Thermoelectric conversion module

Abstract

The present application provides a thermoelectric conversion module having further improved thermoelectric properties, comprising a substrate and a thermoelectric element layer formed of a thermoelectric semiconductor composition, wherein the thermoelectric semiconductor composition comprises a thermoelectric semiconductor material, a heat-resistant resin A, and an ionic liquid and / or an inorganic ionic compound, and the thermal resistance of the substrate is 0.35 K / W or less.

Description

Technical Field

[0001] This invention relates to thermoelectric conversion modules. Background Technology

[0002] Thermoelectric conversion modules, which utilize thermoelectric conversion materials with thermoelectric effects such as Seebeck effect and Peltier effect to directly convert heat energy into electrical energy, have long been considered as an effective means of recovering unused emission heat energy generated from fossil fuel resources used in buildings, factories, etc., in the form of heat sources.

[0003] As for the aforementioned thermoelectric conversion module, a so-called π-type thermoelectric conversion element is known. The π-type is configured as follows: a pair of electrodes spaced apart are disposed on a substrate. For example, a P-type thermoelectric element is disposed on one electrode, and an N-type thermoelectric element is disposed on the other electrode, also spaced apart. The upper surfaces of the thermoelectric materials of both electrodes are connected to the electrodes of the opposing substrate. Additionally, a so-called in-plane type thermoelectric conversion element is known. The in-plane type is configured as follows: P-type and N-type thermoelectric elements are alternately disposed along the in-plane direction of the substrate. For example, the lower portions of the junction between the two thermoelectric elements are connected in series via electrodes.

[0004] In recent years, there has been a demand for further improvements in thermoelectric performance, considering factors such as increased flexibility, miniaturization, and thinning of thermoelectric conversion modules. Among these demands, resin materials have been used as the substrate for the support structure used in thermoelectric conversion modules (Patent Documents 1, 2, etc.).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: International Publication No. 2016 / 104615

[0008] Patent Document 2: Japanese Patent Application Publication No. 2008-182160 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, for the polyimide film, polyamide film and other resin substrates used as support bodies for thermoelectric conversion modules in Patent Document 1, and the polyimide resin, polysulfone resin and other insulating resin substrates used as base layers for flexible substrates constituting flexible thermoelectric conversion elements in Patent Document 2, although they have heat resistance and flexibility, their thermal conductivity is low from the point of view of the original material properties derived from the resin. For example, even if the thickness is reduced to the mechanical strength limit of the thermoelectric conversion module, thermal resistance cannot be sufficiently suppressed, which hinders further improvement of thermoelectric performance.

[0011] In view of the above, the objective of the present invention is to provide a thermoelectric conversion module with further improved thermoelectric performance.

[0012] Methods for solving problems

[0013] In order to solve the above-mentioned problems, the inventors conducted in-depth research and found that by using a substrate with specific thermal resistance as the support body (hereinafter sometimes referred to as "substrate") of the thermoelectric conversion element constituting the thermoelectric conversion module, a thermoelectric conversion module with further improved thermoelectric performance can be obtained, thereby completing the present invention.

[0014] That is, the present invention provides the following (1) to (10).

[0015] (1) A thermoelectric conversion module comprising a substrate and a thermoelectric element layer formed of a thermoelectric semiconductor composition, wherein the thermoelectric semiconductor composition comprises a thermoelectric semiconductor material, a heat-resistant resin A, and an ionic liquid and / or an inorganic ionic compound, and the thermal resistance of the substrate is 0.35 K / W or less.

[0016] (2) The thermoelectric conversion module according to (1) above, wherein the substrate is formed of an insulator.

[0017] (3) The thermoelectric conversion module according to (1) or (2) above, wherein the substrate is flexible.

[0018] (4) The thermoelectric conversion module according to any one of (1) to (3) above, wherein the thermal conductivity of the substrate is 0.5 W / m·K or higher.

[0019] (5) The thermoelectric conversion module according to any one of (1) to (4) above, wherein the thickness of the substrate is 5 to 150 μm.

[0020] (6) The thermoelectric conversion module according to any one of (1) to (5) above, wherein the substrate comprises glass cloth and heat-resistant resin B.

[0021] (7) The thermoelectric conversion module according to (6) above, wherein the glass cloth is a glass woven cloth.

[0022] (8) The thermoelectric conversion module according to (6) above, wherein the heat-resistant resin B is epoxy resin or polyimide resin.

[0023] (9) The thermoelectric conversion module according to any one of (1) to (8) above, wherein the thermoelectric conversion module is composed of a π-type thermoelectric conversion element or an in-plane thermoelectric conversion element.

[0024] (10) The thermoelectric conversion module according to (9) above, wherein the configuration of the π-type thermoelectric conversion element or the in-plane thermoelectric conversion element is used for cooling.

[0025] The effects of the invention

[0026] According to the present invention, a thermoelectric conversion module with further improved thermoelectric performance can be provided. Attached Figure Description

[0027] Figure 1 This is a cross-sectional structural diagram used to illustrate an example of the configuration of the thermoelectric conversion module with a substrate used in this invention.

[0028] Figure 2 This is a cross-sectional structural diagram used to illustrate another example of the configuration of the thermoelectric conversion module with a substrate used in this invention.

[0029] Figure 3 This is a cross-sectional structural diagram used to illustrate the cooling characteristic evaluation unit of the thermoelectric conversion module manufactured in the embodiments of the present invention.

[0030] Symbol Explanation

[0031] 1: Thermoelectric conversion module

[0032] 2a: First substrate

[0033] 2b: Second substrate

[0034] 3a: Electrode 1

[0035] 3b: Second electrode

[0036] 4: P-type thermoelectric element layer

[0037] 5: N-type thermoelectric element layer

[0038] 11: Thermoelectric conversion module

[0039] 12a: First substrate

[0040] 12b: Second substrate

[0041] 13: First electrode

[0042] 14: P-type thermoelectric element layer

[0043] 15: N-type thermoelectric element layer

[0044] 21: Cooling Performance Evaluation Unit

[0045] 22: Thermoelectric conversion module

[0046] 23, 24: Measurement plates

[0047] 25, 26: Temperature controller

[0048] 27: Heat-absorbing surface

[0049] 28: Heat dissipation surface Detailed Implementation

[0050] [Thermoelectric Conversion Module]

[0051] The thermoelectric conversion module of the present invention comprises a substrate and a thermoelectric element layer formed of a thermoelectric semiconductor composition, wherein the thermoelectric semiconductor composition comprises a thermoelectric semiconductor material, a heat-resistant resin A, and an ionic liquid and / or an inorganic ionic compound, and the thermal resistance of the substrate is 0.35 K / W or less.

