Thermoelectric conversion module and method for manufacturing same

Abstract

The thermoelectric conversion module includes a substrate having a first main surface and a second main surface, a thermoelectric conversion portion located on the first main surface, a first heat conduction portion and a second heat conduction portion located on the second main surface, and a heat insulation member located on the second main surface. The thermoelectric conversion unit includes a p-type thermoelectric conversion element and an n-type thermoelectric conversion element, a first end portion of the p-type thermoelectric conversion element is in contact with a first end portion of the n-type thermoelectric conversion element, the first heat conduction portion overlaps a second end portion of the p-type thermoelectric conversion element, and the second heat conduction portion overlaps a second end portion of the n-type thermoelectric conversion element. The thickness of each of the n-type thermoelectric conversion element and the p-type thermoelectric conversion element is 3 [mu] m or more and 30 [mu] m or less, and the difference between the linear expansion coefficients of the first heat conduction part and the heat insulation member and the difference between the linear expansion coefficients of the second heat conduction part and the heat insulation member are each 100 ppm / K or less.

Description

Technical Field

[0001] The invention relates to a thermoelectric conversion module and a manufacturing method thereof. Background Art

[0002] In order to implement power generation using geothermal heat or exhaust heat from factories, thermoelectric conversion elements are sometimes used. The following patent document 1 discloses a method in which a flexible substrate having a pattern layer formed by a resin layer and a metal layer is arranged on both sides of a thermoelectric conversion module having a P-type thermoelectric element material and an N-type thermoelectric element material. In the following patent document 1, a metal layer contained in one flexible substrate overlaps with an electrode contained in the thermoelectric conversion module, and a metal layer contained in another flexible substrate overlaps with another electrode contained in the thermoelectric conversion module. In the above method, a temperature difference is generated in the surface direction of the thermoelectric conversion module by making one flexible substrate a high temperature state and the other flexible substrate a low temperature state. As a result, an electromotive force is generated in the thermoelectric conversion module.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 4895293 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In order to realize the output power of the thermoelectric conversion module as described in the above-mentioned patent document 1, it is considered to increase the thermoelectric conversion efficiency by, for example, expanding the above-mentioned temperature difference. In the above-mentioned patent document 1, in order to expand the above-mentioned temperature difference, for example, the P-type thermoelectric element material and the N-type thermoelectric element material can be thinned and the distance between the above-mentioned metal layers can be increased. However, in the case of the former, the thinner each thermoelectric element material is, the higher the resistance of each thermoelectric element material becomes. In addition, in the case of the latter, the larger the above-mentioned distance is, the fewer the number of elements per unit area becomes. Therefore, in the case of simply expanding the above-mentioned temperature difference, the output power of the thermoelectric conversion module per unit area is sometimes reduced instead.

[0008] In addition, in order to output the power generated by the thermoelectric conversion module stably without depending on the temperature of the heat source, it is considered to maintain the shape of the thermoelectric conversion module and prevent the occurrence of uneven temperature difference. Here, in order to expand the above-mentioned temperature difference, the greater the above-mentioned distance, the more difficult it is to maintain the shape of the thermoelectric conversion module. In addition, in the thermoelectric conversion module described in the above-mentioned patent document 1, there is a tendency that the temperature difference in the surface direction of the thermoelectric conversion module is uneven, especially because the temperature of the part that becomes the above-mentioned low temperature state is unstable.

[0009] An object of one aspect of the present invention is to provide a thermoelectric conversion module and a method for manufacturing the same that can improve output power per unit area and output it stably.

[0010] Means for solving problems

[0011] A thermoelectric conversion module and a method for manufacturing the same according to one aspect of the present invention are as follows.

[0012] [1] A thermoelectric conversion module comprising: a substrate having a first main surface and a second main surface located on the opposite side of the first main surface; a thermoelectric conversion portion located on the first main surface; a first heat conducting portion and a second heat conducting portion, the first heat conducting portion and the second heat conducting portion being located on the second main surface and adjacent to each other along a first direction orthogonal to a thickness direction of the substrate; and a heat insulating member located at least between the first heat conducting portion and the second heat conducting portion on the second main surface, the thermoelectric conversion portion having a p-type thermoelectric conversion element and an n-type thermoelectric conversion element arranged along the first direction, a first end portion of the p-type thermoelectric conversion element in the first direction The first heat conduction part is in contact with the first end of the n-type thermoelectric conversion element in the first direction and overlaps with the thermal insulation component in the thickness direction. In the thickness direction, the first heat conduction part overlaps with the second end of the p-type thermoelectric conversion element in the first direction. In the thickness direction, the second heat conduction part overlaps with the second end of the n-type thermoelectric conversion element in the first direction. The thickness of each of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element is not less than 3 μm and not more than 30 μm. The difference in linear expansion coefficient between the first heat conduction part and the thermal insulation component, and the difference in linear expansion coefficient between the second heat conduction part and the thermal insulation component are not more than 100 ppm / K.

[0013] [2] The thermoelectric conversion module according to [1], wherein the first heat conductive part and the second heat conductive part each have a linear expansion coefficient of 100 ppm / K to 200 ppm / K, and the thermal insulation member has a linear expansion coefficient of 200 ppm / K or less.

[0014] [3] The thermoelectric conversion module according to [1] or [2], wherein the width of each of the first heat conducting portion and the second heat conducting portion along the first direction is not less than 0.5 mm and not more than 1.5 mm.

[0015] [4] The thermoelectric conversion module according to any one of [1] to [3], wherein the thermal conductivity of each of the first heat conducting portion and the second heat conducting portion is 2.0 W / mK to 5.0 W / mK, and the thermal conductivity of the heat insulating member is 0.02 W / mK to 0.05 W / mK.

[0016] [5] The thermoelectric conversion module according to any one of [1] to [4], further comprising a heat dissipation component located on the second main surface, wherein the heat dissipation component surrounds the first heat conduction portion, the second heat conduction portion, and the heat insulating member when viewed in the thickness direction.

[0017] [6] A thermoelectric conversion module as described in any one of [1] to [5], wherein the thickness of each of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element is 5 μm or more and 25 μm or less, and the interval between the first heat conduction portion and the second heat conduction portion in the first direction is 3 mm or more and less than 12 mm.

[0018] [7] A thermoelectric conversion module as described in any one of [1] to [6], further comprising: a first thermoelectric conversion group, which is located on the first main surface and has a thermoelectric conversion portion; and a second thermoelectric conversion group, which is located on the first main surface and is adjacent to the first thermoelectric conversion group along a second direction orthogonal to the thickness direction and the first direction, the second thermoelectric conversion group having a second thermoelectric conversion portion adjacent to the thermoelectric conversion portion along the second direction, the second thermoelectric conversion portion having a second p-type thermoelectric conversion element and a second n-type thermoelectric conversion element arranged along the first direction, The first end of the second p-type thermoelectric conversion element facing upward contacts the first end of the second n-type thermoelectric conversion element in the first direction and overlaps with the heat insulating component in the thickness direction. The first heat conduction part and the second heat conduction part each extend along the second direction. In the thickness direction, the first heat conduction part overlaps with the second end of the second n-type thermoelectric conversion element included in the second thermoelectric conversion part in the first direction. In the thickness direction, the second heat conduction part overlaps with the second end of the second p-type thermoelectric conversion element included in the second thermoelectric conversion part in the first direction.

[0019] [8] The thermoelectric conversion module as described in [7] further comprises: a first conductive portion, which is located on the first main surface and connected to one end of the first thermoelectric conversion group in the first direction; and a second conductive portion, which is located on the first main surface and connected to the other end of the first thermoelectric conversion group in the first direction and one end of the second thermoelectric conversion group in the first direction, wherein the first conductive portion and the second conductive portion have the same conductivity type.

[0020] [9] The thermoelectric conversion module according to any one of [1] to [8], wherein the substrate, the thermoelectric conversion portion, the first heat conductive portion, the second heat conductive portion, and the heat insulating member are each flexible.

[0021]

[10] A method for manufacturing a thermoelectric conversion module, comprising: a first step of forming a first heat conducting portion, a second heat conducting portion, and a heat insulating member on one main surface of a substrate; a second step of forming a first layer containing a p-type thermoelectric conversion material on the other main surface of the substrate; a third step of forming a p-type thermoelectric conversion layer by immersing the other main surface of the substrate in an organic solvent after the second step; and a fourth step of forming a p-type thermoelectric conversion element and an n-type thermoelectric conversion element in the same portion by dripping a dopant solution on the p-type thermoelectric conversion layer after the third step. The conductive part is adjacent along a first direction orthogonal to the thickness direction of the substrate, a first end of the p-type thermoelectric conversion element in the first direction contacts a first end of the n-type thermoelectric conversion element in the first direction, and overlaps with the thermal insulation component in the thickness direction, in the thickness direction, the first heat conductive part overlaps with a second end of the p-type thermoelectric conversion element in the first direction, in the thickness direction, the second heat conductive part overlaps with a second end of the n-type thermoelectric conversion element in the first direction, and a difference in linear expansion coefficient between the first heat conductive part and the thermal insulation component, and a difference in linear expansion coefficient between the second heat conductive part and the thermal insulation component are each less than 100 ppm / K.

[0022] Effects of the Invention

[0023] According to one aspect of the present invention, it is possible to provide a thermoelectric conversion module capable of improving output power per unit area and stably outputting the same, and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] [ Figure 1 ] Figure 1 (a) is a schematic plan view showing a thermoelectric conversion module according to an embodiment. Figure 1 (b) is a schematic bottom view showing the thermoelectric conversion module according to the embodiment.

[0025] [ Figure 2 ] Figure 2 (a) is to Figure 1 A part of (a) (the area surrounded by the single-dot chain line) is enlarged. Figure 2 (b) is along Figure 2 (a) is a cross-sectional view along line IIb-IIb.

[0026] [ Figure 3 ] Figure 3 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to an embodiment.

