thermoelectric conversion module

Abstract

To provide a thermoelectric conversion module having a high thermal electric performance in which a heat transmission performance of an inter member boundary surface is improved.SOLUTION: A thermoelectric conversion module includes: a heat transfer conductive interface A and a heat radiation member on one surface of an in-plane type thermoelectric conversion module, and further includes a heat transfer conductive interface B onto the other surface of the in-plane type thermoelectric conversion module. When a thermal resistance value of the heat transfer conductive interface A is RA(mK / W), a thermal resistance value of the heat transfer conductive interface B is RB(mK / W), a whole thermal resistance value obtained by summing them is RAB(mK / W), and a whole thermal resistance value of the in-plane type thermoelectric conversion module is RM(mK / W), a ratio (RAB / RM) of the RAB against the RM is 1.40 or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a thermoelectric conversion module. [Background technology]

[0002] 2. Description of the Related Art Conventionally, as one of the means for effectively utilizing energy, there has been a device that directly converts thermal energy into electrical energy and vice versa using a thermoelectric conversion module that has a thermoelectric effect such as the Seebeck effect or the Peltier effect. A known thermoelectric conversion module is one that has a so-called in-plane thermoelectric conversion element configuration. From the viewpoint of thermoelectric performance, the in-plane thermoelectric conversion element is typically configured by alternately arranging P-type thermoelectric elements and N-type thermoelectric elements in the in-plane direction of a substrate, and connecting the upper or lower portions of adjacent or abutting P-type and N-type thermoelectric elements in series via electrodes. Under these circumstances, various demands remain for in-plane thermoelectric conversion modules, such as further improvements in thermoelectric performance, thinner modules, improved reliability, and improved mass productivity. In Patent Document 1, for example, in the configuration of an in-plane type thermoelectric conversion module, an insulating layer is provided between a thermoelectric element layer and a heat dissipation layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 179544 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, the insulating layer is used for the purpose of preventing short circuits between the heat source and the thermoelectric element layer, or between the heat dissipation layer and the thermoelectric element layer, etc., from the viewpoint of improving the reliability of the in-plane thermoelectric conversion module, and no consideration is given to arranging another specific insulating layer on the in-plane thermoelectric conversion module from the viewpoint of improving thermoelectric performance, or to the relationship between the thermal resistance value of the other specific insulating layer and the thermal resistance value of the components that make up the in-plane thermoelectric conversion module.

[0005] In view of the above, an object of the present invention is to provide a thermoelectric conversion module having high thermoelectric performance with improved heat conductivity at the interfaces between members. [Means for solving the problem]

