Heat-utilizing power generation module

Abstract

This heat-utilizing power generation module comprises: a first thermoelectric conversion layer and a second thermoelectric conversion layer that are separated from each other; and an electrolyte layer that is flexible and that overlaps the first thermoelectric conversion layer and the second thermoelectric conversion layer in the lamination direction. The electrolyte layer has a first end section, an intermediate section, and a second end section that are arranged in that order in an intersection direction that intersects the lamination direction. In the lamination direction, the first thermoelectric conversion layer and the first end section overlap each other, and the second thermoelectric conversion layer and the second end section overlap each other.

Description

Thermal power generation module

[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.

[0002] Examples of thermal power generation using geothermal energy or factory waste heat include a method utilizing the Seebeck effect. Furthermore, examples of thermal power generation that do not utilize the Seebeck effect include the thermal power generation element disclosed in International Publication No. 2017 / 038988. International Publication No. 2017 / 038988 discloses converting thermal energy 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, stable power can be supplied to the electronic components, for example, even in high-temperature environments (e.g., 50°C or higher) where general batteries are prone to degradation.

[0003] In order to put the above-described power generation device utilizing heat into practical use, it is necessary to achieve the desired performance in a limited space.

[0004] An object of one aspect of the present invention is to provide a thermal power generation module that can achieve desired performance in a limited space.

[0005] A thermal power generation module according to one aspect of the present invention is as follows.

[0006] [1] A thermal power generation module comprising: a first thermoelectric conversion layer and a second thermoelectric conversion layer spaced apart from each other; and a flexible electrolyte layer overlapping the first thermoelectric conversion layer and the second thermoelectric conversion layer in the stacking direction, wherein the electrolyte layer has a first end portion, a middle portion, and a second end portion arranged in order in a cross direction intersecting the stacking direction, and wherein the first thermoelectric conversion layer and the first end portion overlap each other in the stacking direction, and the second thermoelectric conversion layer and the second end portion overlap each other.

[0007] The thermal power generation module of [1] exhibits flexibility without deformation of the first and second thermoelectric conversion layers due to deformation of the intermediate portion of the flexible electrolyte layer. Therefore, the thermal power generation module can be placed, for example, on the surface of a cylindrical exhaust heat pipe without damage to the thermoelectric conversion layers. Furthermore, in the thermal power generation module, the first thermoelectric conversion layer and the first end of the electrolyte layer overlap each other, and the second thermoelectric conversion layer, which is spaced apart from the first thermoelectric conversion layer, overlaps with the second end of the electrolyte layer. This reduces the thickness of the thermal power generation module compared to simply stacking the first and second thermoelectric conversion layers. Here, for example, by connecting the first and second thermoelectric conversion layers in series via the electrolyte layer, the output voltage can be increased. Furthermore, for example, by connecting the first and second thermoelectric conversion layers in parallel via the electrolyte layer, the output current can be increased. As a result, desired performance can be achieved within a limited space.

[0008] [2] A thermal power generation module described in [1], wherein the electrolyte layer has a first surface and a second surface located on the opposite side of the first surface in the stacking direction, the first thermoelectric conversion layer is in contact with the first surface, and the second thermoelectric conversion layer is in contact with the second surface.

[0009] In the thermal power generation module [2], the deformation of the intermediate portion allows the first thermoelectric conversion layer and the second thermoelectric conversion layer to be arranged on the same plane. Therefore, even when the first thermoelectric conversion layer is in contact with the first surface and the second thermoelectric conversion layer is in contact with the second surface, the thickness of the thermal power generation module can be reduced.

[0010] [3] A thermal power generation module described in [1] or [2], wherein the first end is located on one side of the first thermoelectric conversion layer and the second thermoelectric conversion layer in the stacking direction, and the second end is located on the other side of the first thermoelectric conversion layer and the second thermoelectric conversion layer in the stacking direction.

[0011] In the thermal power generation module [3], the thickness of the thermal power generation module can be further reduced.

[0012] [4] A thermal power generation module according to any one of [1] to [3], wherein the first thermoelectric conversion layer has a first electron thermal excitation layer and a first electron transport layer stacked in order in the stacking direction, the first electron thermal excitation layer being in contact with the first end portion, and the second thermoelectric conversion layer has a second electron thermal excitation layer and a second electron transport layer stacked in order in the stacking direction, the second electron transport layer being in contact with the second end portion.

[0013] In the thermal power generation module [4], the first thermoelectric conversion layer and the second thermoelectric conversion layer can be connected in series to each other, thereby increasing the output voltage.

[0014] [5] A thermal power generation module according to any one of [1] to [3], wherein the first thermoelectric conversion layer has a first electronic thermal excitation layer and a first electron transport layer stacked in order in the stacking direction, the first electronic thermal excitation layer being in contact with the first end portion, and the second thermoelectric conversion layer has a second electronic thermal excitation layer and a second electron transport layer stacked in order in the stacking direction, the second electronic thermal excitation layer being in contact with the second end portion.

