafossite-type oxide (CuMO) ２ M is selected from the group consisting of aluminum (Al), chromium (Cr), iron (Fe), and gallium (Ga), The power generation apparatus according to claim 14, wherein the n-type thermoelectric material is selected from the group consisting of indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), antimony-doped tin oxide (ATO), fluorine-doped tin oxide (FTO), fluorine-doped zinc oxide (FZO), and titanium nitride.

16. The power generation device according to claim 1, wherein the substrate has a thickness in the thickness direction of 200 μm or more and 2000 μm or less, and the length of one side in the in-plane direction of 100 μm or more and 50 mm or less.

17. Each of the pair of thin films has a thickness in the range of 100 nm to 500 nm. The power generation apparatus according to claim 1.

18. The power generation device according to claim 1, wherein the at least one thermoelectric power generation element is positioned such that the angle between a direction parallel to the plane of the pair of thin films and a direction parallel to the planes of the light-emitting layer and the light-absorbing layer is 70° or more and 90° or less.

19. A power generation device according to any one of claims 1 to 18, A power generation system comprising a power generation device and a storage device that is electrically connected to the power generation device and stores the electricity generated by the power generation device.

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