Thermoelectric power generation device

Abstract

A thermoelectric power generation device (100) includes: a thermoelectric material (110) having a structure that undergoes a phase transition when subjected to heat; a first electrode (130) and a second electrode (131) provided on an outer surface (111) of the thermoelectric material; and a heat input amount adjustment unit (140) for adjusting the amount of heat inputted to the thermoelectric material to thereby generate a temperature gradient between the first electrode and the second electrode in the thermoelectric material. The heat input amount adjustment unit comprises, on the outer surface of the thermoelectric material, a first region (114) having a first thermal resistance and a second region (115) having a second thermal resistance different from the first thermal resistance. By providing the first region and the second region with said different thermal resistances, the amount of heat inputted to the thermoelectric material is made different.

Description

Thermoelectric power generation device CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-146387 filed on August 28, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure is a thermoelectric power generation device.

[0003] Conventionally, a π-type thermoelectric module in which p-type and n-type thermoelectric materials are electrically connected in series and thermally connected in parallel has been proposed, for example, in Patent Document 1. The carriers of p-type thermoelectric materials are pores (holes), while the carriers of n-type thermoelectric materials are electrons.

[0004] The potential difference generated by the temperature difference between the p-type and n-type thermoelectric materials, i.e., the direction of the current, is opposite. Therefore, in a π-type thermoelectric module, a temperature difference is generated between each thermoelectric material by heating one end of each thermoelectric material to a high temperature. Furthermore, the p-type and n-type thermoelectric materials are electrically connected in series. This increases the potential difference between the p-type and n-type thermoelectric materials, allowing current to flow through the external resistor.

[0005] In such a π-type thermoelectric module, the direction of heat transfer and the direction of current are either the same or opposite within the p-type and n-type thermoelectric materials, i.e., the direction of current is not inclined relative to the direction of heat transfer.

[0006] On the other hand, it is known, for example, from Non-Patent Document 1, that if a unique temperature gradient is applied to a thermoelectric material that has a structure that undergoes a phase transition when heated, a high electromotive force can be generated. Specifically, a part of the thermoelectric material is heated above the phase transition temperature so that the temperature gradient between two electrodes provided on the thermoelectric material becomes oblique. This creates a state inside the thermoelectric material where the direction of current is tilted relative to the direction of heat transfer.

[0007] Japanese Patent Application Laid-Open No. 2008-277404

[0008] Dogyun Byeon Dogyun Byeon, et al., Discovery of colossal Seebeck effect in metallic Cu2Se, Nature Communications, [online], <URL: https: / / www.nature.com / articles / s41467-018-07877-5>

[0009] However, in the above-mentioned Non-Patent Document 1, in order to generate an oblique temperature gradient between the two electrodes, it is necessary to heat the thermoelectric material from at least two directions using two heat sources.

[0010] In view of the above, an object of the present disclosure is to provide a thermoelectric power generation device that can generate a temperature gradient inside a thermoelectric material without using two heat sources.

[0011] In order to achieve the above object, according to a first aspect of the present disclosure, a thermoelectric power generation device includes a thermoelectric material having a structure that undergoes a phase transition when heat is applied; a first electrode and a second electrode provided on an outer surface of the thermoelectric material; and a heat input adjustment unit that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material by adjusting the amount of heat input to the thermoelectric material, wherein the heat input adjustment unit has, on the outer surface of the thermoelectric material, a first region having a first thermal resistance and a second region having a second thermal resistance different from the first thermal resistance, and by providing different thermal resistances to the first region and the second region, the amount of heat input to the thermoelectric material is made different.

[0012] According to a second aspect of the present disclosure, a thermoelectric power generation device includes a thermoelectric material having a structure that undergoes a phase transition when heat is applied; a first electrode and a second electrode provided on an outer surface of the thermoelectric material; and a heat input adjustment unit that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material by adjusting the amount of heat input to the thermoelectric material, wherein the heat input adjustment unit has a first side surface of the outer surface of the thermoelectric material and a second side surface opposite to the first side surface, and the second side surface is inclined with respect to the first side surface, thereby varying the thickness of the thermoelectric material from the first side surface to the second side surface with respect to the first side surface, thereby varying the amount of heat input to the thermoelectric material.

[0013] According to a third aspect of the present disclosure, a thermoelectric power generation device includes a thermoelectric material having a structure that undergoes a phase transition when heat is applied; a first electrode and a second electrode provided on an outer surface of the thermoelectric material; and an internal temperature adjustment unit that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein the internal temperature adjustment unit includes a first side surface of the outer surface of the thermoelectric material and a temperature gradient portion having directionality in heat conduction, and the temperature gradient portion is inclined with respect to the first side surface, thereby generating a temperature gradient that is inclined with respect to the first side surface.

[0014] According to a fourth aspect of the present disclosure, a thermoelectric power generation device includes: a columnar thermoelectric material having a structure that undergoes a phase transition when heat is applied; a ring-shaped first electrode provided at one end side in the extension direction of the thermoelectric material and centered on an axis along the extension direction; a ring-shaped second electrode provided at the other end side in the extension direction of the thermoelectric material; and a heat input adjustment unit that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein the heat input adjustment unit is a highly thermally conductive material that is arranged in the center of the other end face on the other end side of the thermoelectric material and generates a temperature difference at different depths in the extension direction based on the other end face.

[0015] According to a fifth aspect of the present disclosure, a thermoelectric power generation device includes: a thermoelectric material having a structure that undergoes a phase transition when heat is applied, and arranged around a heat source; a first electrode and a second electrode provided on the outer peripheral surface of the thermoelectric material; and a heat input adjustment unit that adjusts the amount of heat input from the heat source to the thermoelectric material to generate a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein, at a cut surface cutting the heat source, the thermoelectric material, the first electrode, and the second electrode, the heat input adjustment unit makes a first distance from the inner peripheral surface of the thermoelectric material to the first electrode different from a second distance from the inner peripheral surface of the thermoelectric material to the second electrode, thereby generating temperature differences of different depths based on the inner peripheral surface.

