Power generation element, electronic device, and method for manufacturing power generation element

Abstract

Provided is a power generation element which can be installed on a curved surface and does not require a temperature difference between electrodes. A power generation device is provided with a lamination structural body (110) having a layer structure layered in the Z direction. The lamination structural body (110) includes a plurality of conductive polymer materials (2-1, 2-2) that have conductivity and flexibility and are layered in a prescribed direction. Each of the conductive polymer materials (2-1, 2-2) has: a first electrode layer (4) that is formed on a first main surface (2b) in a manner mechanically supported by the conductive polymer material (2-1, 2-2) and that comprises a first metal having a first work function; and a second electrode layer (3) that is formed on a second main surface (2a) in a manner mechanically supported by the conductive polymer material (2-1, 2-2) and that comprises a second metal having a second work function different from the first work function. A flexible intermediate layer (5), in which nanoparticles are dispersed, is provided between the first electrode layer (4) and the second electrode layer (3) of the mutually adjacent conductive polymer materials (2-1, 2-2).

Description

Power generating element, electronic device, and method for manufacturing power generating element

[0001] The present invention relates to a power generating element using nanoparticles, an electronic device, and a method for manufacturing a power generating element.

[0002] Thermoelectric elements utilizing the Seebeck effect have been developed (see, for example, Patent Document 1).

[0003] Meanwhile, a thermoelectric element has been proposed in which nanoparticles are interposed between a collector electrode and an emitter electrode, and the difference in work function between the two electrodes is utilized to generate electrical energy, as disclosed in, for example, Patent Document 2. Such a thermoelectric element is expected to be applicable to a variety of uses, compared to a configuration in which electrical energy is generated by utilizing a temperature difference applied to the electrodes.

[0004] Furthermore, when using such a thermoelectric element containing nanoparticles as a power generation device, there have been reports of a configuration in which the thermoelectric elements are stacked in order to increase or enhance the current and voltage obtained (see, for example, Patent Document 3).

[0005] On the other hand, in lithium ion batteries and the like, Patent Document 4 discloses an example in which a metal foil (metal current collector foil) has been used as a current collector, but the metal foil is replaced with a resin containing an added conductive material. However, Patent Document 5 points out that such a metal foil layer or a resin current collector may be torn unintentionally during the manufacturing process unless the tear strength, etc., is appropriately controlled.

[0006] JP 2018-182272 A JP 2023-40688 A JP 2022-13535 A JP 2019-75300 A JP 2021-86782 A

[0007] However, (1) the thermoelectric elements described in Patent Documents 2 and 3 have electrodes formed on a silicon substrate, and therefore the electrodes are hard, making them soft and flexible so that they can expand, contract, and bend, i.e., so-called "flexibility." Furthermore, if a conductor such as a metal foil is used as a support for the electrodes to achieve flexibility, problems arise, such as unintentional tearing during the manufacturing process or poor durability against repeated bending after manufacturing, unless the tear strength is appropriately set. (2) As a result of the difficulty of flexibility, the thermoelectric elements described in Patent Documents 2 and 3 have problems, such as being unable to be thermally efficiently installed on the surface of a curved heat source.

[0008] An object of the present invention is to provide a power generating element that is durable against bending and can be installed on a curved object to be measured.

[0009] Another object of the present invention is to provide an electronic device using a power generating element that is durable against bending and can be installed on a curved surface, and a method for manufacturing the power generating element.

[0010] The power generating element according to the first invention is a power generating element for converting thermal energy into electrical energy, and comprises a laminated structure having a layer structure stacked in a predetermined direction, the laminated structure having electrical conductivity and flexibility and including a plurality of conductive polymer layers stacked in a predetermined direction, each conductive polymer layer including: a sheet-like conductive polymer material having a first main surface and a second main surface; a first electrode layer formed on the first main surface so as to be mechanically supported by the conductive polymer material and made of a first metal having a first work function; and a second electrode layer formed on the second main surface so as to be mechanically supported by the conductive polymer material and made of a second metal having a second work function, and further including a plurality of flexible intermediate layers in which nanoparticles are dispersed, each of which is provided between the first electrode layer and the second electrode layer of adjacent conductive polymer layers, and the second work function is different from the first work function.

[0011] In the power generating element according to the second invention, the first electrode layer is formed in advance on a first main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer material, and the second electrode layer is formed in advance on a second main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer material.

[0012] A power generating element according to a third aspect of the present invention is the power generating element according to the first and second aspects of the present invention, wherein the conductive polymer material is a thermoplastic resin or a thermosetting resin and contains a conductive filler.

[0013] A power generating element according to a fourth aspect of the present invention is the conductive polymer material according to any one of the first to third aspects of the present invention, wherein the volume resistivity is 500 Ω cm or less, the thickness is 50 to 150 μm, and the modulus of elasticity is 30 MPa or less.

[0014] In the power generating element according to the fifth aspect of the present invention, the intermediate layer of any one of the first to fourth aspects of the present invention is formed in a flexible state after applying a material in which nanoparticles are dispersed in an insulating material onto a second electrode layer formed on a sheet-like conductive polymer material.

[0015] A power generating element according to a sixth aspect of the present invention is the power generating element according to any one of the first to fifth aspects of the present invention, wherein the insulating material is an organic polymer compound.

[0016] The electronic device of the seventh invention is an electronic device that measures the physical quantity of an object to be measured, and includes a power generating element that is attached along the curved portion of a heat source having a curved portion and is deformed into a curved shape due to its flexibility, and a detection device that receives electrical energy from the power generating element and measures the physical quantity of the object to be measured. the power generating element is a power generating element for converting thermal energy into electrical energy, and comprises a laminated structure having a layer structure laminated in a predetermined direction, the laminated structure comprising: a plurality of conductive polymer layers that are conductive and flexible and laminated in the predetermined direction, each of the conductive polymer layers comprising: a sheet-like conductive polymer material having a first main surface and a second main surface; a first electrode layer formed on the first main surface so as to be mechanically supported by the conductive polymer material, the first electrode layer being made of a first metal having a first work function; and a second electrode layer formed on a second main surface opposite the first main surface in the predetermined direction so as to be mechanically supported by the conductive polymer material, the second electrode layer being made of a second metal having a second work function; and the power generating element further comprises a plurality of flexible intermediate layers in which nanoparticles are dispersed, the intermediate layers being provided respectively between the first electrode layer and the second electrode layer of the conductive polymer layers adjacent to each other, and the second work function is different from the first work function. In the electronic device of the eighth invention, the first electrode layer is formed in advance on a first main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer material, and the second electrode layer is formed in advance on a second main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer layer.

