Thermoelectric conversion module and method for manufacturing same

Abstract

This thermoelectric conversion module is provided with: a substrate having a first main surface and a second main surface; a thermoelectric conversion part on the first main surface; a sealing layer on the thermoelectric conversion part; the first heat conduction part and the second heat conduction part are located on the second main surface; and a heat insulating member on the second main surface. The thermoelectric conversion part has 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 part overlaps a second end portion of the p-type thermoelectric conversion element, and the second heat conduction part overlaps a second end portion of the n-type thermoelectric conversion element. The sealing layer has a thickness of 5 [mu] m or more and 150 [mu] m or less, a water vapor transmission rate of 100 g / (m < 2 > day) or less, an emissivity of 0.70 or more and 0.99 or less, and a thermal conductivity of 0.01 W / mK or more and 50 W / mK or less.

Description

Technical Field

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

[0002] Thermoelectric conversion elements are sometimes used to generate electricity using geothermal heat or factory exhaust heat. Patent Document 1 below discloses an embodiment in which flexible substrates having patterned layers composed of a resin layer and a metal layer are disposed on both sides of a thermoelectric conversion module comprising P-type thermoelectric element material and N-type thermoelectric element material. In Patent Document 1 below, the metal layer included in one flexible substrate overlaps with one electrode included in the thermoelectric conversion module, and the metal layer included in the other flexible substrate overlaps with another electrode included in the thermoelectric conversion module. In this embodiment, by setting one flexible substrate to a high temperature state and the other flexible substrate to a low temperature state, a temperature difference is generated in the surface direction of the thermoelectric conversion module. This generates an electromotive force in the thermoelectric conversion module.

[0003] Existing technology

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2008-182160 Summary of the Invention

[0005] In order to realize that the output of the thermoelectric conversion module described in the above-mentioned patent document 1 is improved, for example, it is considered to improve the thermoelectric conversion efficiency by expanding the above-mentioned temperature difference. In the above-mentioned patent document 1, in order to expand the above-mentioned temperature difference, for example, thinning the P-type thermoelectric element material and the N-type thermoelectric element material, and increasing the distance between the above-mentioned metal layers can be cited. However, in the case of the former, the thinner each thermoelectric element material is, the higher the resistance of each thermoelectric element material is. In addition, in the case of the latter, the more the above-mentioned distance is increased, the fewer the number of elements per unit area is. Therefore, when only the above-mentioned temperature difference is expanded, the output of the thermoelectric conversion module per unit area is sometimes reduced instead.

[0006] One aspect of the present invention aims to provide a thermoelectric conversion module having stable high output and long-term reliability capable of maintaining the output for a long period of time, and capable of stably generating electricity even when deformed, and a method for manufacturing the same.

[0007] A thermoelectric conversion module and a method for manufacturing the same according to one aspect of the present invention are as follows.

[0008] [1] A thermoelectric conversion module comprising:

[0009] a substrate having a first main surface and a second main surface located on the opposite side of the first main surface;

[0010] a thermoelectric conversion portion, located on the first main surface;

[0011] A sealing layer, located on the thermoelectric conversion portion;

[0012] A first heat conducting portion and a second heat conducting portion are located on the second main surface and are adjacent to each other along a first direction orthogonal to the thickness direction of the substrate; and

[0013] On the second main surface, a heat insulating member is located at least between the first heat conducting portion and the second heat conducting portion.

[0014] The thermoelectric conversion unit includes p-type thermoelectric conversion elements and n-type thermoelectric conversion elements arranged along the first direction.

[0015] The first end portion of the p-type thermoelectric conversion element in the first direction is in contact with the first end portion of the n-type thermoelectric conversion element in the first direction and overlaps with the thermal insulation member in the thickness direction.

[0016] In the thickness direction, the first heat conducting portion overlaps with the 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 the second end portion of the n-type thermoelectric conversion element in the first direction.

[0017] The sealing layer has a thickness of 10 μm or more and 150 μm or less in the thickness direction and a viscosity of 100 g / (m 2 ·day) or less water vapor transmission rate,

[0018] The emissivity of the sealing layer is greater than or equal to 0.70 and less than or equal to 0.99, and the thermal conductivity of the sealing layer is greater than or equal to 0.01 W / mK and less than or equal to 50 W / mK.

[0019] [2] The thermoelectric conversion module according to [1], wherein the sealing layer has a 2 ·day) and above and 100g / (m 2 ·day) or less water vapor transmission rate.

[0020] [3] The thermoelectric conversion module described in [1] or [2], wherein the difference in linear expansion coefficient between the first heat conducting portion and the heat insulating component and the difference in linear expansion coefficient between the second heat conducting portion and the heat insulating component are both less than 100 ppm / K.

[0021] [4] The thermoelectric conversion module according to any one of [1] to [3], wherein 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.

[0022] [5] The thermoelectric conversion module as described in any one of [1] to [4], wherein the linear expansion coefficient of the first heat conducting part and the second heat conducting part is respectively greater than 100 ppm / K and less than 200 ppm / K, and the linear expansion coefficient of the thermal insulation component is less than 200 ppm / K.

[0023] [6] The thermoelectric conversion module according to any one of [1] to [5], 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.

[0024] [7] A thermoelectric conversion module as described in any one of [1] to [6], wherein the thermal conductivity of the first heat conducting part and the second heat conducting part is respectively 2 W / mK or more and 5 W / mK or less, and the thermal conductivity of the thermal insulation component is 0.02 W / mK or more and 0.05 W / mK or less.

[0025] [8] A thermoelectric conversion module as described in any one of [1] to [7], 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 component when viewed in the thickness direction.

[0026] [9] A thermoelectric conversion module according to any one of [1] to [8], wherein the thickness of each of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element is greater than or equal to 5 μm and less than or equal to 25 μm, and the spacing 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.

[0027]

[10] The thermoelectric conversion module according to any one of [1] to [9], further comprising:

[0028] a first thermoelectric conversion group located on the first main surface and having the thermoelectric conversion portion;

[0029] and a second thermoelectric conversion group located on the first main surface and adjacent to the first thermoelectric conversion group along a second direction perpendicular to the thickness direction and the first direction,

[0030] The second thermoelectric conversion group includes a second thermoelectric conversion portion adjacent to the first thermoelectric conversion portion along the second direction, and the second thermoelectric conversion portion includes a second p-type thermoelectric conversion element and a second n-type thermoelectric conversion element arranged along the first direction.

[0031] 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 thermal insulation member in the thickness direction.

[0032] The first heat conducting portion and the second heat conducting portion extend along the second direction respectively.

[0033] In the thickness direction, the first heat transfer portion overlaps with the second end portion of the second p-type thermoelectric conversion element included in the second thermoelectric conversion portion in the first direction.

[0034] In the thickness direction, the second heat transfer 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.

[0035]

[11] The thermoelectric conversion module according to

[10] , further comprising:

[0036] 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

[0037] The second conductive portion is located on the first main surface and is 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.

[0038] The first conductive portion and the second conductive portion have the same conductivity type.

[0039]

[12] The thermoelectric conversion module described in any one of [1] to

[11] , wherein the substrate, the thermoelectric conversion portion, the first heat conduction portion, the second heat conduction portion, and the heat insulating member are each flexible.

[0040]

[13] A method for manufacturing a thermoelectric conversion module, comprising:

[0041] In a first step, a first heat conducting portion, a second heat conducting portion, and a heat insulating member are formed on one main surface of the substrate;

[0042] The second step is to form a first layer containing a p-type thermoelectric conversion material on the other main surface of the substrate;

[0043] 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;

[0044] A fourth step, after the third step, forming a p-type thermoelectric conversion element and an n-type thermoelectric conversion element in the portion by dripping a dopant solution into the p-type thermoelectric conversion layer;

[0045] A fifth step, after the fourth step, is to dispose a sealing layer on the other main surface of the substrate so as to cover the p-type thermoelectric conversion element and the n-type thermoelectric conversion element.

[0046] The first heat conducting portion and the second heat conducting portion are adjacent to each other along a first direction perpendicular to the thickness direction of the substrate.

[0047] 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 thermal insulation member in the thickness direction.

[0048] In the thickness direction, the first heat conducting portion overlaps with the second end portion of the p-type thermoelectric conversion element in the first direction, and in the thickness direction, the second heat conducting portion overlaps with the second end portion of the n-type thermoelectric conversion element in the first direction.

[0049] The sealing layer has a thickness of 10 μm or more and 150 μm or less in the thickness direction and a heat release capacity of 100 g / (m 2 ·day) or less water vapor transmission rate,

[0050] The emissivity of the sealing layer is greater than or equal to 0.70 and less than or equal to 0.99, and the thermal conductivity of the sealing layer is greater than or equal to 0.01 W / mK and less than or equal to 50 W / mK.

[0051]

[14] The manufacturing method according to

[13] , wherein the sealing layer has a viscosity of 0.1 g / (m 2 ·day) and above and 100g / (m 2 ·day) or less water vapor transmission rate.

[0052] According to one aspect of the present invention, a thermoelectric conversion module having stable high output and long-term reliability capable of maintaining the output for a long period of time and capable of stably generating electricity even when deformed, and a method for manufacturing the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] 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.

[0054] Figure 2 (a) is a schematic plan view of a thermoelectric conversion module for explaining an embodiment. Figure 2 (b) is a schematic bottom view of the thermoelectric conversion module for explaining the embodiment.

[0055] Figure 3 (a) is to Figure 2 A part of (a) (the area surrounded by the dot-dashed line) is enlarged. Figure 3 (b) is along Figure 3(a) is a cross-sectional view along line IIIb-IIIb.

[0056] Figure 4 (a) is a schematic cross-sectional view showing an enlarged portion of a thermoelectric conversion module according to an embodiment. Figure 4 (b) is a schematic cross-sectional view showing an enlarged portion of a thermoelectric conversion module according to a modified example.

[0057] Figure 5 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to an embodiment.

[0058] Figure 6 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to an embodiment.

[0059] Figure 7 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to an embodiment.

[0060] Figure 8 Schematic cross-sectional view showing a portion of the thermoelectric conversion module during deformation.

[0061] Figure 9 (a) is a schematic bottom view of a thermoelectric conversion module of a modified example. Figure 9 (b) is along Figure 9 (a) is a schematic cross-sectional view taken along line IXb-IXb.

[0062] Figure 10 It is a schematic plan view of a thermoelectric conversion module for explaining a modified example. DETAILED DESCRIPTION

[0063] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, identical elements or elements having identical functions will be denoted by identical reference numerals, and repeated descriptions will be omitted. The term "identical" and similar terms in this specification are not limited to "identical to the same."

[0064] First, refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 The structure of the thermoelectric conversion module according to this embodiment will be described.

[0065] 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.

[0066] Figure 2 (a) is a schematic plan view of a thermoelectric conversion module for explaining an embodiment. Figure 2(b) is a schematic bottom view of the thermoelectric conversion module for explaining the embodiment. Figure 2 (a) and (b) represent the Figure 1 The figures (a) and (b) of the thermoelectric conversion module 1 with the sealing layer 8 removed can also be referred to as figures showing the state of the thermoelectric conversion module 1. Figure 1 (a) and (b) show the state before the sealing layer 8 is provided during the manufacture of the thermoelectric conversion module 1 . Figure 3 (a) is to Figure 2 A part of (a) (the area surrounded by the dot-dashed line) is enlarged. Figure 3 (b) is along Figure 3 (a) is a cross-sectional view along line IIIb-IIIb. Figure 4 (a) is an enlarged view of a portion of a thermoelectric conversion module according to an embodiment (with Figure 3 (a) a schematic cross-sectional view of the corresponding portion), Figure 4 (b) is an enlarged view of a portion of a thermoelectric conversion module of a modified example (with Figure 3 (a) A schematic cross-sectional view of the corresponding portion).

[0067] Figure 1 and Figure 2 The thermoelectric conversion module 1 shown is a device that can generate electricity by supplying heat from the outside. The thermoelectric conversion module 1 is a so-called in-plane type device. Therefore, the thermoelectric conversion module 1 tends to have excellent processability and flexibility compared to, for example, π-type elements (cross-plane type elements). Therefore, the thermoelectric conversion module 1 can be set along the side of a cylindrical pipe or the like for recovering factory exhaust 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 sensors for equipment that utilizes exhaust heat. In addition, the contact resistance between the thermoelectric conversion material contained in the thermoelectric conversion module 1 and the electrodes 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 set to the temperature measured under natural convection conditions of air.