[0006] As a result of extensive research into solving the above problems, the inventors discovered that by providing, on the top and bottom surfaces of an in-plane thermoelectric conversion module, a thermally conductive interface member (hereinafter sometimes simply referred to as "TIM") having a thermal resistance value at a specific ratio to the total thermal resistance value, which is the sum of the thermal resistance values ​​of the components that make up the in-plane thermoelectric conversion module, the thermal conductivity of the interfaces between the components that make up the in-plane thermoelectric conversion module can be further improved, and thus completed the present invention. That is, the present invention provides the following [1] to [5]. [1] A thermoelectric conversion module including a thermally conductive interface member A and a heat dissipation member on one surface of the in-plane type thermoelectric conversion module, and further including a thermally conductive interface member B on the other surface of the in-plane type thermoelectric conversion module, wherein the thermal resistance value of the thermally conductive interface member A is R A (mK / W), the thermal resistance value of the thermally conductive interface member B is R B (mK / W), and the sum of these is the total thermal resistance, R AB (mK / W), and the total thermal resistance of the in-plane thermoelectric conversion module is R M (mK / W), the R M R AB The ratio (RAB / R M ) is 1.40 or less. [2] The thermoelectric conversion module according to [1] above, wherein the in-plane type thermoelectric conversion module further includes a high thermal conductivity layer A and a high thermal conductivity layer B, the high thermal conductivity layer A constituting the outermost layer of the in-plane type thermoelectric conversion module on the thermally conductive interface member A side, and the high thermal conductivity layer B constituting the outermost layer of the in-plane type thermoelectric conversion module on the thermally conductive interface member B side. [3] The thermoelectric conversion module according to [2] above, wherein the high thermal conductivity layer A is made of a plurality of high thermal conductivity layers a arranged at intervals, with a portion of the thermally conductive interface member A embedded in the gaps between adjacent high thermal conductivity layers a, and the high thermal conductivity layer B is made of a plurality of high thermal conductivity layers b arranged at intervals, with a portion of the thermally conductive interface member B embedded in the gaps between adjacent high thermal conductivity layers b. [4] The thermoelectric conversion module according to the above [2] or [3], wherein a ratio M of the embedding depth of the part of the thermally conductive interface member A to the thickness of the high thermal conductivity layer A is 0.01 to 1.00, and a ratio N of the embedding depth of the part of the thermally conductive interface member B to the thickness of the high thermal conductivity layer B is 0.01 to 1.00. [5] The thermoelectric conversion module according to any one of the above [1] to [4], wherein the thermally conductive interface member A and the thermally conductive interface member B are each independently a resin layer or an organic layer. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a thermoelectric conversion module having high thermoelectric performance with improved heat transfer at the interface between members. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an embodiment of a thermoelectric conversion module of the present invention. [Figure 2]FIG. 2 is a plan view showing an example of the arrangement of electrodes and thermoelectric element layers on a substrate that constitutes a part of a thermoelectric conversion module used in an example of the present invention. [Figure 3] FIG. 1 is a cross-sectional view showing an example of an evaluation configuration of a thermoelectric conversion module used in an example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Thermoelectric conversion module] The thermoelectric conversion module of the present invention is an in-plane type thermoelectric conversion module including a thermally conductive interface member A and a heat dissipation member on one surface of the in-plane type thermoelectric conversion module, and further including a thermally conductive interface member B on the other surface of the in-plane type thermoelectric conversion module, wherein the thermal resistance value of the thermally conductive interface member A is set to R A (mK / W), the thermal resistance value of the thermally conductive interface member B is R B (mK / W), and the sum of these is the total thermal resistance, R AB (mK / W), and the total thermal resistance of the in-plane thermoelectric conversion module is R M (mK / W), the R M R AB The ratio (R AB / R M ) is 1.40 or less. The thermoelectric conversion module of the present invention has a configuration including a thermally conductive interface member A (hereinafter, sometimes simply referred to as "TIMA") and a heat dissipation member on one surface of the in-plane type thermoelectric conversion module, and further including a thermally conductive interface member B (hereinafter, sometimes simply referred to as "TIMB") on the other surface of the in-plane type thermoelectric conversion module, and has a total thermal resistance value R M TIMA's thermal resistance value R A and the thermal resistance value R of the TIMB B The total thermal resistance R AB The ratio (R AB / R M) to 1.40 or less, the heat transfer properties at the interfaces between the members constituting the in-plane thermoelectric conversion module can be further improved, resulting in higher thermoelectric performance.

[0010] In this specification, the "thermoelectric conversion module" is composed of an "in-plane type thermoelectric conversion module", "thermal conductive interface members A and B", and a "heat dissipation member".

[0011] In this specification, preferred definitions can be selected arbitrarily, and combinations of preferred definitions can be considered more preferred. In this specification, the expression "XX to YY" means "XX or more and YY or less." In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60."

[0012] The thermoelectric conversion module of the present invention will be described below with reference to the drawings.