[0017] A method for producing a power generating element according to a ninth aspect of the present invention is a method for producing a power generating element including a laminated structure for converting thermal energy into electrical energy, and includes a base sheet forming step of forming a plurality of sheet-shaped base sheets, the base sheet forming step including a conductive polymer material forming step of forming a sheet-shaped conductive polymer material having conductivity and flexibility, a first electrode forming step of forming a first electrode layer made of a first metal having a first work function on a first main surface of the conductive polymer material so as to be mechanically supported by the conductive polymer material, and a second electrode forming step of forming a second electrode layer made of a second metal having a second work function on a second main surface opposite to the first main surface. The method further includes a second electrode forming step of forming a second electrode layer made of the conductive polymer material so as to be mechanically supported by the conductive polymer material, and a laminated structure forming step of sequentially repeating a plurality of unit structure forming steps to form a laminated structure, wherein each unit structure forming step includes an intermediate layer forming step of forming a flexible intermediate layer having nanoparticles dispersed therein on the first electrode layer of one of the base sheets, and an abutting step of abutting the formed intermediate layer with the second electrode layer of another base sheet, wherein the other base sheet corresponds to one of the base sheets in the next unit structure forming step, and the second work function is different from the first work function.

[0018] In addition, a method for supplying electrical energy using a power generation element of the present invention is a method for supplying electrical energy to a detection device, and includes the steps of: installing a detection device for measuring a physical quantity of an object to be measured at a position where the physical quantity can be measured; attaching the power generation element in a state in which it is deformed into a curved shape due to its flexibility along the curved portion of a heat source having a curved portion; and supplying electrical energy from the power generation element to the detection device.

[0019] According to the present invention, a power generating element capable of measuring the temperature of a curved object to be measured can be provided. Furthermore, since the first electrode and the second electrode have different work functions, a temperature difference between the electrodes is not necessarily required when converting thermal energy into electrical energy. Furthermore, since the conductive polymer material has a first electrode layer formed on the first principal surface so as to be mechanically supported, and a second electrode layer formed on the second principal surface so as to be mechanically supported, the conductive polymer layer can have the mechanical strength of the first electrode layer and the second electrode layer, thereby improving bending durability.

[0020] 1 is a schematic cross-sectional view showing a unit structure 10 of a power generating element 100 according to the first embodiment. FIG. 2 is a schematic cross-sectional view showing an electrode layer and an intermediate layer of a power generating element 100 according to the first embodiment. FIG. 3 is a schematic cross-sectional view showing a configuration of a power generating device 200 according to the first embodiment. FIG. 4 is a flowchart showing a manufacturing method for a power generating element 100 according to the first embodiment. FIG. 5 is a schematic cross-sectional view showing a manufacturing process for a power generating element 100 according to the first embodiment. FIG. 6 is an external perspective view showing an aspect in which a power generating device 200 according to a second embodiment is attached to a heat source A to measure a physical quantity of an object to be measured. FIG. 7 is a flowchart showing a method of supplying electrical energy to a detection device 103 according to the second embodiment. FIG. 8 is a schematic cross-sectional view showing another example of the basic structure of a power generating element 100 according to the third embodiment.

[0021] Hereinafter, examples of a power generating element, a power generating device, a method for manufacturing a power generating element, and an electronic device according to embodiments of the present invention will be described with reference to the drawings. In each drawing, the height direction in which the electrodes are stacked is defined as a first direction Z, one planar direction intersecting with, for example, orthogonal to, the first direction Z is defined as a second direction X, and another planar direction intersecting with, for example, orthogonal to, both the first direction Z and the second direction X is defined as a third direction Y. Furthermore, the configurations in each drawing are shown schematically for the purpose of explanation, and the size of each component and the size comparison between components may differ from those shown in the drawings. [First embodiment]

[0022] A first embodiment of the present invention will be described below with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view showing a unit structure 10 of a power generating element 100 according to the first embodiment of the present invention. As will be described later, the configuration shown in FIG. 1 can be applied to other subsequent embodiments. <Power generating element 100>

[0023] The power generating element 100 according to the first embodiment is a power generating element for converting thermal energy into electrical energy. The unit structure 10 in FIG. 1 is a unit structure in the case where the power generating element 100 has a laminated structure, and as will be described later, a plurality of the unit structures 10 are laminated. A configuration in which a plurality of the unit structures 10 are laminated in this manner is referred to as a "laminated structure." A configuration in which a plurality of the unit structures 10 are laminated to supply power to the outside is referred to as a "power generating device" in this specification.

[0024] The power generating element 100 converts thermal energy from an artificial heat source or thermal energy contained in a natural heat source into electrical energy to generate an electric current. The power generating element 100 is, for example, mounted or installed on a heat source (not shown), and outputs electrical energy generated from the power generating element 100 using the thermal energy of the heat source as a source to a load. The load may be, for example, an electrical device. The load is driven, for example, by using the power generating element 100 as a main power source or an auxiliary power source.

[0025] As shown in FIG. 1 , the unit structure 10 of the power generating element 100 has a minimum configuration for power generation, including a first electrode layer 4-1 made of a first metal formed on a first main surface 2b of a sheet-like conductive polymer material 2-1, an intermediate layer 5, and a second electrode layer 3-2 made of a second metal formed on a second main surface 2a of a sheet-like conductive polymer material 2-2 opposite the first main surface 2b, with the intermediate layer 5 sandwiched between them. As shown in FIG. 1 , a second electrode layer 3-1 made of a second metal is formed on the second main surface 2a of the conductive polymer material 2-1, and a first electrode layer 4-2 made of a first metal is formed on the first main surface 2b of the conductive polymer material 2-2. That is, in the unit structure 10, a second electrode layer 3 is formed on the second main surfaces 2a of the conductive polymer material 2-1 and the conductive polymer material 2-2, and a first electrode layer 4 is formed on the first main surface 2b. Hereinafter, the combination of conductive polymer material 2-1, first electrode layer 4, and second electrode layer 3, and the combination of conductive polymer material 2-2, first electrode layer 4, and second electrode layer 3 will be referred to as conductive polymer layer 2, respectively.