[0068] Thermoelectric conversion module 1 includes a substrate 2, multiple thermoelectric conversion groups 3, multiple conductive portions 4, multiple thermally conductive portions 5, multiple thermally insulating members 6, and a sealing layer 8. At least one of substrate 2, multiple thermoelectric conversion groups 3, multiple conductive portions 4, multiple thermally conductive portions 5, multiple thermally insulating members 6, and sealing layer 8 is flexible.

[0069] The substrate 2 is a sheet member made of a resin exhibiting heat resistance and flexibility, and has, for example, a substantially flat plate shape. Examples of the resin constituting the substrate 2 include polyalkylene resins (e.g., polypropylene resins), (meth)acrylic resins, (meth)acrylonitrile resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins (e.g., polyethylene naphthalate resins, PET resins), epoxy resins, organosiloxane resins, polyimide resins, and polysulfone resins.

[0070] The thickness of the substrate 2 may be, for example, 5 μm or more, 10 μm or more, 15 μm or more, or 20 μm or more. If the thickness of the substrate 2 is thick, there is a tendency that long-term reliability is easily further improved. In addition, the thickness of the substrate 2 may be, for example, 150 μm or less, 100 μm or less, 50 μm or less, or 40 μm or less. If the thickness of the substrate 2 is thin, there is a tendency that flexibility is easily further improved. That is, the thickness of the substrate 2 may be, for example, 5 to 150 μm, 5 to 100 μm, 5 to 50 μm, 5 to 40 μm, 10 to 150 μm, 10 to 100 μm, 10 to 50 μm, 10 to 40 μm, 15 to 150 μm, 15 to 100 μm, 15 to 50 μm, 15 to 40 μm, 20 to 150 μm, 20 to 100 μm, 20 to 50 μm, or 20 to 40 μm.

[0071] The thermal conductivity of the substrate 2 may be, for example, 0.01 W / mK (equivalent to 0.1 Watt per meter Kelvin and 0.1 W×m -1 ×K -1 ) or above, 0.05 W / mK or above, 0.1 W / mK or above, or 0.2 W / mK or above. If the thermal conductivity of the substrate 2 is high, heat transfer from the heat conducting portion 5 to the thermoelectric conversion group 3 is accelerated. Alternatively, the thermal conductivity of the substrate 2 may be, for example, 10 W / mK or below, 5 W / mK or below, 1 W / mK or below, or 0.5 W / mK or below. If the thermal conductivity of the substrate 2 is low, temperature differences are more likely to occur within the thermoelectric conversion group 3. The thermal conductivity of the substrate 2 is measured by the laser flash method. That is, the thermal conductivity of the substrate 2 can be, for example, 0.01 to 10 W / mK, 0.01 to 5 W / mK, 0.01 to 1 W / mK, 0.01 to 0.5 W / mK, 0.05 to 10 W / mK, 0.05 to 5 W / mK, 0.05 to 1 W / mK, 0.05 to 0.5 W / mK, 0.1 to 10 W / mK, 0.1 to 5 W / mK, 0.1 to 1 W / mK, 0.1 to 0.5 W / mK, 0.2 to 10 W / mK, 0.2 to 5 W / mK, 0.2 to 1 W / mK or 0.2 to 0.5 W / mK.

[0072] The water vapor transmission rate in the thickness direction of the substrate 2 can be, for example, 100 g / (m 2·day) or less, 80g / (m 2 ·day) or less, 60g / (m 2 ·day) or less, 40g / (m 2 ·day) or less, 20g / (m 2 ·day) or less than 10g / (m 2 ·day) or less. If the water vapor permeability of the substrate 2 is low, there is a tendency for long-term reliability to be further improved. The lower limit of the water vapor permeability in the thickness direction of the substrate 2 is not particularly limited. The water vapor permeability in the thickness direction of the substrate 2 can be, for example, 0.1 g / (m 2 ·day) or more, 0.5g / (m 2 ·day) or more or 1g / (m 2 That is, the water vapor permeability in the thickness direction of the substrate 2 is, for example, 0.1 to 100 g / (m 2 ·day)、0.1~80g / (m 2 ·day)、0.1~60g / (m 2 ·day)、0.1~40g / (m 2 ·day)、0.1~20g / (m 2 ·day)、0.1~10g / (m 2 ·day)、0.5~100g / (m 2 ·day)、0.5~80g / (m 2 ·day)、0.5~60g / (m 2 ·day)、0.5~40g / (m 2 ·day)、0.5~20g / (m 1 ·day)、0.5~10g / (m 1 ·day)、1~100g / (m 1 ·day)、1~80g / (m 1 ·day)、1~60g / (m 1 ·day)、1~40g / (m 1 ·day)、1~20g / (m 1 ·day), or 1-10g / (m 1 The water vapor transmission rate of the substrate 2 was measured by a cup method.

[0073] The emissivity of the substrate 2 can be, for example, 0.70 or greater, 0.80 or greater, or 0.90 or greater. Alternatively, the emissivity of the substrate 2 can be, for example, 0.99 or less, 0.97 or less, or 0.95 or less. Specifically, the emissivity of the substrate 2 can be, for example, 0.70-0.99, 0.70-0.97, 0.70-0.95, 0.80-0.99, 0.80-0.97, 0.80-0.95, 0.90-0.99, 0.90-0.97, or 0.90-0.95. The emissivity of the substrate 2 is measured using an infrared thermal imaging camera.

[0074] 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 that intersect 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 can be, for example, polygonal, circular, or elliptical. Hereinafter, the direction along the thickness of the substrate 2 will be simply referred to as the thickness direction D1. Viewing from the thickness direction D1 is equivalent to viewing from above. Furthermore, directions orthogonal to the thickness direction D1 are referred to as the first direction D2 and the second direction D3.

[0075] A thermoelectric conversion region R1 and two conductive regions R2 are defined on the first main surface 2a. Multiple thermoelectric conversion groups 3 are provided in the thermoelectric conversion region R1. Multiple 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 greater the proportion of the thermoelectric conversion region R1 on the first main surface 2a, the higher the output 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 on the first main surface 2a is, for example, greater than 50% and less than 90%. Furthermore, when viewed from above, the proportion of the area occupied by the two conductive regions R2 on 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 exhibit good output.

[0076] The plurality of thermoelectric conversion groups 3 are each a portion capable of generating electricity by supplying heat from the outside, and are 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. When viewed from the thickness direction D1, the plurality of thermoelectric conversion groups 3 each have a strip shape. The thermoelectric conversion groups 3 are separated from each other, but 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. The plurality of thermoelectric conversion groups 3 each have a plurality of thermoelectric conversion parts 11. In this 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.

[0077] In the following, Figure 3 One of the two thermoelectric conversion groups 3 shown in (a) can be referred to as a 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 can be referred to as a second thermoelectric conversion group 3b. Furthermore, the thermoelectric conversion cells 11 included in the first thermoelectric conversion group 3a can be referred to as first thermoelectric conversion cells 11a, and the thermoelectric conversion cells 11 included in the second thermoelectric conversion group 3b are sometimes referred to as second thermoelectric conversion cells 11b. The plurality of first thermoelectric conversion cells 11a included in the first thermoelectric conversion group 3a are arranged sequentially along the first direction D2, and the plurality of second thermoelectric conversion cells 11b included in the second thermoelectric conversion group 3b are arranged sequentially 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.

[0078] The multiple thermoelectric conversion sections 11 are each a portion of the thermoelectric conversion module 1 that performs thermoelectric conversion and exhibits flexibility. The shape of the thermoelectric conversion section 11 when viewed from above is not particularly limited and may be, for example, polygonal, circular, or elliptical. The p-type thermoelectric conversion element 21 and the n-type thermoelectric conversion element 22 have the same shape, but are not limited thereto. Each thermoelectric conversion section 11 includes a p-type thermoelectric conversion element 21 and an n-type thermoelectric conversion element 22 arranged along a 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 adjacent thermoelectric conversion sections 11 in the first direction D2 , second end 21 b of p-type thermoelectric conversion element 21 included in one thermoelectric conversion section 11 and second end 22 b of n-type thermoelectric conversion element 22 included in the other thermoelectric conversion section 11 are in contact with each other.

[0079] For 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 3 As shown in (a), in this 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 (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 (second p-type thermoelectric conversion element) of the second thermoelectric conversion section 11b in the second direction D3.

[0080] P-type thermoelectric conversion element 21 is provided on first main surface 2 a of substrate 2 and is in contact with n-type thermoelectric conversion element 22 .

[0081] The thickness T1 of the p-type thermoelectric conversion element 21 can be, for example, 3 μm or greater, 5 μm or greater, 8 μm or greater, or 10 μm or greater. A larger thickness T1 of the p-type thermoelectric conversion element 21 further reduces the resistance of the p-type thermoelectric conversion element 21. The thickness T1 of the p-type thermoelectric conversion element 21 can be, for example, 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less. A smaller thickness T1 of the p-type thermoelectric conversion element 21 facilitates the formation of a temperature gradient within the p-type thermoelectric conversion element 21, making it easier to stably achieve a higher output. That is, the thickness T1 of the p-type thermoelectric conversion element 21 can be, for example, 3 to 30 μm, 3 to 25 μm, 3 to 20 μm, 3 to 15 μm, 5 to 30 μm, 5 to 25 μm, 5 to 20 μm, 5 to 15 μm, 8 to 30 μm, 8 to 25 μm, 8 to 20 μm, 8 to 15 μm, 10 to 30 μm, 10 to 25 μm, 10 to 20 μm or 10 to 15 μm.

[0082] The length L1 of the p-type thermoelectric conversion element 21 in the first direction D2 can be, for example, 2 mm or more, 3 mm or more, or 5 mm or more. A longer length L1 of the p-type thermoelectric conversion element 21 facilitates the formation of a temperature gradient within the p-type thermoelectric conversion element 21, making it easier to stably achieve a higher output. Alternatively, the length L1 of the p-type thermoelectric conversion element 21 in the first direction D2 can be, for example, 10 mm or less, 9 mm or less, or 7 mm or less. A shorter length L1 of the p-type thermoelectric conversion element 21 allows for forming more thermoelectric conversion portions 11 on the first major surface 2a. That is, the length L1 of the p-type thermoelectric conversion element 21 in the first direction D2 can be, for example, 2 to 10 mm, 2 to 9 mm, 2 to 7 mm, 3 to 10 mm, 3 to 9 mm, 3 to 7 mm, 5 to 10 mm, 5 to 9 mm, or 5 to 7 mm.

[0083] The length of p-type thermoelectric conversion element 21 in second direction D3 can be, for example, 0.1 mm or more, 0.5 mm or more, or 1 mm or more. A longer length of p-type thermoelectric conversion element 21 in second direction D3 further reduces the resistance of p-type thermoelectric conversion element 21. Furthermore, the length of p-type thermoelectric conversion element 21 in second direction D3 can be, for example, 20 mm or less, 10 mm or less, or 5 mm or less. A shorter length of p-type thermoelectric conversion element 21 in second direction D3 allows for forming more thermoelectric conversion portions 11 on first major surface 2a. Specifically, the length of p-type thermoelectric conversion element 21 in second direction D3 can be, for example, 0.1 to 20 mm, 0.1 to 10 mm, 0.1 to 5 mm, 0.5 to 20 mm, 0.5 to 10 mm, 0.5 to 5 mm, 1 to 20 mm, 1 to 10 mm, or 1 to 5 mm.

[0084] The thermal conductivity of the p-type thermoelectric conversion element 21 in the in-plane direction can be, for example, 50 W / mK or less, 40 W / mK or less, 30 W / mK or less, or 20 W / mK or less. A low thermal conductivity of the p-type thermoelectric conversion element 21 in the in-plane direction is preferred because it facilitates temperature differences. The lower limit of the thermal conductivity of the p-type thermoelectric conversion element 21 in the in-plane direction is not particularly limited. The thermal conductivity of the p-type thermoelectric conversion element 21 in the in-plane direction can be, for example, 0.01 W / mK or more, 0.5 W / mK or more, or 1 W / mK or more. That is, the thermal conductivity of the p-type thermoelectric conversion element 21 in the in-plane direction can be, for example, 0.01 to 50 W / mK, 0.01 to 40 W / mK, 0.01 to 30 W / mK, 0.01 to 20 W / mK, 0.5 to 50 W / mK, 0.5 to 40 W / mK, 0.5 to 30 W / mK, 0.5 to 20 W / mK, 1 to 50 W / mK, 1 to 40 W / mK, 1 to 30 W / mK or 1 to 20 W / mK.