[0027] [ Figure 4 ] Figure 4 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to an embodiment.

[0028] [ Figure 5 ] Figure 5 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to an embodiment.

[0029] [ Figure 6 ] Figure 6 1 is a schematic cross-sectional view showing a part of the thermoelectric conversion module when deformed.

[0030] [ Figure 7 ] Figure 7 (a) is a schematic bottom view of a thermoelectric conversion module according to a modified example. Figure 7 (b) is along Figure 7 A schematic cross-sectional view taken along line VIIb-VIIb of (a). DETAILED DESCRIPTION

[0031] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same elements or elements having the same functions, and repeated descriptions are omitted. The words "same / identical" and similar words in this specification are not limited to "exactly the same / identical".

[0032] First, refer to Figure 1 and Figure 2 The configuration of the thermoelectric conversion module according to the present embodiment will be described. Figure 1 (a) is a schematic plan view showing a thermoelectric conversion module according to this embodiment, Figure 1 (b) is a schematic bottom view showing the thermoelectric conversion module according to the present embodiment. Figure 2 (a) is to Figure 1 An enlarged view of a portion of (a) (a region surrounded by a single-dot chain line). Figure 2 (b) is along Figure 2 (a) is a cross-sectional view along line IIb-IIb.

[0033] Figure 1The thermoelectric conversion module 1 shown in (a) and (b) is a device that can generate electricity by supplying heat from the outside. Thermoelectric conversion module 1 is a so-called in-plane device. Therefore, the thermoelectric conversion module 1 has a tendency to have excellent processability and flexibility compared with, for example, a π-type element (cross-plane type element (vertical type element)). Therefore, the thermoelectric conversion module 1 can be set along the side of, for example, a cylindrical tube for recovering factory waste heat. That is, the thermoelectric conversion module 1 can be easily configured in various locations. Therefore, the thermoelectric conversion module 1 is used, for example, as a power source for factory sensors that utilize waste heat. In addition, the contact resistance between the thermoelectric conversion material contained in the thermoelectric conversion module 1 and the electrode also tends to be lower than that of the π-type module. In the following, the temperature of each component of the thermoelectric conversion module 1 is measured under the natural convection condition of air.

[0034] Thermoelectric conversion module 1 includes substrate 2, multiple thermoelectric conversion groups 3, multiple conductive parts 4, multiple thermally conductive parts 5, and multiple thermally insulating members 6. At least one of substrate 2, multiple thermoelectric conversion groups 3, multiple conductive parts 4, multiple thermally conductive parts 5, and multiple thermally insulating members 6 is flexible.

[0035] The substrate 2 is a sheet member made of a resin having heat resistance and flexibility, and is, for example, in a substantially flat plate shape. The resin constituting the substrate 2 is, for example, a (meth)acrylic resin, a (meth)acrylonitrile resin, a polyamide resin, a polycarbonate resin, a polyether resin, a polyester resin, an epoxy resin, an organic siloxane resin, a polyimide resin, a polysulfone resin, or the like. The thickness of the substrate 2 is, for example, not less than 5 μm and not more than 50 μm. The thermal conductivity of the substrate 2 is, for example, 0.1 W / mK (0.1 watt per meter per Kelvin, equivalent to 0.1 W×m -1 ×K -1 ) or more and 0.3 W / mK or less. By making the thermal conductivity of the substrate 2 0.3 W / mK or less, a temperature difference can be generated inside the thermoelectric conversion group 3. The thermal conductivity of the substrate 2 is measured by a steady-state method or a non-steady-state method.

[0036] The substrate 2 has a first main surface 2a and a second main surface 2b located on the opposite side of the first main surface 2a. The first main surface 2a and the second main surface 2b are surfaces intersecting the direction along the thickness of the substrate 2. The shapes of the first main surface 2a and the second main surface 2b are not particularly limited, and may be, for example, polygonal, circular, elliptical, etc. Hereinafter, the direction along the thickness of the substrate 2 is simply represented as the thickness direction D1. Observation from the thickness direction D1 is equivalent to a top view. In addition, the directions orthogonal to the thickness direction D1 are set as the first direction D2 and the second direction D3.

[0037] A thermoelectric conversion region R1 and two conductive regions R2 are defined on the first main surface 2a. A plurality of thermoelectric conversion groups 3 are provided in the thermoelectric conversion region R1. A plurality of conductive portions 4 are provided in each conductive region R2. The thermoelectric conversion region R1 is located between the two conductive regions R2 in the first direction D2. The larger the proportion of the thermoelectric conversion region R1 on the first main surface 2a, the higher the output power of the thermoelectric conversion module 1 tends to be. When viewed from above, the proportion of the area occupied by the thermoelectric conversion region R1 in the first main surface 2a is, for example, greater than 50% and less than 90%. In addition, when viewed from above, the proportion of the area occupied by the two conductive regions R2 in the first main surface 2a is, for example, greater than 5% and less than 30%. In this case, a conductive path connecting the thermoelectric conversion groups 3 to each other can be reliably formed, and the thermoelectric conversion module 1 can exert a good output.

[0038] Each of the plurality of thermoelectric conversion groups 3 is a portion capable of generating electricity by supplying heat from the outside, and is located on the first main surface 2a. The plurality of thermoelectric conversion groups 3 extend along the first direction D2 and are arranged along the second direction D3. Each of the plurality of thermoelectric conversion groups 3 has a band shape when viewed from the thickness direction D1. The thermoelectric conversion groups 3 are separated from each other, and on the other hand, are electrically connected in series with each other. In the first direction D2, one end of each thermoelectric conversion group 3 is connected to one of the plurality of conductive parts 4 included in one conductive region R2, and the other end of each thermoelectric conversion group 3 is connected to one of the plurality of conductive parts 4 included in another conductive region R2. Each of the plurality of thermoelectric conversion groups 3 has a plurality of thermoelectric conversion parts 11. In the present embodiment, each thermoelectric conversion group 3 has 10 thermoelectric conversion parts 11, but is not limited thereto. In each thermoelectric conversion group 3, the plurality of thermoelectric conversion parts 11 are arranged along the first direction D2. Two thermoelectric conversion parts 11 adjacent to each other in the first direction D2 are in contact with each other and connected in series.

[0039] Below, we will Figure 2 One of the two thermoelectric conversion groups 3 shown in (a) is referred to as the first thermoelectric conversion group 3a, and the other thermoelectric conversion group 3 adjacent to the first thermoelectric conversion group 3a along the second direction D3 is referred to as the second thermoelectric conversion group 3b. In addition, the thermoelectric conversion section 11 included in the first thermoelectric conversion group 3a is sometimes referred to as the first thermoelectric conversion section 11a, and the thermoelectric conversion section 11 included in the second thermoelectric conversion group 3b is sometimes referred to as the second thermoelectric conversion section 11b. The plurality of first thermoelectric conversion sections 11a included in the first thermoelectric conversion group 3a are arranged in sequence along the first direction D2, and the plurality of second thermoelectric conversion sections 11b included in the second thermoelectric conversion group 3b are arranged in sequence along the first direction D2. The first thermoelectric conversion section 11a and the second thermoelectric conversion section 11b are adjacent to each other along the second direction D3.

[0040] Each of the plurality of thermoelectric conversion sections 11 is a portion that performs thermoelectric conversion in the thermoelectric conversion module 1 and exhibits flexibility. The shape of the thermoelectric conversion section 11 when viewed from above is not particularly limited, and may be, for example, a polygonal shape, a circular shape, an elliptical shape, or the like. The p-type thermoelectric conversion element 21 and the n-type thermoelectric conversion element 22 are of the same shape, but are not limited thereto. Each thermoelectric conversion section 11 has a p-type thermoelectric conversion element 21 and an n-type thermoelectric conversion element 22 arranged along the first direction D2. In each thermoelectric conversion section 11, the first end 21a of the p-type thermoelectric conversion element 21 in the first direction D2 and the first end 22a of the n-type thermoelectric conversion element 22 in the first direction D2 are in contact with each other. In each thermoelectric conversion section 11, the second end 21b of the p-type thermoelectric conversion element 21 in the first direction D2 is located at one end of the corresponding thermoelectric conversion section 11, and the second end 22b of the n-type thermoelectric conversion element 22 in the first direction D2 is located at the other end of the corresponding thermoelectric conversion section 11. In two thermoelectric conversion sections 11 adjacent to each other in the first direction D2, second end 21b of p-type thermoelectric conversion element 21 included in one thermoelectric conversion section 11 and second end 22b of n-type thermoelectric conversion element 22 included in the other thermoelectric conversion section 11 are in contact with each other.

[0041] In each of the plurality of thermoelectric conversion groups 3, the p-type thermoelectric conversion elements 21 and the n-type thermoelectric conversion elements 22 are alternately arranged in the first direction D2. Figure 2 As shown in (a), in the present embodiment, the p-type thermoelectric conversion element 21 of the first thermoelectric conversion section 11a is adjacent to the n-type thermoelectric conversion element 22 (the second n-type thermoelectric conversion element) of the second thermoelectric conversion section 11b in the second direction D3, and the n-type thermoelectric conversion element 22 of the first thermoelectric conversion section 11a is adjacent to the p-type thermoelectric conversion element 21 (the second p-type thermoelectric conversion element) of the second thermoelectric conversion section 11b in the second direction D3.