[0016] This allows a temperature difference to be generated inside the thermoelectric material in a direction oblique to the outer surface of the thermoelectric material, thereby generating a temperature gradient inside the thermoelectric material without using two heat sources.

[0017] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a cross-sectional view of a thermoelectric generator according to a first embodiment, Fig. 2 is a cross-sectional view of a thermoelectric generator according to a second embodiment, Fig. 3 is a cross-sectional view of a thermoelectric generator according to a third embodiment, Fig. 4 is a cross-sectional view of another example of the thermoelectric generator according to the third embodiment, Fig. 5 is a cross-sectional view of a thermoelectric generator according to a fourth embodiment, Fig. 6 is a diagram showing a manufacturing process of the thermoelectric material shown in Fig. 5, Fig. 7 is a cross-sectional view of another example of the thermoelectric generator according to the fourth embodiment, Fig. 8 is a perspective view of a thermoelectric generator according to a fifth embodiment, Fig. 9 is a cross-sectional view taken along line IX-IX of Fig. 8, Fig. 10 is a cross-sectional view of a thermoelectric generator according to a sixth embodiment, Fig. 11 is a cross-sectional view of another example of the thermoelectric generator according to the sixth embodiment, and Fig. 12 is a cross-sectional view of another example of the thermoelectric generator according to the sixth embodiment.

[0018] Hereinafter, several embodiments for carrying out the present disclosure will be described with reference to the drawings. In each embodiment, parts corresponding to matters described in the preceding embodiment will be assigned the same reference numerals, and duplicated explanations may be omitted. In each embodiment, when only a part of the configuration is described, the other previously described embodiments may be applied to the other parts of the configuration.

[0019] In each embodiment, it is possible to combine parts that are specifically expressly possible to combine with each other. Furthermore, even if it is not expressly expressly possible to combine, it is also possible to partially combine embodiments with each other, embodiments with modified examples, and modified examples with each other, as long as there are no particular problems with the combination.

[0020] First Embodiment A thermoelectric power generation device generates electromotive force by generating a temperature gradient inside a thermoelectric material. As shown in Fig. 1, a thermoelectric power generation device 100 includes a thermoelectric material 110, a first electrode 130, a second electrode 131, and a heat input adjustment unit 140.

[0021] The thermoelectric material 110 has a structure that undergoes a phase transition when heat is applied. ２ Se, Ag ２The thermoelectric material 110 may be any chalcogenide transition metal that undergoes a phase transition when heated.

[0022] In this embodiment, the thermoelectric material 110 is formed into a rectangular parallelepiped. However, the thermoelectric material 110 may have a shape other than a rectangular parallelepiped.

[0023] The first electrode 130 and the second electrode 131 are components for extracting electromotive force generated in the thermoelectric material 110. The first electrode 130 and the second electrode 131 are provided on a first end face 112 of the outer surface 111 of the thermoelectric material 110 and a second end face 113 opposite the first end face 112. As a result, the first electrode 130 and the second electrode 131 are installed on the outer surface 111 so as to sandwich the thermoelectric material 110. The path of electrons moving between the first electrode 130 and the second electrode 131 is perpendicular to the end faces 112 and 113 of the thermoelectric material 110.

[0024] The first electrode 130 and the second electrode 131 are formed as thin films of a metal material with low electrical resistivity, such as Cu, Al, Ni, or an alloy containing any of these. The first electrode 130 and the second electrode 131 are formed on each end face 112, 113 by, for example, metal vapor deposition or solder bonding. The first electrode 130 and the second electrode 131 may be formed on the entire end face 112, 113, or may be formed on only a portion of each end face 112, 113.

[0025] The heat input adjusting unit 140 adjusts the amount of heat input to the thermoelectric element 110 to generate a temperature gradient between the first electrode 130 and the second electrode 131 of the thermoelectric element 110 .

[0026] The heat input adjustment unit 140 has a first region 114, a second region 115, and a plurality of heat exchange fins 141 on the outer surface 111 of the thermoelectric material 110. In this embodiment, the first region 114 and the second region 115 are set on a first side surface 116 and a second side surface 117 on the outer surface 111 of the thermoelectric material 110. The first side surface 116 and the second side surface 117 are surfaces connected to the end faces 112, 113 of the thermoelectric material 110. The first side surface 116 is the surface opposite the second side surface 117. In other words, the side surfaces 116, 117 are not adjacent to each other and are not connected to each other.

[0027] The first region 114 has a first thermal resistance. The second region 115 has a second thermal resistance different from the first thermal resistance. The multiple heat exchange fins 141 are components for generating a difference in thermal resistance between the first thermal resistance of the first region 114 and the second thermal resistance of the second region 115. The heat exchange fins 141 are formed in a plate shape using a metal material with high thermal conductivity. The heat exchange fins 141 are not limited to being plate-shaped, and may be formed in a columnar shape. The heat exchange fins 141 are heat exchangers.

[0028] The heat exchange fins 141 are partially embedded in the thermoelectric material 110 with respect to each of the side surfaces 116 and 117. The heat exchange fins 141 may be insert molded when the thermoelectric material 110 is formed, or may be inserted into holes formed in the thermoelectric material 110 and fixed therein after the thermoelectric material 110 is formed. In this embodiment, the heat exchange fins 141 have the same protruding length protruding outward from each of the side surfaces 116 and 117. However, the protruding lengths of the heat exchange fins 141 may be different.