[0052] In the thermoelectric conversion module of the present invention, by making the thermal resistance of the substrate of the thermoelectric conversion element, such as the support body constituting the thermoelectric conversion module, less than 0.35 K / W, a larger temperature difference can be exhibited between the two sides of the thermoelectric conversion module.

[0053] It should be noted that the thermal resistance of the substrate mentioned in this specification refers to the thermal resistance caused by heat conduction. The thermal conductivity of the material is defined as λ [thermal conductivity of the substrate] (W / m·K), the length of the heat flow path is defined as L [thickness of the substrate] (m), and the cross-sectional area of ​​the heat flow path is defined as Ac [area of ​​the cross-section perpendicular to the thickness direction of the substrate] (m²). 2 When ), the thermal resistance Rc is expressed as Rc=L / λAc(K / W).

[0054] In the evaluation of the thermal resistance of the substrates in this specification, since the evaluation is conducted between substrates having the same heat flow path cross-sectional area Ac, the thermal resistance essentially depends on the thermal conductivity and thickness of the substrates.

[0055] Figure 1 This is a cross-sectional structural diagram illustrating an example of the configuration of the thermoelectric conversion module with a substrate used in this invention. The thermoelectric conversion module 1 is configured in the form of a so-called π-type thermoelectric conversion element, and includes a first substrate 2a and an opposing second substrate 2b, a P-type thermoelectric element layer 4 and an N-type thermoelectric element layer 5 formed between the first substrate 2a and the opposing second substrate 2b, a first electrode 3a formed on the first substrate 2a, and a second electrode 3b formed on the opposing second substrate 2b.

[0056] Similarly, Figure 2This is a cross-sectional view used to illustrate another example of the configuration of the thermoelectric conversion module with a substrate used in this invention. The thermoelectric conversion module 11 is configured in the form of a so-called in-plane thermoelectric conversion element, and is provided with a first substrate 12a and an opposing second substrate 12b, a P-type thermoelectric element layer 14 and an N-type thermoelectric element layer 15 formed between the first substrate 12a and the opposing second substrate 12b, and a first electrode 13 formed on the first substrate 12a.

[0057] <Substrate>

[0058] The thermoelectric conversion module of the present invention includes a substrate. As described above, for example, in the case of being configured as a π-type thermoelectric conversion element, it is preferable to include a second substrate having a second electrode opposite to a first substrate having a first electrode. Alternatively, in the case of being configured as an in-plane thermoelectric conversion element, the second substrate opposite to the first substrate having the first electrode may or may not include a substrate. Furthermore, the first substrate and the second substrate opposite to it may be the same or different, and multiple substrates may be used.

[0059] The thermal resistance of the substrate used in this invention is 0.35 K / W or less. When the thermal resistance exceeds 0.35 K / W, the heat dissipation of the substrate decreases, which affects the thermoelectric performance. The thermal resistance is preferably 0.30 K / W or less, more preferably 0.20 K / W or less, and even more preferably 0.15 K / W or less. When the thermal resistance is within this range, the heat dissipation of the substrate is improved, which affects the thermoelectric performance.

[0060] It should be noted that the substrate is only required to form and support the thermoelectric element layer, electrodes, etc. on its surface, and there are no particular restrictions. It is generally preferred that both the front and back surfaces are flat. As for the shape, it can be appropriately selected according to the application, such as cuboid, elliptical cylinder, or cylindrical.

[0061] The thermal conductivity of the substrate used in this invention is preferably 0.5 W / m·K or higher, more preferably 1.5 W / m·K or higher, even more preferably 2.5 to 30.0 W / m·K, and particularly preferably 3.0 to 20.0 W / m·K. When the thermal conductivity is within this range, it is easy to adjust the value of the thermal resistance to the range defined by this invention, and it will affect the improvement of thermoelectric performance.

[0062] The substrate used in this invention is preferably formed of an insulator. By making the substrate an insulator, electrical effects on thermoelectric element layers, electrodes, etc., can be suppressed, and degradation of thermoelectric performance can be prevented.

[0063] In this specification, an insulator refers to an insulator having a strength of 10. 8 Materials with a volume resistivity of Ω·m or higher.

[0064] The thickness of the substrate is preferably 5–150 μm, more preferably 8–120 μm, further preferably 10–100 μm, and particularly preferably 10–70 μm. When the substrate thickness is within this range, mechanical strength can be obtained for use as a support for thermoelectric element layers, etc., and the reduction of thermoelectric performance can be suppressed, which is related to the improvement of thermoelectric performance.

[0065] From the viewpoint of obtaining flexibility and heat resistance, the substrate used in this invention preferably includes glass cloth and heat-resistant resin B.

[0066] Examples of glass cloths include woven glass cloth and nonwoven glass cloth. Woven glass cloth and nonwoven glass cloth can also be used in combination.

[0067] From the perspective of improving thermal conductivity, glass fabric is preferred.

[0068] Glass fabric is an aggregate of glass fibers, woven into yarns that bundle the glass fibers together. Various weaving methods can be employed, including plain weave, basket weave, satin weave, and twill weave. From a thermal conductivity perspective, plain weave is preferred.

[0069] Examples of glass materials used to construct glass fabrics include: E-glass, C-glass, A-glass, S-glass, T-glass, D-glass, NE-glass, quartz, low-dielectric-constant glass, and high-dielectric-constant glass. Among these, E-glass is preferred from the perspective of thermal conductivity and electrical insulation.

[0070] There are no particular limitations on the heat-resistant resin B, and examples include epoxy resins, polyamide-imide resins, and polyimide resins that are crystalline or liquid crystallizable. Among these, epoxy resins and polyimide resins are preferred from the viewpoint of heat resistance and versatility. Epoxy resins are even more preferred. Epoxy resins are not limited, and examples include bisphenol type, phenolic varnish type, dicyclopentadiene type, biphenyl type, and tetrafunctional type.

[0071] Inorganic filler materials can also be further included in the substrate. From the perspective of controlling mechanical strength and thermal conductivity, the following inorganic filler materials can be used appropriately: oxides such as titanium dioxide, aluminum hydroxide, aluminum oxide, magnesium oxide and silicon dioxide, hydroxides such as magnesium hydroxide, nitrides such as boron nitride, aluminum nitride, and silicon nitride, and carbides such as silicon carbide and boron carbide.