[0026] In the unit structure 10, the conductive polymer material 2-1 and the conductive polymer material 2-2 are conductive and flexible. Furthermore, as will be described later, the first electrode layer 4 and the second electrode layer 3 are thin layers, so that the unit structure 10, and further the power generation element 100 in which they are stacked, are flexible as a whole. Here, in this specification, "flexibility" refers to the property of a material to flexibly bend under external force, and refers to the property of being flexible and not easily broken even when bent. A state in which there is little resistance to bending and which can flexibly deform is expressed as "high flexibility."

[0027] FIG. 2 is an enlarged view of the minimum constituent part for generating electricity of the unit structure 10 shown in FIG.

[0028] The first electrode layer 4 and the second electrode layer 3 are provided opposite to each other. The first metal of the first electrode layer 4 and the second metal of the second electrode layer 3 have different work functions.

[0029] The intermediate layer 5 is provided between the first electrode layer 4 and the second electrode layer 3 (gap G). The intermediate layer 5 includes nanoparticles 51 and a solid insulating layer 50. The nanoparticles 51 are fixed in a dispersed state in the insulating layer 50. In this case, movement of the nanoparticles 51 in the gap G is suppressed. This makes it possible to suppress the nanoparticles 51 from being unevenly distributed on one of the electrode layers 3 and 4 over time, which would reduce the amount of electron movement. This makes it possible to stabilize the amount of power generation.

[0030] Here, in the power generating element 100, which does not necessarily require a temperature difference between the electrodes when converting thermal energy into electrical energy, the amount of power generation can be increased by suppressing variations in the gap G on the surfaces along the second direction X and the third direction Y. <Conductive polymer layer 2>

[0031] As described above, when manufacturing the unit structure 10, the conductive polymer layer 2 is used as the substrate.

[0032] Conductive polymer material 2-1 and conductive polymer material 2-2 are thermoplastic resins or thermosetting resins. Examples of thermoplastic resins or thermosetting resins contained in conductive polymer material 2-1 and conductive polymer material 2-2 include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyethernitrile (PEN), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylonitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin, or a mixture thereof. From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), and polymethylpentene (PMP) are preferred. These thermoplastic resins or thermosetting resins may be used alone or in combination. (Thickness of Conductive Polymer Material 2-1 and Conductive Polymer Material 2-2)

[0033] The thickness of the conductive polymer material 2-1 and the conductive polymer material 2-2 is preferably 10 to 200 μm, more preferably 50 to 150 μm. A thickness of 30 μm or more for the conductive polymer material 2-1 and the conductive polymer material 2-2 is preferable because the conductive resin layer has sufficient strength. Furthermore, a thickness of 200 μm or less, preferably 100 μm or less, and more preferably 60 μm or less for the conductive polymer material 2-1 and the conductive polymer material 2-2 is preferable because the electrical resistance (volume resistivity) in the thickness direction is low. If the second electrode layer 3 and the first electrode layer 4 are thin metal layers, the durability to repeated bending may be poor and the tear strength may be low. Therefore, forming the conductive polymer layer 2 with an appropriate thickness allows the production of a power generating element 100 with high bending resistance and tear strength that can withstand the manufacturing process. (Preferable physical properties of the resin made of the conductive polymer material)

[0034] The conductive polymer material 2-1 and the conductive polymer material 2-2 of the power generating element 100 according to this embodiment preferably have a volume resistivity of 500 Ω·cm or less and a thickness of 50 to 150 μm. In addition, in consideration of flexibility, the elastic modulus of the conductive polymer layer 2 is preferably 30 MPa or less.

[0035] Furthermore, by thinning the conductive polymer material 2-1 and the conductive polymer material 2-2 to a predetermined value or less, it is possible to reduce the total thickness when stacking the power generating elements 100. As a result, when the power generating device 200 made up of the power generating elements 100 is installed or attached to a heat source, there are fewer restrictions on the location where the power generating device 200 can be installed or attached to the heat source.

[0036] Furthermore, it is desirable for the thermal conductivity of the conductive polymer material 2-1 and the conductive polymer material 2-2 to be high as a power generating element. For example, the thermal conductivity is desirably 0.1 to 50 W / mK, and more desirably 5 W / mK or higher.

[0037] In order for the conductive polymer material 2-1 and the conductive polymer material 2-2 to exhibit sufficient conductive function, it is preferable that the conductive filler is uniformly dispersed in the conductive polymer material 2-1 and the conductive polymer material 2-2.

[0038] Examples of conductive filler materials include, but are not limited to, metals (nickel, aluminum, stainless steel (SUS), silver, copper, titanium, etc.), conductive carbon (graphite, carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), carbon nanotubes, etc.), and mixtures thereof. The conductive filler may be a particulate ceramic material or a resin material coated with a conductive material (a metal one of the above-mentioned conductive fillers) by plating or the like. These conductive fillers may be used alone or in combination of two or more. Furthermore, alloys or metal oxides of these may also be used.

[0039] Among conductive fillers, metals and conductive carbons are preferred from the viewpoint of electrical stability. Among metals, nickel particles are preferred. Among conductive carbons, carbon black or a mixture of carbon black and carbon nanotubes is preferred, and acetylene black or a mixture of acetylene black and carbon nanotubes is more preferred.

[0040] The shape (form) of the conductive filler is not limited to a particulate form, and may be a form other than a particulate form, such as a carbon nanotube, which is a form that has been put into practical use as a so-called filler-based conductive material.