[0029] For example, of the multiple heat exchange fins 141, the fins embedded in the second region 115 are deeper than the fins embedded in the first region 114. That is, the heat exchange fins 141 embedded in each region 114, 115 have different insertion depths into the thermoelectric material 110 based on the respective side surfaces 116, 117. The greater the insertion depth of the heat exchange fins 141, the easier it is for heat to escape from inside the thermoelectric material 110. In this way, the heat input amount adjustment unit 140 differentiates the amount of heat input to the thermoelectric material 110 by providing different thermal resistances to the first region 114 and the second region 115.

[0030] Then, on each side surface 116, 117, by continuously providing a relationship between the first electrode 130 and the second electrode 131 in which the first thermal resistance of the first region 114 and the second thermal resistance of the second region 115 are different, it is possible to change the thermal resistance between the first electrode 130 and the second electrode 131 in a stepwise manner. In other words, if there is a pair of the first region 114 and the second region 115, the second region 115 of this pair is set to the first region 114 of the adjacent pair.

[0031] For example, on the first side surface 116, the insertion depth of the heat exchange fins 141 increases from the first electrode 130 to the second electrode 131. On the second side surface 117, the insertion depth of the heat exchange fins 141 decreases from the first electrode 130 to the second electrode 131. Because each side surface 116, 117 is a heat exchange surface, as shown in FIG. 1 , the low-temperature phase occurs near the connection between the first side surface 116 and the second end surface 113 of the thermoelectric material 110. The high-temperature phase occurs near the connection between the second side surface 117 and the first end surface 112 of the thermoelectric material 110. Between the low-temperature phase and the high-temperature phase, a mixed phase is formed, in which the low-temperature phase and the high-temperature phase are mixed. Furthermore, because the insertion depth of the heat exchange fins 141 changes in stages, a gradual temperature gradient can be generated.

[0032] 1 is a cross-sectional view, and the isothermal portion of the thermoelectric material 110 is represented by a wavy line. The dashed line does not indicate the boundary between the low-temperature phase, mixed phase, and high-temperature phase, but indicates that the temperature layer is inclined with respect to the first side surface 116. Furthermore, to make the dashed line easier to see, the cross-sectional hatching of the thermoelectric material 110 has been omitted. This also applies to all cross-sectional views shown below.

[0033] Therefore, with the side surfaces 116, 117 serving as heat exchange surfaces as a reference, a temperature difference can be generated in a direction perpendicular to the side surfaces 116, 117. That is, a temperature gradient inclined with respect to the end surfaces 112, 113 on which the electrodes 130, 131 are disposed can be realized inside the thermoelectric material 110. That is, a temperature difference can be generated in a direction parallel to the side surfaces 116, 117 serving as heat exchange surfaces, and a temperature difference can also be generated in a direction perpendicular to the side surfaces 116, 117.

[0034] A phase transition does not occur in the low-temperature portion of the thermoelectric material 110, but a phase transition can occur in the high-temperature portion of the thermoelectric material 110. When a phase transition occurs in a portion of the thermoelectric material 110, the electrical resistivity of the portion where the phase transition occurs decreases. This has the effect of increasing the thermoelectromotive force in this portion.

[0035] Here, a heat source may be used to exchange heat between the inside and outside of the thermoelectric material 110. For example, a high-temperature heat source may be disposed on the second side surface 117 side of the outer surface 111 of the thermoelectric material 110. The high-temperature heat source may be a high-temperature gas, a high-temperature liquid, a device that generates high temperatures, or the like. The first side surface 116 side of the outer surface 111 of the thermoelectric material 110 may be air.

[0036] Alternatively, the heat input is not limited to high-temperature heat being provided to the thermoelectric material 110, and low-temperature heat may be provided to the thermoelectric material 110. Therefore, a low-temperature heat source may be disposed on the first side surface 116 side of the outer surface 111 of the thermoelectric material 110. In this manner, the amount of heat input to the thermoelectric material 110 may be adjusted using a heat source.

[0037] As described above, in this embodiment, the heat input amount is varied depending on the location of the thermoelectric material 110 by the multiple heat exchange fins 141, so that a temperature gradient can be generated in the thermoelectric material 110 in an oblique direction between the electrodes 130, 131. Therefore, a temperature gradient can be generated inside the thermoelectric material 110 without using two heat sources. In addition, a temperature gradient inclined with respect to the electron path can be generated.

[0038] When no heat source or a single heat source is used, the structure of the thermoelectric power generating device 100 can be simplified, thereby reducing costs and energy consumption.

[0039] Furthermore, the thermoelectric material 110 has temperature differences at different depths based on the side surfaces 116 and 117, which are the heat exchange surfaces, due to the heat input adjusting unit 140, so that efficient temperature control is possible.

[0040] Furthermore, since a gradation-like temperature gradient can be generated inside the thermoelectric material 110, temperature control according to the characteristics of the material of the thermoelectric material 110 becomes possible, and improved performance of the thermoelectric power generation device 100 can be expected.

[0041] As another example, the insertion depths (depths) of the heat exchange fins 141 do not have to be different. For example, the insertion depths (depths) of some of the heat exchange fins 141 may be the same.

[0042] As another example, the heat input adjustment unit 140 may be provided on only one side of the outer surface 111 of the thermoelectric material 110. For example, the heat input adjustment unit 140 may be provided on the first side surface 116 and not on the second side surface 117. Alternatively, the heat input adjustment unit 140 may not be provided on the first side surface 116 but may be provided on the second side surface 117.

[0043] Second Embodiment In this embodiment, differences from the first embodiment will be mainly described. First, in this embodiment, the first side surface 116 is divided into two regions: a first region 114 on the first electrode 130 side and a second region 115 on the second electrode 131 side. The second side surface 117 is divided into two regions: the first region 114 on the second electrode 131 side and the second region 115 on the first electrode 130 side. The area of ​​the first region 114 is smaller than the area of ​​the second region 115, for example.