[0085] The p-type thermoelectric conversion element 21 can be formed by, for example, various dry methods or wet methods. Examples of wet methods include doctor blade method, dip coating method, spray coating method, spin coating method, and inkjet method.

[0086] 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 exhibit p-type. The carbon nanotubes may be any of single-layer, double-layer, and multi-layer. From the perspective of the electrical conductivity of the p-type thermoelectric conversion element 21, single-layer carbon nanotubes (SWCNTs) may be used. The ratio of single-layer carbon nanotubes 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 nanotubes is not particularly limited, and may be, 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 nanotubes is also not particularly limited, and may be, for example, greater than 0.4 nm or greater than 0.5 nm. The thermal conductivity of the carbon nanotubes may be, for example, greater than 30 W / mK and less than 40 W / mK.

[0087] 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)) is calculated using the formula "diameter (nm) = 248 / ω". As an evaluation method for single-walled carbon nanotubes, the G / D ratio in laser Raman spectroscopy is known. In the present embodiment, the G / D ratio of the single-walled carbon nanotube in the laser Raman spectrum at a wavelength of 532nm can be 10 or more, or 20 or more. By using such single-walled carbon nanotubes, there is a tendency to obtain a p-type thermoelectric conversion element 21 with better electrical conductivity. In addition, the upper limit of the above-mentioned G / D ratio is not particularly limited, and can be 500 or less, or 300 or less.

[0088] The content of carbon nanotubes in 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 more relative to 100 parts by mass of the material (p-type thermoelectric conversion material) constituting p-type thermoelectric conversion element 21. Furthermore, the content of carbon nanotubes in p-type thermoelectric conversion element 21 can be, for example, 99 parts by mass or less, 95 parts by mass or less, or 90 parts by mass or less relative to 100 parts by mass of the material (p-type thermoelectric conversion material) constituting p-type thermoelectric conversion element 21. That is, the content of carbon nanotubes in p-type thermoelectric conversion element 21 can be, for example, 20 to 99 parts by mass, 20 to 95 parts by mass, 20 to 90 parts by mass, 30 to 99 parts by mass, 30 to 95 parts by mass, 30 to 90 parts by mass, 40 to 99 parts by mass, 40 to 95 parts by mass, or 40 to 90 parts by mass relative to 100 parts by mass of the material (p-type thermoelectric conversion material) constituting p-type thermoelectric conversion element 21.

[0089] The conductive resin of this embodiment is not particularly limited, and known conductive resins can be used without particular limitation. Examples of the conductive resin include polyaniline-based conductive resins, polythiophene-based conductive resins, polypyrrole-based conductive resins, polyacetylene-based conductive resins, polyphenylene-based conductive resins, and polyphenylenevinylene-based conductive resins.

[0090] Examples of the polythiophene-based conductive resin include poly(3,4-ethylenedioxythiophene) (PEDOT).

[0091] In this embodiment, the conductive resin may include a polythiophene-based conductive resin and an electron acceptor. In this case, the effect of the sealing layer 8 is more significantly exerted. Examples of the electron acceptor include polystyrene sulfonic acid (PSS), polyvinyl sulfonic acid, poly(meth)acrylic acid, polyvinyl sulfonic acid, toluenesulfonic acid, dodecylbenzenesulfonic acid, camphorsulfonic 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, and tetracyanoquinodimethane.

[0092] The content ratio (mass ratio) of the electron acceptor relative to the polythiophene-based conductive resin may be, for example, 1 or more, 1.2 or more, 1.3 or more, or 1.5 or more. Furthermore, the content ratio (mass ratio) of the electron acceptor relative to the polythiophene-based conductive resin may be, for example, 40 or less, 30 or less, 25 or less, or 20 or less. That is, the content ratio (mass ratio) of the electron acceptor relative to the polythiophene-based conductive resin may be, for example, 1-40, 1-30, 1-25, 1-20, 1.2-40, 1.2-30, 1.2-25, 1.2-20, 1.3-40, 1.3-30, 1.3-25, 1.3-20, 1.5-40, 1.5-30, 1.5-25, or 1.5-20.

[0093] 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 together by the conductive resin.

[0094] N-type thermoelectric conversion element 22 is provided on first main surface 2 a of substrate 2 and is in contact with p-type thermoelectric conversion element 21 .

[0095] The thickness of the n-type thermoelectric conversion element 22 can be, for example, 3 μm or more, 5 μm or more, 8 μm or more, or 10 μm or more. A greater thickness of the n-type thermoelectric conversion element 22 further reduces the resistance of the n-type thermoelectric conversion element 22. The thickness of the n-type thermoelectric conversion element 22 can be, for example, 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less. A smaller thickness of the n-type thermoelectric conversion element 22 facilitates the formation of a temperature gradient within the n-type thermoelectric conversion element 22, making it easier to stably achieve a higher output. That is, the thickness of n-type thermoelectric conversion element 22 can be, for example, 3-30 μm, 3-25 μm, 3-20 μm, 3-15 μm, 5-30 μm, 5-25 μm, 5-20 μm, 5-15 μm, 8-30 μm, 8-25 μm, 8-20 μm, 8-15 μm, 10-30 μm, 10-25 μm, 10-20 μm, or 10-15 μm. The thickness of n-type thermoelectric conversion element 22 can be the same as or substantially the same as thickness T1 of p-type thermoelectric conversion element 21.

[0096] The length of n-type thermoelectric conversion element 22 in first direction D2 can be, for example, 2 mm or more, 3 mm or more, or 5 mm or more. A longer length of n-type thermoelectric conversion element 22 facilitates the formation of a temperature gradient within n-type thermoelectric conversion element 22, making it easier to stably achieve higher output. Alternatively, the length of n-type thermoelectric conversion element 22 in first direction D2 can be, for example, 10 mm or less, 9 mm or less, or 7 mm or less. A shorter length of n-type thermoelectric conversion element 22 allows for the formation of more thermoelectric conversion portions 11 on first major surface 2a. Specifically, the length of n-type thermoelectric conversion element 22 in first direction D2 can be, for example, 2-10 mm, 2-9 mm, 2-7 mm, 3-10 mm, 3-9 mm, 3-7 mm, 5-10 mm, 5-9 mm, or 5-7 mm. The length of n-type thermoelectric conversion element 22 in first direction D2 can be the same as, or substantially the same as, length L1 of p-type thermoelectric conversion element 21.

[0097] The length of the n-type thermoelectric conversion element 22 in the second direction D3 can be, for example, 0.1 mm or more, 0.5 mm or more, or 1 mm or more. A longer length of the n-type thermoelectric conversion element 22 in the second direction D3 further reduces the resistance of the n-type thermoelectric conversion element 22. Furthermore, the length of the n-type thermoelectric conversion element 22 in the second direction D3 can be, for example, 20 mm or less, 10 mm or less, or 5 mm or less. A shorter length of the n-type thermoelectric conversion element 22 in the second direction D3 allows for forming more thermoelectric conversion portions 11 on the first major surface 2a. That is, the length of the n-type thermoelectric conversion element 22 in the second direction D3 can be, for example, 0.1 to 20 mm, 0.1 to 10 mm, 0.1 to 5 mm, 0.5 to 20 mm, 0.5 to 10 mm, 0.5 to 5 mm, 1 to 20 mm, 1 to 10 mm, or 1 to 5 mm. The length of n-type thermoelectric conversion element 22 in second direction D3 may be the same as or substantially the same as the length of p-type thermoelectric conversion element 21 in second direction D3.

[0098] The in-plane thermal conductivity of n-type thermoelectric conversion element 22 can be, for example, 50 W / mK or less, 40 W / mK or less, 30 W / mK or less, or 20 W / mK or less. If the in-plane thermal conductivity of n-type thermoelectric conversion element 22 is low, temperature differences are more likely to occur. The lower limit of the in-plane thermal conductivity of n-type thermoelectric conversion element 22 is not particularly limited. The in-plane thermal conductivity of n-type thermoelectric conversion element 22 can be, for example, 0.01 W / mK or more, 0.5 W / mK or more, or 1 W / mK or more. That is, the in-plane thermal conductivity of n-type thermoelectric conversion element 22 may be, for example, 0.01 to 50 W / mK, 0.01 to 40 W / mK, 0.01 to 30 W / mK, 0.01 to 20 W / m, 0.5 to 50 W / mK, 0.5 to 40 W / mK, 0.5 to 30 W / mK, 0.5 to 20 W / m, 1 to 50 W / mK, 1 to 40 W / mK, 1 to 30 W / mK, or 1 to 20 W / m. The in-plane thermal conductivity of n-type thermoelectric conversion element 22 may be measured, for example, by an optical AC method, a 3-Omega method, or a laser flash method.

[0099] Similar to p-type thermoelectric conversion element 21 , n-type thermoelectric conversion element 22 is formed by, for example, various dry methods or wet methods.

[0100] The n-type thermoelectric conversion element 22 is, for example, an n-type semiconductor layer. The n-type thermoelectric conversion element 22 may include, for example, a composite of multiple organic substances, or a composite of inorganic and organic substances. In this embodiment, the n-type thermoelectric conversion element 22 may be a portion of the p-type thermoelectric conversion element 21 that exhibits n-type properties by doping with a dopant. Therefore, the n-type thermoelectric conversion element 22 may include carbon nanotubes, a conductive resin, and a dopant. The carbon nanotubes and conductive resin in the n-type thermoelectric conversion element 22 may be the same materials as those used for the carbon nanotubes and conductive resin in the p-type thermoelectric conversion element 21.

[0101] A dopant is a substance that changes the Seebeck coefficient of the material being doped. "Changing the Seebeck coefficient" means decreasing the Seebeck coefficient or changing it from a positive value to a negative value. A thermoelectric conversion material with a positive Seebeck coefficient exhibits p-type conductivity, while a thermoelectric conversion material with a negative Seebeck coefficient exhibits n-type conductivity.

[0102] The dopant of this embodiment may include, for example, a complex salt that can dissociate into anions (hereinafter referred to as "anions") and alkali metal cations (hereinafter referred to as "cations") as complex ions, and a cation scavenger (hereinafter referred to as "scavenger"). The n-type thermoelectric conversion element 22 formed with such a dopant can achieve excellent thermoelectric conversion performance. In addition, by forming the n-type thermoelectric conversion element 22 with such a dopant, the long-term reliability improvement effect brought by the sealing layer 8 can be more significantly exerted.

[0103] In the n-type thermoelectric conversion element 22, at least a portion of the complex salt can be dissociated into the above-mentioned anions and the above-mentioned cations. At this time, the above-mentioned cations can be captured by the above-mentioned scavenger. The dopant can include at least one of a plurality of complex salts and scavengers. The Seebeck coefficient of the portion doped with the above-mentioned dopant in the p-type thermoelectric conversion element 21 changes. Thus, the n-type thermoelectric conversion element 22 is formed in the above-mentioned portion.

[0104] The reason for playing the above-mentioned effect is not particularly limited, but it is believed that one of the reasons is that the scavenger contained in the dopant captures cations, thereby dissociating 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 the interaction of the metal atom and the carbon nanotube is significantly n-typed. In addition, the ion size of the complex ion is large, so it is believed that the dissociation of the cations captured by the scavenger is good and also a reason for 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 included. Therefore, in the present embodiment, the metal atoms remaining in the n-type thermoelectric conversion element 22 can function as an antioxidant.

[0105] The complex ion (anion) obtained can be selected from ferrocyanide ion, ferricyanide ion (ferricyanideion), tetrachlorided iron (III) acid ion, tetrachlorided iron (II) acid ion, tetracyanonickel acid (II) ion, tetrachlorided nickel acid (II) ion, tetracyanocobalt (II) acid ion, tetrachlorocobalt acid (II) ion, tetracyanocuprate (I) acid ion, tetrachlorocopper (II) acid ion, hexacyanochromium (III) ion, tetrahydroxide zinc (II) acid ion and tetrahydroxide dodecaaluminum (III) acid ion. Among them, ferrocyanide ion is preferred. When the above-mentioned anion is ferrocyanide ion, there is a tendency to obtain an n-type thermoelectric conversion material with better characteristics. In addition, when the anion is ferrocyanide ion, the iron atom remaining in the n-type thermoelectric conversion element 22 functions appropriately as an antioxidant, and the physical property changes over time are further suppressed, and there is a tendency for storage stability to further improve.