[0041] In addition to the thermoplastic resin or thermosetting resin and the conductive filler, other components (dispersants, crosslinking accelerators, crosslinking agents, colorants, UV absorbers, plasticizers, etc.) can be appropriately added to the conductive polymer material 2-1 and the conductive polymer material 2-2, as long as the effects of the present invention are not impaired. <Second electrode layer 3, first electrode layer 4>

[0042] 1, conductive polymer material 2-1 and conductive polymer material 2-2 include i) a first electrode layer 4 made of a first metal having a first work function, formed on first main surface 2b so as to be mechanically supported by conductive polymer layer 2, and ii) a second electrode layer 3 made of a second metal having a second work function, formed on second main surface 2a opposite to first main surface 2b in a predetermined direction so as to be mechanically supported by conductive polymer layer 2. The second work function is different from the first work function.

[0043] According to this embodiment, it is possible to provide a power generating element 100 that can be installed along the surface of a curved object A.

[0044] Conductive polymer material 2-1 and conductive polymer material 2-2 are formed so that the first electrode layer 4 is mechanically supported on the first main surface 2b, and so that the second electrode layer 3 is mechanically supported on the second main surface 2a. This allows the conductive polymer layer 2 to have the mechanical strength of the second electrode layer 3 and the first electrode layer 4, thereby enhancing bending durability and preventing tearing during the manufacturing process.

[0045] Here, "mechanically supported" means that, prior to the formation of unit structure 10, second electrode layer 3 and first electrode layer 4, which are thin films, are each supported by conductive polymer layer 2 so as to maintain mechanical strength.

[0046] The term "work function" refers to the minimum energy required to extract electrons from a solid into a vacuum. The work function can be measured using, for example, ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS), or Auger electron spectroscopy (AES).

[0047] In addition, when it is possible to utilize the fact that the work functions are different even if the metal materials are the same, the second electrode layer 3 and the first electrode layer 4 may be made of the same metal material. In this case, the work functions will be different due to differences in the surface conditions of the metal materials (for example, differences in the oxidation state or crystallinity of the surface).

[0048] The power generating element 100 utilizes an electron emission phenomenon that occurs between the second electrode layer 3 and the first electrode layer 4, which have a work function difference, due to the supply of thermal energy from the outside. Therefore, the power generating element 100 emits more electrons as the absolute temperature increases.

[0049] Examples of materials for the second electrode layer 3 and the first electrode layer 4 include materials consisting of a single element such as iron, aluminum, or copper, as well as alloy materials consisting of two or more elements. Non-metallic conductive materials may be used as the material for each of the electrode layers 3 and 4. Examples of non-metallic conductive materials include carbon-based materials such as graphene.

[0050] The thickness of the first electrode layer 4 and the second electrode layer 3 along the first direction Z is, for example, 4 nm to 1 μm. The thickness of the second electrode layer 3 and the first electrode layer 4 along the first direction Z may be, for example, 4 nm to 50 nm.

[0051] The gap G, which indicates the distance between the first electrode layer 4 and the second electrode layer 3, can be set arbitrarily by changing the thickness of the insulating layer 50. For example, by narrowing the gap G, it is possible to increase the electric field generated between the second electrode layer 3 and the first electrode layer 4, thereby increasing the amount of power generated by the power generating element 100. Furthermore, for example, by narrowing the gap G, it is possible to reduce the thickness of the power generating element 100 in the first direction Z.

[0052] The gap G is a finite value of, for example, 500 μm or less. The gap G is, for example, 10 nm or more and 1 μm or less. For example, if the gap G is 200 nm or less, variations in the gap G on the surfaces along the second direction X and the third direction Y may lead to a decrease in the amount of power generation. Furthermore, if the gap G is greater than 1 μm, the electric field generated between the second electrode layer 3 and the first electrode layer 4 may be weakened. For these reasons, it is preferable that the gap G is greater than 200 nm and less than or equal to 1 μm. <Intermediate layer 5>

[0053] 2 , as described above, the power generating element 100 includes the conductive polymer material 2-1, the conductive polymer material 2-2, the second electrode layer 3, and the first electrode layer 4, as well as the intermediate layer 5. The intermediate layer 5 is provided between the second electrode layer 3 and the first electrode layer 4 of the adjacent conductive polymer material 2-1 and conductive polymer material 2-2, respectively, and nanoparticles 51 are dispersed in the intermediate layer 5. The intermediate layer 5 also has flexibility due to the flexibility of the solid insulating layer 50.

[0054] That is, the intermediate layer 5 includes an insulating layer 50 and a plurality of nanoparticles 51. The nanoparticles 51 may have a work function between the work function of the second electrode layer 3 and the work function of the first electrode layer 4.

[0055] Here, the "insulating layer" may be a layer that has insulating properties with respect to electric current but has the property of conducting heat. In fact, it is preferable that the layer has high thermal conductivity for conducting heat.

[0056] The thickness of the insulating layer 50 is a finite value determined by the gap G described above.

[0057] The insulating layer 50 may contain, for example, one type of material, or may contain multiple materials depending on the application. The insulating layer 50 may be configured to include multiple layers containing different materials, or may include a configuration in which each layer is stacked. When the insulating layer 50 includes multiple layers, for example, nanoparticles 51 containing different materials may be dispersed in each layer.

[0058] The material of the insulating layer 50 used in the intermediate layer 5 can be any flexible insulating material that can fix the nanoparticles 51 in a dispersed state, but an organic polymer compound is preferred. When the insulator contains an organic polymer compound, the insulator can be formed flexibly, allowing the power generating element 100 to be formed in a shape suitable for the application, such as curved or bent.

[0059] Examples of organic polymer compounds include polyimide, polyamide, polyester, polycarbonate, poly(meth)acrylate, radical polymerization type photo- or thermosetting resin, photocationic polymerization type photo- or thermosetting resin, epoxy resin, copolymer containing an acrylonitrile component, polyvinylphenol, polyvinyl alcohol, polystyrene, novolac resin, polyvinylidene fluoride, silicone resin, and mixtures thereof.