[0044] As shown in FIG. 2, the heat input adjusting unit 140 includes a first thermally conductive material 142 , a second thermally conductive material 143 , a first heat sink 144 , and a second heat sink 145 .

[0045] The first thermal conductive material 142 is disposed in the first region 114. The second thermal conductive material 143 is disposed in the second region 115. The first thermal conductivity of the first thermal conductive material 142 is smaller than the second thermal conductivity of the second thermal conductive material 143. By disposing the thermal conductive materials 142, 143 on the respective side surfaces 116, 117 of the thermoelectric material 110, the amount of heat input to the thermoelectric material 110 is adjusted. That is, in this embodiment, the difference between the first thermal resistance of the first region 114 and the second thermal resistance of the second region 115 is the difference between the first thermal conductivity of heat to the first region 114 and the second thermal conductivity of heat to the second region 115.

[0046] The first thermally conductive material 142 is, for example, a heat insulating material. The second thermally conductive material 143 is, for example, a metal with high insulating properties. Alternatively, each of the thermally conductive materials 142, 143 may be composed of a metal heat transfer sheet. While each of the thermally conductive materials 142, 143 is composed of, for example, the same material, the first thermal conductivity and the second thermal conductivity may be different by adjusting the compounding ratio of the blended materials. For example, each of the thermally conductive materials 142, 143 may be formed of the same metal material, and the compounding ratio of the blended materials may be adjusted to have different thermal conductivities.

[0047] The first heat sink 144 and the second heat sink 145 are heat exchangers that dissipate heat by exchanging heat with the outside. The first heat sink 144 is disposed on the first thermally conductive material 142 and the second thermally conductive material 143 that are disposed on the first side surface 116 side of the thermoelectric material 110. The second heat sink 145 is disposed on the first thermally conductive material 142 and the second thermally conductive material 143 that are disposed on the second side surface 117 side of the thermoelectric material 110.

[0048] With the above configuration, as shown in FIG. 2 , heat from inside the thermoelectric material 110 is easily dissipated from the first side surface 116 of the thermoelectric material 110 via the second thermally conductive material 143 and the first heat sink 144, which have high thermal conductivity. Therefore, the temperature is low near the connection between the first side surface 116 and the second end surface 113 of the thermoelectric material 110. Meanwhile, heat from outside the thermoelectric material 110 is easily transferred to the second side surface 117 of the thermoelectric material 110 via the second thermally conductive material 143 and the second heat sink 145, which have high thermal conductivity. It is even better if a high-temperature heat source is located on the second side surface 117 side of the thermoelectric material 110. Therefore, the temperature is high near the connection between the second side surface 117 and the first end surface 112 of the thermoelectric material 110. Therefore, a temperature gradient can be generated in an oblique direction between the electrodes 130 and 131.

[0049] As another example, each of the heat sinks 144, 145 may not be provided in the thermoelectric power generation device 100. Alternatively, the first heat sink 144 may be provided in the thermoelectric power generation device 100, and the second heat sink 145 may not be provided in the thermoelectric power generation device 100. Alternatively, the first heat sink 144 may not be provided in the thermoelectric power generation device 100, and the second heat sink 145 may be provided in the thermoelectric power generation device 100.

[0050] As another example, the first thermal conductive material 142 and the second thermal conductive material 143 are not limited to being both provided on each side surface 116, 117 of the thermoelectric material 110. For example, only the first thermal conductive material 142 may be provided on the first side surface 116 of the thermoelectric material 110, and neither the first thermal conductive material 142 nor the second thermal conductive material 143 may be provided on the second side surface 117. Alternatively, only the second thermal conductive material 143 may be provided on the first side surface 116 of the thermoelectric material 110, and neither the first thermal conductive material 142 nor the second thermal conductive material 143 may be provided on the second side surface 117 of the thermoelectric material 110. Alternatively, only the first thermal conductive material 142 may be provided on the second side surface 117 of the thermoelectric material 110, and neither the first thermal conductive material 142 nor the second thermal conductive material 143 may be provided on the first side surface 116. In some cases, only the second thermal conductive material 143 is provided on the second side surface 117 of the thermoelectric material 110, and neither the first thermal conductive material 142 nor the second thermal conductive material 143 is provided on the first side surface 116.

[0051] Alternatively, only the first thermally conductive material 142 may be provided on each side 116, 117 of the thermoelectric material 110. Alternatively, only the second thermally conductive material 143 may be provided on each side 116, 117 of the thermoelectric material 110.

[0052] Alternatively, the first thermal conductive material 142 and the second thermal conductive material 143 may be provided on the first side surface 116 of the thermoelectric material 110, and only the first thermal conductive material 142 may be provided on the second side surface 117. Alternatively, the first thermal conductive material 142 and the second thermal conductive material 143 may be provided on the first side surface 116 of the thermoelectric material 110, and only the second thermal conductive material 143 may be provided on the second side surface 117.

[0053] Alternatively, only the first thermal conductive material 142 may be provided on the first side surface 116 of the thermoelectric material 110, and both the first thermal conductive material 142 and the second thermal conductive material 143 may be provided on the second side surface 117. Alternatively, only the second thermal conductive material 143 may be provided on the first side surface 116 of the thermoelectric material 110, and both the first thermal conductive material 142 and the second thermal conductive material 143 may be provided on the second side surface 117.

[0054] As another example, a plurality of first regions 114 and second regions 115 may be provided between the first electrode 130 and the second electrode 131 on the outer surface 111 of the thermoelectric material 110. That is, on each side surface 116, 117 of the thermoelectric material 110, a relationship in which the first thermal conductivity of the first region 114 and the second thermal conductivity of the second region 115 are different is continuously established between the first electrode 130 and the second electrode 131. This allows the thermal conductivity of each side surface 116, 117 between the first electrode 130 and the second electrode 131 to change stepwise. Therefore, a gradational temperature gradient can be generated inside the thermoelectric material 110.