[0106] The above-mentioned anions may contain iron atoms. That is, the complex salt may contain iron atoms. In this case, the anions may be selected from, for example, ferrocyanide ions, ferric chloride (III) acid ions and ferrous chloride (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 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% by mass or more and 15% by mass or less, or 0.005% by mass or more and 12% by mass or less, or 0.01% by mass or more and 10% by mass or less. In addition, the content of iron atoms in the n-type thermoelectric conversion element 22, for example, represents a value measured by ICP emission spectrometry.

[0107] Examples of the complex salt include potassium ferrocyanide, sodium ferrocyanide, potassium ferrocyanide, sodium ferrocyanide, potassium tetrachloride ferro(III), sodium tetrachloride ferro(III), potassium tetrachloride ferro(II), sodium tetrachloride ferro(II), etc. The complex salt may be a hydrate.

[0108] Examples of the alkali metal cation include sodium ion, potassium ion, and lithium ion.

[0109] The cation scavenger is not particularly limited as long as it is a substance capable of taking up cations. Examples of the cation scavenger include crown ether compounds, cyclodextrin, calixarene, ethylenediaminetetraacetic acid, porphyrin, phthalocyanine, and derivatives thereof.

[0110] In the present embodiment, the cation capture agent can be a crown ether compound. As the crown ether compound, 15-crown-5-ether, 18-crown-6-ether, 12-crown-4-ether, benzo-18-crown-6-ether, benzo-15-crown-5-ether, benzo-12-crown-4-ether, etc. can be mentioned. The crown ether used as the capture agent can select the size of the ring according to the size of the metal ion used as the intake object. For example, when the metal ion is potassium ion, the crown ether compound can be an 18-membered ring crown ether. When the metal ion is sodium ion, the crown ether compound can be a 15-membered ring crown ether. When the metal ion is lithium ion, the crown ether compound can be a 12-membered ring crown ether.

[0111] The crown ether compound may contain a benzene ring. In this case, the stability of the crown ether compound can be improved. Examples of crown ether compounds having a benzene ring include benzo-18-crown-6-ether, benzo-15-crown-5-ether, and benzo-12-crown-4-ether.

[0112] The molar ratio of the scavenger content C2 to the cation content C1 (C2 / C1) can be, for example, 0.1 or greater, 0.3 or greater, or 0.5 or greater. The molar ratio of the scavenger content C2 to the cation content C1 (C2 / C1) can be, for example, 5 or less, 3 or less, or 2 or less. That is, the molar ratio (C2 / C1) can be, for example, 0.1-5, 0.1-3, 0.1-2, 0.3-5, 0.3-3, 0.3-2, 0.5-5, 0.5-3, or 0.5-2.

[0113] Each of the plurality of conductive portions 4 is a conductive portion located on the first major surface 2a and connected to a corresponding thermoelectric conversion group 3. Each conductive portion 4 may be a conductor or a semiconductor. The conductivity of each conductive portion 4 may be equal to or greater than the conductivity of the p-type thermoelectric conversion element 21.

[0114] The thickness of each conductive portion 4 can be, for example, 3 μm or greater, 5 μm or greater, 8 μm or greater, or 10 μm or greater. Furthermore, the thickness of each conductive portion 4 can be, for example, 30 μm or less, 25 μm or less, 20 μm or less, or 15 μm or less. That is, the thickness of each conductive portion 4 can be, for example, 3-30 μm, 3-25 μm, 3-20 μm, 3-15 μm, 5-30 μm, 5-25 μm, 5-20 μm, 5-15 μm, 8-30 μm, 8-25 μm, 8-20 μm, 8-15 μm, 10-30 μm, 10-25 μm, 10-20 μm, or 10-15 μm. The thickness of each conductive portion 4 can be the same as, or substantially the same as, the thickness T1 of the p-type thermoelectric conversion element 21.

[0115] The thermal conductivity of each conductive portion 4 can be, for example, 0.01 W / mK or greater, 0.5 W / mK or greater, 1 W / mK or greater, 3 W / mK or greater, or 10 W / mK or greater. Furthermore, the thermal conductivity of each conductive portion 4 can be, for example, 50 W / mK or less, 40 W / mK or less, 30 W / mK or less, or 20 W / mK or less. That is, the thermal conductivity of each conductive portion 4 can be, for example, 0.01 to 50 W / mK, 0.01 to 40 W / mK, 0.01 to 30 W / mK, 0.01 to 20 W / mK, 0.5 to 50 W / mK, 0.5 to 40 W / mK, 0.5 to 30 W / mK, 0.5 to 20 W / mK, 1 to 50 W / mK, 1 to 40 W / mK, 1 to 30 W / mK, 1 to 20 W / mK, 3 to 50 W / mK, 3 to 40 W / mK, 3 to 30 W / mK, 3 to 20 W / mK, 10 to 50 W / mK, 10 to 40 W / mK, 10 to 30 W / mK or 10 to 20 W / mK. The thermal conductivity of each conductive portion 4 may be the same as or higher than the thermal conductivity of the p-type thermoelectric conversion element 21 .

[0116] At least some of the plurality of conductive parts 4 may have a single-layer structure or a stacked structure. For example, at least some of the plurality of conductive parts 4 may have an organic conductive layer and a metal conductive layer located on the organic conductive layer.

[0117] In this embodiment, the plurality of conductive portions 4 may be formed of the same material as that of the p-type thermoelectric conversion elements 21. Therefore, the conductive portions 4 may have the same conductivity type (p-type).

[0118] The plurality of conductive portions 4 include first conductive portions 4a that function as terminals for connecting to external devices and second conductive portions 4b that function as conductive paths connecting adjacent thermoelectric conversion groups 3. The plurality of conductive portions 4 include two first conductive portions 4a located within one conductive region R2. Only the second conductive portion 4b is provided in the other conductive region R2.

[0119] Multiple thermoelectric conversion groups 3 are connected in series via multiple second conductive portions 4b. Therefore, when thermoelectric conversion module 1 performs thermoelectric conversion, current can flow in series from one first conductive portion 4a to another first conductive portion 4a. For example, a first conductive portion 4a located in one conductive region R2 is connected to one end of a first thermoelectric conversion group 3a in the first direction D2, and a second conductive portion 4b located in another conductive region R2 is connected to the other end of the first thermoelectric conversion group 3a and one end of a second thermoelectric conversion group 3b in the first direction D2.

[0120] The plurality of heat conducting portions 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 portions 5 overlaps with the thermoelectric conversion group 3 (i.e., the thermoelectric conversion portion 11) in the thickness direction D1. More specifically, at least a portion of the plurality of heat conducting portions 5 overlaps with the end of the thermoelectric conversion portion 11. On the other hand, each heat conducting portion 5 does not overlap with the center of the thermoelectric conversion portion 11. As a result, a temperature gradient can be well generated inside the thermoelectric conversion portion 11 along the first direction D2. The plurality of heat conducting portions 5 are separated from each other along the first direction D2 and have a strip shape extending along the second direction when viewed from above. The shape of each heat conducting portion 5 when viewed from above is not particularly limited and may be, for example, polygonal, circular, elliptical, etc. Each heat conducting portion 5 may include, for example, a metal (silver, copper, etc.), carbon, a resin (such as a silicone resin, an epoxy resin, a (meth) acrylic resin), etc. Each heat conducting portion 5 may also include ceramics such as boron nitride and aluminum nitride that exhibit high thermal conductivity. From the viewpoint of manufacturing efficiency, each heat transfer portion 5 may also contain the above-mentioned resin. In this case, the heat transfer portion 5 may also be formed using the resin or a solution containing the resin.

[0121] The thermal conductivity of each heat conducting portion 5 can be, for example, 1 W / mK or greater, 2 W / mK or greater, 3 W / mK or greater, 5 W / mK or greater, or 10 W / mK or greater. High thermal conductivity of each heat conducting portion 5 facilitates heat transfer to the thermoelectric conversion portion 11 via the multiple heat conducting portions 5 when the thermoelectric conversion module 1 is heated. The thermal conductivity of each heat conducting portion 5 can be, for example, 400 W / mK or less, 300 W / mK or less, or 200 W / mK or less. That is, the thermal conductivity of each heat conducting portion 5 may be, for example, 1-400 W / mK, 1-300 W / mK, 1-200 W / mK, 2-400 W / mK, 2-300 W / mK, 2-200 W / mK, 3-400 W / mK, 3-300 W / mK, 3-200 W / mK, 5-400 W / mK, 5-300 W / mK, 5-200 W / mK, 10-400 W / mK, 10-300 W / mK, or 10-200 W / mK. The thermal conductivity of each heat conducting portion 5 may be measured by a steady-state method or a non-steady-state method.

[0122] The linear expansion coefficient of each heat conducting portion 5 in the in-plane direction may be, for example, 1 ppm / K or greater, 10 ppm / K or greater, or 50 ppm / K or greater. Furthermore, the linear expansion coefficient of each heat conducting portion 5 in the in-plane direction may be, for example, 200 ppm / K or less, 150 ppm / K or less, or 100 ppm / K or less. That is, the linear expansion coefficient of each heat conducting portion 5 in the in-plane direction may be, for example, 1-200 ppm / K, 1-150 ppm / K, 1-100 ppm / K, 10-200 ppm / K, 10-150 ppm / K, 10-100 ppm / K, 50-200 ppm / K, 50-150 ppm / K, or 50-100 ppm / K. The linear expansion coefficient of each heat conducting portion 5 is measured, for example, by thermomechanical analysis (TMA).

[0123] The length T2 of each heat conducting portion 5 along the thickness direction D1 can be, for example, 50 μm or more, 100 μm or more, or 200 μm or more. If the length T2 is long, a temperature difference is likely to occur. In addition, the length T2 of each heat conducting portion 5 along the thickness direction D1 can be, for example, 2000 μm or less, 1700 μm or less, or 1500 μm or less. If the length T2 is short, there is a tendency for the module to be thinner and more compact. That is, the length T2 of each heat conducting portion 5 along the thickness direction D1 can be, for example, 50 μm to 2000 μm, 50 μm to 1700 μm, 50 μm to 1500 μm, 100 μm to 2000 μm, 100 μm to 1700 μm, 100 μm to 1500 μm, 200 μm to 2000 μm, 200 μm to 1700 μm, or 200 μm to 1500 μm.

[0124] The width L2 of each heat conducting portion 5 along the first direction D2 can be, for example, 0.2 mm or more, 0.5 mm or more, or 0.8 mm or more. If the width L2 is large, the heat conducting function of each heat conducting portion 5 can be better exerted. In addition, the width L2 of each heat conducting portion 5 along the first direction D2 can be, for example, 2.0 mm or less, 1.8 mm or less, or 1.5 mm or less. If the width L2 is small, a temperature difference can be generated better inside the thermoelectric conversion portion 11. That is, the width L2 of each heat conducting portion 5 along the first direction D2 can be, for example, 0.2 to 2.0 mm, 0.2 to 1.8 mm, 0.2 to 1.5 mm, 0.5 to 2.0 mm, 0.5 to 1.8 mm, 0.5 to 1.5 mm, 0.8 to 2.0 mm, 0.8 to 1.8 mm, or 0.8 to 1.5 mm.

[0125] Between two adjacent heat transfer sections 5, the spacing S along the first direction D2 is greater than the length L1 of the p-type thermoelectric conversion element 21 and the length of the n-type thermoelectric conversion element 22 in the first direction D2. Spacing S may be, for example, 3 mm or greater, 4 mm or greater, 5 mm or greater, or 6 mm or greater. A larger spacing S allows for a more favorable temperature gradient within the thermoelectric conversion section 11. Alternatively, spacing S may be, for example, 15 mm or less, 12 mm or less, 10 mm or less, or 8 mm or less. A smaller spacing S allows for the formation of more thermoelectric conversion sections 11 on the first major surface 2a. Specifically, spacing S may be, for example, 3 to 15 mm, 3 to 12 mm, 3 to 10 mm, 3 to 8 mm, 4 to 15 mm, 4 to 12 mm, 4 to 10 mm, 4 to 8 mm, 5 to 15 mm, 5 to 12 mm, 5 to 10 mm, 5 to 8 mm, 6 to 15 mm, 6 to 12 mm, 6 to 10 mm, or 6 to 8 mm.