[0015] In the thermal power generation module [5], the first thermoelectric conversion layer and the second thermoelectric conversion layer can be connected in parallel to each other, thereby increasing the output current.

[0016] [6] The thermal power generation module according to any one of [1] to [5], wherein the electrolyte layer contains at least one of a low molecular weight organic compound and a high molecular weight organic compound, and polyvalent ions.

[0017] The thermal power generation module [6] exhibits flexibility and allows a current to flow smoothly between the first thermoelectric conversion layer and the second thermoelectric conversion layer.

[0018] [7] The thermal power generation module according to any one of [1] to [6], which is a wound body wound in a direction intersecting the stacking direction.

[0019] The thermal power generation module of [7] can be arranged more efficiently in a space that is limited depending on the application.

[0020] According to one aspect of the present invention, it is possible to provide a thermal power generation module that can achieve desired performance in a limited space.

[0021] FIG. 1 is a schematic cross-sectional view showing a thermal power generation module according to an embodiment. FIG. 2 is another schematic cross-sectional view showing a thermal power generation module according to an embodiment. FIG. 3 is a schematic cross-sectional view showing an example of use of a thermal power generation module according to an embodiment. FIG. 4 is a schematic cross-sectional view showing a thermal power generation module according to a first modified example. FIG. 5 is a schematic cross-sectional view showing a thermal power generation module according to a second modified example. FIG. 6 is a schematic cross-sectional view showing a thermal power generation module according to another example of the second modified example. FIG. 7 is a schematic cross-sectional view showing a thermal power generation module according to a third modified example. FIG. 8 is a schematic cross-sectional view showing a thermal power generation module according to another example of the third modified example.

[0022] 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.

[0023] First, the configuration of a thermal power generation module according to one 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 one embodiment. The thermal power generation module 1 shown in Fig. 1 is an assembly of components that generates electricity when heat is supplied from an external source. In other words, the thermal power generation module 1 is an assembly of thermoelectric generators that convert thermal energy into electrical energy.

[0024] The thermal power generation module 1 has, for example, a sheet shape and is flexible. The shape of the thermal power generation module 1 in plan view is not particularly limited. The shape of the thermal power generation module 1 in plan view may be, for example, a polygonal shape such as a rectangle, a circular shape, or an elliptical shape. The thermal power generation module 1 shown in FIG. 1 is in an undeformed state.

[0025] The thermal power generation module 1 includes a plurality of thermal power generation elements 2 having the same configuration. In FIG. 1 , the plurality of thermal power generation elements 2 are arranged along one direction (the vertical direction on the paper in FIG. 1 ). Furthermore, between two adjacent thermal power generation elements 2 in the one direction, a portion of one thermal power generation element 2 overlaps a portion of the other thermal power generation element 2. Hereinafter, the direction in which a portion of one thermal power generation element 2 overlaps a portion of the other thermal power generation element 2 (the horizontal direction on the paper in FIG. 1 ) will be referred to simply as the stacking direction D1. The stacking direction D1 intersects or is perpendicular to the one direction. For this reason, the one direction will be referred to simply as the intersecting direction D2. Note that in this specification, the term "same" is a concept that includes not only "completely the same" but also "substantially the same."

[0026] The multiple thermal power generation elements 2 are thermoelectric generators having the same shape. The thermal power generation elements 2 generate 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 performed, for example, at a temperature of 25°C or higher and 300°C or lower. From the viewpoint of generating a sufficient amount of thermally excited electrons and holes, the thermal power generation elements 2 may be heated to a temperature of, for example, 50°C or higher during use of the thermal power generation module 1. Note that, for example, a temperature at which a sufficient number of thermally excited electrons are generated is a temperature at which the thermally excited electron density of the thermal power generation elements 2 is 1015 / cm3 or higher. On the other hand, from the viewpoint of effectively preventing deterioration of the thermal power generation elements 2, the thermal power generation elements 2 may be heated to a temperature of, for example, 200°C or lower during use of the thermal power generation module 1. The power generation mechanism of the thermal power generation elements 2 is similar to the power generation mechanism described, for example, in JP 2021-005651 A.

[0027] The thermal power generation element 2 is a laminate including a thermoelectric conversion layer 3 and an electrolyte layer 4 that are stacked in order in the stacking direction D1. The thermoelectric conversion layer 3 includes an electron thermal excitation layer 5 and an electron transport layer 6 that are stacked in order in the stacking direction D1. In this embodiment, the electrolyte layer 4, the electron thermal excitation layer 5, and the electron transport layer 6 are stacked in this order along the stacking direction D1.

[0028] The electron thermal excitation layer 5 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 4. The electron thermal excitation layer 5 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, a metal sulfide semiconductor, or an organic semiconductor. From the viewpoints of generating sufficient thermally excited electrons at a relatively low temperature and of flexibility, the thermoelectric conversion material may be germanium (Ge).

[0029] The electron thermal excitation layer 5 may contain multiple thermoelectric conversion materials. The electron thermal excitation layer 5 may also contain materials other than thermoelectric conversion materials. For example, the electron thermal excitation layer 5 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 5 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. The thickness of the electron thermal excitation layer 5 is, for example, 0.1 μm or more and 5 μm or less.