[0055] As another example, the first thermal conductivity and the second thermal conductivity may be different by adjusting the internal density of the first thermal conductive material 142 and the second thermal conductive material 143. For example, a mesh-like material or a porous material may be used as the first thermal conductive material 142 and the second thermal conductive material 143.

[0056] As another example, the first thermal conductivity and the second thermal conductivity of the first thermal conductive material 142 and the second thermal conductive material 143 may be different by adjusting the thickness of the first thermal conductive material 142 and the second thermal conductive material 143 relative to the outer surface 111 of the thermoelectric material 110. Of course, the thermal conductive materials 142 and 143 may be made of the same material or different materials.

[0057] The above examples can be combined as much as possible. That is, the first thermal conductivity and the second thermal conductivity can be adjusted by appropriately combining the compounding ratio of the materials of the thermally conductive materials 142 and 143, the structure of the mesh or the like, the thickness, and the like.

[0058] Third Embodiment In this embodiment, differences from the first and second embodiments will be mainly described. As shown in Fig. 3 , in this embodiment, the heat input adjustment unit 140 includes a first side surface 116 and a second side surface 117 opposite the first side surface 116 on the outer surface 111 of the thermoelectric material 110. The second side surface 117 is inclined with respect to the first side surface 116. As a result, the thickness of the thermoelectric material 110 from the first side surface 116 to the second side surface 117 varies with respect to the first side surface 116. In other words, the thickness of the thermoelectric material 110 from the first side surface 116 to the second side surface 117 varies in the direction perpendicular to the first side surface 116.

[0059] Since the second side surface 117 is inclined with respect to the first side surface 116, the first end surface 112 is smaller than the second end surface 113. Therefore, the planar size of the first electrode 130 is smaller than the second electrode 131. Of course, the planar size of the second electrode 131 may be set to be the same as that of the first electrode 130. The end surfaces 112, 113 of the thermoelectric material 110 are inclined with respect to the second side surface 117. Note that the end surfaces 112, 113 of the thermoelectric material 110 may also be inclined with respect to the first side surface 116.

[0060] Furthermore, a first heat sink 144 is installed on the first side surface 116. A second heat sink 145 is installed on the second side surface 117. An insulating member (not shown) is installed between each of the side surfaces 116, 117 and each of the heat sinks 144, 145. Note that the heat sinks 144, 145 do not have to be installed on the side surfaces 116, 117. Alternatively, the first heat sink 144 may be installed on the first side surface 116, and the second heat sink 145 may not be installed on the second side surface 117. Alternatively, the first heat sink 144 may not be installed on the first side surface 116, and the second heat sink 145 may be installed on the second side surface 117.

[0061] According to the above configuration, the thickness between the first side surface 116 and the second side surface 117 of the thermoelectric material 110 varies depending on the position on the first side surface 116, so that the amount of heat input to the thermoelectric material 110 can be varied depending on the location. Therefore, a temperature gradient can be generated inside the thermoelectric material 110.

[0062] 4 , the first side surface 116 may be inclined with respect to the second side surface 117. In this case, the temperature of the thermoelectric material 110 is low in the vicinity of the connection portion between the first side surface 116 and the second end surface 113, so the second electrode 131 is provided on a portion of the first side surface 116 side rather than on the entire second end surface 113. Note that although the end surfaces 112 and 113 of the thermoelectric material 110 are inclined with respect to the first side surface 116, they may also be inclined with respect to the second side surface 117.

[0063] 5 , a thermoelectric power generation device 100 includes a thermoelectric material 110, a first electrode 130, a second electrode 131, a first heat sink 144, a second heat sink 145, and an internal temperature adjustment unit 150.

[0064] The internal temperature adjustment unit 150 generates a temperature gradient between the first electrode 130 and the second electrode 131 of the thermoelectric material 110 by controlling the temperature distribution inside the thermoelectric material 110. The internal temperature adjustment unit 150 includes a first side surface 116 of the thermoelectric material 110 and a temperature gradient unit 151 having directional heat conduction.

[0065] The temperature gradient section 151 is provided inside the thermoelectric material 110. The temperature gradient section 151 is made of a fibrous material having a directional property, such as a carbon nanotube or a graphite fiber.

[0066] As shown in Fig. 6, a block 152 of thermoelectric material 110 containing fibrous material such as carbon nanotubes or graphite fibers is prepared as a temperature gradient portion 151. The fibrous material is oriented in the same direction inside block 152. The longer the fibrous material, the more advantageous it is for controlling the temperature gradient.

[0067] Then, a part of the block body 152 is cut in a direction inclined with respect to the extending direction of the fibers to form a pellet 153. After this, the pellet 153 is molded to obtain the thermoelectric material 110 in which the extending direction of the fibers is inclined with respect to the first side surface 116.

[0068] According to the above configuration, the temperature gradient portion 151 is inclined with respect to the first side surface 116 inside the thermoelectric material 110, so that the temperature distribution inside the thermoelectric material 110 can be controlled along the temperature gradient portion 151. Therefore, a temperature gradient inclined with respect to the first side surface 116 of the thermoelectric material 110 can be generated.

[0069] 7 , the second side surface 117 of the thermoelectric material 110 may be inclined with respect to the first side surface 116. In this case, the fibrous material such as carbon nanotubes or graphite fibers that constitutes the temperature gradient portion 151 is disposed along the second side surface 117 inside the thermoelectric material 110. Note that the extending direction of the fiber does not have to be parallel to the surface direction of the second side surface 117.

[0070] As another example, the temperature gradient portion 151 may be made of a material having a thermal interface that is inclined with respect to the first side surface 116. This allows the temperature distribution inside the thermoelectric material 110 to be controlled along the thermal interface. Of course, the temperature gradient portion 151 may also be included inside the thermoelectric material 110.