[0013] 1 is a cross-sectional view showing an embodiment of a thermoelectric conversion module of the present invention. Thermoelectric conversion module 1 includes a thermally conductive interface member A10a and a heat dissipation member 11 on one surface of an in-plane thermoelectric conversion module 9, and further includes a thermally conductive interface member B10b on the other surface of the in-plane thermoelectric conversion module 9. In-plane thermoelectric conversion module 9 includes a thermoelectric element layer 6 formed by P-type thermoelectric element layers 4 and N-type thermoelectric element layers 5 alternately adjacent (abutting) in the in-plane direction of substrate 2 and arranged in series via a common electrode 3. The in-plane thermoelectric conversion module 9 includes a high thermal conductivity layer A8A on one surface of the thermoelectric element layer 6, which is made up of a plurality of high thermal conductivity layers a8a arranged at intervals with a coating layer 7 interposed therebetween, and a high thermal conductivity layer B8B on the other surface of the thermoelectric element layer 6, which is made up of a plurality of high thermal conductivity layers b8b arranged at intervals with the electrode 3 and substrate 2 interposed therebetween. By providing a thermally conductive interface member A10a between the high thermal conductivity layer a8a on the upper surface of the in-plane type thermoelectric conversion module 9 and the heat dissipation member 11, it is possible to reduce the contact thermal resistance that occurs therebetween. Similarly, by providing a thermally conductive interface member B10b between the high thermal conductivity layer b8b on the lower surface of the in-plane type thermoelectric conversion module 9 and, for example, a heat source (not shown), it is possible to reduce the contact thermal resistance that occurs therebetween. The thermally conductive interface member A and the thermally conductive interface member B having such effects are used, and the total thermal resistance value R, which is the sum of the thermal resistance values ​​of the components constituting the in-plane type thermoelectric conversion module, is M The thermal resistance value R of the thermally conductive interface material A A and the thermal resistance value R of thermally conductive interface material B B The total thermal resistance R AB The ratio (R AB / R M By making the ratio 1.40 or less, the heat transfer properties at the interfaces between the members constituting the in-plane thermoelectric conversion module can be further improved, resulting in higher thermoelectric performance.

[0014] The total thermal resistance R is the sum of the thermal resistances of the components that make up the in-plane thermoelectric conversion module. M TIMA's thermal resistance value R A and the thermal resistance value R of the TIMB B The total thermal resistance R AB The ratio (R AB / R M ) is less than or equal to 1.40. Ratio (R AB / R M ) is preferably 0.01 to 1.00, more preferably 0.03 to 0.50, and even more preferably 0.05 to 0.10. Ratio (R AB / R M ) is in this range, the heat transfer at the interface between the members is more likely to be improved, and the thermoelectric performance is improved.

[0015] <Thermal Conductive Interface Member A and the Thermal Conductive Interface Member B> The thermoelectric conversion module of the present invention includes a thermally conductive interface member A between the upper surface of the in-plane type thermoelectric conversion module and the heat dissipation member, and a thermally conductive interface member B on the lower surface of the in-plane type thermoelectric conversion module. By providing a thermally conductive interface member A between the upper surface of the in-plane thermoelectric conversion module and the heat dissipation member, the contact thermal resistance occurring therebetween can be reduced. Similarly, by providing a thermally conductive interface member B between the lower surface of the in-plane thermoelectric conversion module and, for example, a heat source, the contact thermal resistance occurring therebetween can be reduced. In this way, the use of the thermally conductive interface member A and the thermally conductive interface member B facilitates improvement in thermal conduction within the in-plane thermoelectric conversion module, leading to improvement in the thermoelectric performance of the thermoelectric conversion module.

[0016] The thermally conductive interface member A and the thermally conductive interface member B are preferably each independently a resin layer or an organic layer. Hereinafter, "thermal conductive interface member A and said thermal conductive interface member B" may be simply referred to as "thermal conductive interface member".

[0017] The resin material used for the resin layer is not particularly limited, but any resin can be appropriately selected from those used in the field of electronic components, etc. Examples of resin materials include thermosetting resins, thermoplastic resins, photocurable resins, etc. Examples include polyolefin resins such as polyethylene and polypropylene; styrene resins such as polystyrene; acrylic resins such as polymethyl methacrylate; polyamide resins such as polyamide (nylon 6, nylon 66, etc.), poly-m-phenylene isophthalamide, and poly-p-phenylene terephthalamide; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and polyarylate; cycloolefin polymers such as norbornene polymers, monocyclic olefin polymers, cyclic conjugated diene polymers, vinyl alicyclic hydrocarbon polymers, and hydrogenated versions thereof; vinyl chloride; polyimide; polyamideimide; polyphenylene ether; polyether ketone; polyether ether ketone; polycarbonate; polysulfone resins such as polysulfone and polyether sulfone; polyphenylene sulfide; silicone resins; and combinations of two or more of these polymers. Among these, polyamide resins, polyimides, polyamideimides, and silicone resins are preferred from the viewpoint of excellent heat resistance and resistance to deterioration in heat dissipation properties.