[0126] Below, sometimes Figure 3 One of the two heat conducting portions 5 shown in (b) is referred to as a 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 a 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 portion 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 portion 21b of the p-type thermoelectric conversion element 21 included in the first thermoelectric conversion portion 11a. In addition, as Figure 3As shown in (a), in the thickness direction D1, the first heat conducting 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 conducting 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.

[0127] The plurality of heat-insulating components 6 are portions having a thermal conductivity lower than that of the display substrate 2 (preferably lower than that of the substrate 2), and are located on the second main surface 2b. The plurality of heat-insulating components 6 are respectively located between the corresponding first heat-conducting portion 5a and the second heat-conducting portion 5b. The plurality of heat-insulating components 6 are separated 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, polygonal, circular, or elliptical. 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 is equivalent to the interval S.

[0128] The length T3 of each thermal insulation member 6 along the thickness direction D1 is less than the length T2 of each heat conducting portion 5. For example, length T3 may be less than 95% or less than 80% of length T2. In this case, the thermal insulation member 6 is less likely to separate from the substrate 2 when the thermoelectric conversion module 1 deforms. Alternatively, length T3 may be greater than 5% or greater than 10% of length T2. Specifically, length T3 may be, for example, 5-95%, 5-80%, 10-95%, or 10-80% of length T2.

[0129] At least a portion of each of the plurality of thermal insulation members 6 overlaps with the center of the corresponding thermoelectric conversion section 11 in thickness direction D1. In other words, in each thermoelectric conversion section 11, first end 21a of p-type thermoelectric conversion element 21 and first end 22a of n-type thermoelectric conversion element 22 overlap with at least a portion of each of the plurality of thermal insulation members 6 in thickness direction D1. This stabilizes the temperature at the center of each thermoelectric conversion section 11, and thus tends to maintain a stable temperature gradient within thermoelectric conversion section 11 along first direction D2.

[0130] Each heat insulating member 6 may include, for example, cellulose nanofiber (CNF), silica aerogel, resin (for example, silicone), etc. Each heat insulating member 6 may also be a foam.

[0131] The thermal conductivity of each thermal insulating member 6 can be, for example, 0.01 W / mK or higher, 0.02 W / mK or higher, or 0.03 W / mK or higher. Furthermore, the thermal conductivity of each thermal insulating member 6 can be, for example, 0.1 W / mK or lower, 0.08 W / mK or lower, or 0.05 W / mK or lower. That is, the thermal conductivity of each thermal insulating member 6 can be, for example, 0.01 to 0.1 W / mK, 0.01 to 0.08 W / mK, 0.01 to 0.05 W / mK, 0.02 to 0.1 W / mK, 0.02 to 0.08 W / mK, 0.02 to 0.05 W / mK, 0.03 to 0.1 W / mK, 0.03 to 0.08 W / mK, or 0.03 to 0.05 W / mK. The thermal conductivity of each heat insulating member 6 may be lower than or equal to the thermal conductivity of the substrate 2 , or may be lower than the thermal conductivity of the substrate 2 .

[0132] The linear expansion coefficient of each thermal insulation member 6 may be, for example, 200 ppm / K or less, 180 ppm / K or less, or 150 ppm / K or less. In addition, the linear expansion coefficient of each thermal insulation member 6 may be, for example, 0.1 ppm / K or more, 1 ppm / K or more, or 10 ppm / K or more. That is, the linear expansion coefficient of each thermal insulation member 6 may be, for example, 0.1-200 ppm / K, 0.1-180 ppm / K, 0.1-150 ppm / K, 1-200 ppm / K, 1-180 ppm / K, 1-150 ppm / K, 10-200 ppm / K, 10-180 ppm / K, or 10-150 ppm / K. The linear expansion coefficient of each thermal insulation member 6 is measured, for example, by thermomechanical analysis (TMA).

[0133] The difference between the linear expansion coefficient of each heat conducting portion 5 and the linear expansion coefficient of each heat insulating member 6 can be, for example, 100 ppm / K or less, 80 ppm / K or less, 50 ppm / K or less, or 10 ppm / K or less. Since the difference between the linear expansion coefficient of each heat conducting portion 5 and the linear expansion coefficient of each heat insulating member 6 is small, even when the thermoelectric conversion module 1 is attached to a heat source in a deformed state, the thermoelectric conversion module 1 will not separate from the heat source, and a stable temperature gradient can be maintained to generate electricity.

[0134] The sealing layer 8 is disposed on the first major surface 2a of the substrate 2 so as to cover the thermoelectric conversion region R1 and the two conductive regions R2. The sealing layer 8 can be bonded to the multiple thermoelectric conversion groups 3 and the multiple conductive portions 4 in the thermoelectric conversion region R1 and the two conductive regions R2. Alternatively, the sealing layer 8 can be bonded to the first major surface 2a of the substrate 2 outside the thermoelectric conversion region R1 and the two conductive regions R2. The shape of the sealing layer 8 when viewed from above is not particularly limited and can be, for example, polygonal, circular, or elliptical.

[0135] The sealing layer 8 is a sheet member made of a resin exhibiting heat resistance and flexibility, and is, for example, in the form of a substantially flat plate. Examples of the resin constituting the substrate 2 include polyalkylene resins (e.g., polypropylene resins), (meth)acrylic resins, (meth)acrylonitrile resins, polyamide resins, polycarbonate resins, polyether resins, polyester resins (e.g., polyethylene naphthalate resins, PET resins), epoxy resins, organosiloxane resins, polyimide resins, and polysulfone resins.

[0136] The thickness of the sealing layer 8 (thickness in the thickness direction D1) is 5 μm or more, and can be 10 μm or more, 15 μm or more, or 20 μm or more. The thick sealing layer 8 can maintain high output for a long time. The thickness of the sealing layer 8 (thickness in the thickness direction D1) is 150 μm or less, and can be 100 μm or less, 50 μm or less, or 40 μm or less. The thin sealing layer 8 can achieve excellent flexibility. That is, the thickness of the sealing layer 8 (the thickness in the thickness direction D1) can be 5-150μm, 5-100μm, 5-50μm, 5-40μm, 10-150μm, 10-100μm, 10-50μm, 10-40μm, 15-150μm, 15-100μm, 15-50μm, 15-40μm, 20-150μm, 20-100μm, 20-50μm or 20-40μm.

[0137] The water vapor permeability of the sealing layer 8 in the thickness direction D1 is 100 g / (m 2 ·day) or less, or 80g / (m 2 ·day) or less, 60g / (m 2 ·day) or less, 40g / (m 2 ·day) or less, 20g / (m 2 ·day) or less than 10g / (m 2 By making the water vapor permeability of the sealing layer 8 in the thickness direction D1 low, high output can be maintained for a long time. In addition, the water vapor permeability of the sealing layer 8 in the thickness direction D1 can be, for example, 0.001 g / (m 2 ·day) or more, and may be 0.01g / (m 2 ·day) or more, 0.1g / (m 2 ·day) or more, 0.5g / (m 2 ·day) or more, 1g / (m 2 ·day) or more or 2g / (m 2 That is, the water vapor permeability of the sealing layer 8 in the thickness direction D1 can be, for example, 0.001 to 100 g / (m 2·day), 0.001 - 80 g / (m 2 ·day), 0.001 - 60 g / (m 2 ·day), 0.001 - 40 g / (m 2 ·day), 0.001 - 20 g / (m 2 ·day), 0.001 - 10 g / (m 2 ·day), 0.01 - 100 g / (m 2 ·day), 0.01 - 80 g / (m 2 ·day), 0.01 - 60 g / (m 2 ·day), 0.01 - 40 g / (m 2 ·day), 0.01 - 20 g / (m 2 ·day), 0.01 - 10 g / (m 2 ·day), 0.1 - 100 g / (m 2 ·day), 0.1 - 80 g / (m 2 ·day), 0.1 - 60 g / (m 2 ·day), 0.1 - 40 g / (m 2 ·day), 0.1 - 20 g / (m 2 ·day), 0.1 - 10 g / (m 2 / / 这里最后一个原文中“或2~10g / (m”表述不完整,推测是“或2~10g / (m·day)”,翻译如下 ·day), 0.5 - 100 g / (m 2 ·day), 0.5 - 80 g / (m 2 ·day), 0.5 - 60 g / (m 2 ·day), 0.5 - 40 g / (m 2 ·day), 0.5 - 20 g / (m 2 ·day), 0.5 - 10 g / (m 2 ·day), 1 - 100 g / (m 2 ·day), 1 - 80 g / (m 2 ·day), 1 - 60 g / (m 2 ·day), 1 - 40 g / (m 2 ·day), 1 - 20 g / (m 2 ·day), 1 - 10 g / (m 2 ·day), 2 - 100 g / (m 2 ·day), 2 - 80 g / (m 2 ·day), 2 - 60 g / (m 2 ·day), 2 - 40 g / (m 2 ·day), 2 - 20 g / (m 2 ·day), or 2 - 10 g / (m2 The water vapor transmission rate of the sealant layer 8 was measured by a cup method.

[0138] The emissivity of the sealing layer 8 is greater than 0.70, and may be greater than 0.80 or greater than 0.90. Due to the high emissivity of the sealing layer 8, heat can be efficiently discharged from the upper surface of the sealing layer 8 (the surface on the opposite side of the substrate 2), and the thermoelectric conversion performance is improved. In addition, the emissivity of the sealing layer 8 may be less than 0.99, less than 0.97 or less than 0.95. That is, the emissivity of the sealing layer 8 may be, for example, 0.70 to 0.99, 0.70 to 0.97, 0.70 to 0.95, 0.80 to 0.99, 0.80 to 0.97, 0.80 to 0.95, 0.90 to 0.99, 0.90 to 0.97 or 0.90 to 0.95. The emissivity of the sealing layer 8 is measured by an infrared thermal imaging camera.

[0139] The thermal conductivity of the sealing layer 8 is 0.01 W / mK or more, and may be 0.05 W / mK or more, 0.1 W / mK or more, or 0.2 W / mK or more. Due to the high thermal conductivity of the sealing layer 8, heat can be efficiently discharged from the upper surface of the sealing layer 8 (the surface opposite to the substrate 2), thereby improving the thermoelectric conversion performance. In addition, the thermal conductivity of the sealing layer 8 is 50 W / mK or less, and may be 10 W / mK or less, 5 W / mK or less, 1 W / mK or less, or 0.5 W / mK or less. Due to the low thermal conductivity of the sealing layer 8, there is a tendency to easily maintain the temperature difference generated in the thermoelectric conversion layer. That is, the thermal conductivity of the sealing layer 8 can be, for example, 0.01 to 50 W / mK, 0.01 to 10 W / mK, 0.01 to 5 W / mK, 0.01 to 1 W / mK, 0.01 to 0.5 W / mK, 0.05 to 50 W / mK, 0.05 to 10 W / mK, 0.05 to 5 W / mK, 0.05 to 1 W / mK, 0.05 to 0.5 W / mK, 0.1 to 50 W / mK, 0.1 to 10 W / mK, 0.1 to 5 W / mK, 0.1 to 1 W / mK, 0.1 to 0.5 W / mK, 0.2 to 50 W / mK, 0.2 to 10 W / mK, 0.2 to 5 W / mK, 0.2 to 1 W / mK, 0.2 to 0.5 W / mK. The thermal conductivity of the sealing layer 8 was measured by a laser flash method.

[0140] like Figure 4 As shown in (a), the sealing layer 8 of this embodiment can be directly arranged on the thermoelectric conversion part 11 (on the p-type thermoelectric conversion element 21 and the n-type thermoelectric conversion element 22). Figure 4 As shown in (b), in a modified example, the sealing layer 8 may be disposed on the thermoelectric conversion unit 11 via the adhesive layer 9 .

[0141] The adhesive layer 9 can be formed of an adhesive capable of bonding the sealing layer 8 to the thermoelectric conversion unit 11. The adhesive can be, for example, an adhesive. Examples of the adhesive include (meth)acrylic resins, epoxy resins, polyurethane resins, urea resins, phenolic resins, melamine resins, resorcinol resins, isocyanates, silicones, and chloroprene rubber.