[0030] The electron transport layer 6 is a layer that transports thermally excited electrons generated in the electron thermal excitation layer 5 to the outside, and is located on the opposite side of the electrolyte layer 4 across the electron thermal excitation layer 5 in the stacking direction D1. The electron transport layer 6 is in contact with the electron thermal excitation layer 5. In this embodiment, the outer shape of the electron transport layer 6 matches the outer shape of the electron thermal excitation layer 5 in a plan view.

[0031] The electron transport layer 6 includes an electron transport material. The electron transport material is a material whose conduction potential 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 the conduction potential 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, an electron transporting organic substance, or the like. The electron transport layer 6 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, or the like. The thickness of the electron transport layer 6 is, for example, 0.1 μm or more and 5 μm or less.

[0032] 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 5. The electron transport organic material is, for example, an N-type conductive polymer, an N-type small molecule organic semiconductor, a π-electron conjugated compound, etc. The electron transport layer 6 may contain multiple electron transport materials. The electron transport layer 6 may also contain a material other than the electron transport material. For example, the electron transport layer 6 may contain a binder that binds the electron transport material, a sintering aid that assists in molding the electron transport material, etc. From the viewpoint of electron transportability and flexibility, the semiconductor material may be n-type Si. The electron transport layer 6 containing n-type Si is formed, for example, by doping a silicon layer with phosphorus or the like.

[0033] The electrolyte layer 4 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 movement of the charge-transporting ion pairs within the electrolyte layer 4 causes a current to flow through the electrolyte layer 4. A "charge-transporting ion pair" is a stable pair of ions with different valences. 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 4 is more negative than the valence potential of the thermoelectric conversion material contained in the electronic thermal excitation layer 5. Therefore, at the interface between the electronic thermal excitation layer 5 and the electrolyte layer 4, the ion that is more easily oxidized within the charge-transporting ion pair is oxidized and becomes the other ion. Note that the electrolyte layer 4 may contain ions other than the charge-transporting ion pair. The electrolyte layer 4 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.

[0034] The electrolyte contained in the electrolyte layer 4 is not particularly limited. The electrolyte may be, for example, a solid electrolyte or a gel electrolyte. In this embodiment, the electrolyte layer 4 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 4. From the viewpoint of extending the life of the electrolyte layer 4, alkali metal ions may be contained in the electrolyte layer 4. The molecular weight of PEG corresponds to the weight-average molecular weight measured in terms of polystyrene by gel permeation chromatography.

[0035] The electrolyte layer 4 may be an organic electrolyte layer. The organic electrolyte layer is, for example, an electrolyte layer whose main composition is 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 organic electrolyte layer may also include an inorganic substance. The organic substance may be the electrolyte or may be different from the electrolyte. For example, the electrolyte layer 4 may include an organic or inorganic substance that functions as a binder to bind the electrolyte, a sintering aid to assist in forming the electrolyte, or the like.

[0036] The electrolyte layer 4 is flexible. From the viewpoint of durability, flexibility, and the like of the electrolyte layer 4, the thickness of the electrolyte layer 4 is, for example, 0.1 μm or more and 100 μm or less. The electrolyte layer 4 has a first end 7, a second end 8, and an intermediate portion 9. The first end 7 is a portion that includes one end of the electrolyte layer 4 in the cross direction D2. The second end 8 is a portion that includes the other end of the electrolyte layer 4 in the cross direction D2. The intermediate portion 9 is a portion located between the first end 7 and the second end 8 in the cross direction D2. Therefore, the first end 7, the intermediate portion 9, and the second end 8 are arranged in this order in the cross direction D2.

[0037] The electrolyte layer 4 has a first surface 4a and a second surface 4b located on the opposite side of the first surface 4a in the stacking direction D1. In a plan view, the area of ​​the electrolyte layer 4 is, for example, more than twice the area of ​​the thermoelectric conversion layer 3. In addition, in this embodiment, the length of the electrolyte layer 4 along the cross direction D2 is more than twice the length of the thermoelectric conversion layer 3 along the cross direction D2.

[0038] In this embodiment, in the heat-utilizing power generation element 2, the thermoelectric conversion layer 3 is in contact with the first surface 4a of the electrolyte layer 4. In the stacking direction D1, the thermoelectric conversion layer 3 and the first end portion 7 of the electrolyte layer 4 are in contact with and overlap each other. On the other hand, in the stacking direction D1, the second end portion 8 and the middle portion 9 of the electrolyte layer 4 do not overlap the thermoelectric conversion layer 3. One end of the electron thermal excitation layer 5 in the cross direction D2 and one end of the electrolyte layer 4 in the cross direction D2 may be aligned with each other or may be offset from each other.

