Thermal power generation module

Abstract

To provide a thermal power generation modules that can deliver performance according to needs.SOLUTION: A thermal power generation module includes a first thermal power generation element having a first thermoelectric conversion layer and a first electrolyte layer overlapping each other along the stacking direction, a second thermal power generation element having a second thermoelectric conversion layer and a second electrolyte layer overlapping the first thermal power generation element in the stacking direction and overlapping each other along the stacking direction, a first collector electrode located at one end side in the stacking direction, a second collector electrode located at the other end side in the stacking direction, and an insulating member arranged between the first thermal power generation element and the second thermal power generation element in the stacking direction. The first thermal power generation element and the second thermal power generation element are located between the first collector electrode and the second collector electrode in the stacking direction. The first thermal power generation element and the second thermal power generation element are connected in parallel to each other.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermal power generation module, and more particularly to a thermal power generation module that exhibits a thermoelectric conversion function. [Background technology]

[0002] Examples of thermal power generation that utilizes geothermal energy or factory waste heat include methods that utilize the Seebeck effect. Furthermore, examples of thermal power generation that do not utilize the Seebeck effect include the thermal power generation element disclosed in Patent Document 1 listed below. Patent Document 1 listed below discloses that thermal energy is converted into electrical energy by combining an electrolyte with a thermoelectric conversion material that generates thermally excited electrons and holes. By using such a thermal power generation element as a power source for electronic components, it is possible to supply stable power to the electronic components, for example, even in high-temperature environments (e.g., 50°C or higher) where general batteries are prone to degradation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 038988 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described thermal power generation devices can be used under various conditions and for various purposes. Therefore, it is desirable to realize a thermoelectric power generation device that can exhibit performance (e.g., high electromotive force, high output current, etc.) that meets needs.

[0005] An object of one aspect of the present invention is to provide a thermal power generation module that can demonstrate performance that meets needs. [Means for solving the problem]

[0006] A thermal power generation module according to one aspect of the present invention includes a first thermal power generation element having a first thermoelectric conversion layer and a first electrolyte layer overlapping each other along a stacking direction; a second thermal power generation element having a second thermoelectric conversion layer and a second electrolyte layer overlapping the first thermal power generation element in the stacking direction and overlapping each other along the stacking direction; a first collector electrode located at one end side in the stacking direction; a second collector electrode located at the other end side in the stacking direction; and an electron conductive layer located between the first thermal power generation element and the second thermal power generation element in the stacking direction, and the first thermal power generation element and the second thermal power generation element are located between the first collector electrode and the second collector electrode in the stacking direction.

[0007] The thermal power generation module has a first thermal power generation element and a second thermal power generation element that are positioned between the first and second collector electrodes in the stacking direction and overlap each other. For example, by connecting the first and second thermal power generation elements in series, the electromotive force of the thermal power generation module can be improved. Alternatively, by connecting the first and second thermal power generation elements in parallel, the output current of the thermal power generation module can be increased. In this way, by including multiple thermal power generation elements in the thermal power generation module and appropriately adjusting the connection mode of each thermal power generation element, a thermal power generation module that can demonstrate performance tailored to needs can be provided.

[0008] In the thermal power generation module, the first thermal power generation element and the second thermal power generation element may be connected in series via an electron conductive layer. In this case, the first thermal power generation element and the second thermal power generation element are separated from each other by the electron conductive layer. This makes it easier for electrons in the thermal power generation module to flow only in the desired direction, thereby effectively improving the electromotive force of the thermal power generation module.

[0009] The first thermoelectric conversion layer has an electron thermal excitation layer and an electron transport layer stacked in the stacking direction, the electron thermal excitation layer being located between the electron transport layer and the first electrolyte layer, the electron conduction layer being in contact with the electron transport layer and the second electrolyte layer, and the work function or band gap of the electron conduction layer being larger than the band gap of the electron transport layer. In this case, oxidation of the electrolyte at the interface between the electron conduction layer and the second electrolyte layer can be prevented. This makes it easier for electrons in the second electrolyte layer to flow only in the desired direction.

[0010] The second electrolyte layer may be an organic or inorganic electrolyte layer containing metal ions, and the electron-conducting layer may contain a metal, graphite, a conductive oxide, or an electron-conducting polymer material that has a lower ionization tendency than the metal ions in the second electrolyte layer. In this case, even when an organic or inorganic electrolyte layer is used, electrons in the second electrolyte layer tend to flow only in the desired direction.

[0011] In the above case, the electron conductive layer may contain at least one of platinum, gold, silver, and an aluminum alloy as a metal having a lower ionization tendency than the metal ions in the second electrolyte layer, and may contain at least one of indium tin oxide and fluorine-doped tin oxide as a conductive oxide.

[0012] A thermal power generation module according to another aspect of the present invention includes a first thermal power generation element having a first thermoelectric conversion layer and a first electrolyte layer overlapping each other in a stacking direction; a second thermal power generation element having a second thermoelectric conversion layer and a second electrolyte layer overlapping the first thermal power generation element in the stacking direction and overlapping each other in the stacking direction; a first collector electrode located at one end in the stacking direction; a second collector electrode located at the other end in the stacking direction; and an insulating member disposed between the first and second thermal power generation elements in the stacking direction, wherein the first and second thermal power generation elements are located between the first and second collector electrodes in the stacking direction, and the first and second thermal power generation elements are connected in parallel. By appropriately adjusting the connection of the thermal power generation elements, this thermal power generation module can provide performance tailored to specific needs. Furthermore, an insulating member is disposed between the first and second thermal power generation elements, and the first and second thermal power generation elements are connected in parallel. Therefore, the thermal power generation module can be made smaller when viewed in the stacking direction, while increasing the output current of the thermal power generation module.

[0013] The thermal power generation module may further include a third collector located between the insulating member and the first thermal power generation element in the stacking direction, and a fourth collector located between the insulating member and the second thermal power generation element in the stacking direction, wherein the first collector and the third collector are electrically connected to each other, and the second collector and the fourth collector are electrically connected to each other.