[0042] The p-type thermoelectric conversion element 21 is provided on the first main surface 2a of the substrate 2 and is in contact with the n-type thermoelectric conversion element 22. The thickness T1 of the p-type thermoelectric conversion element 21 is, for example, 3 μm or more and 30 μm or less. By setting the thickness T1 to be 3 μm or more, the resistance of the p-type thermoelectric conversion element 21 can be well reduced. By setting the thickness T1 to be 30 μm or less, a temperature gradient can be easily formed inside the p-type thermoelectric conversion element 21. The thickness T1 can be 5 μm or more, 8 μm or more, 10 μm or more, 25 μm or less, 20 μm or less, or 15 μm or less. The length L1 of the p-type thermoelectric conversion element 21 in the first direction D2 is, for example, 2 mm or more and 10 mm or less. In this case, a temperature gradient can be easily formed inside the p-type thermoelectric conversion element 21. The length of the p-type thermoelectric conversion element 21 in the second direction D3 is, for example, 5 mm or more and 30 mm or less. In this case, a sufficient number of thermoelectric conversion parts 11 can be formed on the first main surface 2a. The thermal conductivity of the p-type thermoelectric conversion element 21 in the in-plane direction is, for example, 0.01 W / mK or more and 40.0 W / mK or less. The thermal conductivity of the p-type thermoelectric conversion element 21 in the in-plane direction is measured, for example, by a photoelectric alternating current method or a 3-Omega method. The p-type thermoelectric conversion element 21 is formed, for example, by various dry methods or wet methods. Wet methods include, for example, a doctor blade method, a dip coating method, a spray coating method, a spin coating method, an inkjet method, and the like.

[0043] The p-type thermoelectric conversion element 21 is, for example, a p-type semiconductor layer. The p-type thermoelectric conversion element 21 includes, for example, carbon nanotubes (CNTs) and a conductive resin different from the carbon nanotubes. The carbon nanotubes show a p-type. The carbon nanotubes may be any of single-layer, double-layer, and multilayer. From the perspective of the conductivity of the p-type thermoelectric conversion element 21, single-layer carbon nanotubes (SWCNTs) may also be used. The proportion of single-layer carbon nanotubes relative to the total amount of carbon nanotubes may be 25% by mass or more, 50% by mass or more, or 100% by mass. The diameter of the single-layer carbon nanotube is not particularly limited, for example, less than 20 nm, less than 10 nm, or less than 3 nm. The lower limit of the diameter of the single-layer carbon nanotube is also not particularly limited, and may be more than 0.4 nm, or more than 0.5 nm. The thermal conductivity of the carbon nanotube is, for example, more than 30 W / mK and less than 40 W / mK.

[0044] In this specification, the diameter of a single-walled carbon nanotube can be determined by Raman spectroscopy in the range of 100 to 300 cm -1 The wave number of the peak (ω(cm -1)), calculated using the formula "diameter (nm) = 248 / ω". As an evaluation method for single-layer carbon nanotubes, the G / D ratio in laser Raman spectroscopy is known. In the present embodiment, the G / D ratio of the single-layer carbon nanotube in the laser Raman spectrum at a wavelength of 532nm can be greater than 10, or greater than 20. By using such single-layer carbon nanotubes, there is a tendency to obtain a p-type thermoelectric conversion element 21 with better electrical conductivity. It should be noted that the upper limit of the above-mentioned G / D ratio is not particularly limited, and can be less than 500, or less than 300.

[0045] The content of carbon nanotubes in the p-type thermoelectric conversion element 21 can be, for example, 20 parts by mass or more, 30 parts by mass or more, or 40 parts by mass or less, or 99 parts by mass or less, or 95 parts by mass or less, or 90 parts by mass or less, relative to 100 parts by mass of the material constituting the p-type thermoelectric conversion element 21 (p-type thermoelectric conversion material).

[0046] The conductive resin of the present embodiment is not particularly limited, and known conductive resins can be used without particular restrictions. As the conductive resin, for example, conductive resins including polyaniline conductive resins, polythiophene conductive resins, polypyrrole conductive resins, polyacetylene conductive resins, polyphenylene conductive resins, polyphenylene ethylene conductive resins, etc. can be cited. As a polythiophene conductive resin, for example, poly (3,4-ethylenedioxythiophene) (PEDOT) can be exemplified. In the present embodiment, the conductive resin includes PEDOT and an electron acceptor. In this case, there is a tendency for the conductivity of the p-type thermoelectric conversion element 21 to be further improved. Examples of the electron acceptor include polystyrene sulfonic acid, polyvinyl sulfonic acid, poly(meth)acrylic acid, polyvinyl sulfonic acid, toluene sulfonic acid, dodecylbenzene sulfonic acid, camphor sulfonic acid, bis(2-ethylhexyl)sulfosuccinate, chlorine, bromine, iodine, phosphorus pentafluoride, arsenic pentafluoride, boron trifluoride, hydrogen chloride, sulfuric acid, nitric acid, tetrafluoroboric acid, perchloric acid, iron (III) chloride, tetracyanoquinodimethane, etc. From the viewpoint of the conductivity of the p-type thermoelectric conversion element 21, the electron acceptor may also be polystyrene sulfonic acid (PSS).

[0047] The carbon nanotubes and the conductive resin may be aggregated in the p-type thermoelectric conversion element 21. The p-type thermoelectric conversion element 21 may include a porous structure in which the carbon nanotubes are bonded to each other by the conductive resin.

[0048] The n-type thermoelectric conversion element 22 is provided on the first main surface 2a of the substrate 2 and is in contact with the p-type thermoelectric conversion element 21. The thickness of the n-type thermoelectric conversion element 22 is the same as or substantially the same as the thickness T1 of the p-type thermoelectric conversion element 21. The length of the n-type thermoelectric conversion element 22 in the first direction D2 is the same as or substantially the same as the length L1 of the p-type thermoelectric conversion element 21. The length of the n-type thermoelectric conversion element 22 in the second direction D3 is, for example, 2 mm or more and 10 mm or less. In this case, a sufficient number of thermoelectric conversion portions 11 can be formed on the first main surface 2a. The thermal conductivity of the n-type thermoelectric conversion element 22 in the in-plane direction is, for example, 0.01 W / mK or more and 40.0 W / mK or less. The thermal conductivity of the n-type thermoelectric conversion element 22 in the in-plane direction is measured, for example, by a photoelectric alternating current method or a 3-Omega method. Similar to the p-type thermoelectric conversion element 21, the n-type thermoelectric conversion element 22 is formed, for example, by various dry methods or wet methods.

[0049] The n-type thermoelectric conversion element 22 is, for example, an n-type semiconductor layer. The n-type thermoelectric conversion element 22 includes, for example, a composite of multiple organic substances, or a composite of inorganic substances and organic substances. In the present embodiment, the n-type thermoelectric conversion element 22 is a portion showing an n-type by causing the p-type thermoelectric conversion element 21 to contain a dopant. Therefore, the n-type thermoelectric conversion element 22 includes carbon nanotubes, a conductive resin, and a dopant. In the present embodiment, the dopant refers to a substance that changes the Seebeck coefficient of the portion that is doped with the dopant. "Changing the Seebeck coefficient" means reducing the value of the Seebeck coefficient, or changing the value of the Seebeck coefficient from a positive value to a negative value. A thermoelectric conversion material whose Seebeck coefficient shows a positive value has p-type conductivity, and a thermoelectric conversion material whose Seebeck coefficient shows a negative value has an n-type material.

[0050] The dopant of the present embodiment contains, for example, a coordination compound that can dissociate into anions (hereinafter also referred to as "anions") and alkali metal cations (hereinafter also referred to as "cations") as complex ions, and a cation capture agent (hereinafter also referred to as "capture agent"). In the n-type thermoelectric conversion element 22, at least a portion of the coordination compound can be dissociated into the above-mentioned anions and the above-mentioned cations. At this time, the above-mentioned cations can also be captured by the above-mentioned capture agent. In the dopant, at least one of the coordination compound and the capture agent can be included in multiple forms. In the portion of the p-type thermoelectric conversion element 21 containing the above-mentioned dopant, the Seebeck coefficient changes. Thus, an n-type thermoelectric conversion element 22 is formed in the above-mentioned portion.

[0051] The reason for achieving the above-mentioned effect is not particularly limited, and it is believed that one reason is that the capture agent contained in the dopant captures cations and dissociates anions, and the anions change the carriers of the carbon nanotubes from holes to electrons. At this time, in the present embodiment, the anion is a complex ion with a metal atom at the center, so it is believed that n-type is significantly generated by the interaction of the metal atom and the carbon nanotubes, and in addition, because the ion size of the complex ion is large, it is believed that the dissociation of the cation captured by the capture agent is good and is also a reason for achieving the above-mentioned effect. In the dopant of the present embodiment, the anion is a complex ion. Therefore, in the n-type thermoelectric conversion element 22, metal atoms from complex ions are contained. Therefore, in the present embodiment, the metal atoms remaining in the n-type thermoelectric conversion element 22 can function as an antioxidant.

[0052] The complex ion (anion) obtained by dissociation of the coordination compound can be selected from the group consisting of ferrocyanide ion, ferricyanide ion, tetrachloroferric (III) acid ion, tetrachloroferric (II) acid ion, tetracyanonickelic acid (II) ion, tetrachloronickelic acid (II) ion, tetracyanocobalt (II) acid ion, tetrachlorocobaltic acid (II) ion, tetracyanocuprate (I) acid ion, tetrachlorocopper (II) acid ion, hexacyanochromium (III) ion, tetrahydroxyzinc (II) acid ion and tetrahydroxyaluminum (III) acid ion. Among them, ferrocyanide ion is preferred. When the above-mentioned anion is ferrocyanide ion, a material with better characteristics can be obtained. In addition, if the anion is ferrocyanide ion, the iron atom remaining in the n-type thermoelectric conversion element 22 functions appropriately as an antioxidant, and there is a trend that the physical property changes over time are further suppressed and the storage stability is further improved.

[0053] The above-mentioned anions may contain iron atoms. That is, the coordination compound may contain iron atoms. In this case, the anions may be selected from the group consisting of, for example, ferrocyanide ions, ferricyanide ions, tetrachloroferric (III) acid ions and tetrachloroferric (II) acid ions. From the perspective of the characteristics of the n-type thermoelectric conversion element 22, the above-mentioned anions containing iron atoms may also be ferrocyanide ions. From the perspective of the antioxidant effect, the content of iron atoms in the n-type thermoelectric conversion element 22 may be 0.001 mass % to 15 mass %, or 0.005 mass % to 12 mass %, or 0.01 mass % to 10 mass %. It should be noted that the content of iron atoms in the n-type thermoelectric conversion element 22 represents, for example, a value measured by ICP emission analysis.