[0039] For ease of explanation, the thermal power generation element 2 arranged on one side of the intersecting direction D2 in Fig. 1 (the lower side of the paper in Fig. 1 ) may be referred to as the first thermal power generation element 10. The thermal power generation element 2 adjacent to the first thermal power generation element 10 in the intersecting direction D2 may be referred to as the second thermal power generation element 20. Additionally, the thermoelectric conversion layer 3, electrolyte layer 4, electron thermal excitation layer 5, and electron transport layer 6 of the first thermal power generation element 10 may be referred to as the first thermoelectric conversion layer 31, first electrolyte layer 41, first electron thermal excitation layer 51, and first electron transport layer 61, respectively. Furthermore, the thermoelectric conversion layer 3, electrolyte layer 4, electron thermal excitation layer 5, and electron transport layer 6 of the second thermal power generation element 20 may be referred to as the second thermoelectric conversion layer 32, second electrolyte layer 42, second electron thermal excitation layer 52, and second electron transport layer 62, respectively.

[0040] 1 , a portion of the first heat-utilizing power generation element 10 and a portion of the second heat-utilizing power generation element 20 overlap with each other in the stacking direction D1. Specifically, the second end 8 of the first electrolyte layer 41 included in the first heat-utilizing power generation element 10 overlaps with the second thermoelectric conversion layer 32 included in the second heat-utilizing power generation element 20 in the stacking direction D1. Here, the first end 7 of the first electrolyte layer 41 included in the first heat-utilizing power generation element 10 overlaps with the first thermoelectric conversion layer 31 in the stacking direction D1. Therefore, the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 do not overlap with each other in the stacking direction D1 and are spaced apart from each other in the cross direction D2. Furthermore, the middle portion 9 of the first electrolyte layer 41 does not overlap with either the first thermoelectric conversion layer 31 or the second thermoelectric conversion layer 32 in the stacking direction D1.

[0041] The first surface 4a of the first electrolyte layer 41 contacts the first thermoelectric conversion layer 31. The second surface 4b of the first electrolyte layer 41 contacts the second thermoelectric conversion layer 32. As shown in FIG. 1 , in the undeformed thermal power generation module 1, the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 are located on the same plane perpendicular to the stacking direction D1. In this case, the first end 7 of the first electrolyte layer 41 is located on one side of the stacking direction D1 (the right side of the paper in FIG. 1 ) relative to the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32. The second end 8 of the first electrolyte layer 41 is located on the other side of the stacking direction D1 (the left side of the paper in FIG. 1 ) relative to the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32. That is, the position of the first end 7 in the stacking direction D1 and the position of the second end 8 in the stacking direction D1 may differ from each other. For example, the amount of deviation between the position of the first end 7 in the stacking direction D1 and the position of the second end 8 in the stacking direction D1 is equal to or greater than the thickness of the thermoelectric conversion layer 3. The intermediate portion 9 of the first electrolyte layer 41 deforms (for example, curves or bends) into a shape that connects the first end 7 and the second end 8. As a result, the first end 7 and the second end 8 of the first electrolyte layer 41 are electrically connected to each other via the intermediate portion 9.

[0042] The first electron thermal excitation layer 51 contacts the first end 7 of the first electrolyte layer 41, the second electron transport layer 62 contacts the second end 8 of the first electrolyte layer 41, and the second electron thermal excitation layer 52 contacts the first end 7 of the second electrolyte layer 42. Therefore, the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 are connected in series to each other via the first electrolyte layer 41.

[0043] The first heat power generation element 10 and the second heat power generation element 20 have been described above as an example of the heat power generation element 2. The positional relationship between two adjacent heat power generation elements 2 in the cross direction D2 is the same as the positional relationship between the first heat power generation element 10 and the second heat power generation element 20. Therefore, the multiple heat power generation elements 2 are connected in series with each other.

[0044] The thermal power generation module 1 includes a pair of insulating layers 71, 72. Each of the insulating layers 71, 72 protects the thermal power generation element 2 and exhibits flexibility. The insulating layer 71 is located at one end of the thermal power generation module 1 in the stacking direction D1. The insulating layer 72 is located at the other end of the thermal power generation module 1 in the stacking direction D1. Each of the insulating layers 71, 72 is flexible and heat-resistant. For example, each of the insulating layers 71, 72 is a heat-resistant resin substrate such as a polyimide substrate or a polyphenol substrate. The thickness of each of the insulating layers 71, 72 is, for example, not less than 0.1 μm and not more than 100 μm. In this case, each of the insulating layers 71, 72 exhibits good flexibility.

[0045] The thermal power generation module 1 includes a pair of current collectors (not shown). Each of the pair of current collectors functions as an extraction electrode for power generated by the thermal power generation module 1. One current collector functions as one of the positive and negative electrodes of the thermal power generation module 1. One current collector is connected to the thermal power generation element 2 located at one end of the thermal power generation module 1 in the cross direction D2. The other current collector functions as the other of the positive and negative electrodes of the thermal power generation module 1. The other current collector is connected to the thermal power generation element 2 located at the other end of the thermal power generation module 1 in the cross direction D2. At least a portion of each current collector may be covered with insulating layers 71, 72.