[0072] As a commercially available substrate that satisfies the thermal resistance limitation of the present invention, examples include a high thermal conductivity substrate with copper foil bonded to it (manufactured by Toshiaki Kogyo Co., Ltd., product name: CS-3295). The high thermal conductivity substrate monomer is formed from glass cloth and epoxy resin, and has a very high thermal conductivity of 3.0 W / m·K.

[0073] There are no particular restrictions on the manufacture of the substrate. For example, it can be manufactured by impregnating the glass fabric with a high thermal conductivity resin such as epoxy resin and pre-drying it to obtain a prepreg. After cutting the prepreg into a given size, a given number of sheets are stacked. In the case of copper-clad laminate, copper foil is placed on its outer side, and it is heated and pressed under given conditions to form an integral piece.

[0074] The preferred substrate has a 5% weight loss temperature of 250°C or higher, more preferably 400°C or higher, as measured in thermogravimetric analysis. The heating dimensional change rate measured at 200°C according to JIS K7133 (1999) is preferably 0.5% or less, more preferably 0.3% or less. The linear expansion coefficient in the planar direction, measured according to JIS K7197 (2012), is 0.1 ppm·°C. -1 ~50ppm·℃ -1 More preferably 0.1 ppm·℃ -1 ~30ppm·℃ -1 .

[0075] <Thermoelectric Element Layer>

[0076] The thermoelectric element layer used in this invention is formed from a thermoelectric semiconductor composition comprising a thermoelectric semiconductor material, a heat-resistant resin A, and an ionic liquid and / or an inorganic ionic compound.

[0077] (Thermoelectric semiconductor materials)

[0078] The thermoelectric semiconductor material used in the thermoelectric element layer is preferably pulverized to a given size using a micro-pulverizing device or the like to form thermoelectric semiconductor particles for use (hereafter, the thermoelectric semiconductor material is sometimes referred to as "thermoelectric semiconductor particles").

[0079] In the thermoelectric element layers used in this invention, the thermoelectric semiconductor materials constituting the P-type and N-type thermoelectric element layers can be any materials capable of generating a thermoelectric electromotive force by imparting a temperature difference; there are no particular limitations. For example, bismuth-telluride thermoelectric semiconductor materials such as P-type bismuth telluride and N-type bismuth telluride can be used; telluride thermoelectric semiconductor materials such as GeTe and PbTe can be used; antimony-telluride thermoelectric semiconductor materials can be used; zinc-antimony thermoelectric semiconductor materials such as ZnSb, Zn3Sb2, and Zn4Sb3 can be used; silicon-germanium thermoelectric semiconductor materials such as SiGe can be used; bismuth selenide thermoelectric semiconductor materials such as Bi2Se3 can be used; β-FeSi2, CrSi2, and MnSi can be used. 1.73 Silicide-based thermoelectric semiconductor materials such as Mg2Si; oxide-based thermoelectric semiconductor materials; Hassler alloy materials such as FeVAl, FeVAlSi, and FeVTiAl; and sulfide-based thermoelectric semiconductor materials such as TiS2.

[0080] The thermoelectric semiconductor material used in this invention is preferably a bismuth-telluride thermoelectric semiconductor material such as P-type bismuth telluride or N-type bismuth telluride.

[0081] For the aforementioned p-type bismuth telluride, the charge carriers are holes, and the Seebeck coefficient is positive. For example, it is preferable to use Bi... X Te3Sb 2-X The compound is represented by X. In this case, X is preferably 0 < X ​​≤ 0.8, more preferably 0.4 ≤ X ≤ 0.6. When X is greater than 0 and less than 0.8, the Seebeck coefficient and electrical conductivity increase, and the characteristics as a p-type thermoelectric conversion material can be maintained, which is therefore preferred.

[0082] Furthermore, for the aforementioned N-type bismuth telluride, the charge carriers are electrons, and the Seebeck coefficient is negative. For example, Bi₂Te₂ is preferred. 3-Y Se Y The compound is indicated. In this case, Y is preferably 0 ≤ Y ≤ 3 (when Y = 0: Bi2Te3), and more preferably 0.1 < Y ​​≤ 2.7. When Y is 0 or more and 3 or less, the Seebeck coefficient and electrical conductivity increase, and the characteristics as an N-type thermoelectric conversion material can be maintained, so it is preferred.

[0083] The amount of thermoelectric semiconductor particles in the above-mentioned thermoelectric semiconductor composition is preferably 30 to 99% by mass, more preferably 50 to 96% by mass, and even more preferably 70 to 95% by mass. When the amount of thermoelectric semiconductor particles is within the above range, the Seebeck coefficient (the absolute value of the Peltier coefficient) is large, and the decrease in electrical conductivity can be suppressed, with only the thermal conductivity decreasing. Therefore, a film exhibiting high thermoelectric performance while having sufficient film strength and flexibility can be obtained, which is therefore preferred.

[0084] The average particle size of the thermoelectric semiconductor particles is preferably 10 nm to 200 μm, more preferably 10 nm to 30 μm, even more preferably 50 nm to 10 μm, and particularly preferably 1 to 6 μm. Within the above range, they are easy to disperse uniformly, which can improve electrical conductivity.

[0085] There are no particular limitations on the method of obtaining thermoelectric semiconductor particles from thermoelectric semiconductor materials. They can be pulverized to a given size using known micro-pulverizing devices such as jet mills, ball mills, bead mills, colloid mills, conical ball mills, disc mills, roller mills, grinding mills, hammer mills, particle mills, Willie mills, and roller mills.

[0086] It should be noted that the average particle size of the thermoelectric semiconductor particles can be obtained by measuring it using a laser diffraction particle size analyzer (Mastersizer 3000, manufactured by Malvern), and is the median of the particle size distribution.

[0087] Furthermore, the thermoelectric semiconductor particles are preferably subjected to an annealing treatment (hereinafter sometimes referred to as "annealing treatment A"). Annealing treatment A improves the crystallinity of the thermoelectric semiconductor particles. Furthermore, since the surface oxide film of the thermoelectric semiconductor particles is removed, the Seebeck coefficient (the absolute value of the Peltier coefficient) of the thermoelectric conversion material increases, further improving the thermoelectric performance index. Annealing treatment A is not particularly limited, but it is preferably carried out before the preparation of the thermoelectric semiconductor composition in a manner that does not adversely affect the thermoelectric semiconductor particles, under controlled gas flow conditions such as nitrogen or argon, similarly under a reducing gas atmosphere such as hydrogen, or under vacuum conditions. It is more preferably carried out under a mixed gas atmosphere of inactive and reducing gases. Specific temperature conditions depend on the thermoelectric semiconductor particles used, but it is generally preferred to carry out the treatment at a temperature below the melting point of the particles and at 100–1500°C for several minutes to tens of hours.