[0071] Fifth Embodiment In this embodiment, differences from the above-described embodiments will be mainly described. As shown in FIGS. 8 and 9, the thermoelectric material 110 according to this embodiment has a cylindrical shape along the extension direction. The shape of the thermoelectric material 110 is not limited to a cylindrical shape, and may be another columnar shape such as a square prism. The thermoelectric material 110 may also have a cylindrical shape. In other words, the columnar shape includes a cylindrical shape. Alternatively, the thermoelectric material 110 may have holes or through-holes.

[0072] The first electrode 130 is provided on one end surface 119 of one end side 118 in the extension direction of the thermoelectric material 110. The first electrode 130 is ring-shaped with its center on an axis along the extension direction. The ring-shaped first electrode 130 includes not only one that is continuous around the axis along the extension direction, but also one that is interrupted halfway and does not make a full revolution around the axis along the extension direction.

[0073] In this embodiment, the first electrode 130 is fixed to the outer edge of one end surface 119 of the thermoelectric material 110. Therefore, a portion of the one end surface 119 of the thermoelectric material 110 is exposed in the hollow portion of the first electrode 130. Note that a groove may be formed in the outer edge portion of one end side 118 of the thermoelectric material 110, and the first electrode 130 may be placed in the groove. As a result, a portion of the thermoelectric material 110 is disposed in the hollow portion of the first electrode 130.

[0074] The second electrode 131 is provided on the other end surface 121 of the other end side 120 in the extension direction of the thermoelectric material 110. The second electrode 131 is ring-shaped, similar to the first electrode 130. The second electrode 131 is fixed to the outer edge of the other end surface 121 of the thermoelectric material 110.

[0075] The heat input adjustment unit 140 is disposed in the center of the other end surface 121 of the thermoelectric material 110 in order to generate a temperature gradient between the first electrode 130 and the second electrode 131 of the thermoelectric material 110. The heat input adjustment unit 140 is a highly thermally conductive material made of a metal such as Cu. Note that the highly thermally conductive material is not limited to a metal material, and other materials may also be used.

[0076] The heat input adjustment unit 140 is disposed, for example, in the hollow portion of the second electrode 131. The heat input adjustment unit 140 is insulated from the second electrode 131 by an insulating material (not shown). The heat input adjustment unit 140 may be disposed in a groove (not shown) provided in the other end surface 121 of the thermoelectric material 110. In other words, the heat input adjustment unit 140 may be disposed appropriately according to the shape of the other end side 120 of the thermoelectric material 110.

[0077] The heat input adjustment unit 140 is thermally connected to the high-temperature heat source 200. This makes it easier for the heat from the heat source 200 to be transferred to the center of the other end surface 121 of the thermoelectric material 110 via the heat input adjustment unit 140. The heat input adjustment unit 140 may be connected to a heat exchanger such as a fin or a heat sink instead of the heat source 200.

[0078] With the above configuration, the heat input adjusting unit 140 can generate a temperature difference of a different depth in the extension direction depending on the location of the other end surface 121 of the thermoelectric material 110, with the other end surface 121 as a reference. As shown in Fig. 9 , the center of the other end surface 121 inside the thermoelectric material 110 is the hottest, and the outer edge of the one end surface 119 is the coldest. That is, a cone-shaped temperature distribution can be formed inside the thermoelectric material 110, with the center of the other end surface 121 of the thermoelectric material 110 being the hottest. Therefore, a temperature gradient can be generated inside the thermoelectric material 110.

[0079] 10 shows a cut surface 122 along which the heat source 200, the thermoelectric material 110, the first electrode 130, and the second electrode 131 are cut.

[0080] 10, the thermoelectric material 110 according to this embodiment is configured in the shape of a rectangular plate. The thermoelectric material 110 is arranged around the axis of the tubular heat source 200.

[0081] The thermoelectric material 110 is formed, for example, directly on the outer wall of a prepared heat source 200. Alternatively, after the thermoelectric material 110 is formed, a through-hole may be formed in the thermoelectric material 110 and the heat source 200 may be passed through the through-hole. An insulating film 210 is provided between the thermoelectric material 110 and the heat source 200. Therefore, the heat source 200 and the thermoelectric material 110 are thermally connected via the insulating film 210.

[0082] The heat source 200 is, for example, a circular pipe. A high-temperature fluid flows inside the pipe. FIG. 10 shows a cross section perpendicular to the direction in which the pipe extends. The thermoelectric material 110 is not limited to a circular pipe, but may be a polygonal pipe such as a square. Of course, the heat source 200 is not limited to a pipe, but may be a part of a device that generates heat itself.

[0083] The first electrode 130 and the second electrode 131 are provided on an outer peripheral surface 123 of the thermoelectric material 110. The outer peripheral surface 123 is an outer wall surface of the thermoelectric material 110 centered on the axis of the heat source 200. In this embodiment, the first electrode 130 is provided on a first end surface 112 and a second end surface 113 corresponding to the short sides of the rectangular cut surface 122. The first electrode 130 is provided on the entirety of each end surface 112, 113. However, the first electrode 130 may be provided on only a portion of each end surface 112, 113.

[0084] The second electrode 131 is provided on the first side surface 116 and the second side surface 117 corresponding to the long sides of the rectangular cut surface 122. The second electrode 131 is provided on a part of each of the side surfaces 116, 117, but not on the entirety thereof.

[0085] In the above configuration, the heat input adjustment unit 140 adjusts the amount of heat input from the heat source 200 to the thermoelectric material 110, thereby generating a temperature gradient between the first electrode 130 and the second electrode 131 of the thermoelectric material 110. That is, the heat input adjustment unit 140 makes a first distance from the inner circumferential surface 124 of the thermoelectric material 110 to the first electrode 130 different from a second distance from the inner circumferential surface 124 of the thermoelectric material 110 to the second electrode 131. Because the cut surface 122 of the thermoelectric material 110 is rectangular, the distance between the first electrode 130 and the heat source 200 is longer than the distance between the second electrode 131 and the heat source 200. That is, the second electrode 131 is closer to the heat source 200 than the first electrode 130. The first distance and the second distance may be defined as shortest distances.