[0046] Each of the pair of current collectors 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. The thickness of each of the pair of current collectors is, for example, 0.1 μm or more and 100 μm or less. In this case, each of the pair of current collectors exhibits good flexibility. From the viewpoint of exhibiting good performance of the thermal power generation module 1, at least one of the pair of current collectors may exhibit high thermal conductivity. For example, the thermal conductivity of at least one of the pair of current collectors may be 10 W / m·K or more. Since a temperature difference is not required in the thermal power generation module 1, it is desirable that both of the pair of current collectors exhibit high thermal conductivity.

[0047] Next, an example of a method for manufacturing the thermal power generation module 1 described above will be described. First, the thermoelectric conversion layer 3 is produced. The thermoelectric conversion layer 3 is formed, for example, by depositing an electron thermal excitation layer 5 on a current collector or an electron transport layer 6 using a thermoelectric conversion material. The thermoelectric conversion material may be deposited by sputtering, for example. The thermoelectric conversion material may also be applied to the current collector in a binder-supported state, or may be applied to the current collector by spraying, for example. For example, when the electron transport layer 6 is a Si substrate, the electron thermal excitation layer 5 may be formed by vacuum-depositing germanium on the electron transport layer 6.

[0048] A flexible electrolyte layer 4 is also fabricated. First, an organic solvent (e.g., dimethyl sulfoxide) to which a polymeric material (ion-conductive polymer) having ion conductivity is added is stirred. Next, a charge-transporting ion pair and a promoting additive (e.g., a solution containing copper (II) chloride, lithium chloride, etc.) are added to the organic solvent and then stirred. This produces an electrolyte solution in which the polymeric material, charge-transporting ion pair, and promoting additive are dissolved.

[0049] Next, an ion-permeable and insulating separator is placed on the glass plate, and the above-mentioned electrolyte solution is applied to the separator. This allows the separator to be impregnated with the electrolyte solution. The electrolyte solution is then dried to form a flexible electrolyte layer 4. The electrolyte solution may be dried by natural drying, vacuum drying, or a known heat drying method.

[0050] Next, multiple thermal power generation elements 2 are fabricated. First, one electrolyte layer 4 is prepared. Next, one thermoelectric conversion layer 3 is placed on the first end 7 of the one electrolyte layer 4. At this time, the thermoelectric conversion layer 3 is placed on the first surface 4a of the electrolyte layer 4. In this way, one thermal power generation element 2 is fabricated. Multiple thermal power generation elements 2 are fabricated using the same procedure. Next, one thermal power generation element 2 and another thermal power generation element 2 are aligned in a predetermined direction, and then the thermoelectric conversion layer 3 of the other thermal power generation element 2 is placed on the second end 8 of the electrolyte layer 4 included in the one thermal power generation element 2. By repeating the process of placing the electrolyte layer 4 and the thermoelectric conversion layer 3 in this way, multiple thermal power generation elements 2 arranged in a predetermined direction (e.g., the intersecting direction D2) can be fabricated.

[0051] Next, an insulating layer 71 is disposed at one end of the plurality of thermal power generation elements 2 in the stacking direction D1, and an insulating layer 72 is disposed at the other end in the stacking direction D1. Through the above steps, the thermal power generation module 1 described above is manufactured.

[0052] The above-described effects of the thermal power generation module 1 according to this embodiment will be described with reference to Fig. 2. Fig. 2 is another schematic cross-sectional view showing the thermal power generation module according to one embodiment.

[0053] As described above, the electrolyte layer 4 of the thermal power generation element 2 is flexible, and the intermediate portion 9 of the electrolyte layer 4 does not overlap with the thermoelectric conversion layer 3 in the stacking direction D1. This makes the intermediate portion 9 of the electrolyte layer 4 most susceptible to deformation in the thermal power generation element 2. Therefore, as shown in FIG. 2 , when the thermal power generation module 1 is wound in the transverse direction D2 so that the center of the thermal power generation module 1 protrudes in the stacking direction D1, each intermediate portion 9 deforms. This allows the thermal power generation module 1 as a whole to exhibit sufficient flexibility. Therefore, the first end 7 and the second end 8 of the electrolyte layer 4 do not deform, and the thermal power generation module 1 as a whole can exhibit sufficient flexibility. Therefore, the thermal power generation module 1 can be placed on, for example, the surface of a cylindrical exhaust heat pipe without damaging the thermoelectric conversion layer 3. Furthermore, the thermal power generation module 1 may be wound in the transverse direction D2 to form a wound body (e.g., a cylindrical wound body) wound in the transverse direction D2. Here, in Figure 2, the center of the thermal power generation module 1 protrudes toward one side in the stacking direction D1 (the left side of the paper in Figure 2), but the center may also protrude toward the other side in the stacking direction D1 (the right side of the paper in Figure 2).

[0054] Furthermore, in the thermal power generation module 1, the first thermoelectric conversion layer 31 and the first end 7 of the electrolyte layer 4 overlap each other, and the second thermoelectric conversion layer 32, which is spaced apart from the first thermoelectric conversion layer 31, and the second end 8 of the electrolyte layer 4 overlap each other. This allows the thickness of the thermal power generation module 1 to be reduced compared to when the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 are simply stacked. Here, by connecting the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 in series via the first electrolyte layer 41, the output voltage can be increased.