[0054] The coordination compound may be a complex salt. Examples of the complex salt include potassium ferrocyanide, sodium ferrocyanide, potassium ferrocyanide, sodium ferrocyanide, potassium tetrachloroferrate (III), sodium tetrachloroferrate (III), potassium tetrachloroferrate (II), sodium tetrachloroferrate (II), etc. The complex salt may also be a hydrate.

[0055] Examples of the alkali metal cation obtained by dissociation of the coordination compound include sodium ions, potassium ions, and lithium ions. The coordination compound preferably contains at least one of ferrocyanide and ferrocyanide.

[0056] The cation capture agent is not particularly limited as long as it is a substance with the ability to absorb cations. Cation capture agents are, for example, crown ether compounds, cyclodextrins, calixarene, ethylenediaminetetraacetic acid, porphyrin, phthalocyanine and their derivatives. In the present embodiment, the cation capture agent is a crown ether compound. As crown ether compounds, 15-crown-5-ether, 18-crown-6-ether, 12-crown-4-ether, benzo-18-crown-6-ether, benzo-15-crown-5-ether and benzo-12-crown-4-ether can be cited. The crown ether used as a capture agent can select the size of the ring according to the size of the metal ion that becomes the object of intake. For example, when the metal ion is a potassium ion, the crown ether compound can be an 18-membered ring crown ether. When the metal ion is a sodium ion, the crown ether compound can be a 15-membered ring crown ether. When the metal ion is a lithium ion, the crown ether compound can be a 12-membered ring crown ether.

[0057] The crown ether compound may contain a benzene ring. In this case, the stability of the crown ether compound can be improved. Examples of the crown ether compound having a benzene ring include benzo-18-crown-6-ether, benzo-15-crown-5-ether, and benzo-12-crown-4-ether.

[0058] The molar ratio of the content C2 of the scavenger to the content C1 of the cation (C2 / C1) may be 0.1 to 5, 0.3 to 3, or 0.5 to 2.

[0059] In each of the plurality of thermoelectric conversion sections 11, the mass ratio of the carbon nanotubes relative to the total mass of the thermoelectric conversion section 11 is, for example, 30% to 70% to be inclusive. By making the mass ratio 30% to 30%, the thermoelectric conversion section 11 can have good electrical conductivity. By making the mass ratio 70% to 70%, the temperature difference in the thermoelectric conversion section 11 is easily increased. The mass ratio may be 35% to 35%, 40% to 45% to 50% to be inclusive. The mass ratio may be 65% to 60% to 55% to be inclusive. The mass ratio of the carbon nanotubes relative to the total mass of the p-type thermoelectric conversion element 21 may be 30% to 70% to be inclusive, and the mass ratio of the carbon nanotubes relative to the total mass of the n-type thermoelectric conversion element 22 may be 30% to 70% to be inclusive. In each of the plurality of thermoelectric conversion groups 3, the mass ratio of the carbon nanotubes relative to the total mass of the thermoelectric conversion group 3 may be 30% to 70% to be inclusive, or 40% to 60% to be inclusive. It should be noted that the internal temperature difference of the thermoelectric conversion unit 11 and the like is measured using, for example, a thermal imager.

[0060] Each of the plurality of conductive parts 4 is a conductive part located on the first main surface 2a and is connected to the corresponding thermoelectric conversion group 3. Each conductive part 4 may also be a semiconductor instead of a conductor. The thickness of each conductive part 4 is the same as or substantially the same as the thickness T1 of the p-type thermoelectric conversion element 21. The conductivity of each conductive part 4 only needs to be greater than the conductivity of the p-type thermoelectric conversion element 21. The thermal conductivity of each conductive part 4 only needs to be greater than the thermal conductivity of the p-type thermoelectric conversion element 21. At least a portion of the plurality of conductive parts 4 may have a single-layer structure or a stacked structure. For example, at least a portion of the plurality of conductive parts 4 may have an organic conductive layer and a metal conductive layer located on the organic conductive layer. In the present embodiment, the plurality of conductive parts 4 are formed of the same material as the p-type thermoelectric conversion element 21. Therefore, each conductive part 4 has the same conductivity type (p-type).

[0061] The plurality of conductive parts 4 have a first conductive part 4a that functions as a terminal connected to the external device, and a second conductive part 4b that functions as a conductive path that connects adjacent thermoelectric conversion groups 3 to each other. The plurality of conductive parts 4 have two first conductive parts 4a, and the two first conductive parts 4a are located in one conductive region R2. Only the second conductive part 4b is provided in another conductive region R2. The plurality of thermoelectric conversion groups 3 are connected in series with each other via the plurality of second conductive parts 4b. Therefore, when the thermoelectric conversion module 1 implements thermoelectric conversion, current can flow in series from one first conductive part 4a to another first conductive part 4a. For example, a first conductive part 4a located in one conductive region R2 is connected to one end of the first thermoelectric conversion group 3a in the first direction D2, and a second conductive part 4b located in another conductive region R2 is connected to the other end of the first thermoelectric conversion group 3a in the first direction D2 and one end of the second thermoelectric conversion group 3b.

[0062] The plurality of heat conducting parts 5 are portions showing a higher thermal conductivity than the substrate 2, and are located on the second main surface 2b. At least a portion of the plurality of heat conducting parts 5 overlaps with the thermoelectric conversion group 3 (i.e., the thermoelectric conversion part 11) in the thickness direction D1. More specifically, at least a portion of the plurality of heat conducting parts 5 overlaps with the end of the thermoelectric conversion part 11. On the other hand, each heat conducting part 5 does not overlap with the center of the thermoelectric conversion part 11. Thus, a temperature gradient inside the thermoelectric conversion part 11 along the first direction D2 can be well generated. The plurality of heat conducting parts 5 are spaced from each other along the first direction D2, and have a belt shape extending along the second direction when viewed from above. The shape of each heat conducting part 5 when viewed from above is not particularly limited, and may be, for example, a polygonal shape, a circular shape, an elliptical shape, or the like. Each heat conducting part 5 includes, for example, a metal (silver, copper, etc.), carbon, a resin (for example, a silicone resin, an epoxy resin, a (meth) acrylic resin), or the like. Each heat conducting part 5 may also include a ceramic such as boron nitride and aluminum nitride showing high thermal conductivity. From the viewpoint of manufacturing efficiency, each heat conducting portion 5 may contain the above resin. In this case, the heat conducting portion 5 may be formed using the resin or a solution containing the resin.

[0063] The thermal conductivity of each heat conducting part 5 is, for example, 1 W / mK or more and 400 W / mK or less. Thus, when the thermoelectric conversion module 1 is heated, heat is well transferred to the thermoelectric conversion part 11 via the plurality of heat conducting parts 5. The thermal conductivity may be, for example, 2.0 W / mK or more, 3.0 W / mK or more, 5.0 W / mK or more, or 10.0 W / mK or more. In the present embodiment, the thermal conductivity of each heat conducting part 5 is 2.0 W / mK or more and 5.0 W / mK or less, but is not limited thereto. The thermal conductivity of each heat conducting part 5 is measured by a steady-state method or a non-steady-state method. The linear expansion coefficient of each heat conducting part 5 in the in-plane direction is, for example, 100 ppm / K or more and 200 ppm / K or less. The linear expansion coefficient of each heat conducting part 5 is measured, for example, by thermomechanical analysis (TMA).

[0064] The length T2 of each heat conduction part 5 along the thickness direction D1 is, for example, not less than 50 μm and not more than 2000 μm. The width L2 of each heat conduction part 5 along the first direction D2 is, for example, not less than 0.5 mm and not more than 2.0 mm. In these cases, the heat conduction function of each heat conduction part 5 can be well exerted. In two adjacent heat conduction parts 5, the interval S along the first direction D2 is larger than the length L1 of the p-type thermoelectric conversion element 21 in the first direction D2 and the length of the n-type thermoelectric conversion element 22 in the first direction D2, and is not less than 3 mm and not more than 15 mm. The interval S can be not less than 4 mm, or not less than 5 mm, or not less than 6 mm, or not more than 12 mm, or not more than 10 mm, or not more than 8 mm. Alternatively, the interval S can be less than 12 mm, or less than 10 mm.

[0065] Below, sometimes Figure 2 One of the two heat-conducting portions 5 shown in (b) is referred to as the first heat-conducting portion 5a, and the other heat-conducting portion 5 adjacent to the first heat-conducting portion 5a along the first direction D2 is referred to as the second heat-conducting portion 5b. In this case, in the thickness direction D1, the first heat-conducting portion 5a overlaps with one end of the first thermoelectric conversion portion 11a in the first direction D2. In addition, in the thickness direction D1, the second heat-conducting portion 5b overlaps with the other end of the first thermoelectric conversion portion 11a in the first direction D2. More specifically, in the thickness direction D1, the first heat-conducting portion 5a overlaps with the second end 22b of the n-type thermoelectric conversion element 22 included in the first thermoelectric conversion portion 11a, and the second heat-conducting portion 5b overlaps with the second end 21b of the p-type thermoelectric conversion element 21 included in the first thermoelectric conversion portion 11a. In addition, as Figure 2As shown in (a), in the thickness direction D1, the first heat conductive portion 5a overlaps with the second end portion 21b of the p-type thermoelectric conversion element 21 included in the second thermoelectric conversion portion 11b, and the second heat conductive portion 5b overlaps with the second end portion 22b of the n-type thermoelectric conversion element 22 included in the second thermoelectric conversion portion 11b.