[0014] The thermal power generation module may further include a third thermal power generation element located between the insulating member and the second thermal power generation element in the stacking direction, the third thermal power generation element having a third thermoelectric conversion layer and a third electrolyte layer overlapping each other along the stacking direction, and an electron conducting layer located between the second thermal power generation element and the third thermal power generation element in the stacking direction, the second thermal power generation element and the third thermal power generation element being connected in series via the electron conducting layer. In this case, it is possible to achieve both an improvement in the electromotive force of the thermal power generation module and an increase in the current output from the thermal power generation module.

[0015] The first thermoelectric conversion layer has an electron thermal excitation layer and an electron transport layer stacked in the stacking direction, the electron thermal excitation layer being located between the electron transport layer and the first electrolyte layer, the electron conduction layer being in contact with the electron transport layer and the third electrolyte layer, and the work function or band gap of the electron conduction layer being larger than the band gap of the electron transport layer. In this case, oxidation of the electrolyte at the interface between the electron conduction layer and the third electrolyte layer can be prevented. This makes it easier for electrons in the third electrolyte layer to flow only in the desired direction.

[0016] A thermoelectric power generation device according to another aspect of the present invention includes the above-described multiple thermal power generation modules, and in each of the multiple thermal power generation modules, the first thermal power generation element and the second thermal power generation element are connected in series, and the multiple thermal power generation modules are arranged in a direction intersecting the stacking direction, connected in parallel, and integrated with each other. In this case, it is possible to realize a thermoelectric power generation device that achieves both improved electromotive force and increased output current. Therefore, for example, by adjusting the number of thermal power generation modules included in the thermoelectric power generation device, it is possible to provide a thermoelectric power generation device that can demonstrate performance tailored to needs.

[0017] A thermoelectric power generation device according to yet another aspect of the present invention includes the above-described multiple thermal power generation modules, and in each of the multiple thermal power generation modules, the first thermal power generation element and the second thermal power generation element are connected in series, and the multiple thermal power generation modules are arranged in a direction intersecting the stacking direction, connected in series, and integrated with each other. In this case, a thermoelectric power generation device capable of further improving electromotive force can be realized. Therefore, for example, by adjusting the number of thermal power generation modules included in the thermoelectric power generation device, a thermoelectric power generation device that can demonstrate performance according to needs can be provided.

[0018] The thermoelectric power generation device may further include an insulating member provided between adjacent thermal power generation modules, which effectively prevents short circuits between adjacent thermal power generation modules. [Effects of the Invention]

[0019] According to one aspect of the present invention, it is possible to provide a thermal power generation module that can demonstrate performance that meets needs. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a schematic cross-sectional view showing a thermal power generation module according to a first embodiment. [Figure 2] FIG. 2(a) is a schematic cross-sectional view showing a single heat-utilization power generation element and a terminal, and FIG. 2(b) is a schematic diagram for explaining the power generation mechanism of the heat-utilization power generation element. [Figure 3] FIG. 3 is a schematic cross-sectional view showing a thermal power generation module according to a comparative example. [Figure 4] Figure 4(a) is a schematic diagram for explaining the movement of electrons within a thermal power generation module according to a comparative example, and Figure 4(b) is a schematic diagram for explaining the movement of electrons within a thermal power generation module according to the first embodiment. [Figure 5] FIG. 5 is a schematic cross-sectional view showing a thermal power generation module according to the second embodiment. [Figure 6] FIG. 6 is a schematic cross-sectional view showing a thermal power generation module according to a modified example of the second embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view showing an example of a thermoelectric power generation device. [Figure 8] FIG. 8 is a schematic cross-sectional view showing another example of a thermoelectric power generating device. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same elements or elements having the same functions will be denoted by the same reference numerals, and redundant description will be omitted.

[0022] (First embodiment) First, the configuration of a thermal power generation module according to the first embodiment will be described with reference to FIG. 1. FIG. 1 is a schematic cross-sectional view showing a thermal power generation module according to the first embodiment. The thermal power generation module 1 shown in FIG. 1 is an assembly of components that generate electricity when heat is supplied from the outside (i.e., thermoelectric generators that convert thermal energy into electrical energy). The thermal power generation module 1 includes a plurality of thermal power generation elements 2, a plurality of electron conductive layers 3, and a pair of collector electrodes 4, 5. The shape of the thermal power generation module 1 is not particularly limited. The shape of the thermal power generation module 1 in a plan view may be, for example, a polygonal shape such as a rectangle, a circle, or an ellipse.

[0023] The plurality of thermal power generation elements 2, the plurality of electron conductive layers 3, and the pair of collector electrodes 4, 5 are stacked one on top of the other in a predetermined direction. The plurality of thermal power generation elements 2 and the plurality of electron conductive layers 3 are located between the pair of collector electrodes 4, 5. Hereinafter, the predetermined direction will be referred to simply as the "stacking direction." In addition, in this specification, "same" is a concept that includes not only "completely same" but also "substantially same."

[0024] Each of the multiple thermal power generation elements 2 is a thermoelectric power generator having the same shape, and generates thermally excited electrons and holes when heat is supplied from the outside. The generation of thermally excited electrons and holes by the thermal power generation elements 2 is carried out, for example, at a temperature of 25°C or higher and 300°C or lower. From the viewpoint of generating a sufficient number of thermally excited electrons and holes, the thermal power generation elements 2 may be heated to, for example, 50°C or higher when the thermal power generation module 1 is in use. From the viewpoint of effectively preventing deterioration of the thermal power generation elements 2, the thermal power generation elements 2 may be heated to, for example, 200°C or lower when the thermal power generation module 1 is in use. The temperature at which a sufficient number of thermally excited electrons are generated is, for example, when the thermally excited electron density of the thermal power generation elements 2 is 10 15 / cm 3 The temperature at which the temperature is equal to or higher than this.

[0025] In the first embodiment, the plurality of thermal power generation elements 2 are stacked one on top of the other in the stacking direction and connected in series. The number of the plurality of thermal power generation elements 2 varies depending on the performance required for the thermal power generation module 1.

[0026] The thermal power generation element 2 is a laminated body having a thermoelectric conversion layer 12 and an electrolyte layer 13 that overlap each other in the stacking direction. The thermoelectric conversion layer 12 has an electron thermal excitation layer 12a and an electron transport layer 12b that overlap each other in the stacking direction. In the first embodiment, the stacking order of the electron thermal excitation layer 12a, the electron transport layer 12b, and the electrolyte layer 13 in each thermal power generation element 2 is the same.