[0055] An example of use of the thermal power generation module 1 described above will now be described with reference to FIG. 3 . FIG. 3 is a schematic cross-sectional view illustrating an example of use of a thermal power generation module according to one embodiment. As shown in FIG. 3 , multiple thermal power generation modules 1 having identical configurations are stacked one on top of the other in the stacking direction D1. In this case, for example, by connecting one thermal power generation module 1 and another thermal power generation module 1 adjacent to the one thermal power generation module 1 in the stacking direction D1 in series via current collectors, the output voltage can be increased. Furthermore, for example, by connecting the one thermal power generation module 1 and the other thermal power generation module 1 in parallel, the output current can be increased. Therefore, according to this example of use, the desired performance can be more suitably achieved compared to when a single thermal power generation module 1 is used.

[0056] In this embodiment, the electrolyte layer 4 has a first surface 4a and a second surface 4b located on the opposite side of the first surface 4a in the stacking direction D1, and the first thermoelectric conversion layer 31 is in contact with the first surface 4a, and the second thermoelectric conversion layer 32 is in contact with the second surface 4b. In this case, the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 can be arranged on the same plane by deformation of the intermediate portion 9. Therefore, even when the first thermoelectric conversion layer 31 is in contact with the first surface 4a and the second thermoelectric conversion layer 32 is in contact with the second surface 4b, the thickness of the thermal power generation module 1 can be reduced.

[0057] In this embodiment, the first end 7 is located on one side of the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 in the stacking direction D1, and the second end 8 is located on the other side of the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 in the stacking direction D1. In this case, the thickness of the thermal power generation module 1 can be further reduced.

[0058] In this embodiment, the first thermoelectric conversion layer 31 has a first electron thermal excitation layer 51 and a first electron transport layer 61 that are sequentially stacked in the stacking direction D1, and the first electron thermal excitation layer 51 is in contact with the first end portion 7, and the second thermoelectric conversion layer 32 has a second electron thermal excitation layer 52 and a second electron transport layer 62 that are sequentially stacked in the stacking direction D1, and the second electron transport layer 62 is in contact with the second end portion 8. In this case, the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 can be connected in series with each other, which can increase the output voltage.

[0059] In this embodiment, the electrolyte layer 4 contains at least one of a low-molecular-weight organic compound and a high-molecular-weight organic compound, and polyvalent ions. In this case, the electrolyte layer 4 exhibits flexibility and allows a current to flow smoothly between the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32.

[0060] In this embodiment, the thermal power generation module 1 may be a wound body wound in the cross direction D2, which allows the thermal power generation module 1 to be arranged more efficiently in a limited space depending on the application.

[0061] Next, we will explain thermal power generation modules according to modified examples. In the explanation of each modified example, we will omit descriptions that overlap with the above-described embodiment and only describe the differences. In other words, to the extent technically possible, the descriptions of the above-described embodiment may be used appropriately for each modified example.

[0062] Fig. 4 is a schematic cross-sectional view showing a thermal power generation module according to a first modified example. The thermal power generation module 1A shown in Fig. 4 differs from the thermal power generation module 1 of the above embodiment in that it includes a third thermal power generation element 30 instead of the second thermal power generation element 20.

[0063] The third heat-utilizing power generation element 30 is an element adjacent to the first heat-utilizing power generation element 10 in the cross direction D2, and has a third thermoelectric conversion layer 33 and a third electrolyte layer 43 that overlap each other in the stacking direction D1. The third thermoelectric conversion layer 33 has a third electronic thermal excitation layer 53 and a third electron transport layer 63. In the third heat-utilizing power generation element 30, the third electrolyte layer 43, the third electron transport layer 63, and the third electronic thermal excitation layer 53 are stacked in this order in the stacking direction D1. The third electron transport layer 63 is in contact with the first end portion 7 of the third electrolyte layer 43 and the first surface 4a of the third electrolyte layer 43. The third electronic thermal excitation layer 53 is in contact with the second end portion 8 of the first electrolyte layer 41 included in the first heat-utilizing power generation element 10 and the second surface 4b of the first electrolyte layer 41. Therefore, the first thermoelectric conversion layer 31 and the third thermoelectric conversion layer 33 are connected in parallel to each other via the first electrolyte layer 41 .

[0064] In the first modified example described above, the first heat power generation element 10 and the third heat power generation element 30 are connected in parallel to each other within the thermal power generation module 1A. This makes it possible to increase the output current. Here, in the thermal power generation module 1A, groups of multiple thermal power generation elements 2 that are connected in series to each other are connected in parallel to each other. This makes it possible to achieve both an increase in output voltage and an increase in output current. As described above, even in the first modified example, it is possible to achieve the desired performance in a limited space.

[0065] Next, a thermal power generation module 1B according to a second modification will be described. Fig. 5 is a schematic cross-sectional view showing the thermal power generation module according to the second modification. In Fig. 5, the insulating layers 71 and 72 are not shown.