[0066] The plurality of heat insulating components 6 are portions having a thermal conductivity lower than that of the display substrate 2, and are located on the second main surface 2b. The plurality of heat insulating components 6 are each located between the corresponding first heat conducting portion 5a and the second heat conducting portion 5b. The plurality of heat insulating components 6 are spaced apart from each other along the first direction D2. The shape of each heat insulating component 6 when viewed from above is not particularly limited, and may be, for example, a polygonal shape, a circular shape, an elliptical shape, or the like. In the present embodiment, each heat insulating component 6 has a band shape extending along the second direction when viewed from above, and is in contact with both the corresponding first heat conducting portion 5a and the second heat conducting portion 5b. Therefore, the width of each heat insulating component 6 along the first direction D2 in the present embodiment corresponds to the interval S. The length T3 of each heat insulating component 6 along the thickness direction D1 is smaller than the length T2 of each heat conducting portion 5. For example, the length T3 is less than 80% or less than 70% of the length T2. In this case, when the thermoelectric conversion module 1 is deformed, the heat insulating component 6 becomes less likely to be peeled off from the substrate 2.

[0067] At least a portion of each of the plurality of heat insulating members 6 overlaps with the center of the corresponding thermoelectric conversion section 11 in the thickness direction D1. In other words, in each thermoelectric conversion section 11, the first end 21a of the p-type thermoelectric conversion element 21 and the first end 22a of the n-type thermoelectric conversion element 22 overlap with at least a portion of each of the plurality of heat insulating members 6 in the thickness direction D1. As a result, the temperature of the center of each thermoelectric conversion section 11 can be stabilized, so there is a tendency to stably generate a temperature gradient inside the thermoelectric conversion section 11 along the first direction D2. Therefore, the deviation range of the temperature difference in each thermoelectric conversion section 11 within a predetermined period can be, for example, 2.5°C or less, 2.0°C or less, or 1.0°C or less. The deviation range of the temperature difference of the thermoelectric conversion section 11 is obtained by measuring the time-dependent changes of the high temperature region of the thermoelectric conversion section 11 (for example, both ends of the thermoelectric conversion section 11 in the first direction D2) and the low temperature region of the thermoelectric conversion section 11 (for example, the center of the thermoelectric conversion section 11 in the first direction D2). It should be noted that the predetermined period is not particularly limited, and is, for example, not less than 10 seconds and not more than 100 hours.

[0068] Each thermal insulation component 6 includes, for example, cellulose nanofibers (CNF), silica aerogel, resin (such as silicone), etc. Each thermal insulation component 6 may also be a foam. The thermal conductivity of each thermal insulation component 6 is, for example, 0.01W / mK or more and 0.1W / mK or less. The thermal conductivity may be 0.02W / mK or more, 0.03W / mK or more, 0.08W / mK or less, or 0.05W / mK or less. In the present embodiment, the thermal conductivity of each thermal insulation component 6 is, for example, 0.02W / mK or more and 0.05W / mK or less, but is not limited thereto. The linear expansion coefficient of each thermal insulation component 6 is, for example, less than 200ppm / K. The linear expansion coefficient of each thermal insulation component 6 is measured, for example, by thermomechanical analysis (TMA). The difference between the linear expansion coefficient of each heat conduction part 5 and the linear expansion coefficient of each thermal insulation component 6 is, for example, less than 100ppm / K. Thus, even when the thermoelectric conversion module 1 is attached to a heat source in a deformed state, the thermoelectric conversion module 1 will not be separated from the heat source, and a stable temperature gradient can be maintained to generate electricity. The difference may be less than 80 ppm / K, less than 50 ppm / K, or less than 10 ppm / K.

[0069] Thermoelectric conversion module 1 may include configurations other than those described above. For example, thermoelectric conversion module 1 may include wiring for electrically connecting to other thermoelectric conversion modules, wiring for extracting electric power to an external circuit, and the like.

[0070] Next, refer to Figure 3 to Figure 5 An example of a method for manufacturing the thermoelectric conversion module 1 according to the present embodiment will be described. Figure 3 (a), (b), Figure 4 (a), (b) and Figure 5 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to the present embodiment.

[0071] First, if Figure 3 As shown in (a) and (b), a plurality of heat conduction parts 5 and a plurality of heat insulating components 6 are formed on the second main surface 2b (one main surface) of the pre-prepared substrate 2 (first process). In the first process, a high thermal conductivity material and a heat insulating material are applied to the second main surface 2b by a known method such as an inkjet method, a dispensing method, a doctor blade method, a screen printing method, etc. The high thermal conductivity material and the heat insulating material can be applied at the same time or at different times. Then, the high thermal conductivity material and the heat insulating material are cured by heating, thereby forming a plurality of heat conduction parts 5 and heat insulating components 6 on the second main surface 2b.

[0072] Then, if Figure 4As shown in (a), the first layer 41 is formed on the first main surface 2a (on the other main surface) (second process). In the second process, first, a dispersion is dripped on the first main surface 2a by a known method such as an inkjet method, a dispensing method, a doctor blade method, a screen printing method, a casting method, a dip coating method, a spray coating method, etc. Then, the first layer 41 is formed by drying the dispersion. For example, the substrate 2 is heated by placing it in an air-supplied dryer set to 25°C to 90°C for 10 minutes to 21600 minutes. Thus, the dispersion is dried to form the first layer 41.

[0073] The dispersion used in the second step is, for example, a liquid in which a p-type thermoelectric conversion material is dispersed. In the present embodiment, the dispersion is a liquid in which carbon nanotubes and a conductive resin are dispersed. The content of carbon nanotubes in the dispersion is, based on the total amount of the conductive resin and the carbon nanotubes, for example, 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more, and 80% by mass or less, 75% by mass or less, 70% by mass or less, or 60% by mass or less. In this case, there is a tendency that the first layer 41 is prone to temperature difference and the conductivity of the first layer 41 is improved. In addition, in each of the multiple thermoelectric conversion units 11 described later, it is easy to adjust the mass ratio of carbon nanotubes relative to the total mass of the thermoelectric conversion unit 11 to 30% or more and 70% or less. The total mass concentration of the carbon nanotubes and the conductive resin in the dispersion is, for example, 0.05 mass % or more, 0.06 mass % or more, 0.07 mass % or more, 0.10 mass % or more, 0.12 mass % or more, or 0.15 mass % or more. The total mass concentration of the carbon nanotubes and the conductive resin in the dispersion may be 10 mass % or less, or 2 mass % or less. The dispersion used in the second step is, for example, a mixed liquid formed by mixing a first liquid containing carbon nanotubes and a second liquid containing a conductive resin. It should be noted that the content of carbon nanotubes in the dispersion based on the total amount of the conductive resin and the carbon nanotubes is substantially equal to the mass ratio of the carbon nanotubes to the total mass of the thermoelectric conversion unit 11. Therefore, in this specification, the content of carbon nanotubes in the dispersion based on the total amount of the conductive resin and the carbon nanotubes can be regarded as the mass ratio of the carbon nanotubes to the total mass of the thermoelectric conversion unit 11.

[0074] The first liquid, for example, contains carbon nanotubes and a first solvent. The concentration of carbon nanotubes in the first liquid is, for example, 0.01 mass % or more and 10 mass % or less. The first solvent can be any solvent capable of dispersing carbon nanotubes, for example, a polar liquid or an aqueous solvent. The aqueous solvent is water, or a mixed solvent of water and an organic solvent. The first solvent can be a protic solvent or an aprotic solvent. Specific examples of the first solvent include water, alcohols (methanol, ethanol, etc.), amides (N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.), ketones (acetone, methyl ethyl ketone, etc.), glycols (ethylene glycol, diethylene glycol, etc.), dimethyl sulfoxide, acetonitrile, etc. Among them, preferably one or more of the group consisting of water, methanol, ethanol, N-methylpyrrolidone and dimethyl sulfoxide, more preferably water. The first liquid may further include additives such as surfactants and organic binders.

[0075] The second liquid includes, for example: a conductive resin (PEDOT / PSS) containing PEDOT and PSS; and a second solvent. In PEDOT / PSS, the content ratio of PEDOT and PSS is not particularly limited. The ratio (mass ratio) of PSS to PEDOT is, for example, greater than 1, greater than 1.25 or greater than 1.5, and less than 30 or less than 20. The second solvent can be any solvent that can disperse PEDOT / PSS, such as a polar liquid or an aqueous solvent. The second solvent can be a protic solvent or an aprotic solvent. Specific examples of the second solvent are the same as those of the first solvent. Among them, preferably one or more of the group consisting of water, methanol and ethanol, more preferably water. In one embodiment, the second liquid can be an aqueous dispersion of PEDOT / PSS. It should be noted that the second solvent can be used alone or as a mixture of two or more. The second liquid may also contain various additives.

[0076] Then, if Figure 4As shown in (b), the p-type thermoelectric conversion layer 42 is formed by immersing the substrate 2 in an organic solvent (third step). In the present embodiment, after the second step, the first main surface 2a of the substrate 2 is immersed in dimethyl sulfoxide (DMSO) as the above-mentioned organic solvent (immersion treatment). For example, the first main surface 2a of the substrate 2 is immersed in dimethyl sulfoxide set to room temperature for more than 1 minute and less than 7200 minutes. After the above-mentioned immersion treatment, the substrate 2 can also be heated in an air-supplied dryer. For example, the substrate 2 is heated by placing it in an air-supplied dryer set to more than 25°C and less than 90°C for more than 10 minutes and less than 21600 minutes. Thus, a patterned p-type thermoelectric conversion layer 42 is formed. A portion of the p-type thermoelectric conversion layer 42 subsequently becomes the n-type thermoelectric conversion element 22. Another portion of the p-type thermoelectric conversion layer 42 subsequently becomes the p-type thermoelectric conversion element 21. Another portion of the p-type thermoelectric conversion layer 42 subsequently becomes the conductive portion 4.