[0027] The electron thermal excitation layer 12a is a layer that generates thermally excited electrons and holes in the thermal power generation element 2 and is in contact with the electrolyte layer 13. The electron thermal excitation layer 12a includes a thermoelectric conversion material. The thermoelectric conversion material is a material in which excited electrons increase in a high-temperature environment, and is, for example, a semiconductor material such as a metal semiconductor (Si, Ge), a tellurium compound semiconductor, a silicon germanium (Si-Ge) compound semiconductor, a silicide compound semiconductor, a skutterudite compound semiconductor, a clathrate compound semiconductor, a Heusler compound semiconductor, a half-Heusler compound semiconductor, a metal oxide semiconductor, or an organic semiconductor. From the viewpoint of generating sufficient thermally excited electrons at a relatively low temperature, the thermoelectric conversion material may be germanium (Ge).

[0028] The electron thermal excitation layer 12a may contain multiple thermoelectric conversion materials. The electron thermal excitation layer 12a may also contain materials other than thermoelectric conversion materials. For example, the electron thermal excitation layer 12a may contain a binder that binds the thermoelectric conversion materials together, a sintering aid that assists in molding the thermoelectric conversion materials, etc. The electron thermal excitation layer 12a may be formed by, for example, a squeegee method, a screen printing method, a spark plasma sintering method, a compression molding method, a sputtering method, a vacuum deposition method, a chemical vapor deposition method (CVD method), a spin coating method, etc.

[0029] The electron transport layer 12b transports thermally excited electrons generated in the electron thermal excitation layer 12a to the outside and is located on the opposite side of the electrolyte layer 13 in the stacking direction via the electron thermal excitation layer 12a. Therefore, in the thermal power generation element 2, the electron transport layer 12b, the electron thermal excitation layer 12a, and the electrolyte layer 13 are stacked in this order in the stacking direction. The electron transport layer 12b contains an electron transport material. The electron transport material has a conduction potential that is the same as or more positive than that of the thermoelectric conversion material. The difference between the conduction potential of the electron transport material and that of the thermoelectric conversion material is, for example, 0.01 V or more and 0.1 V or less. The electron transport material is, for example, a semiconductor material or an electron-transporting organic material. The electron transport layer 12b can be formed by, for example, a squeegee method, a screen printing method, a spark plasma sintering method, a compression molding method, a sputtering method, a vacuum deposition method, a CVD method, a spin coating method, or the like.

[0030] The semiconductor material used for the electron transport material is, for example, the same as the semiconductor material contained in the electron thermal excitation layer 12a. Examples of electron transport organic materials include N-type conductive polymers, N-type small molecule organic semiconductors, and π-electron conjugated compounds. The electron transport layer 12b may contain multiple electron transport materials. The electron transport layer 12b may also contain materials other than the electron transport material. For example, the electron transport layer 12b may contain a binder that binds the electron transport material, a sintering aid that assists in molding the electron transport material, and the like. From the viewpoint of electron transport properties, the semiconductor material may be n-type Si. The electron transport layer 12b containing n-type Si is formed, for example, by doping a silicon layer with phosphorus or the like.

[0031] The electrolyte layer 13 is a layer containing an electrolyte through which charge-transporting ion pairs can migrate at a temperature at which a sufficient number of thermally excited electrons are generated in the thermal power generation element 2. The migration of the charge-transporting ion pairs within the electrolyte layer 13 causes a current to flow through the electrolyte layer 13. A "charge-transporting ion pair" is a stable pair of ions with different valences, such as metal ions. When one ion is oxidized or reduced, it becomes the other ion, allowing the transfer of electrons and holes. The redox potential of the charge-transporting ion pair within the electrolyte layer 13 is more negative than the valence potential of the thermoelectric conversion material contained in the electronic thermal excitation layer 12a. Therefore, at the interface between the electronic thermal excitation layer 12a and the electrolyte layer 13, the ion that is easily oxidized within the charge-transporting ion pair is oxidized and becomes the other ion. The electrolyte layer 13 may also contain ions other than the charge-transporting ion pair. The electrolyte layer 13 can be formed by, for example, a squeegee method, a screen printing method, a sputtering method, a vacuum deposition method, a CVD method, a sol-gel method, or a spin coating method.

[0032] The electrolyte contained in the electrolyte layer 13 is not particularly limited. The electrolyte may be, for example, a liquid electrolyte, a solid electrolyte, or a gel electrolyte. In the first embodiment, the electrolyte layer 13 includes a solid electrolyte. The solid electrolyte is, for example, a substance that is physically and chemically stable at the above-mentioned temperatures and may contain multivalent ions. Examples of the solid electrolyte include sodium ion conductors, copper ion conductors, iron ion conductors, lithium ion conductors, silver ion conductors, hydrogen ion conductors, strontium ion conductors, aluminum ion conductors, fluorine ion conductors, chloride ion conductors, and oxide ion conductors. The solid electrolyte may be, for example, polyethylene glycol (PEG) or a derivative thereof having a molecular weight of 600,000 or less. When the solid electrolyte is PEG, a multivalent ion source such as copper ions or iron ions may be contained in the electrolyte layer 13. From the viewpoint of improving the lifespan, alkali metal ions may be contained in the electrolyte layer 13. The molecular weight of PEG corresponds to the weight-average molecular weight measured in terms of polystyrene by gel permeation chromatography.

[0033] The electrolyte layer 13 may be an organic electrolyte layer or an inorganic electrolyte layer. Whether the electrolyte layer 13 is an organic electrolyte layer or an inorganic electrolyte layer is determined, for example, depending on the composition of the electron conductive layer 3. The organic electrolyte layer is an electrolyte layer whose main component is, for example, one or more organic substances. The organic substance includes at least one of a low-molecular-weight organic compound and a high-molecular-weight organic compound. The inorganic electrolyte layer is an electrolyte layer whose main component is, for example, one or more inorganic substances. The inorganic substance may be a single substance or an inorganic compound. The organic electrolyte layer may contain an inorganic substance, and the inorganic electrolyte layer may contain an organic substance. Each of the organic and inorganic substances may be an electrolyte or may be different from the electrolyte. For example, the electrolyte layer 13 may contain an organic or inorganic substance that functions as a binder to bind the electrolyte or a sintering aid to assist in forming the electrolyte. Examples of organic substances include PEDOT / PSS, N-methylpyrrolidone (NMP), acetonitrile, etc., and inorganic substances include silicon dioxide (SiO2), titanium dioxide (TiO2), aluminum oxide (AlOx), etc. An organic compound with a molecular weight of 10,000 or more is considered a polymer organic compound.