[0018] Examples of the organic layer include an adhesive layer, a pressure-sensitive adhesive layer, a gel layer, a grease layer, and a clay layer. Among these, from the viewpoints of workability and ability to conform to irregularities, an adhesive layer and a pressure-sensitive adhesive layer are preferred.

[0019] The adhesive used in the adhesive layer is not particularly limited, and may be a two-component curing adhesive, a thermosetting adhesive, a moisture-curing adhesive, or a hot-melt adhesive. Examples of adhesives include acrylic adhesives, urethane adhesives, silicone adhesives, rubber adhesives, olefin adhesives, and epoxy adhesives.

[0020] The adhesive used in the adhesive layer is not particularly limited and may be any of an acrylic adhesive, a silicone adhesive, a polyester adhesive, a polyurethane adhesive, a rubber adhesive, etc. The adhesive may be an emulsion type, a solvent type, or a solventless type, and may be a crosslinked type or a non-crosslinked type. Among them, an acrylic adhesive or a silicone adhesive is preferred.

[0021] To improve thermal conductivity, the resin layer may be filled with a thermally conductive filler. The thermally conductive filler is not particularly limited, but may be, for example, at least one selected from silica, alumina, magnesium oxide, silicon nitride, aluminum nitride, magnesium nitride, boron nitride, copper, and aluminum. These thermally conductive fillers may be used alone or in combination of two or more. The thermally conductive filler preferably has an average particle size of 0.1 to 200 μm, more preferably 1 to 100 μm, even more preferably 5 to 50 μm, and particularly preferably 10 to 30 μm. The average particle size can be measured, for example, by a Coulter counter method. The content of the thermally conductive filler is adjusted appropriately depending on the desired thermal conductivity, and is preferably 40 to 99 mass %, more preferably 50 to 95 mass %, and particularly preferably 50 to 80 mass % of the resin composition. When the content of the thermally conductive filler is within this range, the thermally conductive interface member has excellent heat dissipation properties, folding resistance, and flex resistance, and maintains its strength.

[0022] The thickness of the thermally conductive interface member is preferably 0.05 to 1.50 mm, more preferably 0.08 to 1.20 mm, and even more preferably 0.10 to 1.00 mm. If the thickness of the thermally conductive interface member is within this range, the thermal resistance of the thermally conductive interface member can be kept low, and the contact thermal resistance generated between the heat source and the heat dissipation member can be efficiently reduced.

[0023] Examples of commercially available thermally conductive interface members include the following: High thermal conductivity heat dissipation sheet (manufactured by Sekisui Polymatech Co., Ltd., product number: Manion50α, thickness: 0.50 mm, thermal conductivity: 17 W / (m·K)), heat dissipation sheet TIMLIGHT (manufactured by Sekisui Polymatech Co., Ltd., product number: PT-V, thickness: 0.50 mm, thermal conductivity: 12 W / (m·K)), thermally conductive double-sided tape (manufactured by 3M Co., Ltd., product number: 8926, thickness: 0.20 mm, thermal conductivity: 1.5 W / (m·K)), thermally conductive double-sided tape (manufactured by 3M Co., Ltd., product number: VHR0601, thickness: 0.30 mm, thermal conductivity: 0.6 W / (m·K)).

[0024] <Heat dissipation materials> The heat dissipation member may be any member that conducts generated heat and dissipates it to the outside, and is not particularly limited to, but examples thereof include a heat sink and a heat spreader. Examples of materials for heat sinks and heat spreaders include copper and aluminum. In addition to heat spreaders and heat sinks, examples of materials include radiators, coolers, cooling fans, heat pipes, vapor chambers, metal covers, and housings. A heat pipe is, for example, a hollow structure that is cylindrical, approximately cylindrical, or flattened.

[0025] (High thermal conductivity layer A and high thermal conductivity layer B) From the viewpoint of efficiently applying a temperature difference to the thermoelectric element layer, it is preferable that the in-plane type thermoelectric conversion module further includes a high thermal conductivity layer A and a high thermal conductivity layer B, and that the high thermal conductivity layer A constitutes the outermost layer of the in-plane type thermoelectric conversion module on the thermally conductive interface member A side, and that the high thermal conductivity layer B constitutes the outermost layer of the in-plane type thermoelectric conversion module on the thermally conductive interface member B side.