[0088] (Heat-resistant resin A)

[0089] The heat-resistant resin A used in this invention functions as a binder between thermoelectric semiconductor particles to improve the flexibility of the thermoelectric element layer. There are no particular limitations on the heat-resistant resin A used; it is a heat-resistant resin A whose properties, such as mechanical strength and thermal conductivity, are maintained without damage when the thermoelectric semiconductor particles undergo crystal growth through annealing or other processes on a thin film formed from the thermoelectric semiconductor composition.

[0090] Examples of heat-resistant resin A mentioned above include: polyamide resin, polyamide-imide resin, polyimide resin, polyether-imide resin, and polybenzo[a]pyrene resin. The heat-resistant resin A can be categorized into several types, including azole resin, polybenzimidazole resin, epoxy resin, and copolymers having the chemical structures of these resins. The aforementioned heat-resistant resin A can be used alone or in combination of two or more. From the viewpoint of higher heat resistance and without adversely affecting the crystallization growth of thermoelectric semiconductor particles in the film, polyamide resin, polyamide-imide resin, polyimide resin, and epoxy resin are preferred; from the viewpoint of excellent flexibility, polyamide resin, polyamide-imide resin, and polyimide resin are more preferred. When using a polyimide film as the support, from the viewpoint of good adhesion to the polyimide film, polyimide resin is more preferred as the heat-resistant resin A. It should be noted that in this invention, the term "polyimide resin" is a general term for polyimide and its precursors.

[0091] Preferably, the decomposition temperature of the heat-resistant resin A is 300°C or higher. When the decomposition temperature is within the above range, as described later, even if the film formed from the thermoelectric semiconductor composition is annealed, its function as an adhesive is not lost, and the flexibility of the thermoelectric element layer can be maintained.

[0092] Furthermore, the weight loss rate of the aforementioned heat-resistant resin A at 300°C, obtained based on thermogravimetric analysis (TG), is preferably 10% or less, more preferably 5% or less, and even more preferably 1% or less. When the weight loss rate is within the above range, as described later, even if the film formed from the thermoelectric semiconductor composition is annealed, its function as an adhesive is not lost, and the flexibility of the thermoelectric element layer can be maintained.

[0093] The amount of the heat-resistant resin A in the thermoelectric semiconductor composition is preferably 0.1 to 40% by mass, more preferably 0.5 to 20% by mass, and even more preferably 1 to 20% by mass. When the amount of the heat-resistant resin A is within the above range, a film that balances high thermoelectric performance and film strength can be obtained.

[0094] (Ionic liquid)

[0095] The ionic liquid that can be included in the thermoelectric semiconductor composition is a molten salt composed of cations and anions, referring to a salt that can exist as a liquid in any temperature range of -50°C to 400°C. In other words, the ionic liquid is an ionic compound with a melting point in the range of -50°C to 400°C. The melting point of the ionic liquid is preferably -25°C to 200°C, more preferably 0°C to 150°C. Ionic liquids have the following characteristics: extremely low vapor pressure and non-volatility, excellent thermal and electrochemical stability, low viscosity, and high ionic conductivity, thus they can effectively suppress the decrease in conductivity between thermoelectric semiconductor materials as conductive additives. In addition, ionic liquids exhibit high polarity based on aprotic ionic structures and have excellent compatibility with heat-resistant resin A, thus enabling the conductivity of the thermoelectric conversion material to become uniform.

[0096] Ionic liquids can be known or commercially available. Examples include ionic liquids composed of a cation and an anion, wherein the cation is pyridine. Pyrimidine pyrazole pyrrolidine Piperidine imidazole Nitrogen-containing cyclic cationic compounds and their derivatives; tetraalkylammonium ammonium cations and their derivatives; Trialkyl Tetraalkyl wait Cations and their derivatives; lithium cations and their derivatives, etc., wherein the anionic component is Cl. - ,Br - I - AlCl4 - Al2Cl7 - BF4 - PF6 - ClO4 - NO3 - CH3COO - CF3COO - CH3SO3 - CF3SO3 - (FSO2)2N - (CF3SO2)2N - (CF3SO2)3C - AsF6 - SbF6 - NbF6 - TaF6 - F(HF) n -(CN)2N - C4F9SO3 - (C2F5SO2)2N - C3F7COO - (CF3SO2)(CF3CO)N - wait.

[0097] From the perspectives of high-temperature stability, compatibility with thermoelectric semiconductor materials and resins, and suppression of the decrease in conductivity between thermoelectric semiconductor materials, the cationic component of the aforementioned ionic liquid preferably includes pyridine. Cations and their derivatives, imidazole At least one of a cation and its derivatives.

[0098] Pyridine is included as a cationic component. Specific examples of ionic liquids containing cations and their derivatives include: 4-methylbutylpyridine chloride, 3-methylbutylpyridine chloride, 4-methylhexylpyridine chloride, 3-methylhexylpyridine chloride, 4-methyloctylpyridine chloride, 3-methyloctylpyridine chloride, 3,4-dimethylbutylpyridine chloride, 3,5-dimethylbutylpyridine chloride, 4-methylbutylpyridine tetrafluoroborate, 4-methylbutylpyridine hexafluorophosphate, 1-butylpyridine bromide, 1-butyl-4-methylpyridine bromide, and 1-butyl-4-methylpyridine hexafluorophosphate. These can be used individually or in combination of two or more. Preferably, 1-butyl-4-methylpyridine bromide, 1-butylpyridine bromide, and 1-butyl-4-methylpyridine hexafluorophosphate are used.

[0099] In addition, it contains imidazole as a cationic component. Specific examples of ionic liquids containing cations and their derivatives include: [1-butyl-3-(2-hydroxyethyl)imidazolium bromide], [1-butyl-3-(2-hydroxyethyl)imidazolium tetrafluoroborate], 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium chloride, 1-decyl... 1-3-methylimidazolium bromide, 1-dodecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-methyl-3-butylimidazolium methanesulfonate, 1,3-dibutylimidazolium methanesulfonate, etc. Among these, [1-butyl-3-(2-hydroxyethyl)imidazolium bromide] and [1-butyl-3-(2-hydroxyethyl)imidazolium tetrafluoroborate] are preferred.