[0034] The electron conductive layer 3 is a layer for conducting electrons moving within the thermal power generation module 1 only in a predetermined direction. In the first embodiment, the electron conductive layer 3 is a layer that exhibits electronic conductivity but does not exhibit ionic conductivity. Therefore, the electron conductive layer 3 can also be considered an ion conduction prevention layer. The electron conductive layer 3 is located between adjacent thermal power generation elements 2 in the stacking direction. Therefore, two adjacent thermal power generation elements 2 in the stacking direction are connected in series to each other via the electron conductive layer 3. In the first embodiment, the electron conductive layer 3 is in contact with both the electrolyte layer 13 of one thermal power generation element 2 and the electron transport layer 12b of the other thermal power generation element 2.

[0035] The electron conductive layer 3 is formed by, for example, a squeegee method, a screen printing method, a spark plasma sintering method, a compression molding method, a sputtering method, a vacuum deposition method, a CVD method, a spin coating method, a plating method, or the like. For example, when the electrolyte layer 13 is an organic electrolyte layer, the electron conductive layer 3 located between adjacent thermal power generation elements 2 is provided on the surface of the electron transport layer 12b included in one of the thermal power generation elements 2 (the surface opposite to the surface on which the electron thermal excitation layer 12a is provided). For example, when the electrolyte layer 13 is an inorganic electrolyte layer, the electron conductive layer 3 is provided on the surface of the electrolyte layer 13 included in the thermal power generation element 2. The thickness of the electron conductive layer 3 is, for example, 0.1 μm or more and 100 μm or less.

[0036] In the first embodiment, the work function (or band gap) of the electron conductive layer 3 is larger than the band gap of the electron transport layer 12b. The difference between the work function or band gap of the electron conductive layer 3 and the band gap of the electron transport layer 12b is, for example, 0.1 eV or more. The valence charge potential of the electron conductive layer 3 may be more positive than the reduction potential of the ions contained in the electrolyte layer 13. In this case, oxidation of the ions is less likely to occur at the interface between the electron conductive layer 3 and the electrolyte layer 13. For example, when the electrolyte layer is an organic electrolyte layer, the electron conductive layer 3 includes a conductive oxide such as ITO (indium tin oxide) or FTO (fluorine-doped tin oxide), an electron-conducting polymer material, or the like. For example, when the electrolyte layer is an inorganic electrolyte layer, the electron conductive layer 3 includes Pt (platinum), Au (gold), Ag (silver), an aluminum alloy (e.g., duralumin, Si-Al alloy), an electron-conducting polymer material, or the like. The electron-conducting polymer material is, for example, PEDOT / PSS. The conduction charge potential of the electron conductive layer 3 may be more negative than the conduction charge potential of the electron transport layer 12b. In this case, electrons are more likely to move from the electron transport layer 12b to the electron conductive layer 3. When the electrolyte layer 13 contains metal ions, the electron conductive layer 3 may contain a metal, graphite, a conductive oxide, or an electron-conducting polymer material that has a lower ionization tendency than the metal ions. Examples of such metals, conductive oxides, and electron-conducting polymer materials are as described above.

[0037] The collector electrode 4 is an electrode that functions as one of the positive and negative electrodes of the thermal power generation module 1 and is located at one end of the thermal power generation module 1 in the stacking direction. The collector electrode 5 is an electrode that functions as the other of the positive and negative electrodes of the thermal power generation module 1 and is located at the other end of the thermal power generation module 1 in the stacking direction. Each of the collector electrodes 4, 5 is, for example, a conductive plate having a single-layer structure or a laminated structure. The conductive plate is, for example, a metal plate, an alloy plate, or a composite plate thereof. To ensure good performance of the thermal power generation module 1, at least one of the collector electrodes 4, 5 may exhibit high thermal conductivity. Because a temperature difference is not required in the thermal power generation module 1, it is desirable that both of the collector electrodes 4, 5 exhibit high thermal conductivity. For example, the thermal conductivity of at least one of the collector electrodes 4, 5 may be 10 W / m·K or higher.

[0038] Next, an overview of the power generation mechanism of the thermal power generation element will be described with reference to FIG. 2. FIG. 2(a) is a schematic cross-sectional view showing a single thermal power generation element and terminals, and FIG. 2(b) is a schematic view for explaining the power generation mechanism of the thermal power generation element. For the purpose of explanation, the charge transport ion pair contained in the electrolyte layer 13 shown in FIGS. 2(a) and 2(b) is assumed to be iron ions (Fe 2+ ,Fe 3+ As shown in FIG. 2(b), first, when the electron thermal excitation layer 12a absorbs heat in a high-temperature environment, electrons e excited in the electron thermal excitation layer 12a are - This electron e - The electrons move to the electron transport layer 12b. As a result, the electron thermal excitation layer 12a receives the electrons h + This hole h + is Fe at the first interface BS1 between the electron thermal excitation layer 12a and the electrolyte layer 13. 2+ That is, this hole h + At the first interface BS1, Fe 2+ As a result, the Fe 2+ Fe 3+ On the other hand, excess electrons e - The electrons e move to the outside, pass through the resistor R and the terminal T, and reach the electrolyte layer 13. The electrons e that have reached the electrolyte layer 13- is Fe at the second interface BS2 between the electrolyte layer 13 and the terminal T. 3+ This reduces the Fe at the second interface BS2. 3+ Fe 2+ Then, the oxidized Fe at the first interface BS1 3+ is diffused toward the second interface BS2, and the reduced Fe 2+ is diffused toward the first interface BS1. This maintains the redox reaction between the first interface BS1 and the second interface BS2. The generation of electrons by thermal excitation and the occurrence of the redox reaction cause the thermal power generation element 2 to generate electricity. Note that the work generated when the electrons pass through the resistance R corresponds to power generation.