[0026] From the viewpoint of suppressing the contact thermal resistance at the interfaces between the components of the in-plane thermoelectric conversion module and further improving the heat transfer, it is preferable that the high thermal conductivity layer A is made up of a plurality of high thermal conductivity layers a arranged at intervals, and that a portion of the thermally conductive interface member A is embedded in the gaps between adjacent high thermal conductivity layers a. Similarly, the high thermal conductivity layer B is preferably made up of a plurality of high thermal conductivity layers b arranged at intervals, with a portion of the thermally conductive interface member B embedded in the gaps between adjacent high thermal conductivity layers b.

[0027] The ratio M of the embedding depth of the part of the thermally conductive interface member A to the thickness of the high thermal conductivity layer A is preferably 0.01 to 1.00, more preferably 0.10 to 0.95, and even more preferably 0.60 to 0.90. The ratio N of the embedding depth of the part of the thermally conductive interface member B to the thickness of the high thermal conductivity layer B is preferably 0.01 to 1.00, more preferably 0.10 to 0.95, and even more preferably 0.60 to 0.90. When the ratios M and N are within these ranges, the heat transfer at the interfaces between the members is more likely to be improved, and the thermoelectric performance is further improved. Here, the "embedding depth of a portion of the thermally conductive interface member A" refers to, for example, the maximum distance in the thickness direction from the upper surface of the high thermal conductivity layer a8a when a portion of the thermally conductive interface member A10a in contact with the upper surface of the high thermal conductivity layer a8a in FIG. 1 partially enters the gap between the high thermal conductivity layers a8a. Similarly, the "embedding depth of a portion of the thermally conductive interface member B" refers to, for example, in FIG. 1, the maximum distance in the thickness direction from the lower surface of the high thermal conductivity layer b8b when a portion of the thermally conductive interface member B10b in contact with the lower surface of the high thermal conductivity layer b8b partially enters a gap between the high thermal conductivity layers b8b.

[0028] The highly thermally conductive layer A and the highly thermally conductive layer B used in the present invention can efficiently create a temperature difference between the thermoelectric element layers arranged in the in-plane direction. Hereinafter, the high thermal conductive layer A, the high thermal conductive layer a, the high thermal conductive layer B, and the high thermal conductive layer b may be simply referred to as "high thermal conductive layers."

[0029] The arrangement of the high thermal conductivity layer used in the present invention is not particularly limited, but must be appropriately adjusted depending on the arrangement and shape of the thermoelectric element layers of the thermoelectric conversion module used, i.e., the P-type thermoelectric element layer and the N-type thermoelectric element layer. In the present invention, it is preferable that high thermal conductive layers b8b or a8a are repeatedly arranged at predetermined intervals on the surface of the substrate 2 or the covering layer 7 opposite the thermoelectric element layer 6, respectively, so as to straddle an extension of the boundary surface joining the P-type thermoelectric element layer 4 and the N-type thermoelectric element layer 5. Furthermore, it is preferable that only one high thermal conductive layer a8a or high thermal conductive layer b8b straddles the extension of the boundary surface, and that the high thermal conductive layers a and b are arranged alternately when viewed in a cross section in the thickness direction, as shown in Figure 1. By arranging the high thermal conductive layers a and b in this manner, high temperature regions and low temperature regions are continuously and sequentially formed within the thermoelectric element layer 6 in a direction parallel to the plane of the substrate 2 and the plane of the covering layer 7, which is presumed to improve power generation efficiency. For example, as shown in FIG. 1, high thermal conductivity layers a8a and a8b are alternately arranged in the in-plane direction of the coating layer 7 and the substrate 2 across electrodes 3 that join P-type thermoelectric element layers 4 and N-type thermoelectric element layers 5 that are alternately adjacent (abutting) in the in-plane direction of the substrate 2. In this case, a temperature difference can be created in the in-plane direction of the thermoelectric element layer 6. The ratio of the high thermal conductivity layer to the total width of the pair of P-type thermoelectric element layer 4 and N-type thermoelectric element layer 5 in the series direction is preferably 0.30 to 0.70, more preferably 0.40 to 0.60, even more preferably 0.48 to 0.52, and particularly preferably 0.50. When the ratio of the high thermal conductivity layer is within this range, heat can be selectively dissipated in a specific direction, and a temperature difference can be created efficiently in the in-plane direction of the thermoelectric element layer 6. Furthermore, it is preferable that the high thermal conductivity layer is symmetrically arranged at the abutting portion of the pair of P-type thermoelectric element layer 4 and N-type thermoelectric element layer 5 in the series direction while satisfying the above conditions.