[0100] The conductivity of the aforementioned ionic liquid is preferably 10. -7 When the ionic conductivity is above S / cm, it can effectively suppress the decrease in conductivity between thermoelectric semiconductor materials as a conductive aid.

[0101] Furthermore, it is preferable that the decomposition temperature of the aforementioned ionic liquid is 300°C or higher. When the decomposition temperature is within the aforementioned range, as described later, the effect as a conductive aid can be maintained even when the thin film formed from the thermoelectric semiconductor composition has undergone annealing treatment.

[0102] Furthermore, the weight loss rate of the aforementioned ionic liquid at 300°C, obtained based on thermogravimetric analysis (TG), is preferably 10% or less, more preferably 5% or less, and even more preferably 1% or less. When the weight loss rate is within the above range, as described later, even when the thin film formed from the thermoelectric semiconductor composition has undergone annealing treatment, it is possible to maintain its effect as a conductive aid.

[0103] The amount of ionic liquid incorporated in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and even more preferably 1.0 to 20% by mass. When the amount of ionic liquid is within the above range, the decrease in conductivity can be effectively suppressed, thereby obtaining a film with high thermoelectric properties.

[0104] (Inorganic ionic compounds)

[0105] The inorganic ionic compounds used in this invention are compounds composed of at least cations and anions. These inorganic ionic compounds are characterized by being solid at room temperature, having a melting point at any temperature within the range of 400–900°C, and high ionic conductivity, and can be used as conductive additives to suppress the decrease in conductivity between thermoelectric semiconductor particles.

[0106] The amount of the aforementioned inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and even more preferably 1.0 to 10% by mass. When the amount of the aforementioned inorganic ionic compound is within the above range, the decrease in conductivity can be effectively suppressed, resulting in a film with improved thermoelectric properties.

[0107] It should be noted that, when inorganic ionic compounds and ionic liquids are used in combination, the total content of inorganic ionic compounds and ionic liquids in the above-mentioned thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and even more preferably 1.0 to 10% by mass.

[0108] The thickness of the thermoelectric element layer is not particularly limited, but from the viewpoint of thermoelectric performance and film strength, it is preferably 100nm to 1000μm, more preferably 300nm to 600μm, and even more preferably 5 to 400μm.

[0109] For P-type and N-type thermoelectric element layers formed from thin films of thermoelectric semiconductor compositions, further annealing (hereinafter sometimes referred to as "annealing treatment B") is preferable. Annealing treatment B stabilizes the thermoelectric properties and induces crystal growth of the thermoelectric semiconductor particles in the thin film, further improving the thermoelectric performance. Annealing treatment B is not particularly limited and is typically performed in a controlled atmosphere of inert gases such as nitrogen or argon, a reducing atmosphere, or under vacuum conditions. While the specific treatment depends on the heat resistance temperature of the resin and ionic compound used, it can be carried out at 100–500°C for several minutes to tens of hours.

[0110] <Electrode>

[0111] The thermoelectric conversion module of the present invention preferably includes a first electrode. In the case of a π-type thermoelectric conversion element, it is preferable to further include a second electrode on a second substrate opposite to the first substrate having the first electrode. The first electrode and the second electrode on the second substrate opposite the first substrate may be the same or different. Furthermore, in the case of an in-plane thermoelectric conversion element, only the first electrode is required; the second electrode may or may not be present.

[0112] There are no particular limitations on the metallic materials used for the first and second electrodes, and each is preferably made of copper, gold, nickel, aluminum, rhodium, platinum, chromium, palladium, stainless steel, molybdenum, or an alloy containing any of these metals. Furthermore, it can be not only a single layer, but also a multilayer structure formed by combining multiple materials.

[0113] The thickness of each of the first and second electrode layers is preferably 10 nm to 200 μm, more preferably 30 nm to 150 μm, and even more preferably 50 nm to 120 μm. When the thickness of the first and second electrode layers is within the above range, the conductivity is high, the resistance is low, and sufficient strength as an electrode can be obtained.

[0114] The first electrode and the second electrode are formed using the aforementioned metallic material. Methods for forming the first electrode and the second electrode include: after setting an unpatterned electrode on a substrate, processing it into a given pattern shape using known physical or chemical processing methods, primarily photolithography, or a combination thereof; or methods for directly forming electrode patterns using screen printing, inkjet printing, or similar methods.

[0115] Methods for forming electrodes without patterns include: vacuum evaporation, sputtering, ion plating, and other PVD (physical vapor deposition) processes; thermal CVD, atomic layer evaporation (ALD), and other CVD (chemical vapor deposition) processes; various coating methods such as dip coating, spin coating, spray coating, gravure coating, mold coating, and scraper coating; wet processes such as electrodeposition; silver halide, electrolytic plating, chemical plating; and metal foil stacking. The appropriate method can be selected based on the electrode material.

[0116] From a thermoelectric performance perspective, high electrical and thermal conductivity are required; therefore, electrodes obtained by deposition methods such as plating or vacuum deposition are preferred. From the perspective of easily obtaining high electrical and thermal conductivity, vacuum deposition methods such as vacuum evaporation and sputtering, as well as electroplating and electroless plating, are preferred. Depending on the required size and dimensional accuracy of the pattern, patterns can also be easily formed using hard masks such as metal masks.

[0117] The thermoelectric conversion module of the present invention is not particularly limited, but it is preferably constructed using a π-type thermoelectric conversion element or an in-plane thermoelectric conversion element. Furthermore, as an alternative, it is preferably constructed using a π-type thermoelectric conversion element or an in-plane thermoelectric conversion element for cooling applications. Additionally, as another alternative, it is preferably constructed using a π-type thermoelectric conversion element or an in-plane thermoelectric conversion element for power generation applications.

[0118] (Manufacturing method of thermoelectric conversion module)

[0119] The thermoelectric conversion module of the present invention can be manufactured by a method including the following steps: a step of forming an electrode on a substrate (hereinafter sometimes referred to as the "electrode forming step"); a step of coating the above-mentioned thermoelectric semiconductor composition and drying it to form a thermoelectric element layer (hereinafter sometimes referred to as the "thermoelectric element layer forming step"); then, a step of annealing the thermoelectric element layer (hereinafter sometimes referred to as the "annealing step"); and a step of further bonding the annealed substrate to other substrates (hereinafter sometimes referred to as the "bonding step").