[0142] The thickness of the adhesive layer 9 (thickness in the thickness direction D1) can be, for example, 0.1 μm or more, 1 μm or more, or 10 μm or more. Furthermore, the thickness of the adhesive layer 9 (thickness in the thickness direction D1) can be, for example, 500 μm or less, 200 μm or less, or 100 μm or less. That is, the thickness of the adhesive layer 9 (thickness in the thickness direction D1) can be, for example, 0.1 to 500 μm, 0.1 to 200 μm, 0.1 to 100 μm, 1 to 500 μm, 1 to 200 μm, 1 to 100 μm, 10 to 500 μm, 10 to 200 μm, or 10 to 100 μm.

[0143] The thermal conductivity of the adhesive layer 9 can be, for example, 0.01 W / mK or greater, 0.05 W / mK or greater, or 0.1 W / mK or greater. A high thermal conductivity of the adhesive layer 9 tends to more significantly enhance the effect of heat removal from the upper surface of the sealing layer 8. Alternatively, the thermal conductivity of the adhesive layer 9 can be, for example, 10 W / mK or less, 5 W / mK or less, or 1 W / mK or less. A low thermal conductivity of the adhesive layer 9 tends to facilitate the retention of temperature differences generated in the thermoelectric conversion layer. That is, the thermal conductivity of the adhesive layer 9 may be, for example, 0.01-10 W / mK, 0.01-5 W / mK, 0.01-1 W / mK, 0.05-10 W / mK, 0.05-5 W / mK, 0.05-1 W / mK, 0.1-10 W / mK, 0.1-5 W / mK, or 0.1-1 W / mK.

[0144] Thermoelectric conversion module 1 may further include structures 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.

[0145] Next, refer to Figures 5 to 7 An example of a method for manufacturing the thermoelectric conversion module 1 according to this embodiment will be described. Figure 5 (a), (b), Figure 6 (a), (b) and Figure 7 (a) and (b) are diagrams for explaining a method for manufacturing a thermoelectric conversion module according to this embodiment.

[0146] First, if Figure 5As shown in (a) and (b), a plurality of heat-conducting parts 5 and a plurality of heat-insulating parts 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 on the second main surface 2b by a known method such as an inkjet method, a dispensing method, a doctor blade method, or a screen printing method. 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-conducting parts 5 and heat-insulating parts 6 on the second main surface 2b.

[0147] Then, if Figure 6 As shown in (a), a first layer 41 is formed on the first main surface 2a (on the other main surface) (second step). In the second step, first, a dispersion is dripped onto 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, or a spray coating method. Then, the dispersion is dried to form the first layer 41. For example, the substrate 2 is placed in an air drying machine set at a temperature of 25°C to 90°C for 10 minutes to 21600 minutes to heat the substrate 2. Thus, the dispersion is dried to form the first layer 41.

[0148] The dispersion liquid used in the second step is, for example, a liquid in which a p-type thermoelectric conversion material is dispersed. In this embodiment, the dispersion liquid is a liquid in which carbon nanotubes and a conductive resin are dispersed.

[0149] The carbon nanotube content in the dispersion can be, for example, 20% by mass or greater, 30% by mass or greater, or 40% by mass or greater, based on the total amount of the conductive resin and the carbon nanotubes. Alternatively, the carbon nanotube content in the dispersion can be, for example, 99% by mass or less, 95% by mass or less, or 90% by mass or less, based on the total amount of the conductive resin and the carbon nanotubes.

[0150] The total mass concentration of the carbon nanotubes and the conductive resin in the dispersion can be, for example, 0.05 mass% or greater, 0.06 mass% or greater, 0.07 mass% or greater, 0.10 mass% or greater, 0.12 mass% or greater, or 0.15 mass% or greater. Alternatively, the total mass concentration of the carbon nanotubes and the conductive resin in the dispersion can be, for example, 10 mass% or less, 5 mass% or less, or 2 mass% or less. That is, the total mass concentration of the carbon nanotubes and the conductive resin in the dispersion can be, for example, 0.05 to 10 mass%, 0.05 to 5 mass%, 0.05 to 2 mass%, 0.06 to 10 mass%, 0.06 to 5 mass%, 0.06 to 2 mass%, 0.07 to 10 mass%, 0.07 to 5 mass%, 0.07 to 2 mass%, 0.10 to 10 mass%, 0.10 to 5 mass%, 0.10 to 2 mass%, 0.12 to 10 mass%, 0.12 to 5 mass%, 0.12 to 2 mass%, 0.15 to 10 mass%, 0.15 to 5 mass% or 0.15 to 2 mass%.

[0151] The dispersion used in the second step can be, for example, a mixed liquid formed by mixing a first liquid containing carbon nanotubes with a second liquid containing a conductive resin. Furthermore, the carbon nanotube content in the dispersion, based on the total amount of the conductive resin and carbon nanotubes, and the mass ratio of the carbon nanotubes to the total mass of the thermoelectric conversion unit 11 are substantially equal. Therefore, in this specification, the carbon nanotube content in the dispersion, based on the total amount of the conductive resin and carbon nanotubes, can be considered the mass ratio of the carbon nanotubes to the total mass of the thermoelectric conversion unit 11.

[0152] The first liquid, for example, contains carbon nanotubes and a first solvent. The first liquid can be a liquid in which carbon nanotubes are dispersed in the first solvent. The concentration of the carbon nanotubes in the first liquid is, for example, 0.01% by mass or more and 10% by mass or less. The first solvent can be any solvent that can disperse the 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, one or more of water, methanol, ethanol, N-methylpyrrolidone and dimethyl sulfoxide are preferred, and water is more preferred. The first liquid may also contain additives such as surfactants and organic binders.

[0153] The second liquid, for example, contains a conductive resin and a second solvent. The second solvent can be any solvent that can disperse the conductive resin, for example, 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, one or more of water, methanol and ethanol are preferred, and water is more preferred. In one embodiment, the second liquid can be an aqueous dispersion of PEDOT / PSS. In addition, the second solvent can be used alone or as a mixture of two or more. The second liquid can also contain various additives.

[0154] Then, if Figure 6 As shown in (b), the p-type thermoelectric conversion layer 42 is formed by immersing the substrate 2 in an organic solvent (third step). In this embodiment, after the second step, the first main surface 2a of the substrate 2 is immersed in dimethyl sulfoxide (DMSO) as the 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 a period of not less than 1 minute and not more than 7200 minutes. After the above immersion treatment, the substrate 2 can be heated in an air-flow dryer. For example, the substrate 2 can be placed in an air-flow dryer set to not less than 25°C and not more than 90°C for not less than 10 minutes and not more than 21600 minutes to heat the substrate 2. In this way, a patterned p-type thermoelectric conversion layer 42 is formed. A portion of the p-type thermoelectric conversion layer 42 will later become the n-type thermoelectric conversion element 22. Another portion of the p-type thermoelectric conversion layer 42 will later become the p-type thermoelectric conversion element 21. Another portion of the p-type thermoelectric conversion layer 42 will later become the conductive portion 4.

[0155] Then, if Figure 7 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 n-type thermoelectric conversion elements 22 in the p-type thermoelectric conversion elements 21 and the portion 42a (fourth step). In the fourth step, the dopant solution 51 is impregnated into the portion 42a of the p-type thermoelectric conversion layer 42 using a known method such as an inkjet method or a dispenser method. In this embodiment, the p-type thermoelectric conversion layer 42 alternates between areas where the dopant solution 51 has been dripped and areas where the dopant solution 51 has not been dripped. Next, the dopant solution 51 is dried, transforming the portion 42a into the n-type thermoelectric conversion element 22. For example, the substrate 2 is heated by placing it on a hot plate set at a temperature of 25°C to 90°C for 10 minutes to 21600 minutes. This dries the dopant solution 51. 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 7As shown in (b), the portion of the p-type thermoelectric conversion layer 42 where the dopant solution 51 has not been dripped becomes the p-type thermoelectric conversion element 21 or the conductive portion 4. In this way, a plurality of thermoelectric conversion portions 11 are formed.

[0156] Next, a sealing layer 8 is provided to cover the formed plurality of thermoelectric conversion sections 11 and conductive sections 4, thereby forming the thermoelectric conversion module 1 (fifth step). The sealing layer 8 can be bonded to the first main surface 2a of the substrate 2 via an adhesive (e.g., a bonding agent). Alternatively, the sealing layer 8 can be bonded to the first main surface 2a of the substrate 2 by welding.

[0157] Next, the effects achieved by the thermoelectric conversion module 1 formed by the manufacturing method of the present embodiment described above will be described.

[0158] The thermoelectric conversion module 1 of this embodiment includes a first heat conducting portion 5a and a second heat conducting portion 5b located on the second main surface 2b. In the thickness direction D1, 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, and in the thickness direction D1, 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. Furthermore, a heat insulating member 6 is provided between the first and second heat conducting portions 5a, 5b on the second main surface 2b. Consequently, the first and second heat conducting portions 5a, 5b overlap with both ends of the first thermoelectric conversion portion 11a in the thickness direction D1, but do not overlap with the center of the first thermoelectric conversion portion 11a. Therefore, for example, by heating the first and second heat conducting portions 5a, 5b, a favorable internal temperature difference can be generated between the p-type thermoelectric conversion element 21 and the n-type thermoelectric conversion element 22. Furthermore, at least a portion of the thermal insulation member 6 overlaps the center of the thermoelectric conversion section 11 in the thickness direction D1. This stabilizes the temperature of the center portion of the thermoelectric conversion section 11, which becomes relatively cold during heating. Consequently, temperature variations within the thermoelectric conversion section 11 are less likely to occur. Therefore, by employing the thermoelectric conversion module 1 of this embodiment, it is possible to achieve increased output per unit area and stable output, independent of the temperature of the heat source.

[0159] The thermoelectric conversion module 1 of this embodiment has a sealing layer 8 provided on the first main surface 1a so as to cover the thermoelectric conversion unit 11. The sealing layer 8 has a thickness in the thickness direction D1 of 5 μm to 150 μm and a strength of 100 g / (m 2According to the findings of the present inventors, the thermoelectric conversion module 1 of this embodiment has a water vapor transmission rate of less than 100 g / (m2 / day). In the past, the output of the thermoelectric conversion module 1 of this embodiment was sometimes reduced due to the conversion of the n-type thermoelectric conversion element to p-type during long-term use. However, by providing the above-mentioned sealing layer 8, this p-type conversion is suppressed, and high output can be maintained for a long time. In this embodiment, by making the thickness of the sealing layer 8 in the thickness direction D1 not less than 5 μm and the water vapor transmission rate of 100 g / (m2 / day) 2 ·day) or less, the above-mentioned p-type conversion can be significantly suppressed. In addition, in this embodiment, the thickness of the sealing layer 8 in the thickness direction D1 is 150 μm or less (depending on the situation, the water vapor permeability is further 0.1 g / (m 2 / day) or more), thereby preventing the sealing layer 8 from being easily peeled off from the thermoelectric conversion unit 11 even when the thermoelectric conversion module 1 is attached to a heat source in a deformed state, thereby enabling stable power generation.

[0160] Furthermore, in this embodiment, the sealing layer 8 has an emissivity of 0.70 to 0.99, and a thermal conductivity of 0.01 W / mK to 50 W / mK. In this embodiment, by setting the emissivity of the sealing layer 8 to 0.70 or higher and the thermal conductivity to 0.01 W / mK or higher, heat retained in the thermoelectric conversion section 11 can be efficiently dissipated through the sealing layer 8, achieving stable high output. Furthermore, in this embodiment, by setting the thermal conductivity of the sealing layer 8 to 50 W / mK or lower, heat transfer from the high-temperature portion to the low-temperature portion of the thermoelectric conversion section 11 through the sealing layer 8 can be sufficiently suppressed, enabling power generation while maintaining a stable temperature gradient.

[0161] In this embodiment, the difference in linear expansion coefficient between the first heat conducting portion 5a and the second heat conducting portion 5b and the heat insulating member 6 can be 100 ppm / K or less. In this case, even when the thermoelectric conversion module 1 is attached to a heat source in a deformed state, the thermoelectric conversion module 1 is unlikely to separate from the heat source, enabling more stable power generation.