[0066] 5 differs from the thermal power generation module 1 of the above embodiment in the positional relationship between the two thermal power generation elements 2 adjacent in the intersecting direction D2. Specifically, in a state in which a portion of the second thermal power generation element 20 is stacked on a portion of the first thermal power generation element 10, the second thermoelectric conversion layer 32 of the second thermal power generation element 20 is in contact with the first surface 4a of the first electrolyte layer 41 of the first thermal power generation element 10. In other words, both the first thermoelectric conversion layer 31 and the second thermoelectric conversion layer 32 are in contact with the first surface 4a of the first electrolyte layer 41.

[0067] When the thermal power generation module 1B is in an undeformed state, the electrolyte layers 4 are not curved between the thermoelectric conversion layers 3 and extend along the intersecting direction D2. Therefore, the position of the first end 7 in the stacking direction D1 and the position of the second end 8 in the stacking direction D1 coincide with each other.

[0068] The thermal power generation module 1B according to the second modified example described above also provides the same effects as those of the above embodiment.

[0069] Fig. 6 is a schematic cross-sectional view showing a thermal power generation module according to another example of the second modified example. As in Fig. 5, the insulating layers 71 and 72 are not shown in Fig. 6. The thermal power generation module 1C shown in Fig. 6 corresponds to a combination of the above-described embodiment, the first modified example, and the second modified example.

[0070] In one heat-utilizing power generation element 2 arranged on one side of the intersecting direction D2 in Fig. 6 (the lower side of the paper in Fig. 6), an electrolyte layer 4, an electron thermal excitation layer 5, and an electron transport layer 6 are stacked in this order in the stacking direction D1. In another heat-utilizing power generation element 2 adjacent to the one heat-utilizing power generation element 2 in the intersecting direction D2, an electrolyte layer 4, an electron transport layer 6, and an electron thermal excitation layer 5 are stacked in this order in the stacking direction D1. The thermoelectric conversion layer 3 included in the other heat-utilizing power generation element 2 is in contact with the first surface 4a of the electrolyte layer 4 included in the one heat-utilizing power generation element 2. The one heat-utilizing power generation element 2 and the other heat-utilizing power generation element 2 are connected in parallel to each other.

[0071] 6 ) arranged on the other side of the intersecting direction D2 (upper side of the paper in FIG. 6 ), and in another intersecting heat power generation element 2 adjacent to the one intersecting heat power generation element 2 in the intersecting direction D2, the electrolyte layer 4, the electron transport layer 6, and the electron thermal excitation layer 5 are stacked in this order in the stacking direction D1. The thermoelectric conversion layer 3 included in the other intersecting heat power generation element 2 is in contact with the first surface 4a of the electrolyte layer 4 included in the one intersecting heat power generation element 2. The one intersecting heat power generation element 2 and the other intersecting heat power generation element 2 are connected in series with each other.

[0072] As described above, the thermal power generation module 1C according to another example of the second modified example has two sets of thermal power generation elements 2 connected in parallel and adjacent to each other in the cross direction D2, and also has two sets of thermal power generation elements 2 connected in series and adjacent to each other in the cross direction D2.

[0073] 7 is a schematic cross-sectional view showing a thermal power generation module according to a third modification. In Fig. 7, similarly to Figs. 5 and 6, the insulating layers 71 and 72 are omitted.

[0074] The thermal power generation module 1D shown in FIG. 7 corresponds to a combination of the above embodiment and the second modified example. Specifically, the positional relationship between the first thermal power generation element 10 and the second thermal power generation element 20 is the same as in the second modified example. That is, when a portion of the first thermal power generation element 10 is stacked on a portion of the second thermal power generation element 20, the second thermoelectric conversion layer 32 of the second thermal power generation element 20 contacts the second surface 4b of the first electrolyte layer 41 of the first thermal power generation element 10. In addition, the positional relationship between the second thermal power generation element 20 and another thermal power generation element 2 adjacent to the second thermal power generation element 20 in the cross direction D2 is the same as in the above embodiment. That is, when a portion of the other thermal power generation element 2 is stacked on a portion of the second thermal power generation element 20, the thermoelectric conversion layer 3 of the other thermal power generation element 2 contacts the first surface 4a of the second electrolyte layer 42 of the second thermal power generation element 20.

[0075] In the thermal power generation module 1D according to the third modified example described above, at least a portion of the electrolyte layer 4 is deformed, thereby achieving the same effects as those of the above embodiment.

[0076] Fig. 8 is a schematic cross-sectional view showing a thermal power generation module according to another example of the third modified example. As in Figs. 5 to 7, the insulating layers 71 and 72 are omitted from Fig. 8. The thermal power generation module 1E shown in Fig. 8 corresponds to a combination of the above-described embodiment, the first modified example, and the third modified example.