[0077] Then, if Figure 5 As shown in (a), after the third step, a solution containing a dopant (dopant solution 51) is dripped onto a portion 42a of the p-type thermoelectric conversion layer 42, thereby forming a p-type thermoelectric conversion element 21, and an n-type thermoelectric conversion element 22 is formed on the portion 42a (the fourth step). In the fourth step, the dopant solution 51 is impregnated into a portion 42a of the p-type thermoelectric conversion layer 42 by a known method such as an inkjet method or a dispensing method. In the present embodiment, in the p-type thermoelectric conversion layer 42, regions to which the dopant solution 51 is dripped and regions to which the dopant solution 51 is not dripped are alternately provided. Next, the dopant solution 51 is dried, thereby converting the portion 42a into the n-type thermoelectric conversion element 22. For example, the substrate 2 is heated by placing it on a heating plate set to a temperature of 25° C. to 90° C. for 10 minutes to 21600 minutes. Thus, the dopant solution 51 is dried. The solvent contained in the dopant solution 51 is, for example, water, acetonitrile, ethanol, ethylene glycol, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, etc. Figure 5 As shown in (b), the portion of the p-type thermoelectric conversion layer 42 to which the dopant solution 51 is not dropped becomes the p-type thermoelectric conversion element 21 or the conductive portion 4. Thus, the thermoelectric conversion module 1 having a plurality of thermoelectric conversion portions 11 is formed.

[0078] Next, the effects achieved by the thermoelectric conversion module 1 formed by the manufacturing method according to the present embodiment described above will be described.

[0079] The thermoelectric conversion module 1 according to the present embodiment includes a first heat conducting portion 5a and a second heat conducting portion 5b located on the second main surface 2b, and the first heat conducting portion 5a overlaps with the second end portion 22b of the n-type thermoelectric conversion element 22 included in the first thermoelectric conversion portion 11a in the thickness direction D1, and the second heat conducting portion 5b overlaps with the second end portion 21b of the p-type thermoelectric conversion element 21 included in the first thermoelectric conversion portion 11a in the thickness direction D1. In addition, a heat insulating member 6 is provided between the first heat conducting portion 5a and the second heat conducting portion 5b on the second main surface 2b. Thus, the first heat conducting portion 5a and the second heat conducting portion 5b each overlap with both ends of the first thermoelectric conversion portion 11a in the thickness direction D1, and do not overlap with the center of the first thermoelectric conversion portion 11a. Therefore, for example, by heating the first heat conduction part 5a and the second heat conduction part 5b, it is possible to generate a good internal temperature difference in each of the p-type thermoelectric conversion element 21 and the n-type thermoelectric conversion element 22. Here, the thickness T1 of the p-type thermoelectric conversion element 21 (and the thickness of the n-type thermoelectric conversion element 22) is 3 μm or more and 30 μm or less. By making the thickness T1 within the above range, the increase in the number of elements per unit area and the internal resistance of the element can be suppressed. In addition, at least a portion of the heat insulating component 6 overlaps with the center of the thermoelectric conversion part 11 in the thickness direction D1. As a result, the temperature of the center of the thermoelectric conversion part 11, which becomes a relatively low temperature in the thermoelectric conversion part 11 during heating, can be stabilized. Therefore, it is not easy to generate uneven temperature differences inside the thermoelectric conversion part 11. Furthermore, the difference in linear expansion coefficient between the first heat conduction part 5a and the second heat conduction part 5b and the heat insulating component 6 is 100 ppm / K or less. Thus, even when the thermoelectric conversion module 1 is installed on the heat source in a deformed state, the thermoelectric conversion module 1 will not be separated from the heat source, and a stable temperature gradient can be maintained to generate electricity. Therefore, by adopting the thermoelectric conversion module 1 involved in this embodiment, the output power per unit area can be increased and output stably without relying on the temperature of the heat source.

[0080] In the present embodiment, the linear expansion coefficient of each of the first heat conducting portion 5a and the second heat conducting portion 5b is 100 ppm / K or more and 200 ppm / K or less, and the linear expansion coefficient of the heat insulating member 6 can be 200 ppm / K or less. In this case, even when the thermoelectric conversion module 1 is attached to the heat source in a deformed state, the thermoelectric conversion module 1 will not be separated from the heat source, and a more stable temperature gradient can be maintained to generate electricity.

[0081] In the present embodiment, the width L2 of each heat conducting portion 5 along the first direction D2 may be 0.5 mm or more and 1.5 mm or less. In this case, the heat transfer performance of each heat conducting portion 5 can be well exerted, and the internal temperature difference of the thermoelectric conversion portion 11 can be increased.

[0082] In this embodiment, the thermal conductivity of the first heat conducting part 5a and the second heat conducting part 5b is 2.0 W / mK to 5.0 W / mK, and the thermal conductivity of the heat insulating member 6 is 0.01 W / mK to 0.05 W / mK. In this case, the internal temperature difference of the thermoelectric conversion part 11 can be more effectively generated.

[0083] In the present embodiment, the thickness T1 of the p-type thermoelectric conversion element 21 may be 5 μm or more and 25 μm or less. The interval S may be 3 mm or more and less than 12 mm. In these cases, the output per unit area of ​​the thermoelectric conversion module 1 can be further improved.

[0084] In this embodiment, the substrate 2, the thermoelectric conversion unit 11, the heat conducting unit 5, and the heat insulating member 6 may each be flexible. In this case, for example, the thermoelectric conversion module 1 can be easily installed along the surface of the cylindrical tube. That is, the restrictions on the installation position of the thermoelectric conversion module 1 can be relaxed.

[0085] In this embodiment, by dropping a dopant solution 51 onto a portion 42a of the p-type thermoelectric conversion layer 42, the portion 42a is formed into an n-type thermoelectric conversion element 22. In this case, the contact resistance between the p-type thermoelectric conversion element 21 and the n-type thermoelectric conversion element 22 can be well reduced. In addition, the dopant solution 51 is dropped after forming the heat conducting portion 5. Thus, the material contained in the dopant solution 51 is not easily degraded by heating or the like.

[0086] In this embodiment, the length T3 of each heat insulating member 6 along the thickness direction D1 is smaller than the length T2 of each heat conducting portion 5. For example, the length T3 is less than 80% or less than 70% of the length T2. Figure 6 As shown, each insulating member 6 is unlikely to hinder deformation of the substrate 2. Thus, for example, excessive compressive stress is unlikely to be applied to the boundary between the heat conducting portion 5 and the insulating member 6, and thus the insulating member 6 is unlikely to be peeled off from the substrate 2 when the thermoelectric conversion module 1 is deformed.

[0087] The thermoelectric conversion module and the manufacturing method thereof according to the present invention are not limited to the above-described embodiment and the above-described modified examples, and various other modifications are possible.

[0088] Figure 7 (a) is a schematic bottom view of a thermoelectric conversion module according to a modification example. Figure 7 (b) is along Figure 7 A schematic cross-sectional view of line VIIb-VIIb of (a). Figure 7 In (b), the structure provided on the first main surface 2a is omitted. Figure 7The thermoelectric conversion module 1A shown in (a) and (b) is different from the thermoelectric conversion module 1 in the above-mentioned embodiment in that it also includes a heat dissipation component 7 located on the second main surface 2b. In addition, the shape of the heat insulation component 6A provided in the thermoelectric conversion module 1A is different from the shape of the heat insulation component 6 in the above-mentioned embodiment. The heat dissipation component 7 is a component for dissipating heat accumulated in the thermoelectric conversion module 1A, and has a frame shape surrounding each heat conduction part 5 and the heat insulation component 6A when viewed from above. In this modification, the heat dissipation component 7 has a rectangular frame shape, but is not limited to this. The heat insulation component 6A is provided in a manner that fills the area surrounded by the heat dissipation component 7. Therefore, the heat insulation component 6A is not only in contact with each heat conduction part 5, but also in contact with the heat dissipation component 7, and each heat conduction part 5 is surrounded by the heat insulation component 6A when viewed from above.

[0089] The thermal conductivity of the heat dissipation component 7 is at least higher than the thermal conductivity of the substrate 2, for example, not less than 1 W / mK and not more than 400 W / mK. The thermal conductivity of the heat dissipation component 7 is measured by a steady-state method or a non-steady-state method. The difference between the linear expansion coefficient of the heat dissipation component 7 in the in-plane direction and the linear expansion coefficient of the heat insulation component 6 is, for example, not more than 100 ppm / K. Thus, even when the thermoelectric conversion module 1A is installed on the heat source in a deformed state, the thermoelectric conversion module 1A will not be separated from the heat source, and a stable temperature gradient can be maintained to generate electricity. In the above-described modified example, the same effect as the above-mentioned embodiment can also be achieved. In addition, by providing the heat dissipation component 7, heat is not easily accumulated in the thermoelectric conversion module 1A, so it is easy to maintain the temperature difference in the thermoelectric conversion section 11.

[0090] In the above-mentioned embodiment and the above-mentioned modification, the thermoelectric conversion element is exposed on the first main surface, but it is not limited to this. For example, the thermoelectric conversion element may also be covered by a sealing layer made of resin or the like. In addition, an insulator may also be provided between two adjacent thermoelectric conversion groups. In this case, from the viewpoint of maintaining the internal temperature difference of the thermoelectric conversion part, it is preferred that the thermal conductivity of the insulator is low.

[0091] In the above-mentioned embodiment and the above-mentioned modification, the heat insulating member is formed by drying the heat insulating material applied on the substrate, but the present invention is not limited thereto. For example, a heat insulating member formed in advance may be fixed on the substrate.

[0092] Example

[0093] One aspect of the present invention will be described in more detail with reference to the following examples, but one aspect of the present invention is not limited to these examples.

[0094] (Example 1)

[0095] <Thermal insulation parts>

[0096] A heat insulating material sheet ("Finesulight (registered trademark) Standard Type" manufactured by Sumitomo Riko Co., Ltd., thickness: 0.63 mm) was cut into pieces having a width of 10 mm and a length of 96 mm to prepare a heat insulating member.