[0162] In this embodiment, thickness T1 of p-type thermoelectric conversion element 21 (and thickness of n-type thermoelectric conversion element 22) can be 3 μm to 30 μm. By setting thickness T1 within this range, the number of elements per unit area can be increased, and the internal resistance of the elements can be sufficiently suppressed.

[0163] In this embodiment, the linear expansion coefficient of each of the first heat conducting portion 5a and the second heat conducting portion 5b can be 100 ppm / K or higher and 200 ppm / K or lower, and the linear expansion coefficient of the heat insulating member 6 can be 200 ppm / K or lower. In this case, even when the thermoelectric conversion module 1 is attached to a heat source in a deformed state, the thermoelectric conversion module 1 will not separate from the heat source, and a more stable temperature gradient can be maintained to generate electricity.

[0164] In this embodiment, the width L2 of each heat transfer portion 5 along the first direction D2 may be 0.5 mm to 1.5 mm. In this case, the heat transfer performance of each heat transfer portion 5 can be better exerted, further increasing the internal temperature difference of the thermoelectric conversion portion 11.

[0165] In this embodiment, the thermal conductivity of the first heat conducting portion 5a and the second heat conducting portion 5b can be 2 W / mK or higher and 5 W / mK or lower, and the thermal conductivity of the heat insulating member 6 can be 0.01 W / mK or higher and 0.05 W / mK or lower. In this case, a better internal temperature difference can be generated in the thermoelectric conversion portion 11.

[0166] In this embodiment, thickness T1 of p-type thermoelectric conversion element 21 may be 5 μm to 25 μm. Interval S may be 3 mm to less than 12 mm. In these cases, the output per unit area of ​​thermoelectric conversion module 1 can be further improved.

[0167] In this embodiment, the substrate 2, thermoelectric conversion unit 11, heat transfer unit 5, and thermal insulation member 6 can each exhibit flexibility. In this case, for example, the thermoelectric conversion module 1 can be easily installed along the surface of a cylindrical tube. In other words, restrictions on the installation location of the thermoelectric conversion module 1 can be alleviated.

[0168] In this embodiment, by dripping a dopant solution 51 onto a portion 42a of the p-type thermoelectric conversion layer 42, the portion 42a can be converted 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 significantly reduced. Furthermore, in this case, the output reduction caused by the p-type conversion is more likely to occur, thus more significantly exerting the effect of the sealing layer 8. Furthermore, the dripping of the dopant solution 51 can be performed after the formation of the heat conducting portion 5. As a result, the material contained in the dopant solution 51 is less likely to degrade due to heating, etc.

[0169] 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 8 As shown, the thermal insulation members 6 are less likely to be hindered during deformation of the substrate 2. Therefore, for example, compressive stress is less likely to be excessively applied to the boundary between the heat conducting portion 5 and the thermal insulation member 6, and thus the thermal insulation member 6 is less likely to be separated from the substrate 2 when the thermoelectric conversion module 1 is deformed.

[0170] 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.

[0171] Figure 9 (a) is a schematic bottom view of a thermoelectric conversion module according to a modified example. Figure 9 (b) is along Figure 9 (a) is a schematic cross-sectional view of the IXb-IXb line. Figure 9 In (b), the structure provided on the first major surface 2a is omitted. Figure 9 The difference between the thermoelectric conversion module 1A shown in (a) and (b) and the thermoelectric conversion module 1 of the above embodiment is that it further 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 of the above 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 four-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 in contact not only with each heat conduction part 5, but also with the heat dissipation component 7, and each heat conduction part 5 is surrounded by the heat insulation component 6A when viewed from above.

[0172] The thermal conductivity of the heat dissipation member 7 is at least higher than the thermal conductivity of the substrate 2, and can be, for example, 1 W / mK or higher, 1.5 W / mK or higher, or 2 W / mK or higher. Furthermore, the thermal conductivity of the heat dissipation member 7 can be, for example, 400 W / mK or lower, 200 W / mK or lower, or 100 W / mK or lower. That is, the thermal conductivity of the heat dissipation member 7 can be, for example, 1-400 W / mK, 1-200 W / mK, 1-100 W / mK, 1.5-400 W / mK, 1.5-200 W / mK, 1.5-100 W / mK, 2-400 W / mK, 2-200 W / mK, or 2-100 W / mK. The thermal conductivity of the heat dissipation member 7 is measured by a steady-state method or a non-steady-state method.

[0173] The difference between the linear expansion coefficient of the heat dissipation member 7 in the in-plane direction and the linear expansion coefficient of the heat insulating member 6 can be, for example, 100 ppm / K or less, 80 ppm / K or less, or 50 ppm / K or less. Thus, even when the thermoelectric conversion module 1A is attached to a heat source in a deformed state, the thermoelectric conversion module 1A does not separate from the heat source, and a stable temperature gradient can be maintained to generate electricity.

[0174] The above-described modified examples also have the same effects as those of the above-described embodiment. Furthermore, the provision of the heat dissipating member 7 makes it difficult for heat to accumulate in the thermoelectric conversion module 1A, making it easier to maintain the temperature difference within the thermoelectric conversion section 11.

[0175] Figure 10 This is a schematic top view of a thermoelectric conversion module for explaining a modified example. Figure 10In the embodiment, the sealing layer 8 is omitted. That is, Figure 10 It can be considered as a diagram showing a state where the sealing layer 8 is removed from the thermoelectric conversion module 1 b , or a diagram showing a state before the sealing layer 8 is provided during the manufacture of the thermoelectric conversion module 1 b .

[0176] Figure 10 Thermoelectric conversion module 1b described in the preceding embodiment differs from thermoelectric conversion module 1 in that the length of each of the multiple thermoelectric conversion groups 3 in the second direction D3 is shorter than its length in the first direction. Furthermore, the number of thermoelectric conversion groups 3 in thermoelectric conversion module 1b differs from that in thermoelectric conversion module 1 in the preceding embodiment. In thermoelectric conversion module 1b, by shortening the length of the thermoelectric conversion groups 3 in the second direction D3, more thermoelectric conversion groups 3 are arranged side by side in the second direction D3.

[0177] The above-described modified examples can also achieve the same operational effects as those of the above-described embodiment.

[0178] In the above embodiment and the above 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 pre-formed heat insulating member may be fixed to the substrate.

[0179] Example

[0180] One aspect of the present disclosure is described in more detail with reference to the following examples, but one aspect of the present disclosure is not limited to these examples.

[0181] (Example 1)

[0182] The thermoelectric conversion module was produced as follows.

[0183] <Thermal insulation components>

[0184] A thermal insulation material sheet (Sumitomo Riko Co., Ltd. "FINSULITE (registered trademark) Standard Type", thickness: 0.63 mm, silica aerogel, thermal conductivity: 0.02 W / mK, linear expansion coefficient: 136 ppm / K) was cut into pieces with a width of 10 mm and a length of 96 mm to prepare a thermal insulation component.

[0185] <Dispersion>

[0186] 80 g of a carbon nanotube dispersion (concentration: 0.2% by mass, G / D ratio: 41, aqueous dispersion, single-walled carbon nanotubes, diameter 0.9 nm to 1.7 nm, thermal conductivity 30 W / mK) was concentrated by vacuum until the carbon nanotube concentration became 0.4% by mass. Subsequently, 5.7 g of a PEDOT / PSS aqueous dispersion ("Clevious PH1000" manufactured by Heraeus Co., Ltd., solid content concentration: 1.2% by mass) and the concentrated carbon nanotube dispersion were fully stirred (stirring time: 30 minutes) using a Three-One Motor ("PM203 type" manufactured by AS One Co., Ltd.). Thus, a dispersion having a carbon nanotube content of 50% by mass relative to the total amount of PEDOT / PSS and carbon nanotubes was prepared. Shear rate 0.01 s -1 The viscosity of the dispersion at 1320000 mPa·sec was measured using a rheometer ("MCR302" manufactured by Anton Paar). The measurement conditions were temperature: 25°C, plate: Parallel plates, gap: 1mm.

[0187] <Dopant Solution>

[0188] 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 0.2 M, respectively. The molar ratio (C2 / C1) was 1.

[0189] <Substrate>

[0190] As a substrate, a 100 mm square polyethylene naphthalate film (manufactured by Toyobo Co., Ltd., film thickness 25 μm, water vapor transmission rate 6.0 g / (m 2 ·day), emissivity 0.93, thermal conductivity 0.33 W / mK, flexural modulus 2.3 GPa). The polyethylene naphthalate film was cleaned with acetone and used as a substrate.

[0191] <Sealing layer>

[0192] As a sealant layer, a 100 mm square polyethylene naphthalate film (manufactured by Toyobo Co., Ltd., film thickness 25 μm, water vapor transmission rate 6.0 g / (m 2 The polyethylene naphthalate film was cleaned with acetone, and an adhesive tape (Nitto Denko Co., Ltd., No. 585, with an acrylic adhesive layer) was attached to one main surface.

[0193] <Manufacturing of Thermoelectric Conversion Module>

[0194] The dispersion was applied to the first main surface of the substrate using a Musashi Engineering "AeroJet" jet dispenser and a "SHOTMASTER 400ΩX" desktop robot. The laminate coated with the dispersion was then placed in a forced-air dryer set at 60°C for 3 hours. This formed a 21μm-thick composite film on the first main surface of the substrate. The composite film provided both a thermoelectric conversion region and a conductive portion on the first main surface of the substrate.

[0195] The direction in which the thermoelectric conversion region extends is perpendicular to the direction in which the heat conducting portion and the heat insulating member extend. The thickness of the composite film was measured using a high-precision digital micrometer (MDH-25MB, manufactured by Mitutoyo Corporation). Specifically, the thickness of the portion where the composite film was provided and the thickness of the portion where the composite film was not provided (only the substrate portion) were measured, and the difference between the two was taken as the thickness of the composite film.

[0196] Next, the first main surface of the substrate was immersed in room-temperature DMSO (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) for 30 minutes. The substrate was then removed from the DMSO and placed on a hot plate set at 60°C for 120 minutes. This formed a p-type thermoelectric conversion layer on the first main surface of the substrate. In Example 1, the p-type thermoelectric conversion layer had a thickness of 4.7 μm. The in-plane thermal conductivity of the p-type thermoelectric conversion layer was 32 W / mK.

[0197] Next, a dopant solution was dripped onto a portion of the p-type thermoelectric conversion layer, which functions as a thermoelectric conversion element, using a Fujifilm inkjet printer, the "Material Printer DMP2850." In Example 1, the dopant solution was first dripped onto an area with a width of 2 mm along the first direction and a length of 5.5 mm along the second direction. Next, the dopant solution was dripped onto an area with a width of 2 mm and a length of 5.5 mm, spaced 5.5 mm apart along the first direction. This dripping operation was repeated until the areas with and without the dopant solution alternated.

[0198] Next, the substrate was dried for 30 minutes, and then placed in a blown dryer set at 100° C. for 60 minutes.

[0199] Thus, 48 ​​p-type thermoelectric conversion elements and 48 n-type thermoelectric conversion elements are formed on the substrate. That is, a total of 96 thermoelectric conversion elements are formed on the substrate. Therefore, a total of 48 thermoelectric conversion sections are formed, each including one p-type thermoelectric conversion element and one n-type thermoelectric conversion element. Here, the thickness of the n-type thermoelectric conversion element is substantially the same as that of the p-type thermoelectric conversion element. In addition, the end of each thermoelectric conversion section overlaps with the heat conduction section, and at least the center of each thermoelectric conversion section does not overlap with the heat conduction section. The content of iron atoms in the n-type thermoelectric conversion element is greater than 0.01 mass% and less than 10 mass%.

[0200] Next, the adhesive tape side of the sealant layer was pressed against the first major surface of the substrate on which the p-type and n-type thermoelectric conversion elements were formed. The substrate was placed in the chamber of a manual hydraulic vacuum hot press (IMC-11FD, manufactured by Imoto Seisakusho Co., Ltd.), the temperature of the plate set to 80°C, and vacuumed for 1 minute. The press was then applied at a pressure of 1 kN for at least 10 minutes. This procedure yielded a laminated body in which the thermoelectric conversion elements were sandwiched between the substrate and the sealant layer.