[0030] The highly thermally conductive layer used in the present invention is formed using a highly thermally conductive material from the viewpoint of thermoelectric performance. The method for forming the highly thermally conductive layer is not particularly limited, but may include a method in which a sheet-shaped highly thermally conductive material is processed into a predetermined pattern shape in advance by a known physical or chemical treatment, mainly based on photolithography, or a combination of these.

[0031] Examples of materials for the high thermal conductivity layer include metal materials, ceramic materials, carbon-based materials such as carbon fiber, and mixtures of these materials with resins. Among these, the high thermal conductivity layer is preferably at least one material selected from the group consisting of metal materials, ceramic materials, mixtures of metal materials and resins, and mixtures of ceramic materials and resins, and more preferably at least one material selected from the group consisting of metal materials and ceramic materials. Examples of metal materials include single metals such as gold, silver, copper, nickel, tin, iron, chromium, platinum, palladium, rhodium, iridium, ruthenium, osmium, indium, zinc, molybdenum, manganese, titanium, and aluminum, and alloys containing two or more metals such as stainless steel and brass. Examples of ceramic materials include barium titanate, aluminum nitride, boron nitride, aluminum oxide, silicon carbide, and silicon nitride. Among these, metal materials are preferred from the viewpoints of high thermal conductivity, workability, and flexibility. Among metal materials, copper (including oxygen-free copper) and stainless steel are preferred, and copper is more preferred because of its high thermal conductivity and easier workability. As the resin, the resins described above can be used. Representative metal materials having high thermal conductivity that can be used in the present invention are listed below. Oxygen-free copper Oxygen-free copper (OFC) generally refers to high-purity copper with a purity of 99.95% (3N) or higher, which is free of oxides. The Japanese Industrial Standards specify oxygen-free copper (JIS H 3100, C1020) and oxygen-free copper for electronic devices (JIS H 3510, C1011). Stainless steel (JIS) SUS304: 18Cr-8Ni (containing 18% Cr and 8% Ni) SUS316: 18Cr-12Ni (18% Cr, 12% Ni, containing molybdenum (Mo)) stainless steel

[0032] The thermal conductivity of the high thermal conductive layer is preferably 5 to 500 W / (m·K), more preferably 12 to 450 W / (m·K), and even more preferably 15 to 420 W / (m·K). When the thermal conductivity of the high thermal conductive layer is in the above range, a temperature difference can be efficiently created.

[0033] The thickness of the highly thermally conductive layer is preferably 40 to 550 μm, more preferably 60 to 530 μm, and even more preferably 80 to 510 μm. If the thickness of the highly thermally conductive layer is within this range, heat can be selectively dissipated in a specific direction, and a temperature difference can be efficiently created in the in-plane direction of the thermoelectric element layer in which P-type thermoelectric element layers and N-type thermoelectric element layers are alternately adjacent to each other in the in-plane direction and arranged in series with electrodes interposed therebetween.

[0034] <substrate> The substrate of the thermoelectric conversion module used in the present invention is not particularly limited, but it is preferable to use a film substrate that does not affect the decrease in electrical conductivity or the increase in thermal conductivity of the thermoelectric element layer. Among them, polyimide films, polyamide films, polyetherimide films, polyaramid films, and polyamideimide films are preferred because they have excellent flexibility, can maintain the performance of the thermoelectric element layer without thermal deformation even when a thin film made of a thermoelectric semiconductor composition described below is annealed, and have high heat resistance and dimensional stability. Furthermore, polyimide films are particularly preferred because of their high versatility.