[0060] The insulating layer 50 includes, for example, a hydrophilic material. In this case, it is easy to maintain the state in which water molecules are in close proximity to the fine particles. For example, materials such as polyvinyl alcohol, methyl cellulose, and polyethylene glycol are used as the insulating layer 50. Note that examples of hydrophilic materials include well-known materials such as nonionic polymers, anionic polymers, cationic polymers, acrylic resins, polyester resins, and polyurethane resins.

[0061] The plurality of nanoparticles 51 are dispersed in the insulating layer. The intermediate layer 5 can be obtained, for example, by applying an insulator in which the nanoparticles 51 are dispersed to the first electrode layer 4.

[0062] The particle diameter of the nanoparticles 51 is set to a finite value, for example, equal to or less than 1 / 10 of the thickness in the predetermined direction Z(+) of the intermediate layer 5. When the particle diameter of the nanoparticles 51 is set to 1 / 10 of the thickness in the predetermined direction Z(+) of the intermediate layer 5, it becomes easier to form the intermediate layer 5 containing the nanoparticles 51 between the second electrode layer 3 and the first electrode layer 4. This improves workability when manufacturing the power generating element 100.

[0063] Here, "nanoparticles" refers to a substance containing a plurality of particles. The nanoparticles 51 are particles having a particle diameter of, for example, 2 nm or more and 100 nm or less. The nanoparticles 51 may include, for example, particles having a median diameter (median diameter: D50) of 3 nm or more and 8 nm or less, or may include, for example, particles having an average particle diameter of 3 nm or more and 8 nm or less. The median diameter or average particle diameter can be measured, for example, using a particle size distribution measuring instrument. As the particle size distribution measuring instrument, for example, a particle size distribution measuring instrument using dynamic light scattering (e.g., Zetasizer Ultra manufactured by Malvern Panalytical, etc.) may be used.

[0064] The nanoparticles 51 may include, for example, a conductive material, and any material may be used depending on the application. The nanoparticles 51 may include one type of material or may include multiple materials depending on the application. The value of the work function of the nanoparticles 51 may be, for example, between the work function of the first electrode layer 4 and the work function of the second electrode layer 3, or may be any value other than between the work function of the first electrode layer 4 and the work function of the second electrode layer 3.

[0065] The nanoparticles 51 include, for example, a metal. As the nanoparticles 51, particles containing one type of material such as gold, silver, or nickel, as well as alloy particles containing, for example, two or more types of materials, may be used.

[0066] The nanoparticles 51 include, for example, a metal oxide. Examples of the nanoparticles 51 that include a metal oxide include metal oxides of at least one element selected from the group consisting of metals and Si, such as zirconia (ZrO2), titania (TiO2), alumina (Al2O3), iron oxide (Fe2O3, Fe3O4), copper oxide (CuO), zinc oxide (ZnO), yttria (Y2O3), niobium oxide (Nb2O5), molybdenum oxide (MoO3), indium oxide (In2O3), tin oxide (SnO2), tantalum oxide (Ta2O5), tungsten oxide (WO3), lead oxide (PbO), bismuth oxide (Bi2O3), ceria (CeO2), and antimony oxide (Sb2O5, Sb2O3). The nanoparticles 51 may include a dielectric material such as barium titanate (BaTiO3) or strontium titanate (SrTiO3).

[0067] Furthermore, the nanoparticles 51 may include, for example, a coating (not shown) on their surfaces. The thickness of the coating is a finite value, for example, 20 nm or less. By providing such a coating on the surfaces of the nanoparticles 51, it is possible to suppress aggregation when the nanoparticles 51 are dispersed in the insulating layer 50, for example. It is also possible to increase the possibility that electrons will move between the second electrode layer 3 and the nanoparticles 51, between multiple nanoparticles 51, and between the first electrode layer 4 and the nanoparticles 51 by utilizing the tunneling effect, for example.

[0068] For example, a material having a carboxyl group, a phosphate group, a thiol group, or a disulfide group is used as the coating. For example, a fatty acid such as oleic acid is used as a material having a carboxyl group. For example, a long-chain alkyl phosphate such as oleyl phosphate is used as a material having a phosphate group. For example, an alkanethiol such as dodecanethiol is used as a material having a thiol group. For example, an alkanedisulfide is used as a material having a disulfide group. <Power Generation Device 200>

[0069] FIG. 3 is a schematic cross-sectional view showing an example of a power generating device including the power generating element according to the first embodiment.

[0070] As shown in FIG. 3 , the power generating device 200 includes a plurality of stacked unit structures 10 to increase electromotive force, a first wiring 101, and a second wiring 102. The unit structures 10 of the power generating element 100 convert thermal energy into electrical energy. Such a power generating device 200 is mounted or installed on, for example, a heat source (not shown), and outputs electrical energy generated by the power generating element 100 using the thermal energy of the heat source to a load R via the first wiring 101 and the second wiring 102. One end of the load R is electrically connected to the first wiring 101, and the other end is electrically connected to the second wiring 102. The load R represents, for example, an electrical device. The load R is driven using the power generating device 200 as a main power source or an auxiliary power source.

[0071] In FIG. 3, the first wiring 101 is connected to the first electrode layer 4, and the second wiring 102 is connected to the second electrode layer 3.

[0072] However, it is desirable that the outermost layer of the laminated unit structures 10 be a thicker electrode layer rather than the first electrode layer 4 or the second electrode layer 3, which are thin-film electrode layers. In this case, the outermost layer may be configured to have a thicker electrode layer adhered thereto or to have an additional metal layer formed to increase the film thickness. Alternatively, the outermost layer may be configured such that the conductive polymer material 2-1 and the conductive polymer material 2-2 are connected to the first wiring and the second wiring, without providing the first electrode layer 4 or the second electrode layer 3.

[0073] Examples of heat sources for the power generating element 100 include electronic devices or electronic components such as a CPU (Central Processing Unit), light-emitting elements such as LEDs (Light Emitting Diodes), engines of automobiles, factory production equipment, the human body, sunlight, and environmental temperature. For example, electronic devices, electronic components, light-emitting elements, engines, and production equipment are artificial heat sources. The human body, sunlight, and environmental temperature are natural heat sources. A power generating device including the power generating element 100 can be installed inside or outside mobile devices such as IoT (Internet of Things) devices and wearable devices, or standalone sensor terminals, and can be used as a replacement for or supplement to batteries. Furthermore, the power generating element 100 can also be applied to larger power generating devices such as solar power generation.