[0120] The following describes the steps included in the manufacturing method of the thermoelectric conversion module of the present invention.

[0121] (Electrode forming process)

[0122] The electrode forming process is, for example, a process of forming a pattern made of the aforementioned metal material on a first substrate. The method of forming on the substrate and the method of forming the pattern are as described above. In addition, especially in the case of manufacturing the aforementioned π-type thermoelectric conversion module, a process of forming a pattern made of the aforementioned metal material on a second substrate opposite to the aforementioned first substrate is included.

[0123] (Thermoelectric element layer formation process)

[0124] The thermoelectric element layer formation process is the process of coating a thermoelectric semiconductor composition onto, for example, an electrode. Examples of methods for coating the thermoelectric semiconductor composition onto the electrode on the first substrate include well-known methods such as screen printing, flexographic printing, gravure printing, spin coating, dip coating, die coating, spray coating, rod coating, and squeegee coating, without particular limitation. When the coating is to be patterned, screen printing or slot die coating, which allow for easy pattern formation using a screen with the desired pattern, are preferred.

[0125] Next, by drying the obtained coating, a thermoelectric element layer can be formed. As a drying method, existing and known drying methods such as hot air drying, hot roller drying, and infrared irradiation can be used. The heating temperature is typically 80–150°C, and the heating time varies depending on the heating method, but is usually from a few seconds to tens of minutes.

[0126] Furthermore, when a solvent is used in the preparation of the thermoelectric semiconductor composition, the heating temperature is not particularly limited as long as it is within the temperature range that can dry the solvent used.

[0127] It should be noted that the same applies to the case where the thermoelectric semiconductor composition is coated on the electrodes of the second substrate.

[0128] As another example of the thermoelectric element layer formation process, a method can be given in which the thermoelectric element layer is first made into a chip of thermoelectric conversion material, and multiple chips are placed on a given electrode on a substrate and bonded together.

[0129] For example, a chip made of a thermoelectric semiconductor composition can be manufactured by the following method as a method for producing a chip of thermoelectric conversion material.

[0130] First, a sacrificial layer is formed on a substrate such as glass, alumina, or silicon. A thermoelectric element layer (hereinafter sometimes referred to as a "chip of thermoelectric conversion material") is then formed on the sacrificial layer using the method described above. Next, the resulting chip of thermoelectric conversion material is annealed (according to the conditions of annealing process B), and the chip of thermoelectric conversion material is peeled off from the sacrificial layer on the substrate, thereby forming a monolithic wafer and manufacturing the chip of thermoelectric conversion material.

[0131] As a sacrificial layer, resins such as polymethyl methacrylate or polystyrene, or release agents such as fluorinated or silicone release agents can be used.

[0132] (Annealing process)

[0133] The annealing process is, for example, a process of annealing the thermoelectric element layer in the form of the first substrate, the electrode, and the thermoelectric element layer obtained above in sequence. The annealing process can be performed according to the annealing process B described above.

[0134] (Lamination process)

[0135] The bonding process is, for example, a process of bonding a first substrate having electrode and thermoelectric element layers obtained in the above-mentioned annealing process to an opposing second substrate or a second substrate having a second electrode to manufacture a thermoelectric conversion module.

[0136] As the adhesive used for the above-mentioned bonding, when the second substrate has the second electrode, conductive paste can be cited as an example. Examples of conductive pastes include copper paste, silver paste, and nickel paste. When an adhesive is used, epoxy resin, acrylic resin, and urethane resin can be cited as examples.

[0137] Alternatively, in the absence of a second substrate having a second electrode, a resin material can be used. Preferably, the resin material comprises a polyolefin resin, an epoxy resin, or an acrylic resin. Furthermore, the aforementioned resin material preferably possesses adhesive properties, low water vapor permeability, and insulating properties. In this specification, adhesive properties refer to the resin material having adhesiveness, bonding properties, and pressure-sensitive adhesiveness that allows it to bond upon initial application.

[0138] Methods for applying adhesive to a substrate include well-known methods such as screen printing and dispensing.

[0139] In the bonding process, when a solder material layer is used for bonding with the electrode, a solder receiving layer can be used to improve the bonding strength.

[0140] For example, the method for forming a solder receiving layer on a chip of thermoelectric conversion material obtained by the above manufacturing method is as follows.

[0141] After a solder receiving layer is formed on all surfaces of a chip with a thermoelectric conversion material having an upper surface, a lower surface, and a side surface, the solder receiving layer formed on the side surface of the thermoelectric conversion material chip is completely or partially removed, thereby forming a solder receiving layer.

[0142] The solder receiving layer preferably comprises a metallic material. The metallic material is preferably at least one selected from gold, silver, rhodium, platinum, chromium, palladium, tin, nickel, and alloys containing any of these metals. More preferably, it is a double-layer structure of gold, silver, nickel, or tin and gold, nickel and gold. From the viewpoints of material cost, high thermal conductivity, and bonding stability, silver is further preferred.

[0143] From the viewpoint of maintaining thermoelectric performance, the solder receiving layer is required to have high electrical conductivity and high thermal conductivity. Moreover, from the viewpoint of reducing the contact resistance at the interface with the chip of the thermoelectric conversion material, it is preferable to use a solder receiving layer obtained by plating or vacuum deposition.

[0144] As for the solder material constituting the above-mentioned solder material layer, appropriate selection can be made considering factors such as the heat resistance temperature of the resin film, the heat resistance of the resin A contained in the thermoelectric conversion material chip, as well as electrical conductivity and thermal conductivity. Examples include: Sn, Sn / Pb alloy, Sn / Ag alloy, Sn / Cu alloy, Sn / Sb alloy, Sn / In alloy, Sn / Zn alloy, Sn / In / Bi alloy, Sn / In / Bi / Zn alloy, Sn / Bi / Pb / Cd alloy, Sn / Bi / Pb alloy, Sn / Bi / Cd alloy, Bi / Pb alloy, Sn / Bi / Zn alloy, Sn / Bi alloy, Sn / Bi / Pb alloy, Sn / Pb / Cd alloy, Sn / Cd alloy, and other known materials. From the viewpoints of being lead-free and / or cadmium-free, having a low melting point, and good electrical and thermal conductivity, alloys such as 43Sn / 57Bi, 42Sn / 58Bi, 40Sn / 56Bi / 4Zn, 48Sn / 52In, and 39.8Sn / 52In / 7Bi / 1.2Zn are preferred.

[0145] As a method for applying solder material to the electrodes of a substrate, known methods such as screen printing and dispensing can be cited.