[0086] This makes it possible to generate temperature differences at different depths (distances) based on the inner circumferential surface 124 of the thermoelectric material 110. Because the second distance related to the second electrode 131 is short, the temperature near the second electrode 131 becomes high. In contrast, because the first distance related to the first electrode 130 is longer than the second distance, the temperature near the first electrode 130 becomes low. Therefore, a temperature gradient can be generated inside the thermoelectric material 110.

[0087] 11 , the thermoelectric material 110 may have a slit-shaped cutout portion 125 that divides the first end face 112 and the first electrode 130 into two parts on the side of each end face 112, 113 of the thermoelectric material 110 along the heat source 200. That is, the thermoelectric material 110 may have a cutout portion 125 that divides the first end face 112 and the first electrode 130 into two parts.

[0088] 12 , the corners of the connection portions between the end faces 112, 113 and the side faces 116, 117 of the thermoelectric material 110 may be cut off. That is, the thermoelectric material 110 may have a notch 126 between the first electrode 130 and the second electrode 131.

[0089] The present disclosure is not limited to the above-described embodiments, and various modifications can be made as follows within the scope of the present disclosure.

[0090] For example, by electrically connecting a plurality of thermoelectric power generating devices 100 in series, it is possible to obtain a thermoelectromotive force equal to the number of connected thermoelectric power generating devices 100 .

[0091] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

[0092] The technical features of the thermoelectric power generation device 100 disclosed in this specification are as follows: (Item 1) A thermoelectric power generation device including: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a first electrode (130) and a second electrode (131) provided on an outer surface (111) of the thermoelectric material; and a heat input adjustment unit (140) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material by adjusting the amount of heat input to the thermoelectric material, wherein the heat input adjustment unit includes, on the outer surface of the thermoelectric material, a first region (114) having a first thermal resistance and a second region (115) having a second thermal resistance different from the first thermal resistance, and the first region and the second region have different thermal resistances, thereby differentiating the amount of heat input to the thermoelectric material. (Item 2) The thermoelectric power generation device according to Item 1, wherein the heat input adjustment unit has a plurality of heat exchange fins (141), and the depths to which the plurality of heat exchange fins are embedded in the thermoelectric material with respect to the outer surface being different between the first region and the second region, thereby adjusting the heat input to the thermoelectric material. (Item 3) The thermoelectric power generation device according to Item 1 or 2, wherein the difference between the first thermal resistance of the first region and the second thermal resistance of the second region is the difference between a first thermal conductivity of heat to the first region and a second thermal conductivity of heat to the second region. (Item 4) The thermoelectric power generation device according to Item 3, wherein a plurality of the first region and the second region are set between the first electrode and the second electrode on the outer surface of the thermoelectric material, thereby causing the thermal conductivity of the outer surface between the first electrode and the second electrode to change stepwise. (Item 5) The thermoelectric power generation device according to Item 3 or 4, wherein the heat input adjustment unit comprises a thermally conductive material (142, 143) disposed in either one or both of the first region and the second region, and wherein the first thermal conductivity and the second thermal conductivity are made different by adjusting a blending ratio of materials blended in the thermally conductive material. (Item 6) The thermoelectric power generation device according to Item 3 or 4, wherein the heat input adjustment unit comprises a thermally conductive material (142, 143) disposed in either one or both of the first region and the second region, and wherein the internal density of the thermally conductive material is adjusted to make the first thermal conductivity and the second thermal conductivity different.(Item 7) The thermoelectric power generation device according to Item 3, wherein the heat input adjustment unit includes a thermally conductive material (142, 143) disposed in either or both of the first region and the second region, and the thermally conductive material has a thickness adjusted based on the outer surface of the thermoelectric material, thereby making the first thermal conductivity and the second thermal conductivity different. (Item 8) A thermoelectric power generation device comprising: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a first electrode (130) and a second electrode (131) provided on an outer surface (111) of the thermoelectric material; and a heat input adjustment unit (140) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material by adjusting the amount of heat input to the thermoelectric material, wherein the heat input adjustment unit has a first side surface (116) of the outer surface of the thermoelectric material and a second side surface (117) opposite to the first side surface, and the second side surface is inclined with respect to the first side surface, thereby varying the thickness of the thermoelectric material from the first side surface to the second side surface with respect to the first side surface, thereby varying the amount of heat input to the thermoelectric material. (Item 9) A thermoelectric power generation device including: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a first electrode (130) and a second electrode (131) provided on an outer surface (111) of the thermoelectric material; and an internal temperature adjustment unit (150) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein the internal temperature adjustment unit includes a first side surface (116) of the outer surface of the thermoelectric material and a temperature gradient unit (151) having directional heat conduction, and the temperature gradient unit is inclined with respect to the first side surface, thereby generating a temperature gradient that is inclined with respect to the first side surface. (Item 10) The thermoelectric power generation device according to Item 9, wherein the temperature gradient unit is provided inside the thermoelectric material and is made of a fibrous material having directional properties. (Item 11) The thermoelectric power generation device according to Item 9 or 10, wherein the temperature gradient unit is made of a material having a thermal interface that is inclined with respect to the first side surface.(Item 12) A thermoelectric power generation device comprising: a columnar thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a ring-shaped first electrode (130) provided at one end (118) of the thermoelectric material in an extension direction and centered on an axis along the extension direction; a ring-shaped second electrode (131) provided at the other end (120) of the thermoelectric material in the extension direction; and a heat input adjustment unit (140) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein the heat input adjustment unit is a highly thermally conductive material that is arranged in a center portion of the other end face (121) of the thermoelectric material, and generates temperature differences at different depths in the extension direction based on the other end face. (Item 13) A thermoelectric power generation device comprising: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied, and arranged around a heat source (200) at the center; a first electrode (130) and a second electrode (131) provided on an outer peripheral surface (123) of the thermoelectric material; and a heat input adjustment unit (140) that adjusts the amount of heat input from the heat source to the thermoelectric material to generate a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein, at a cutting surface (122) that cuts the heat source, the thermoelectric material, the first electrode, and the second electrode, the heat input adjustment unit makes a first distance from an inner peripheral surface (124) of the thermoelectric material to the first electrode different from a second distance from the inner peripheral surface of the thermoelectric material to the second electrode, thereby generating temperature differences at different depths based on the inner peripheral surface.