[0201] Next, a spray adhesive (manufactured by 3M Japan Co., Ltd., conventional 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 second main surface of the above-mentioned substrate and attached. Next, a high thermal conductivity material (manufactured by Shin-Etsu Chemical Co., Ltd., G-789) is applied to the above-mentioned gap using a dispenser "AD3000C" manufactured by Iwashita Engineering and a desktop robot "EzROBO-5GX". At this time, the interval along the first direction of the nozzle position for discharging the high thermal conductivity material is set to 11 mm, and the nozzle is moved along a second direction orthogonal to the first direction and applied. Thus, a plurality of high thermal conductivity materials having a band shape are applied to the second main surface. After coating, the substrate is placed on a heating plate set at 120°C for 60 minutes. Thus, a plurality of heat-conducting portions (linear expansion coefficient: 140 ppm / K, thermal conductivity: 3.0 W / mK) are formed. The heat conducting portion 5 has a length T2 of 1 mm, a width L2 of 1 mm, and a spacing S between the heat conducting portions in the first direction of 10 mm. Furthermore, a heat insulating member (linear expansion coefficient: 136 ppm / K, thermal conductivity: 0.02 W / mK) is positioned and secured to fill the 10 mm spacing.

[0202] In the above manner, the thermoelectric conversion module of Example 1 was manufactured.

[0203] (Example 2)

[0204] In the production of the substrate and the sealing layer, a PET film (manufactured by Toray Industries, Ltd., with a film thickness of 25 μm and a water vapor transmission rate of 25 g / (m 2·day), emissivity 0.92, thermal conductivity 0.31 W / mK, flexural modulus 2.5 GPa), a thermoelectric conversion module was manufactured in the same manner as in Example 1.

[0205] (Example 3)

[0206] In the production of the substrate and the sealing layer, a polypropylene film (manufactured by Toray Industries, Ltd., with a film thickness of 25 μm and a water vapor transmission rate of 8.0 g / (m 2 ·day), emissivity 0.90, thermal conductivity 0.13 W / mK, flexural modulus 2.3 GPa), a thermoelectric conversion module was manufactured in the same manner as in Example 1.

[0207] (Example 4)

[0208] In the production of the substrate and the sealing layer, a PET film (manufactured by Toray Industries, Ltd., with a film thickness of 12 μm and a water vapor transmission rate of 50 g / (m 2 ·day), emissivity 0.92, thermal conductivity 0.31 W / mK, flexural modulus 2.5 GPa), a thermoelectric conversion module was manufactured in the same manner as in Example 1.

[0209] (Example 5)

[0210] In the production of the substrate and the sealing layer, a polyethylene naphthalate film (manufactured by Toyobo Co., Ltd., with a film thickness of 100 μm and a water vapor transmission rate of 1.6 g / (m 2 ·day), emissivity 0.93, thermal conductivity 0.33 W / mK, flexural modulus 2.3 GPa), a thermoelectric conversion module was manufactured in the same manner as in Example 1, except for the above.

[0211] (Example 6)

[0212] In the production of the substrate and the sealing layer, a polyimide film (manufactured by Toray Industries, Ltd., with a film thickness of 25 μm and a water vapor transmission rate of 76 g / (m 2 ·day), emissivity 0.95, thermal conductivity 0.29 W / mK, flexural modulus 3.5 GPa), a thermoelectric conversion module was manufactured in the same manner as in Example 1, except for the above.

[0213] (Comparative Example 1)

[0214] In the production of the sealing layer, a polyimide film (manufactured by Toray Industries, Ltd., film thickness 25 μm, water vapor transmission rate 76 g / (m 2·day), emissivity 0.95, thermal conductivity 0.29 W / mK, flexural modulus 3.5 GPa), and no sealing layer was provided. A thermoelectric conversion module was manufactured in the same manner as in Example 1.

[0215] (Comparative Example 2)

[0216] In the production of the substrate and the sealing layer, a polyimide film (manufactured by Toray Industries, Ltd., with a film thickness of 12.5 μm and a water vapor transmission rate of 161 g / (m 2 ·day), emissivity 0.95, thermal conductivity 0.29 W / mK, flexural modulus 3.5 GPa), a thermoelectric conversion module was manufactured in the same manner as in Example 1, except for the above.

[0217] (Comparative Example 3)

[0218] In the production of the substrate, a polyimide film (manufactured by Toray Industries, Ltd., film thickness 25 μm, water vapor transmission rate 76 g / (m 2 ·day), emissivity 0.95, thermal conductivity 0.29W / mK, flexural modulus 3.5GPa) instead of polyethylene naphthalate film, and in the manufacture of the sealing layer, aluminum foil (Mitsubishi Aluminum Co., Ltd., film thickness 25μm, water vapor transmission rate 0.001g / (m 2 A thermoelectric conversion module was manufactured in the same manner as in Example 1 except that the polyethylene naphthalate film was replaced with a film having an emissivity of 0.04 and a thermal conductivity of 204 W / mK.

[0219] (Comparative Example 4)

[0220] In the production of the substrate and the sealing layer, a polyethylene naphthalate film (manufactured by Toyobo Co., Ltd., with a film thickness of 188 μm and a water vapor transmission rate of 0.9 g / (m 2 ·day), emissivity 0.93, thermal conductivity 0.33 W / mK, flexural modulus 2.3 GPa), a thermoelectric conversion module was manufactured in the same manner as in Example 1, except for the above.

[0221] (Evaluation of Thermoelectric Conversion Modules)

[0222] The thermoelectric conversion modules of Examples 1 to 6 and Comparative Examples 1 to 4 were evaluated by the following method. The results are shown in Tables 1 and 2.

[0223] <Evaluation of Flexibility>

[0224] The manufactured thermoelectric conversion modules were bent, and those that were easily bendable and had excellent flexibility were rated A, those that were bendable and had sufficient flexibility were rated B, and those that were difficult to bend and had poor flexibility were rated C.

[0225] <Output Evaluation>

[0226] The heat transfer portion of the thermoelectric conversion module was placed in contact with a 100°C hot plate to generate a temperature difference within each thermoelectric conversion element. The maximum output of the thermoelectric conversion module was evaluated using a source meter (Keithley 2612B manufactured by Techtronics). The maximum output of the thermoelectric conversion module in Comparative Example 1 was set to 100, and the maximum output of each thermoelectric conversion module was evaluated.

[0227] <Evaluation of long-term reliability>

[0228] The thermoelectric conversion module was left to stand in an environment of 85°C and 85% humidity for a specified period of time. The module's maximum output was then evaluated using a source meter (Keithley 2612B, manufactured by Techtronics). The time it took for the output to fall below 20% of its initial value was calculated and used as the reliability evaluation result.

[0229] Table 1

[0230]

[0231] Table 2

[0232]

[0233] As shown in Tables 1 and 2, in Examples 1 to 6, thermoelectric conversion modules with high output, high long-term reliability, and good flexibility were obtained. In contrast, in Comparative Example 1 without a sealing layer and in Comparative Example 2 with a sealing layer having a water vapor transmission rate exceeding 100 g / (m 2 In Comparative Example 2 (with a sealing layer thickness of 150 μm), the n-type thermoelectric conversion element rapidly transitioned to p-type, resulting in poor long-term reliability. Furthermore, in Comparative Example 3, where the sealing layer had a thermal conductivity of less than 0.01 W / mK and an emissivity of less than 0.70, the temperature gradient in the thermoelectric conversion section was insufficient, resulting in poor maximum output. Furthermore, in Comparative Example 4, where the sealing layer thickness exceeded 150 μm, flexibility was poor.

[0234] Explanation of symbols

[0235] 1, 1A, 1b…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, 8…Sealing layer, 9…Adhesive layer, 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…Spacing, R1…Thermoelectric conversion region, R2…Conductive region, T1…Thickness, T2, T3…Length

Claims

1. A thermoelectric conversion module comprising: a substrate having a first major surface and a second major surface located on an opposite side of the first major surface; a thermoelectric conversion portion located on the first main surface; a sealing layer located on the thermoelectric conversion portion; a first heat conducting portion and a second heat conducting portion located on the second main surface and adjacent to each other along a first direction perpendicular to the thickness direction of the substrate; as well as On the second main surface, a heat insulating member is located at least between the first heat conducting portion and the second heat conducting portion, The thermoelectric conversion portion includes a p-type thermoelectric conversion element and an n-type thermoelectric conversion element arranged along the first direction, wherein a first end portion of the p-type thermoelectric conversion element in the first direction contacts a first end portion of the n-type thermoelectric conversion element in the first direction and overlaps with the thermal insulation member in the thickness direction. In the thickness direction, the first heat conducting portion overlaps with the 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 the second end portion of the n-type thermoelectric conversion element in the first direction, and the sealing layer has a thickness of 5 μm to 150 μm in the thickness direction and a heat release rate of 100 g / (m 2 ·day) or less, wherein the emissivity of the sealing layer is 0.70 to 0.99, and the thermal conductivity of the sealing layer is 0.01 W / mK to 50 W / mK.

2. The thermoelectric conversion module according to claim 1, wherein The sealing layer has a 0.1 g / (m 2 ·day) and above and 100g / (m 2 ·day) or less water vapor transmission rate.

3. The thermoelectric conversion module according to claim 1 or 2, wherein: A difference in linear expansion coefficient between the first heat conducting portion and the heat insulating member, and a difference in linear expansion coefficient between the second heat conducting portion and the heat insulating member are each 100 ppm / K or less.

4. The thermoelectric conversion module according to claim 1 or 2, wherein: The p-type thermoelectric conversion element and the n-type thermoelectric conversion element each have a thickness of 3 μm or more and 30 μm or less.

5. The thermoelectric conversion module according to claim 1 or 2, wherein: The linear expansion coefficient of each of the first heat conducting portion and the second heat conducting portion is 100 ppm / K or more and 200 ppm / K or less, and the linear expansion coefficient of the heat insulating member is 200 ppm / K or less.

6. 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 greater than or equal to 0.5 mm and less than or equal to 1.5 mm.

7. 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 W / mK or more and 5 W / mK or less. The thermal conductivity of the thermal insulation member is greater than or equal to 0.02 W / mK and less than or equal to 0.05 W / mK.

8. The thermoelectric conversion module according to claim 1 or 2, wherein: The invention further includes a heat dissipation member located on the second main surface, wherein the heat dissipation member surrounds the first heat conduction portion, the second heat conduction portion, and the heat insulating member when viewed in the thickness direction.

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

10. 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, and the second thermoelectric conversion portion includes a second p-type thermoelectric conversion element and a second n-type thermoelectric conversion element arranged along the first direction. The first end portion of the second p-type thermoelectric conversion element in the first direction contacts the first end portion 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 extend along the second direction, respectively. In the thickness direction, the first heat conducting portion overlaps with the 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 conduction 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.

11. The thermoelectric conversion module according to claim 10, 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.

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

13. A method for manufacturing a thermoelectric conversion module, comprising: In a first step, a first heat conducting portion, a second heat conducting portion, and a heat insulating member are formed on one main surface of the substrate; In a second step, a first layer containing a p-type thermoelectric conversion material is formed 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; a fourth step of forming a p-type thermoelectric conversion element and an n-type thermoelectric conversion element in a portion of the p-type thermoelectric conversion layer by dripping a dopant solution onto the portion after the third step; A fifth step is to dispose a sealing layer on the other main surface of the substrate so as to cover the p-type thermoelectric conversion element and the n-type thermoelectric conversion element after the fourth step. The first heat conducting portion and the second heat conducting portion are adjacent to each other along a first direction perpendicular to the thickness direction of the substrate, the first end portion of the p-type thermoelectric conversion element in the first direction is in contact with the first end portion of the n-type thermoelectric conversion element in the first direction, and overlap with the heat insulating member in the thickness direction. In the thickness direction, the first heat conducting portion overlaps with the second end portion of the p-type thermoelectric conversion element in the first direction, and in the thickness direction, the second heat conducting portion overlaps with the second end portion of the n-type thermoelectric conversion element in the first direction. The sealing layer has a thickness of 5 μm or more and 150 μm or less in the thickness direction and a heat release rate of 100 g / (m 2 The sealing layer has a water vapor transmission rate of not more than 0.1 W / day, an emissivity of not less than 0.70 and not more than 0.99, and a thermal conductivity of not less than 0.01 W / mK and not more than 50 W / mK.

14. The manufacturing method according to claim 13, wherein: The sealing layer has a 0.1 g / (m 2 ·day) and above and 100g / (m 2 ·day) or less water vapor transmission rate.

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