[0074] The power generating element 100 converts, for example, thermal energy emitted by the artificial heat source or thermal energy possessed by the natural heat source into electrical energy to generate current. The power generating element 100 can be provided not only in the electronic device 300, but also in the mobile device, the standalone sensor terminal, or the like. In this case, the power generating element 100 itself can be used as a substitute or auxiliary component for a battery in the mobile device, the standalone sensor terminal, or the like. <Method for Manufacturing the Power Generating Element 100>

[0075] Next, a method for manufacturing the power generating element 100 according to the first embodiment will be described with reference to FIGS.

[0076] FIG. 4 is a flowchart showing a method for manufacturing the power generating element 100 according to the first embodiment of the present invention.

[0077] 5A to 5F are schematic cross-sectional views showing the manufacturing process of the power generating element 100 according to the first embodiment of the present invention.

[0078] As shown in FIG. 4, the flowchart showing the method for manufacturing the power generating element 100 according to the first embodiment includes steps S10 to S14.

[0079] Steps S10 to S12 in Fig. 4 represent a base sheet forming process, which includes a conductive polymer layer forming process (step S10), a second electrode forming process (step S11), and a first electrode forming process (step S12).

[0080] As shown in steps S10 to S12, in the base sheet forming step, a plurality of sheet-shaped base sheets 1 are formed (FIGS. 5(a) to 5(c)). In the base sheet forming step, the number of base sheets to be laminated is previously manufactured.

[0081] As shown in step S10, in the conductive polymer material forming step, a conductive polymer material 2-1 having conductivity and flexibility is formed into a sheet shape (FIG. 5(a)).

[0082] Subsequently, as shown in step S11, in the second electrode formation process, a second electrode layer 3 made of a second metal having a second work function is formed on the second main surface 2a of the conductive polymer material 2-1 so as to be mechanically supported by the conductive polymer material 2-1 (FIG. 5(b)).

[0083] As shown in step S12, in the first electrode formation step, a first electrode layer 4 made of a first metal having a first work function is formed on the first main surface 2b opposite the second main surface 2a so as to be mechanically supported by the conductive polymer layer 2. The second work function is different from the first work function.

[0084] Steps S10 to S12 form a plurality of sheet-like base sheets 1 (FIG. 5(c)). For example, a plurality of sheets of conductive polymer material of a predetermined size may be prepared, and electrode layers 3, 4 may be formed on each main surface of each sheet-like conductive polymer layer 2. Alternatively, a sheet-like base sheet 1 having a large area may be formed first, and then cut and divided into desired sizes to form a plurality of base sheets 1 of the same size.

[0085] The formation of the first electrode layer 4 and the second electrode layer 3 is not particularly limited, but a film formation method capable of forming a metal layer on the surface of a resin, such as a vacuum deposition method or a sputtering method, or an electroless plating method, can be used.

[0086] As described above, "mechanically supported" means that at the stage when the base sheet 1 is formed before the laminate structure is formed, the first electrode layer 4 and the second electrode layer 3 are supported by the conductive polymer material 2-1 and the conductive polymer material 2-22 so as to maintain mechanical strength.

[0087] As shown in step S13, in the laminate structure forming step, although not particularly limited, first, a base sheet 1 is adhered to an outermost electrode layer of a predetermined thickness, or an outermost electrode layer is additionally formed on the second electrode layer 3 of the base sheet 1. Then, an intermediate layer 5 is formed on the first electrode layer 4 of the base sheet 1 (FIG. 5(d)). Note that the outermost layer may be configured such that the conductive polymer material is exposed on the surface without providing the second electrode layer 3.

[0088] After the intermediate layer 5 is formed, the base sheet 1 is further laminated repeatedly, thereby forming a plurality of unit structures in sequence and forming a laminated structure 110 (FIGS. 5(d) and 5(e)).

[0089] That is, the second electrode layer 3 of one of the plurality of base sheets 1 is brought into contact with the intermediate layer 5 formed on the first electrode layer 4 of another base sheet 1. The same lamination process is repeated for this other base sheet, corresponding to the role of the one base sheet in the next unit structure forming step.

[0090] At least the following two processes are conceivable for solidifying the insulating layer 50 in the intermediate layer 5. First, after applying the intermediate layer onto the electrode, solidification (solvent drying, curing by light or heat) is performed layer by layer. This process is desirable when the intermediate layer contains a solvent. Alternatively, second, after completing the process of sequentially forming and stacking unit structures, it is possible to perform a process of solidifying the insulating layer 50 in the intermediate layer 5, for example, by a heat treatment. However, the process of solidifying the insulating layer 50 is not limited to this process, and the timing of solidification can be adjusted depending on the properties of the material used to form the insulating layer 50.

[0091] As shown in step S14, after forming the laminated structure 110, in the process of forming an outermost electrode, an outermost electrode layer of a predetermined thickness is adhered to the first electrode layer 4, which is the outermost layer of the finally formed laminated structure, or an outermost electrode layer is additionally formed ( FIG. 5( f) ). Note that the outermost layer may be configured such that the conductive polymer material appears on the surface without providing the first electrode layer 4.

[0092] As described above, according to the manufacturing method of this embodiment, it is possible to easily manufacture the power generating element 100 that has high bending durability and is capable of measuring the temperature of a curved object to be measured.

[0093] 5(a) to 5(c), the conductive polymer material 2-1 (in the following description, all conductive polymer materials will be referred to as "2-1") of the power generating element 100 according to the first embodiment is a sheet-like material, and the second electrode layer 3 is formed in advance on the second main surface 2a of the conductive polymer material 2-1 so as to be mechanically supported by the conductive polymer material 2-1 before the formation of the laminate structure 110. The first electrode layer 4 is formed in advance on the first main surface 2b of the conductive polymer material 2-1 so as to be mechanically supported by the conductive polymer material 2-1 before the formation of the laminate structure 110.