[0039] Next, the effects of the thermal power generation module 1 according to the first embodiment described above will be described using the following comparative example. FIG. 3 is a schematic cross-sectional view of a thermal power generation module according to the comparative example. The thermal power generation module 101 shown in FIG. 3 differs from the thermal power generation module 1 according to the first embodiment in that it does not include an electron conduction layer. Therefore, in the thermal power generation module 101, the thermal power generation elements 2 are in contact with each other and are connected in series with each other. Therefore, between adjacent thermal power generation elements 2, the electron transport layer 12b included in one thermal power generation element 2 and the electrolyte layer 13 included in the other thermal power generation element 2 are in contact with each other.

[0040] FIG. 4(a) is a schematic diagram illustrating the movement of electrons in a thermal power generation module according to a comparative example, and FIG. 4(b) is a schematic diagram illustrating the movement of electrons in a thermal power generation module according to the first embodiment. For the purpose of explanation, in FIGS. 4(a) and 4(b), one of the adjacent thermal power generation elements 2 is referred to as the first thermal power generation element 11, and the other is referred to as the second thermal power generation element 21. The electron thermal excitation layer 12a includes a first semiconductor, the electron transport layer 12b includes a second semiconductor, and the electrolyte layer 13 includes a charge transport ion pair (I1, I2). The redox potential of the charge transport ion pair in the electrolyte layer 13 is located within the band gap of the first semiconductor and is more negative than the valence charge potential of the first semiconductor. The valence charge potential of the second semiconductor is more positive than the valence charge potential of the first semiconductor. That is, the redox potential of the charge transport ion pair is more negative than the valence charge potential of the second semiconductor. The valence of the ions I1 is greater than the valence of the ions I2.

[0041] As shown in FIG. 4(a), the electrolyte layer 13 of the first heat power generating element 11 is in contact with both the electron thermal excitation layer 12a included in the first heat power generating element 11 and the electron transport layer 12b included in the second heat power generating element 21. As described above, in the first heat power generating element 11, ions I1 diffuse to the first interface BS1 in the electrolyte layer 13. Although not shown, ions I2 diffuse to the third interface BS3 between the electron transport layer 12b of the second heat power generating element 21 and the electrolyte layer 13 of the first heat power generating element 11. As a result, electrons e from the second heat power generating element 21 to the first heat power generating element 11. - That is, electrons e move along one side of the stacking direction in the thermal power generation module 101. - moves.

[0042] Here, since the electron transport layer 12b contains the second semiconductor, the excited electrons e - can be generated. This electron e - As a result, holes h are also transported to the electron transport layer 12b. +As described above, the valence charge potential of the second semiconductor is more positive than that of the first semiconductor, and the redox potential of the charge-transporting ion pair is more negative than that of the second semiconductor. Therefore, the holes h generated in the electron transport layer 12b + At the third interface BS3, the ions I1 contained in the electrolyte layer 13 are oxidized. Therefore, an oxidation reaction occurs at both ends of the electrolyte layer 13 in the stacking direction. In this case, the ions I1 diffuse not only toward the first interface BS1 side but also toward the third interface BS3 side. As a result, in the electrolyte layer 13, electrons e - Not only do electrons move from the first heat-utilizing power generating element 11 to the second heat-utilizing power generating element 21, but electrons e - In other words, when multiple heat-utilizing power generation elements 2 are simply stacked, electrons e - may move to both sides in the stacking direction of the thermal power generation module 101. In such a case, it becomes difficult to widen the potential difference between adjacent thermal power generation elements 2. Therefore, in the comparative example, even when multiple thermal power generation elements 2 are used, it is difficult to increase the electromotive force of the thermal power generation module 101, and as a result, the output of the thermal power generation module 101 may become lower than the theoretical value.

[0043] In contrast, in the thermal power generation module 1 according to the first embodiment, as shown in FIG. 4(b), an electron conduction layer 3 is located between adjacent thermal power generation elements 2. By providing such an electron conduction layer 3, the electrolyte layer 13 of one thermal power generation element 2 and the electron transport layer 12b of the other thermal power generation element 2 are separated from each other. In this case, holes h + Even if the hole h +cannot take electrons from the ions I1 contained in the electrolyte layer 13. Therefore, the oxidation reaction of the ions I1 can occur only at the first interface BS1. Therefore, the ions I1 contained in the electrolyte layer 13 are less likely to diffuse toward the fourth interface BS4 between the electrolyte layer 13 and the electron conducting layer 3. In other words, the ions I1 tend to diffuse only toward the first interface BS1 in the electrolyte layer 13. This reduces the electron e - is likely to flow only in the desired direction. Therefore, in the thermal power generation module 1, the potential difference between adjacent thermal power generation elements 2 is likely to widen, which can effectively improve the electromotive force of the thermal power generation module 1. In addition, by adjusting the number of thermal power generation elements 2 included in the thermal power generation module 1, the electromotive force of the thermal power generation module 1 can be set to a value that meets needs.

[0044] In the first embodiment, the thermoelectric conversion layer 12 has an electron thermal excitation layer 12a and an electron transport layer 12b stacked in the stacking direction, and the electron thermal excitation layer 12a is located between the electron transport layer 12b included in one of the thermal power generation elements 2 and the electrolyte layer 13 included in the other of the thermal power generation elements 2. The electron conduction layer 3 is in contact with the electron transport layer 12b and the electrolyte layer 13, and the work function or band gap of the electron conduction layer 3 may be larger than the band gap of the electron transport layer 12b. In this case, it is possible to prevent the occurrence of an oxidation reaction of the electrolyte (ions I1) at the fourth interface BS4 between the electron conduction layer 3 and the electrolyte layer 13. This prevents the electrons e in the electrolyte layer 13 from oxidizing. - tends to flow only along the desired direction.

[0045] In the first embodiment, the electrolyte layer 13 is an organic or inorganic electrolyte layer containing metal ions, and the electron conducting layer 3 may contain a metal, graphite, a conductive oxide, or an electron conducting polymer material that has a lower ionization tendency than the metal ions in the electrolyte layer 13. In this case, even if an organic or inorganic electrolyte layer is used as the electrolyte layer 13, the electron e - tends to flow only along the desired direction.