[0146] According to the manufacturing method of the thermoelectric conversion module of the present invention, a thermoelectric conversion module with flexibility and improved thermoelectric performance can be easily obtained.

[0147] Example

[0148] The invention will now be described in more detail by way of examples, but the invention is not limited to these examples.

[0149] The evaluation of the substrates used in the examples and comparative examples, and the evaluation of the thermoelectric performance of the fabricated thermoelectric conversion modules, were conducted using the following methods.

[0150] <Substrate Evaluation>

[0151] (a) Thermal conductivity and thermal resistance of the substrate

[0152] The thermal conductivity of the substrate was measured at 23°C using a GH-1 steady-state thermal conductivity measuring apparatus (Advance Riko) according to ASTM E1530, via a disk heat flow meter method. The results were based on the obtained thermal conductivity λ (W / m·K), substrate thickness L (m), and substrate cross-sectional area (the cross-sectional area of ​​the heat flow path) Ac (m²). 2 The thermal resistance Rc was calculated as follows: Rc = L / λAc (K / W).

[0153] <Thermoelectric Performance Evaluation>

[0154] (b) Resistance evaluation of the thermoelectric conversion module

[0155] The resistance between the lead electrodes of the obtained thermoelectric conversion module (module resistance) was measured using a low resistance measuring device (manufactured by Hioki Electric Co., Ltd., model: RM3545) in an environment of 25°C and 50% RH.

[0156] (c) Evaluation of the cooling characteristics of the thermoelectric conversion module

[0157] The cooling characteristics of the obtained thermoelectric conversion module were evaluated using a cooling characteristic evaluation unit.

[0158] Figure 3 This is a cross-sectional structural diagram used to illustrate the cooling characteristic evaluation unit of the thermoelectric conversion module used in the embodiment.

[0159] The cooling characteristic evaluation unit 21 consists of temperature measuring plates 23 and 24 with K-type thermocouples inserted on both sides of the thermoelectric conversion module 22, and temperature controllers 25 and 26. The module is pre-insulated under vacuum (vacuum degree: below 0.1 Pa) so that the temperature of the heat-absorbing surface 27 and the heat-dissipating surface 28 of the thermoelectric conversion module reaches 85°C, which is then adjusted by the temperature controllers 25 and 26. Then, a current is applied to the thermoelectric conversion module 22, and the temperature difference between the heat-absorbing surface 27 and the heat-dissipating surface 28 is measured. It should be noted that when the current is applied, the temperature controllers are used to maintain the temperature of the heat-absorbing surface 27 at 85°C.

[0160] (Example 1)

[0161] (1) Fabrication of thermoelectric semiconductor composition

[0162] (Fabrication of thermoelectric semiconductor particles)

[0163] Bismuth p-type telluride (Bi) used as a bismuth-telluride thermoelectric semiconductor material was milled using a planetary ball mill (Fritsch Japan, Premium line P-7). 0.4 Te3Sb 1.6Thermoelectric semiconductor particles T1 with an average particle size of 2.0 μm were produced by pulverizing the particles in a nitrogen atmosphere. (Made by High Purity Chemical Research Institute Co., Ltd., particle size: 90 μm)

[0164] In addition, N-type bismuth telluride Bi2Te3 (manufactured by Koujuku Chemical Research Institute Co., Ltd., particle size: 90 μm), which is a bismuth-telluride thermoelectric semiconductor material, was pulverized in the same manner as above to produce thermoelectric semiconductor particles T2 with an average particle size of 2.8 μm.

[0165] The particle size distribution of the thermoelectric semiconductor particles T1 and T2 obtained by pulverization was determined using a laser diffraction particle size analyzer (Malvern Mastersizer 3000).

[0166] (Preparation of coating solution for thermoelectric semiconductor composition)

[0167] Application solution (P)

[0168] A coating solution (P) comprising a thermoelectric semiconductor composition was prepared, wherein the thermoelectric semiconductor composition is mixed and dispersed with the obtained p-type bismuth telluride Bi. 0.4 Te 3.0 Sb 1.6 The composition includes 72.0 parts by mass of particle T1, 15.5 parts by mass of polyamide-imide (manufactured by Arakawa Chemical Industry Co., Ltd., COMPOCERAN AI301, solvent: N-methylpyrrolidone, solid content concentration: 19% by mass) as heat-resistant resin A, and 12.5 parts by mass of N-butylpyridine bromide as ionic liquid.

[0169] Application solution (N)

[0170] A coating solution (N) comprising a thermoelectric semiconductor composition was prepared, wherein the thermoelectric semiconductor composition contains 78.9 parts by mass of the obtained N-type bismuth telluride Bi2Te3 particles T2, 17.0 parts by mass of polyamide-imide (manufactured by Arakawa Chemical Industry Co., Ltd., COMPOCERAN AI301, solvent: N-methylpyrrolidone, solid content concentration: 19% by mass) as heat-resistant resin A, and 4.1 parts by mass of N-butylpyridine bromide as an ionic liquid.

[0171] (2) Formation of thin films of thermoelectric conversion materials

[0172] On a 0.7 mm thick glass substrate (manufactured by Kawamura Kyuzo Shoten Co., Ltd., trade name: Blue Plate Glass), as a sacrificial layer, a 10% by mass polymethyl methacrylate resin solution (manufactured by Sigma-Aldrich Co., Ltd., trade name: polymethyl methacrylate) was formed by dissolving polymethyl methacrylate resin (PMMA) in toluene to achieve a thickness of 3.0 μm after drying by spin coating.

[0173] Next, the coating solution (P) prepared in (1) was applied to the sacrificial layer via screen printing through a metal mask, and dried at 125°C in an argon atmosphere for 15 minutes to form a thin film with a thickness of 270 μm. Then, the obtained film was annealed in a mixed atmosphere of hydrogen and argon (hydrogen:argon = 3 vol%: 97 vol%) at a heating rate of 5 K / min and held at 450°C for 1 hour to induce crystal growth of the thermoelectric semiconductor material particles, yielding a film containing p-type bismuth telluride (Bi). 0.4 Te3Sb 1.6 A chip of P-type thermoelectric conversion material with a cuboid shape, having an upper and lower surface of 1.65mm × 1.65mm and a thickness of 200μm.

[0174] In addition, the coating solution (N) prepared in (1) above was dried in an argon atmosphere at 125°C for 7 minutes. In addition, a chip of N-type thermoelectric conversion material containing N-type bismuth telluride Bi2Te3 with upper and lower surfaces of 1.65 mm × 1.65 mm and a thickness of 250 μm was also obtained.