[0094] As shown in FIG. 5( d ), the intermediate layer 5 of the power generating element 100 according to the first embodiment is formed by applying a material in which nanoparticles 51 are dispersed in an insulating material onto the first electrode layer 4 formed on the sheet-like conductive polymer material 2-1, and then solidifying the material into a flexible state.

[0095] As a result, the first electrode layer 4, the second electrode layer 3, and the conductive polymer material 2-1 are also flexible, and therefore, according to this embodiment, it is possible to easily manufacture a power generating element 100 that is durable against bending and can be placed on the surface of a curved heat source A.

[0096] Furthermore, by forming the second electrode layer 3 and the first electrode layer 4 so as to be mechanically supported by the conductive polymer material 2-1, it is possible to suppress a decrease in tear strength due to the second electrode layer 3 and the first electrode layer 4 being thin layers, and it is possible to suppress unintentional tearing of the second electrode layer 3 or the first electrode layer 4 during the manufacturing process of the power generating element 100. [Second Embodiment]

[0097] Next, an electronic device 300 according to a second embodiment will be described with reference to FIG.

[0098] The electronic device 300 includes the power generation device 200 described in the first embodiment, and a detection device 103 that receives a supply of electric power from the power generation device 200 and measures a predetermined physical quantity.

[0099] The first wiring 101 and the second wiring 102 are connected to the detection device 103 , and the current generated by the power generation device 200 is supplied to the detection device 103 .

[0100] FIG. 6 is an external perspective view showing a state in which the power generating device 200 according to the second embodiment is attached to a heat source A.

[0101] The heat source A is, for example, a cylindrical pipe through whose interior B hot water (or other fluid as a heat medium) at a predetermined temperature flows.

[0102] Here, as an example, the detection device 103 will be described as measuring a physical quantity on the surface of the heat source A, for example, the surface temperature of a pipe.

[0103] The power generation device 200 can be attached in a state where it is deformed into a curved shape due to its flexibility along a curved portion C on the surface of the heat source A, which is both a heat supply source and an object to be measured. The detection device 103 receives a supply of electric energy from the power generation device 200 and measures a physical quantity (for example, temperature) of the object to be measured A.

[0104] As a method for measuring temperature, well-known temperature measurement methods such as infrared rays and thermocouples can be used. Furthermore, since the detection device 103 functions as an IoT (Internet of Things) device, it is possible to transmit measurement result data to the outside, for example, by a predetermined wireless communication method. Power for such communication is also supplied from the power generation device 200.

[0105] The above-described configuration for measuring a physical quantity is merely an example, and the heat supply source and the object to be measured do not necessarily have to be the same. The power generation device 200 may be configured to receive heat from a heat source, while the detection device 103 measures the physical quantity of another object to be measured.

[0106] Furthermore, the physical quantity measured by the detection device 103 is not limited to temperature. Therefore, the detection device 103 may be a temperature detection device, or may be a device that detects other physical quantities, such as a current detection device, a voltage detection device, or a pressure detector.

[0107] Next, a method of supplying electrical energy to the detection device 103 according to the second embodiment will be described with reference to FIG.

[0108] FIG. 7 is a flowchart showing a method for supplying electrical energy to the detection device 103 according to the second embodiment.

[0109] Referring to FIG. 7, as shown in step 20, a detection device 103 for measuring a physical quantity of an object to be measured is installed at a position where the physical quantity can be measured.

[0110] Next, in step S21, the power generating device 200 is attached along the curved portion C of the heat source A having the curved portion C in a state where it is deformed into a curved shape due to its flexibility.

[0111] In step S22, the power generation device 200 supplies electrical energy to the detection device 103, thereby starting to operate as an IoT device.

[0112] With the above-described configuration, the power generating element 100 of the power generating device 200 is flexible, so that the power generating element 100 can be arranged along a curved surface, and the area of ​​the power generating element 100 can be increased while improving the efficiency of receiving heat supplied from a heat source. This allows for greater freedom in the installation location of the power generating device 200, and makes it possible to increase the power supplied by the power generating device 200. [Third Embodiment]

[0113] FIG. 8 is a schematic cross-sectional view showing another example of the basic structure of the power generating element 100 according to the third embodiment.

[0114] The difference between the first embodiment shown in Fig. 2 and the third embodiment is that the intermediate layer 5 includes a locking member 52. Note that a description of the same configuration as that described above will be omitted.

[0115] 8, the intermediate layer 5 includes a plurality of locking members 52 for maintaining a constant distance between the first electrode layer 4 and the second electrode layer 3. The locking members 52 may have any shape, such as a spherical shape or a cylindrical shape, depending on the application.

[0116] The locking member 52 is made of an insulating material, such as a metal oxide, such as zirconia (ZrO2), silica (SiO2), or alumina (Al2O3).

[0117] The locking member 52 has a size equivalent to the value of the gap G described above. In other words, the locking member 52 has a size equivalent to the thickness of the insulating layer 50 described above. The locking member 52 is, for example, spherical and has a median diameter larger than that of the nanoparticles 51.

[0118] Next, an example of a method for manufacturing the power generating element 100 according to the third embodiment will be described. The difference between the first embodiment and the third embodiment is that in the step of forming the intermediate layer, not only the nanoparticles 51 but also the locking members 52 are dispersed in the intermediate layer 5.

[0119] Therefore, in the process of forming the intermediate layer 5 , an insulating material containing a mixture of nanoparticles 51 and a plurality of locking members 52 is applied to the surface of the first electrode layer 4 .

[0120] Before the insulating layer 50 solidifies, the width of the gap G can be easily controlled by applying an appropriate pressure when the second electrode layer 3 of the conductive polymer layer 2 is placed on the insulating material.

[0121] According to this embodiment, the intermediate layer 5 includes a plurality of locking members 52 that maintain the distance between the first electrode layer 4 and the second electrode layer 3, thereby suppressing variations in the gap caused by variations in the thickness of the insulating layer 50. This makes it possible to further increase the amount of power generation.