Claims

1. A thermoelectric power generation device comprising: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a first electrode (130) and a second electrode (131) provided on the outer surface (111) of the thermoelectric material; and a heat input adjustment unit (140) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material by adjusting the amount of heat input to the thermoelectric material, wherein the heat input adjustment unit has, on the outer surface of the thermoelectric material, a first region (114) having a first thermal resistance and a second region (115) having a second thermal resistance different from the first thermal resistance, and by providing different thermal resistances to the first region and the second region, the amount of heat input to the thermoelectric material is made different.

2. The thermoelectric power generation device according to claim 1, wherein the heat input adjustment unit has a plurality of heat exchange fins (141), and the depth to which the plurality of heat exchange fins are embedded in the thermoelectric material with respect to the outer surface differs between the first region and the second region, thereby adjusting the amount of heat input to the thermoelectric material.

3. A thermoelectric power generation device as described in claim 1 or 2, wherein the difference between the first thermal resistance of the first region and the second thermal resistance of the second region is the difference between a first thermal conductivity of heat to the first region and a second thermal conductivity of heat to the second region.

4. A thermoelectric power generation device as described in claim 3, wherein the first region and the second region are set in multiple locations on the outer surface of the thermoelectric material between the first electrode and the second electrode, so that the thermal conductivity of the outer surface between the first electrode and the second electrode changes in stages.

5. A thermoelectric power generation device as described in claim 3, wherein the heat input adjustment section comprises a thermally conductive material (142, 143) arranged in either or both of the first region and the second region, and the thermally conductive material has a composition ratio of the materials mixed therein adjusted to make the first thermal conductivity and the second thermal conductivity different.

6. A thermoelectric power generation device as described in claim 3, wherein the heat input adjustment unit comprises a thermally conductive material (142, 143) arranged in either or both of the first region and the second region, and the thermally conductive material has an internal density adjusted to make the first thermal conductivity different from the second thermal conductivity.

7. The thermoelectric power generation device according to claim 3, wherein the heat input adjustment unit comprises a thermally conductive material (142, 143) disposed in either or both of the first region and the second region, and the thickness of the thermally conductive material is adjusted based on the outer surface of the thermoelectric material, thereby making the first thermal conductivity and the second thermal conductivity different.

8. A thermoelectric power generation device comprising: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a first electrode (130) and a second electrode (131) provided on an outer surface (111) of the thermoelectric material; and a heat input adjustment unit (140) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material by adjusting the amount of heat input to the thermoelectric material, wherein the heat input adjustment unit has a first side surface (116) of the outer surface of the thermoelectric material and a second side surface (117) opposite to the first side surface, and the second side surface is inclined with respect to the first side surface, thereby varying the thickness of the thermoelectric material from the first side surface to the second side surface depending on the position on the first side surface, thereby varying the amount of heat input to the thermoelectric material.

9. A thermoelectric power generation device comprising: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a first electrode (130) and a second electrode (131) provided on an outer surface (111) of the thermoelectric material; and an internal temperature adjustment unit (150) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein the internal temperature adjustment unit has a first side surface (116) of the outer surface of the thermoelectric material and a temperature gradient portion (151) having directionality in heat conduction, and the temperature gradient portion is inclined with respect to the first side surface, thereby generating a temperature gradient that is inclined with respect to the first side surface.

10. The thermoelectric power generating device according to claim 9, wherein the temperature gradient section is provided inside the thermoelectric material and is made of a fibrous material having a directionality.

11. A thermoelectric power generating device according to claim 9 or 10, wherein the temperature gradient portion is made of a material having a thermal interface that is inclined relative to the first side surface.

12. A thermoelectric power generation device comprising: a columnar thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied; a ring-shaped first electrode (130) provided at one end (118) of the thermoelectric material in the extension direction and centered on an axis along the extension direction; a ring-shaped second electrode (131) provided at the other end (120) of the thermoelectric material in the extension direction; and a heat input adjustment unit (140) that generates a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein the heat input adjustment unit is a highly thermally conductive material located in the center of the other end face (121) of the other end of the thermoelectric material, and generates temperature differences at different depths in the extension direction with the other end face as the reference.

13. A thermoelectric power generation device comprising: a thermoelectric material (110) having a structure that undergoes a phase transition when heat is applied, and arranged around a heat source (200) at the center; a first electrode (130) and a second electrode (131) provided on the outer peripheral surface (123) of the thermoelectric material; and a heat input adjustment unit (140) that adjusts the amount of heat input from the heat source to the thermoelectric material to generate a temperature gradient between the first electrode and the second electrode of the thermoelectric material, wherein, at a cutting surface (122) that cuts the heat source, the thermoelectric material, the first electrode, and the second electrode, the heat input adjustment unit makes a first distance from an inner peripheral surface (124) of the thermoelectric material to the first electrode different from a second distance from the inner peripheral surface of the thermoelectric material to the second electrode, thereby generating temperature differences at different depths based on the inner peripheral surface.

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