[0046] In the first embodiment, the electron conducting layer 3 may contain at least one of platinum, gold, silver, and an aluminum alloy as a metal having a lower ionization tendency than the metal ions in the electrolyte layer 13, and may contain at least one of indium tin oxide and fluorine-doped tin oxide as a conductive oxide.

[0047] (Second embodiment) The following describes a thermal power generation module according to the second embodiment. In the description of the second embodiment, descriptions that overlap with the first embodiment will be omitted, and only differences from the first embodiment will be described. In other words, to the extent technically possible, the descriptions of the first embodiment may be used appropriately in the second embodiment.

[0048] Fig. 5 is a schematic cross-sectional view showing a thermal power generation module according to embodiment 2. As shown in Fig. 5, the thermal power generation module 1A includes a plurality of thermal power generation elements 2 stacked on top of each other in the stacking direction, a plurality of collector electrodes 4A, 5A, outer electrodes 31, 32, and a plurality of insulating members 33.

[0049] Each thermal power generation element 2 is located between the collector electrodes 4A and 5A in the stacking direction. That is, each thermal power generation element 2 is sandwiched between the collector electrodes 4A and 5A in the stacking direction. In the thermal power generation module 1A, an insulating member 33 is provided between each thermal power generation element 2. Specifically, an insulating member 33 is provided between adjacent collector electrodes 4A and 5A in the stacking direction. Therefore, between two adjacent thermal power generation elements 2, the collector electrode 5A, the insulating member 33, and the collector electrode 4A are stacked in this order along the stacking direction. In other words, the collector electrode 5A is located between the insulating member 33 and one of the thermal power generation elements 2 in the stacking direction, and the collector electrode 4A is located between the insulating member 33 and the other thermal power generation element 2 in the stacking direction. Furthermore, the collector electrode 4A, the thermal power generation element 2, and the collector electrode 5A are stacked in this order between adjacent insulating members 33 in the stacking direction.

[0050] The collector electrode 4A is a conductor that functions as one of the positive and negative electrodes of the thermal power generation element 2 and has a substantially plate shape. The collector electrode 5A is a conductor that functions as the other of the positive and negative electrodes of the thermal power generation element 2 and has a substantially plate shape. The collector electrodes 4A and 5A are made of, for example, the same material as the collector electrodes 4 and 5 of the first embodiment. Parts of the collector electrodes 4A and 5A protrude from each thermal power generation element 2 in a direction intersecting the stacking direction (for example, the horizontal direction). From the viewpoint of preventing contact between the outer electrodes 31 and 32, it is desirable that parts of the collector electrode 4A and the collector electrode 5A protrude in opposite directions.

[0051] The outer electrode 31 is a conductor that functions as one of the positive and negative electrodes of the thermal power generation module 1A and is electrically connected to each collector electrode 4A. The outer electrode 32 is a conductor that functions as the other of the positive and negative electrodes of the thermal power generation module 1A and is electrically connected to each collector electrode 5A. Therefore, in the thermal power generation module 1A, the thermal power generation elements 2 are connected in parallel to each other. To ensure good performance of the thermal power generation module 1A, at least one of the outer electrodes 31, 32 may exhibit high thermal conductivity. For example, the thermal conductivity of at least one of the outer electrodes 31, 32 may be 10 W / m·K or higher. Because the outer electrodes 31, 32 are spaced apart from the thermal power generation elements 2, the outer electrodes 31, 32 may contain copper or the like. Because a temperature difference is not required in the thermal power generation module 1A, it is desirable that both the outer electrodes 31, 32 exhibit high thermal conductivity.

[0052] The insulating member 33 is an insulator that prevents short-circuiting between adjacent thermal power generation elements 2 in the stacking direction and has a generally plate-like shape. The edges of the insulating member 33 may or may not be aligned with the edges of the thermal power generation elements 2 in the horizontal direction. To ensure that the insulating member 33 functions properly, the edges of the insulating member 33 may be positioned outward from the edges of the thermal power generation elements 2 in the horizontal direction. In this case, at least a portion of the edges of the insulating member 33 may be positioned outward from the edges of the thermal power generation elements 2. The insulating member 33 includes, for example, a heat-resistant organic or inorganic insulator. The organic insulator is, for example, a heat-resistant plastic. The inorganic insulator is, for example, a ceramic such as alumina. To ensure that each thermal power generation module 1 performs well, the insulating member 33 may have high thermal conductivity. For example, the thermal conductivity of the insulating member 33 may be 10 W / m·K or more. Alternatively, the insulating member 33 may include a material, particle, or the like that exhibits high thermal conductivity. The member 33 may be electrically conductive, in which case it is completely covered with an insulating material, for example, by painting, vapor deposition, powder coating, extrusion coating, cold spraying, etc.

[0053] To ensure good performance of the thermal power generation module 1A, the insulating member 33 may have high thermal conductivity. For example, the thermal conductivity of the insulating member 33 may be 10 W / m·K or higher. Alternatively, the insulating member 33 may include a thermally conductive member that exhibits high thermal conductivity. This thermally conductive member may be electrically conductive. In this case, the member is completely covered with an insulator. The insulating member 33 may be formed by, for example, painting, vapor deposition, powder coating, extrusion coating, cold spraying, or the like.

[0054] In the thermal power generation module 1A according to the second embodiment described above, the thermal power generation elements 2 are stacked in the stacking direction and connected in parallel to each other, which allows the area of ​​the thermal power generation module 1A as viewed in the stacking direction to be reduced while increasing the output current of the thermal power generation module 1A.

[0055] In the second embodiment, the thermal power generation module 1A includes a collector 5A located between the insulating member 33 and one of the thermal power generation elements 2 in the stacking direction, and a collector 4A located between the insulating member 33 and the other of the thermal power generation elements 2 in the stacking direction, and the collectors 4A are electrically connected to each other, and the collectors 5A are electrically connected to each other. In this case, short circuits between the thermal power generation elements 2 can be effectively prevented.

[0056] Fig. 6 is a schematic cross-sectional view showing a thermal power generation module according to a modified example of the second embodiment. The thermal power generation module 1B shown in Fig. 6 is a combination of the thermal power generation module 1 shown in the first embodiment and the thermal power generation module 1A shown in the second embodiment. Specifically, in the thermal power generation module 1B, a plurality of thermal power generation elements 2 are stacked in the stacking direction between a pair of collector electrodes 4A, 5A and connected in series. Furthermore, an electron conduction layer 3 is located between adjacent thermal power generation elements 2.