[0122] Therefore, according to the power generating element and the power generating device of each of the above-described embodiments, the first electrode layer and the second electrode layer are formed in advance on the conductive polymer layer formed from a sheet-like material before the laminate structure is formed, which facilitates the formation of the power generating element. Furthermore, by forming the first electrode layer and the second electrode layer so as to be mechanically supported by the conductive polymer layer, it is possible to suppress a decrease in tear strength due to the first electrode layer and the second electrode layer being thin layers, and it is possible to suppress unintentional tearing of the first electrode layer or the second electrode layer during the manufacturing process.

[0123] Furthermore, by including a conductive filler in the conductive polymer layer, the polymer layer can be made conductive. Furthermore, conductive fillers have the advantage of being relatively less susceptible to deterioration over time compared to other materials, making their conductivity less susceptible to deterioration over time. This improves the ease of handling during the polymer layer formation process and material storage. Furthermore, polythermoplastic resins or thermosetting resins have excellent mechanical properties such as tensile strength, tear strength, and impact strength, as well as excellent waterproofness, moisture resistance, chemical resistance, and light weight.

[0124] Furthermore, the strength of the conductive resin layer can be maintained sufficiently, which in turn can maintain the strength of the power generating element sufficiently, and the electrical resistance value in the thickness direction (volume resistivity) can be reduced.

[0125] Furthermore, an electronic device can be obtained that includes a detection device that measures the physical quantity of an object to be measured, without necessarily having a separate power supply.

[0126] As described above, several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions and their equivalents as defined in the claims.

[0127] REFERENCE SIGNS LIST 100 Power generating element 1 Base material sheet 10 Unit structure 2 Conductive polymer layer 2-1 Conductive polymer material 2-2 Conductive polymer material 2a Second main surface 2b First main surface 3 Second electrode layer 4 First electrode layer 5 Intermediate layer 50 Insulating layer 51 Nanoparticles 52 Locking member 101 First wiring 102 Second wiring 103 Detector 110 Laminated structure 200 Power generating device 300 Electronic device

Claims

1. A power generating element for converting thermal energy into electrical energy, comprising a laminated structure having a layer structure stacked in a predetermined direction, the laminated structure comprising: a plurality of conductive polymer layers that are conductive and flexible and stacked in the predetermined direction, each of the conductive polymer layers comprising: a sheet-like conductive polymer material having a first main surface and a second main surface; a first electrode layer formed on the first main surface so as to be mechanically supported by the conductive polymer material, the first electrode layer being made of a first metal and having a first work function; and a second electrode layer formed on the second main surface so as to be mechanically supported by the conductive polymer material, the second electrode layer being made of a second metal and having a second work function, the power generating element further comprising a plurality of flexible intermediate layers in which nanoparticles are dispersed, the intermediate layers being provided respectively between the first electrode layer and the second electrode layer of the conductive polymer layers adjacent to each other, and the second work function being different from the first work function.

2. A power generating element as described in claim 1, wherein the first electrode layer is formed in advance on the first main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer material, and the second electrode layer is formed in advance on the second main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer material.

3. The power generating element according to claim 1 or 2, wherein the conductive polymer material is a thermoplastic resin or a thermosetting resin and contains a conductive filler.

4. The power generating element according to claim 1 or 2, wherein the conductive polymer material has a volume resistivity of 500 Ω·cm or less, a thickness of 50 to 150 μm, and a modulus of elasticity of 30 MPa or less.

5. A power generating element according to claim 1 or claim 2, wherein the intermediate layer is formed by applying a material in which the nanoparticles are dispersed in an insulating material onto the second electrode layer formed on the sheet-like conductive polymer material, and then solidifying the material into a flexible state.

6. The power generating element according to claim 5, wherein the insulating material is an organic polymer compound.

7. An electronic device for measuring a physical quantity of an object to be measured, comprising: a power generating element attached in a state where it is deformed into a curved shape due to its flexibility along a curved portion of a heat source having a curved portion; and a detection device that receives electrical energy from the power generating element and measures the physical quantity of the object to be measured, wherein the power generating element is a power generating element for converting thermal energy into electrical energy, and comprises a laminated structure having a layer structure stacked in a predetermined direction, the laminated structure having electrical conductivity and flexibility and including a plurality of conductive polymer layers stacked in the predetermined direction, each of the conductive polymer layers comprising: a sheet-like conductive polymer material having a first main surface and a second main surface; a first electrode layer formed on the first main surface so as to be mechanically supported by the conductive polymer material and made of a first metal having a first work function; and a second electrode layer formed on the second main surface so as to be mechanically supported by the conductive polymer material and made of a second metal having a second work function. the second work function is different from the first work function, and the second work function is different from the first work function.

8. An electronic device as described in claim 7, wherein the first electrode layer is formed in advance on the first main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer material, and the second electrode layer is formed in advance on the second main surface of the conductive polymer material before the formation of the laminate structure so as to be mechanically supported by the conductive polymer layer.

9. A method for manufacturing a power generating element including a laminated structure for converting thermal energy into electrical energy, comprising: a base sheet forming step of forming a plurality of sheet-like base sheets, the base sheet forming step comprising: a conductive polymer material forming step of forming a sheet-like conductive polymer material having conductivity and flexibility; a first electrode forming step of forming a first electrode layer made of a first metal having a first work function on a first main surface of the conductive polymer material so as to be mechanically supported by the conductive polymer material; and a second electrode forming step of forming a second electrode layer made of a second metal having a second work function on a second main surface opposite to the first main surface so as to be mechanically supported by the conductive polymer material; and a laminated structure forming step of forming the laminated structure by sequentially repeating a plurality of unit structure forming steps, each unit structure forming step comprising: an intermediate layer forming step of forming a flexible intermediate layer having nanoparticles dispersed on the first electrode layer of one of the plurality of base sheets; and an abutting step of abutting the formed intermediate layer with the second electrode layer of another base sheet, The method for manufacturing a power generating element, wherein the other base material sheet corresponds to the one base material sheet in the next unit structure forming step, and the second work function is different from the first work function.

Images