[0175] (3) Formation of solder receiving layer

[0176] After annealing, the P-type and N-type thermoelectric conversion material chips are peeled off from the glass substrate, and a solder receiving layer is deposited on the entire surface of the P-type and N-type thermoelectric conversion material chips by chemical plating [Au (thickness: 30nm) is stacked on Ni (thickness: 2μm)].

[0177] Next, the solder receiving layer on the sides of the P-type and N-type thermoelectric conversion material chips was removed using mechanical polishing, i.e., sandpaper (model 2000), to achieve a chip size of 1.5mm × 1.5mm, resulting in P-type and N-type thermoelectric conversion material chips with solder receiving layers only on the top and bottom surfaces. It should be noted that, in order to completely remove the solder receiving layer, a portion of the sidewalls was also polished.

[0178] <Fabrication of the Thermoelectric Conversion Module>

[0179] Using the obtained chips of P-type and N-type thermoelectric conversion materials with solder receiving layers only on the upper and lower surfaces, π-type thermoelectric conversion elements formed by 18 pairs of each of P-type and N-type thermoelectric conversion material chips were fabricated as described below.

[0180] First, a high thermal conductivity substrate (manufactured by Richang Industrial Co., Ltd., product name: CS-3295; 10mm×20mm, thickness: 60μm; copper foil, thickness: 35μm) with copper foil adhered to both sides was prepared. A nickel layer (thickness: 3μm) and a gold layer (thickness: 40nm) were sequentially deposited onto the copper foil of this high thermal conductivity substrate using chemical plating. Next, an electrode pattern (1.5×3.2mm, distance between adjacent electrodes: 0.2mm, 6 columns×3 rows) was formed on only one side to create a substrate with electrodes (lower electrode substrate). Then, a solder paste 42Sn / 57Bi / Ag alloy (manufactured by Nippon Solder Co., Ltd., product name: PF141-LT7H0) was used as the solder material for stencil printing on the electrodes (thickness before heating: 50μm).

[0181] Next, the solder receiving layer of each chip of the P-type and N-type thermoelectric conversion materials obtained above is placed on the solder material layer, heated at 180°C for 1 minute, and then cooled (the thickness of the solder material layer after heating and cooling is 30 μm). Thus, the chips of the P-type and N-type thermoelectric conversion materials are respectively disposed on the electrodes.

[0182] Furthermore, the aforementioned solder paste (thickness before heating: 50 μm) is printed as a solder material layer on the other side of the solder receiving layer of each of the P-type and N-type thermoelectric conversion material chips. The obtained solder material layer is then bonded to the electrodes of the upper electrode substrate (which is an electrode substrate with the electrodes patterned in a manner to obtain a π-type thermoelectric conversion module when bonded to the lower electrode substrate; the materials, thicknesses, etc. of the substrate and electrodes are the same as those of the lower electrode substrate). The substrate is heated at 190°C for 2 minutes, thereby obtaining a π-type thermoelectric conversion module formed by 18 pairs of each of the P-type and N-type thermoelectric conversion material chips.

[0183] For the obtained thermoelectric conversion module, the module resistance and the temperature difference ΔT between the heat-absorbing and heat-dissipating surfaces were evaluated under the above evaluation conditions. The evaluation results, including thermal conductivity and thermal resistance, are shown in Table 1.

[0184] (Comparative Example 1)

[0185] In Example 1, the high thermal conductivity substrate was replaced with a polyimide film substrate (manufactured by DU PONT-TORAY, trade name "KAPTON"; 10mm × 20mm, thickness: 12.5μm). Otherwise, the thermoelectric conversion module of Comparative Example 1 was fabricated in the same manner as in Example 1.

[0186] For the obtained thermoelectric conversion module, the module resistance (resistance) and the temperature difference ΔT between the heat-absorbing surface and the heat-dissipating surface were evaluated under the same evaluation conditions as in Example 1. The evaluation results, including thermal conductivity and thermal resistance, are shown in Table 1.

[0187] [Table 1]

[0188]

[0189] * The evaluation of the substrate was carried out without copper foil.

[0190] It can be seen that, compared with the thermoelectric conversion module of Comparative Example 1, which uses a low thermal conductivity polyimide film of the existing substrate as the substrate of the thermoelectric conversion module, the thermoelectric conversion module of Example 1, which uses a flexible high thermal conductivity substrate as the substrate, has a larger temperature difference and therefore can obtain better cooling performance.

[0191] Industrial applicability

[0192] The thermoelectric conversion module of the present invention is flexible and has excellent thermoelectric performance, and therefore can be used for applications such as suppressing heat storage generated in the miniaturization and thinning of electronic devices.

[0193] Specifically, examples include: cooling of the CPU (Central Processing Unit) in smartphones, tablet PCs, etc., and temperature control of various sensors, such as CMOS (Complementary Metal Oxide Semiconductor Image Sensor) and CCD (Charge Coupled Device) image sensors, which are semiconductor elements.

[0194] In addition, it can also be used for power generation by converting the heat emitted from various combustion furnaces such as factories, waste incinerators, and cement incinerators, the heat emitted from automobile combustion gases, and the heat emitted from electronic devices into electricity.

Claims

1. A thermoelectric conversion module comprising a substrate, and a thermoelectric element layer formed of a thermoelectric semiconductor composition, wherein the thermoelectric semiconductor composition comprises a thermoelectric semiconductor material, a heat-resistant resin A, and an ionic liquid and / or an inorganic ionic compound, the thermal resistance of the substrate is 0.35 K / W or less, the substrate is formed of an insulator, the substrate has flexibility, the thermal conductivity of the substrate is 0.5 W / m-K or more, the thickness of the substrate is 5 to 150 μm, and the substrate comprises a glass cloth and a heat-resistant resin B.

2. The thermoelectric conversion module according to claim 1, wherein the glass cloth is a glass woven cloth.

3. The thermoelectric conversion module according to claim 1, wherein the heat-resistant resin B is an epoxy resin, a polyamide-imide resin, or a polyimide resin.

4. The thermoelectric conversion module according to any one of claims 1 to 3, wherein the thermoelectric conversion module is composed of a π-type thermoelectric conversion element or an in-plane type thermoelectric conversion element.

5. The thermoelectric conversion module according to claim 4, wherein the composition of the π-type thermoelectric conversion element or the in-plane type thermoelectric conversion element is used for cooling. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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