[0057] If the thermal power generation elements 2 and electron conductive layers 3 sandwiched between the pair of collector electrodes 4A, 5A are defined as an assembly 41, the thermal power generation module 1B has multiple assemblies 41. From the viewpoint of stabilizing the electromotive force of the thermal power generation module 1B, it is desirable that the numbers of thermal power generation elements 2 and electron conductive layers 3 included in each assembly 41 match each other.

[0058] The thermal power generation module 1B according to this modification achieves the effects of both the first and second embodiments. For example, by adjusting the number of thermal power generation elements 2 included in each assembly 41, the electromotive force of the thermal power generation module 1B can be set to a value that meets the needs. Alternatively, by adjusting the number of assemblies 41, the output current of the thermal power generation module 1B can be set to a value that meets the needs.

[0059] (Third embodiment) Below, a thermoelectric power generation device including a thermal power generation module according to the third embodiment will be described. In the description of the third embodiment, descriptions that overlap with the first and second embodiments will be omitted, and only differences from the first and second embodiments will be described. In other words, to the extent technically possible, the descriptions of the first and second embodiments may be used appropriately in the third embodiment.

[0060] FIG. 7 is a schematic cross-sectional view showing an example of a thermal power generation device. The thermal power generation device 200 shown in FIG. 7 includes a plurality of thermal power generation modules 1 according to the first embodiment. In the thermal power generation device 200, the plurality of thermal power generation modules 1 are connected in parallel and arranged in a direction intersecting the stacking direction (for example, horizontally). In addition, the plurality of thermal power generation modules 1 are integrated with each other. In this example, each pair of collector electrodes included in each thermal power generation module 1 is shared. Specifically, the thermal power generation device 200 includes a pair of collector electrodes 51, 52 that sandwich the thermal power generation element 2 and the electron conduction layer 3 included in each thermal power generation module 1 in the stacking direction. In addition, the thermal power generation device 200 includes an insulating member 53 sandwiched between the pair of collector electrodes 51, 52 in the stacking direction.

[0061] The collector electrode 51 is an electrode that functions as one of the positive and negative electrodes of the thermal power generation device 200 and is located at one end of each thermal power generation module 1 in the stacking direction. That is, the collector electrode 51 functions as one of the positive and negative electrodes of each thermal power generation module 1. The collector electrode 52 is an electrode that functions as the other of the positive and negative electrodes of the thermal power generation device 200 and is located at the other end of each thermal power generation module 1 in the stacking direction. That is, the collector electrode 52 functions as the other of the positive and negative electrodes of each thermal power generation module 1. Each of the collector electrodes 51 and 52 is made of, for example, the same material as the collector electrodes 4 and 5 of the first embodiment. In FIG. 5, each of the collector electrodes 51 and 52 has a single plate shape, but this is not limited to this. For example, each of the collector electrodes 51 and 52 may be a composite of an electrode provided in each thermal power generation module and a wiring or conductive plate that electrically connects these electrodes.

[0062] The insulating member 53 is an insulator located between adjacent thermal power generation modules 1 when viewed from the stacking direction. The insulating member 53 is made of the same material as the insulating member 33 shown in the second embodiment, for example. From the perspective of protecting the thermal power generation device 200, the insulating member 53 surrounds the thermal power generation module 1 when viewed from the stacking direction. From the perspective of preventing contact between adjacent thermal power generation modules 1, it is desirable for the insulating member 53 to be in contact with both of the collector electrodes 51, 52 without any gaps.

[0063] In such a thermoelectric power generation device 200, the electromotive force of the thermoelectric power generation device 200 can be set to a value that meets needs by adjusting the number of thermal power generation elements 2 included in each thermal power generation module 1. In addition, the output current of the thermoelectric power generation device 200 can be set to a value that meets needs by adjusting the number of thermal power generation modules 1. Therefore, it is possible to provide a thermoelectric power generation device 200 that can demonstrate performance that meets needs.

[0064] The thermal power generation device 200 includes an insulating member 53 provided between adjacent thermal power generation modules 1. This effectively prevents short circuits between adjacent thermal power generation modules 1.

[0065] FIG. 8 is a schematic cross-sectional view showing another example of a thermal power generation device. As shown in FIG. 8, the thermal power generation device 300 includes multiple thermal power generation modules 1 connected in series and arranged in a direction intersecting the stacking direction (for example, horizontally). The multiple thermal power generation modules 1 are integrated with each other. For ease of explanation, the thermal power generation device 300 includes a first thermal power generation module 1a, a second thermal power generation module 1b, and a third thermal power generation module 1c arranged in this order from the left side of the page in FIG. 8. The first thermal power generation module 1a and the second thermal power generation module 1b are adjacent to each other, and the second thermal power generation module 1b and the third thermal power generation module 1c are adjacent to each other. The stacking order of the thermal power generation elements 2 included in the first thermal power generation module 1a is the same as the stacking order of the thermal power generation elements 2 included in the third thermal power generation module 1c. On the other hand, the stacking order of the thermal power generation elements 2 included in the second thermal power generation module 1b is different from the stacking order of the first thermal power generation module 1a and the third thermal power generation module 1c.

[0066] The thermal power generation device 300 includes collector electrodes 61 to 64. The collector electrode 61 is a conductor that functions as one of the positive and negative electrodes of the first thermal power generation module 1a and is located at one end of the thermal power generation device 300 in the stacking direction. The collector electrode 62 is a conductor that functions as the other of the positive and negative electrodes of the first thermal power generation module 1a and one of the positive and negative electrodes of the second thermal power generation module 1b and is located at the other end of the thermal power generation device 300 in the stacking direction. The collector electrode 63 is a conductor that functions as the other of the positive and negative electrodes of the second thermal power generation module 1b and one of the positive and negative electrodes of the third thermal power generation module 1c and is located at one end of the thermal power generation device 300 in the stacking direction. The collector electrode 64 is a conductor that functions as the other of the positive and negative electrodes of the third thermal power generation module 1c and is located at the other end of the thermal power generation device 300 in the stacking direction. 8, each of the collector electrodes 62, 63 has a single plate shape, but this is not limited to this. For example, the collector electrode 62 may be a composite of an electrode provided in the first thermal power generation module 1a, an electrode provided in the second thermal power generation module 1b, and wiring or a conductive plate that electrically connects these electrodes.