[0077] In one heat-utilizing power generation element 2 arranged on one side of the intersecting direction D2 in Fig. 8 (the lower side of the paper in Fig. 8), an electrolyte layer 4, an electron thermal excitation layer 5, and an electron transport layer 6 are stacked in this order in the stacking direction D1. In another heat-utilizing power generation element 2 adjacent to the one heat-utilizing power generation element 2 in the intersecting direction D2, an electrolyte layer 4, an electron transport layer 6, and an electron thermal excitation layer 5 are stacked in this order in the stacking direction D1. The thermoelectric conversion layer 3 included in the other heat-utilizing power generation element 2 is in contact with the first surface 4a of the electrolyte layer 4 included in the one heat-utilizing power generation element 2. The one heat-utilizing power generation element 2 and the other heat-utilizing power generation element 2 are connected in parallel to each other.

[0078] On the other hand, in one heat-utilization power generation element 2 arranged on the other side of the intersecting direction D2 in Fig. 8 (the upper side of the paper in Fig. 8), and in another heat-utilization power generation element 2 adjacent to the one heat-utilization power generation element 2 in the intersecting direction D2, the electrolyte layer 4, the electron transport layer 6, and the electron thermal excitation layer 5 are stacked in this order in the stacking direction D1. The thermoelectric conversion layer 3 included in the one heat-utilization power generation element 2 is in contact with the second surface 4b of the electrolyte layer 4 included in the other heat-utilization power generation element 2. The one heat-utilization power generation element 2 and the other heat-utilization power generation element 2 are connected in series to each other.

[0079] As described above, the thermal power generation module 1E according to another example of the third modified example also has a set of two thermal power generation elements 2 connected in parallel and adjacent to each other in the cross direction D2, and also has a set of two thermal power generation elements 2 connected in series and adjacent to each other in the cross direction D2.

[0080] The thermal power generation module according to one aspect of the present invention is not limited to the above embodiment and the above modification, and various other modifications are possible. For example, the above embodiment and the above modification may be appropriately combined as described above. For example, the first modification may be combined with the second or third modification.

[0081] In the above embodiment, an example has been described in which the thermal power generation module 1 is a wound body wound in the transverse direction D2. However, if the electron thermal excitation layer 5 and the electron transport layer 6, in addition to the electrolyte layer 4, are flexible, the thermal power generation module 1 may be a wound body wound in a direction different from the transverse direction D2. For example, the thermal power generation module 1 may be a wound body wound in a direction perpendicular to both the stacking direction D1 and the transverse direction D2 (a direction perpendicular to the plane of the paper in FIG. 2 ).

[0082] In the above embodiment and modified example, the thermal power generation element 2 has the thermoelectric conversion layer 3 and the electrolyte layer 4, but is not limited to this. The thermal power generation element 2 may have layers other than the above two layers. Furthermore, in the above embodiment, the thermoelectric conversion layer 3 has the electron thermal excitation layer 5 and the electron transport layer 6, but is not limited to this. The thermoelectric conversion layer 3 may have a single-layer structure consisting of only the electron thermal excitation layer 5.

[0083] The electron transport layer 6 is not limited to a semiconductor material. For example, the electron transport layer 6 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.

Claims

1. A thermal power generation module comprising: a first thermoelectric conversion layer and a second thermoelectric conversion layer spaced apart from each other; and a flexible electrolyte layer overlapping the first thermoelectric conversion layer and the second thermoelectric conversion layer in the stacking direction, wherein the electrolyte layer has a first end portion, a middle portion, and a second end portion arranged in order in a cross direction intersecting the stacking direction, and wherein the first thermoelectric conversion layer and the first end portion overlap each other in the stacking direction, and the second thermoelectric conversion layer and the second end portion overlap each other.

2. The thermal power generation module described in claim 1, wherein the electrolyte layer has a first surface and a second surface located on the opposite side of the first surface in the stacking direction, the first thermoelectric conversion layer is in contact with the first surface, and the second thermoelectric conversion layer is in contact with the second surface.

3. A thermal power generation module as described in claim 1 or 2, wherein the first end is located on one side of the first thermoelectric conversion layer and the second thermoelectric conversion layer in the stacking direction, and the second end is located on the other side of the first thermoelectric conversion layer and the second thermoelectric conversion layer in the stacking direction.

4. A thermal power generation module as described in claim 1 or 2, wherein the first thermoelectric conversion layer has a first electronic thermal excitation layer and a first electron transport layer stacked in order in the stacking direction, the first electronic thermal excitation layer being in contact with the first end portion; and the second thermoelectric conversion layer has a second electronic thermal excitation layer and a second electron transport layer stacked in order in the stacking direction, the second electron transport layer being in contact with the second end portion.

5. A thermal power generation module as described in claim 1 or 2, wherein the first thermoelectric conversion layer has a first electronic thermal excitation layer and a first electron transport layer stacked in order in the stacking direction, the first electronic thermal excitation layer being in contact with the first end portion; the second thermoelectric conversion layer has a second electronic thermal excitation layer and a second electron transport layer stacked in order in the stacking direction, the second electronic thermal excitation layer being in contact with the second end portion.

6. The thermal power generation module according to claim 1 or 2, wherein the electrolyte layer contains at least one of a low molecular weight organic compound and a high molecular weight organic compound, and polyvalent ions.

7. The thermal power generation module according to claim 1 or 2, which is a wound body wound in a direction intersecting the stacking direction.

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