[0097] <Dispersion liquid>

[0098] 80 g of carbon nanotube dispersion (concentration: 0.2 mass%, G / D ratio: 41, aqueous dispersion, single-walled carbon nanotubes, diameter 0.9-1.7 nm, thermal conductivity 30 W / mK) was concentrated by vacuuming until the carbon nanotube concentration reached 0.4 mass%. Then, 5.7 g of PEDOT / PSS aqueous dispersion ("Clevious PH1000" manufactured by Heraeus Co., Ltd., solid content concentration: 1.2 mass%) and the concentrated carbon nanotube dispersion were fully stirred with Three-One Motor ("PM203" manufactured by ASONE Co., Ltd.) (stirring time: 30 minutes). Thus, a dispersion having a carbon nanotube content of 75 mass% relative to the total amount of PEDOT / PSS and carbon nanotubes was prepared. The dispersion was stirred at a shear rate of 0.01 s -1 The viscosity under the conditions was 1320000 mPa·sec. The viscosity of the dispersion was measured using a rheometer ("MCR302" (product name) manufactured by Anton Paar). The measurement conditions were temperature: 25°C, plate: Parallel plates, gap: 1mm.

[0099] <Dopant solution>

[0100] A dopant solution was prepared by dissolving 0.32 g of potassium ferrocyanide trihydrate and 0.94 g of benzo-18-crown-6-ether in 15 mL of ultrapure water. The concentrations of potassium ions and benzo-18-crown-6-ether in the dopant solution were each 0.2 M. The molar ratio (C2 / C1) was 1.

[0101] <Substrate>

[0102] As a substrate, a 100 mm square polyimide film (manufactured by Du Pont-Toray Co., Ltd., Kapton H type, film thickness 25 μm, thermal conductivity 0.16 W / mK) was prepared and the polyimide film was washed with acetone.

[0103] <Thermoelectric conversion module>

[0104] Spray glue (manufactured by 3M Japan Ltd., ordinary series S / N55) is applied to one side of the above-mentioned thermal insulation component, and a gap of 1.0 mm is set on the above-mentioned polyimide film and pasted. Next, a high thermal conductivity material (manufactured by Shin-Etsu Chemical Co., Ltd., G-789) is applied to the above-mentioned gap using a dispensing machine "AD3000C" manufactured by Iwashita Engineering, Inc. and a desktop robot arm "EzROBO-5GX". At this time, the interval along the first direction of the nozzle position for ejecting the high thermal conductivity material is set to 11 mm, and the coating is performed while the nozzle is moved along the second direction orthogonal to the first direction. Thus, a plurality of high thermal conductivity materials having a band shape are coated on the second main surface. After coating, the substrate is placed on a heating plate set to 120°C for 60 minutes. Thus, a plurality of thermal conductivity parts are formed. The thickness and width of the thermal conductivity part are each 1 mm, and the interval between the thermal conductivity parts in the first direction is 10 mm. Furthermore, the heat insulating member was arranged and fixed so as to fill the above-mentioned interval of 10 mm.

[0105] The dispersion was applied to the first main surface of the polyimide film using the jet dispensing machine "AeroJetR" and the desktop robot arm "SHOTMASTER400ΩX" manufactured by Musashi Engineering, Inc. Next, the laminate coated with the dispersion was placed in an air supply dryer set at 60°C for 3 hours. Thus, a composite film with a thickness of 62 μm was formed on the polyimide film. As for the composite film, both a thermoelectric conversion region and a conductive portion are provided on the polyimide film. It should be noted that the direction in which the thermoelectric conversion region extends is orthogonal to the extension direction of the above-mentioned heat conduction portion and the above-mentioned heat insulation component.

[0106] The thickness of the composite film was measured using a high-precision digital micrometer (MDH-25MB, manufactured by Mitutoyo Co., Ltd.) Specifically, the thickness of the portion with the composite film and the thickness of the portion without the composite film (the portion with only the polyimide film) were measured, and the difference between the two was taken as the thickness of the composite film.

[0107] Next, the first main surface of the polyimide film was immersed in DMSO (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) at room temperature for 30 minutes. Next, the polyimide film taken out of DMSO was placed on a hot plate set at 60° C. for 120 minutes. Thus, a p-type thermoelectric conversion layer was formed on the first main surface of the polyimide film. In Example 1, the thickness of the p-type thermoelectric conversion layer was 14.7 μm.

[0108] Next, a dopant solution is dripped onto a portion of the p-type thermoelectric conversion layer that functions as a thermoelectric conversion element using an inkjet printer made by FUJIFILM Corporation - "Materials Printer DMP2850". In Example 1, first, a dopant solution is dripped within a range of 10 mm in width and 5.5 mm in length. Then, a dopant solution is dripped within a range of 10 mm in width and 5.5 mm in length, separated by an interval of 5.5 mm in length. By repeatedly performing the dripping operation, the area to which the dopant solution is dripped and the area to which the dopant solution is not dripped are arranged alternately. Thus, 48 ​​p-type thermoelectric conversion elements and n-type thermoelectric conversion elements are formed on the polyimide film. That is, a total of 96 thermoelectric conversion elements are formed on the polyimide film. Thus, a total of 48 thermoelectric conversion sections including one p-type thermoelectric conversion element and one n-type thermoelectric conversion element are formed. Here, the thickness of the n-type thermoelectric conversion element is substantially the same as the thickness of the p-type thermoelectric conversion element. It should be noted that the end of each thermoelectric conversion part overlaps with the heat conduction part, and at least the center of each thermoelectric conversion part does not overlap with the heat conduction part. In addition, the area occupied by the thermoelectric conversion element on the polyimide film is 52.8 cm 2 The area occupied by the two conductive regions R2 on the polyimide film is 17.4 cm 2 The mass ratio of the carbon nanotubes to the total mass of the thermoelectric conversion unit is 30% to 70%. The content of iron atoms in the n-type thermoelectric conversion element is 0.01% to 10% by mass.

[0109] Next, the polyimide film provided with the above-mentioned thermoelectric conversion element was dried for 30 minutes while being arranged on a hot plate. Next, the polyimide film was placed in a blower dryer set at 100° C. for 60 minutes. Thus, a thermoelectric conversion module in which p-type thermoelectric conversion elements and n-type thermoelectric conversion elements were alternately connected in series was prepared. The thermal conductivity in the in-plane direction of the p-type thermoelectric conversion element was 32 W / mK. The parameters of the thermoelectric conversion module involved in Example 1 are shown in the following Table 1.

[0110] (Comparative Example 1)

[0111] The thermoelectric conversion module was formed in the same manner as in Example 1 except that no heat insulating member was provided on the second main surface of the substrate. Therefore, a space was provided between two adjacent heat conducting parts. The parameters of the thermoelectric conversion module involved in Comparative Example 1 are shown in Table 1 below. It should be noted that the thermal conductivity of the space (air) is 0.02 W / mK.

[0112] (Comparative Example 2)

[0113] A thermoelectric conversion module was formed in the same manner as in Example 1 except that foamed silicone "KE-521" manufactured by Shin-Etsu Chemical Co., Ltd. was used as the heat insulating member. Parameters of the thermoelectric conversion module according to Comparative Example 2 are shown in Table 1 below.

[0114] (Comparative Example 3)

[0115] A thermoelectric conversion module was formed in the same manner as in Example 1 except that a square rod made of aluminum was used as the heat conducting portion. Parameters of the thermoelectric conversion module according to Comparative Example 3 are shown in Table 1 below.

[0116] (Method for measuring linear expansion coefficient)

[0117] A test piece of 3 cm square and 1 mm thick was formed from the same material as the heat conduction part of Example 1. Next, the test piece was clamped with an anti-adhesion plate of 2 mm thickness and placed on a 10 mm quartz standard sample, and the linear expansion coefficient of the test piece in the in-plane direction was measured using a thermomechanical analyzer "TMA-4000SA" of Bruker Japan KK. In addition, the above-mentioned test piece formed of the same material as the heat conduction part of Comparative Example 3, the above-mentioned test piece formed of the same material as the heat insulation component of Example 1, and the above-mentioned test piece formed of the same material as the heat insulation component of Comparative Example 2 were prepared, and the linear expansion coefficient of each test piece in the in-plane direction was measured. The results of the measurement of the linear expansion coefficient of each test piece are shown in Table 1 below.

[0118] [Table 1]

[0119] unit Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 The distance between heat transfer parts mm 10 10 10 10 Linear expansion coefficient of heat transfer part ppm / K 140 140 140 23 Thermal conductivity of heat transfer part W / mK 3.0 3.0 3.0 204 The feeling of the insulation parts to each other mm 1.0 1.0 1.0 1.0 Linear expansion coefficient of thermal insulation components ppm / K 136 - 500 136 Thermal conductivity of insulation components W / mK 0.03 0.02 0.06 0.03 Length of thermoelectric conversion element mm 5.5 5.5 5.5 5.5 Thickness of thermoelectric conversion element μm 11.1 11.1 11.1 11.1 Number of thermoelectric conversion elements - 96 96 96 96 Thermoelectric conversion element area <![CDATA[cm 2 ]]> 52.8 52.8 52.8 52.8

[0120] (Evaluation of power generation of thermoelectric conversion modules)

[0121] The heat conduction part of the thermoelectric conversion module of Example 1 and Comparative Examples 1 to 3 was brought into contact with a SUS tube of 76 mm in diameter heated to 100°C by a silicone rubber heater in a wound manner. As a result, a temperature difference was generated in each thermoelectric conversion element, and the thermoelectric conversion module was made to generate electricity (hereinafter referred to as the "power generation state"). Then, a source meter ("Keithley2612B" manufactured by Tektronix) was used to evaluate the resistance value, open circuit voltage, short circuit current, maximum output power and maximum power density per unit area of ​​the thermoelectric conversion element of each thermoelectric conversion module. In addition, the temperature difference in the thermoelectric conversion part was measured by a thermal imager ("InfRec R550Pro" manufactured by Avionics Co., Ltd., Japan). When the resistance value, open circuit voltage, short circuit current and maximum output power of the thermoelectric conversion module of Comparative Example 1 were each set to 100, the evaluation results of Example 1 and Comparative Examples 1 to 3 are shown in the following Table 2.