[0067] The thermal power generation device 300 includes insulating members 65 and 66. The insulating member 65 is an insulator provided between the first thermal power generation module 1a and the second thermal power generation module 1b. To prevent a short circuit between the first thermal power generation module 1a and the second thermal power generation module 1b, the insulating member 65 is provided between the collector electrodes 61 and 63. The insulating member 66 is an insulator provided between the second thermal power generation module 1b and the third thermal power generation module 1c. To prevent a short circuit between the second thermal power generation module 1b and the third thermal power generation module 1c, the insulating member 66 is provided between the collector electrodes 62 and 64. The insulating members 65 and 66 are made of the same material as the insulating member 33 shown in the second embodiment, for example.

[0068] In such a thermoelectric power generation device 300, multiple thermal power generation modules 1 are connected in series to each other, which allows for further improvement in electromotive force. Therefore, it is possible to provide a thermoelectric power generation device 300 that can demonstrate performance that better meets needs.

[0069] The thermal power generation device 300 includes insulating members 65, 66 provided between adjacent thermal power generation modules 1. In this case, short circuits between adjacent thermal power generation modules 1 can be effectively prevented.

[0070] The thermal power generation module and the thermal power generation device including the same according to the present invention are not limited to the above-described embodiment and the above-described modified examples, and various other modifications are possible. For example, while the first embodiment and the like include multiple electron conductive layers, this is not limiting. When the thermal power generation module includes two thermal power generation elements, the thermal power generation module may have one electron conductive layer.

[0071] In the above embodiment and modified example, the thermal power generation element has a thermoelectric conversion layer and an electron transport layer, but is not limited to this. The thermal power generation element may have layers other than the above two layers. Furthermore, the electron conduction layer is in contact with both the electron transport layer and the electrolyte layer, but is not limited to this. For example, some layer may be provided between the electron conduction layer and the electron transport layer. In other words, some layer may be provided between the electron conduction layer and the thermal power generation element.

[0072] In the above embodiment and modified example, the thermal power generation module and the thermal power generation device may each be covered with a protective material or the like. In this case, damage to the thermal power generation module and the thermal power generation device can be suppressed. The protective material may cover the entire thermal power generation module or only a portion of it. For example, the protective material may cover only the side surface of the thermal power generation module. In this case, it is desirable that the protective material cover the side surface without any gaps. Similarly, the protective material may cover the entire thermal power generation device or only a portion of it. From the viewpoint of thermal power generation efficiency, it is desirable that the protective material exhibit high thermal conductivity. Examples of the protective material include a resin containing Si (Si heat transfer resin), ceramics, and highly thermally conductive glass. The protective material may include a thermally conductive material exhibiting high thermal conductivity. This thermally conductive material may be electrically conductive. In this case, the thermally conductive material is completely covered by an insulator.

[0073] In the second embodiment, the electron transport layer is not limited to a semiconductor material. For example, the electron transport layer may be a metal material. Examples of the metal material include metals, alloys, N-type metal oxides, N-type metal sulfides, alkali metal halides, and alkali metals. Examples of the N-type metal include niobium, titanium, zinc, tin, vanadium, indium, tungsten, tantalum, zirconium, molybdenum, and manganese. [Explanation of symbols]

[0074] 1, 1A, 1B...thermal power generation module, 1a...first thermal power generation module, 1b...second thermal power generation module, 1c...third thermal power generation module, 2...thermal power generation element, 3...electron conduction layer, 4, 4A, 5, 5A, 51, 52, 61-64...collecting electrode, 11...first thermal power generation element, 12...thermoelectric conversion layer, 12a...electron thermal excitation layer, 12b...electron transport layer, 13...electrolyte layer, 21...second thermal power generation element, 31, 32...outer electrode, 33, 53, 65, 66...insulating member, 200, 300...thermal power generation device.

Claims

1. a first thermoelectric power generating element having a first thermoelectric conversion layer and a first electrolyte layer overlapping each other along a stacking direction; a second thermoelectric power generating element that overlaps the first thermoelectric power generating element in the stacking direction and has a second thermoelectric conversion layer and a second electrolyte layer that overlap each other along the stacking direction; a first collector electrode located on one end side in the stacking direction; a second collector electrode located on the other end side in the stacking direction; an insulating member disposed between the first heat-utilizing power generation element and the second heat-utilizing power generation element in the stacking direction; a third heat-utilizing power generating element located between the insulating member and the first heat-utilizing power generating element in the stacking direction, the third heat-utilizing power generating element having a third thermoelectric conversion layer and a third electrolyte layer overlapping each other along the stacking direction; an electron conducting layer located between the first thermoelectric power generating element and the third thermoelectric power generating element in the stacking direction and in contact with the first thermoelectric conversion layer and the third electrolyte layer; Equipped with the first heat utilization power generating element and the second heat utilization power generating element are located between the first collector electrode and the second collector electrode in the stacking direction, the first heat utilization power generation element and the second heat utilization power generation element are connected in parallel with each other, the first heat utilization power generation element and the third heat utilization power generation element are connected in series with each other via the electron conduction layer that conducts electrons moving between the first heat utilization power generation element and the third heat utilization power generation element only in a predetermined direction; Thermal power generation module.

2. a third collector electrode located between the insulating member and the first heat-utilizing power generating element in the stacking direction; a fourth collector electrode located between the insulating member and the second heat-utilizing power generating element in the stacking direction, the first collecting electrode and the third collecting electrode are electrically connected to each other; The thermal power generation module according to claim 1 , wherein the second collector electrode and the fourth collector electrode are electrically connected to each other.

3. the first thermoelectric conversion layer has an electron thermal excitation layer and an electron transport layer stacked in the stacking direction, the electron thermal excitation layer is located between the electron transport layer and the first electrolyte layer; the electron conducting layer is in contact with the electron transport layer and the third electrolyte layer; The thermal power generation module according to claim 1 or 2, wherein the work function or band gap of the electron conduction layer is larger than the band gap of the electron transport layer.

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