[0122] In addition, while the thermoelectric conversion module is wound on the above-mentioned SUS tube, a durability test is carried out to maintain the power generation state for 100 hours in the atmosphere. The thermoelectric conversion modules of Example 1 and Comparative Example 1 are still wound on the SUS tube even after 100 hours, and there is no deformation. On the other hand, the thermoelectric conversion module of Comparative Example 2 is peeled off from the SUS tube before the end of the durability test, but no damage is found in the thermoelectric conversion element. In addition, the thermoelectric conversion module of Comparative Example 3 is bent after the durability test, and cracks are generated in a part of the thermoelectric conversion element. Therefore, it can be said that the thermoelectric conversion modules of Example 1 and Comparative Examples 1 and 2 are flexible, while the thermoelectric conversion module of Comparative Example 3 is not flexible.

[0123] After 100 hours, the power generation and temperature difference of Example 1 and Comparative Example 1 were measured using the above-mentioned source meter and thermal imager. In addition, the power generation and temperature difference after 100 hours were divided by the initial power generation and temperature difference, respectively, to obtain the "maintenance rate", and the calculation results are shown in Table 3. It should be noted that in Table 3, the power generation maintenance rate of Comparative Examples 2 and 3 is 0%, and the temperature difference maintenance rate cannot be measured.

[0124] [Table 2]

[0125] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Resistance value (standardized value) 100 100 100 100 Open circuit voltage (standardized value) 180 100 120 110 Short circuit current (standardized value) 180 100 120 110 Output power (normalized value) 324 100 144 121 Temperature difference (standard value) 180 100 120 110

[0126] [Table 3]

[0127] Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Temperature difference deviation range (℃) 1.0 3.0-7.0 1.0-2.0 1.0 Power generation maintenance rate (%) 100 90 0 0 Temperature difference maintenance rate (%) 100 95 - -

[0128] As shown in Table 2, the open circuit voltage of Example 1 is about 1.8 times higher than that of Comparative Example 1. The short circuit current of Example 1 is also about 1.8 times higher than that of Comparative Example 1. The deviation range of the temperature difference of Example 1 is smaller than the deviation range of the temperature of Comparative Example 1. Specifically, the deviation range of the temperature difference of Example 1 is about 1 / 7 to 1 / 3 of that of Comparative Example 1. On the other hand, the open circuit voltage and short circuit current of Comparative Examples 2 and 3 are both higher than those of Comparative Example 1. Here, as mentioned above, the thermoelectric conversion module of Comparative Example 3 is not flexible, so it can be said to be impractical as a power source. From the above, it can be seen that Example 1 and Comparative Example 2 are more practical as power sources than Comparative Examples 1 and 3.

[0129] The power generation maintenance rate and temperature difference maintenance rate after the durability test of Example 1 were both 100%, which were higher than those of Comparative Example 1. On the other hand, as described above, the thermoelectric conversion module of Comparative Example 2 peeled off from the SUS tube before the end of the durability test, and the thermoelectric conversion module of Comparative Example 3 had cracks in a part of the thermoelectric conversion element after the durability test. Therefore, in Comparative Examples 2 and 3, the power generation of the thermoelectric conversion module could not be maintained. From the above results, it can be seen that Example 1 is more useful as a thermoelectric conversion module than Comparative Examples 1 to 3.

[0130] Description of Reference Numerals

[0131] 1, 1A…thermoelectric conversion module; 2…substrate; 2a…first main surface; 2b…second main surface; 3…thermoelectric conversion group; 3a…first thermoelectric conversion group; 3b…second thermoelectric conversion group; 4…conductive portion; 5…heat conduction portion; 5a…first heat conduction portion; 5b…second heat conduction portion; 6, 6A…heat insulating member; 7…heat dissipation member; 11…thermoelectric conversion portion; 11a…first thermoelectric conversion portion; 11b…second thermoelectric conversion portion; 21…p-type thermoelectric conversion element; 21a…first end portion; 21b…second end portion; 22…n-type thermoelectric conversion element; 22a…first end portion; 22b…second end portion; D1…thickness direction; D2…first direction; D3…second direction; L1…length; L2…width; S…interval; R1…thermoelectric conversion region; R2…conductive region; T1…thickness; T2, T3…length.

Claims

1. A thermoelectric conversion module, comprising: a substrate having a first main surface and a second main surface located on the opposite side of the first main surface; a thermoelectric conversion portion, which is located on the first main surface; a first heat conducting portion and a second heat conducting portion, the first heat conducting portion and the second heat conducting portion being located on the second main surface and adjacent to each other along a first direction orthogonal to a thickness direction of the substrate; and a heat insulating member located at least between the first heat conducting portion and the second heat conducting portion on the second main surface, The thermoelectric conversion section includes a p-type thermoelectric conversion element and an n-type thermoelectric conversion element arranged along the first direction. The first end of the p-type thermoelectric conversion element in the first direction contacts the first end of the n-type thermoelectric conversion element in the first direction and overlaps with the heat insulating member in the thickness direction. In the thickness direction, the first heat conducting portion overlaps with a second end portion of the p-type thermoelectric conversion element in the first direction. In the thickness direction, the second heat conducting portion overlaps with a second end portion of the n-type thermoelectric conversion element in the first direction. The thickness of each of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element is 3 μm or more and 30 μm or less, A difference in linear expansion coefficient between the first heat conducting part and the heat insulating member, and a difference in linear expansion coefficient between the second heat conducting part and the heat insulating member are each 100 ppm / K or less.

2. The thermoelectric conversion module according to claim 1, wherein: The first heat conducting part and the second heat conducting part each have a linear expansion coefficient of 100 ppm / K or more and 200 ppm / K or less. The thermal insulation member has a linear expansion coefficient of 200 ppm / K or less.

3. The thermoelectric conversion module according to claim 1 or 2, wherein: The width of each of the first heat conducting portion and the second heat conducting portion along the first direction is not less than 0.5 mm and not more than 1.5 mm.

4. The thermoelectric conversion module according to claim 1 or 2, wherein: The thermal conductivity of each of the first heat conducting portion and the second heat conducting portion is 2.0 W / mK or more and 5.0 W / mK or less. The thermal conductivity of the heat insulating member is not less than 0.02 W / mK and not more than 0.05 W / mK.

5. The thermoelectric conversion module according to claim 1 or 2, further comprising a heat dissipation member located on the second main surface. The heat dissipation member surrounds the first heat conducting part, the second heat conducting part, and the heat insulating member when viewed in the thickness direction.

6. The thermoelectric conversion module according to claim 1 or 2, wherein: The thickness of each of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element is 5 μm or more and 25 μm or less, A distance between the first heat conducting portion and the second heat conducting portion in the first direction is greater than or equal to 3 mm and less than 12 mm.

7. The thermoelectric conversion module according to claim 1 or 2, further comprising: a first thermoelectric conversion group located on the first main surface and having the thermoelectric conversion portion; and a second thermoelectric conversion group located on the first main surface and adjacent to the first thermoelectric conversion group along a second direction orthogonal to the thickness direction and the first direction, The second thermoelectric conversion group includes a second thermoelectric conversion portion adjacent to the first thermoelectric conversion portion along the second direction. The second thermoelectric conversion section includes a second p-type thermoelectric conversion element and a second n-type thermoelectric conversion element arranged along the first direction. The first end of the second p-type thermoelectric conversion element in the first direction contacts the first end of the second n-type thermoelectric conversion element in the first direction and overlaps with the heat insulating member in the thickness direction. The first heat conducting portion and the second heat conducting portion each extend along the second direction. In the thickness direction, the first heat conducting portion overlaps with a second end portion of the second p-type thermoelectric conversion element included in the second thermoelectric conversion portion in the first direction. In the thickness direction, the second heat conducting portion overlaps with a second end portion of the second n-type thermoelectric conversion element included in the second thermoelectric conversion portion in the first direction.

8. The thermoelectric conversion module according to claim 7, further comprising: a first conductive portion located on the first main surface and connected to one end of the first thermoelectric conversion group in the first direction; and a second conductive portion located on the first main surface and connected to the other end of the first thermoelectric conversion group in the first direction and one end of the second thermoelectric conversion group in the second direction, The first conductive portion and the second conductive portion have the same conductivity type.

9. The thermoelectric conversion module according to claim 1 or 2, wherein: The substrate, the thermoelectric conversion part, the first heat conductive part, the second heat conductive part, and the heat insulating member each exhibit flexibility.

10. A method for manufacturing a thermoelectric conversion module, comprising: A first step of forming a first heat conducting portion, a second heat conducting portion, and a heat insulating member on one main surface of the substrate; A second step of forming a first layer including a p-type thermoelectric conversion material on the other main surface of the substrate; a third step of forming a p-type thermoelectric conversion layer by immersing the other main surface of the substrate in an organic solvent after the second step; and A fourth step, after the third step, forming a p-type thermoelectric conversion element by dropping a dopant solution into a portion of the p-type thermoelectric conversion layer and forming an n-type thermoelectric conversion element in the portion, The first heat conducting portion and the second heat conducting portion are adjacent to each other along a first direction orthogonal to a thickness direction of the substrate. The first end of the p-type thermoelectric conversion element in the first direction contacts the first end of the n-type thermoelectric conversion element in the first direction and overlaps with the heat insulating member in the thickness direction. In the thickness direction, the first heat conducting portion overlaps with a second end portion of the p-type thermoelectric conversion element in the first direction. In the thickness direction, the second heat conducting portion overlaps with a second end portion of the n-type thermoelectric conversion element in the first direction. A difference in linear expansion coefficient between the first heat conducting part and the heat insulating member, and a difference in linear expansion coefficient between the second heat conducting part and the heat insulating member are each 100 ppm / K or less.

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