[0035] From the viewpoints of flexibility, heat resistance, and dimensional stability, the thickness of the substrate is preferably 1 μm to 1000 μm, more preferably 10 μm to 500 μm, and even more preferably 20 μm to 100 μm. The film preferably has a decomposition temperature of 300° C. or higher.

[0036] <Electrode layer> The electrode layer used in the present invention is provided to electrically connect the P-type thermoelectric element layer and the N-type thermoelectric element layer that constitute the thermoelectric element layer described below. Examples of electrode materials include gold, silver, nickel, copper, and alloys thereof. The thickness of the electrode layer 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 electrode layer is within the above range, the electrical conductivity is high and the resistance is low, and the total electrical resistance value of the thermoelectric element layer can be kept low. In addition, sufficient strength as an electrode can be obtained. Examples of methods for forming an electrode on a film substrate include a method in which an electrode layer without a pattern is provided on a film substrate, and then processed into a predetermined pattern shape by known physical or chemical treatments, mainly photolithography, or a combination of these, or a method in which a pattern of the electrode layer is directly formed by screen printing, inkjet printing, or the like. Examples of methods for forming an electrode layer without a pattern include dry processes such as PVD (physical vapor deposition) methods such as vacuum deposition, sputtering, and ion plating, or CVD (chemical vapor deposition) methods such as thermal CVD and atomic layer deposition (ALD), or wet processes such as various coating methods and electrodeposition methods such as dip coating, spin coating, spray coating, gravure coating, die coating, and doctor blade methods, silver halide plating, electrolytic plating, electroless plating, and lamination of metal foil, and are selected appropriately depending on the material of the electrode layer.

[0037] <Thermoelectric element layer> As described above, the thermoelectric element layer of the thermoelectric conversion module used in the present invention includes a P-type thermoelectric element layer and an N-type thermoelectric element layer, and the P-type thermoelectric element layers and the N-type thermoelectric element layers are alternately arranged adjacent to each other in the in-plane direction and are electrically connected in series. Furthermore, the P-type thermoelectric element layer and the N-type thermoelectric element layer may be connected via the aforementioned electrode layer made of a highly conductive metal material or the like from the viewpoints of connection stability and thermoelectric performance.

[0038] The thermoelectric element layer used in the present invention is preferably a layer formed on a substrate and comprising thermoelectric semiconductor particles, a heat-resistant resin, and a thermoelectric semiconductor composition containing one or both of an ionic liquid and an inorganic ionic compound.

[0039] (Thermoelectric semiconductor particles) The thermoelectric semiconductor particles used in the thermoelectric element layer are preferably prepared by pulverizing a thermoelectric semiconductor material to a predetermined size using a fine pulverizer or the like.

[0040] The materials constituting the P-type thermoelectric element layer and the N-type thermoelectric element layer used in the present invention are not particularly limited as long as they are materials that can generate thermoelectric power by applying a temperature difference. Examples of such materials include bismuth-tellurium-based thermoelectric semiconductor materials such as P-type bismuth telluride and N-type bismuth telluride; telluride-based thermoelectric semiconductor materials such as GeTe and PbTe; antimony-tellurium-based thermoelectric semiconductor materials; ZnSb, ZnSb 2、 Zinc-antimony thermoelectric semiconductor materials such as Zn4Sb3; silicon-germanium thermoelectric semiconductor materials such as SiGe; bismuth selenide thermoelectric semiconductor materials such as Bi2Se3; β-FeSi2, CrSi2, MnSi 1.73 Examples of thermoelectric semiconductor materials that can be used include silicide-based thermoelectric semiconductor materials such as Mg2Si; oxide-based thermoelectric semiconductor materials; Heusler materials such as FeVAl, FeVAlSi, and FeVTiAl; and sulfide-based thermoelectric semiconductor materials such as TiS2.

[0041] Among these, the thermoelectric semiconductor material used in the present invention is preferably a bismuth-tellurium based thermoelectric semiconductor material such as P-type bismuth telluride or N-type bismuth telluride. The p-type bismuth telluride has a positive Seebeck coefficient and a positive carrier, for example, Bi X Te3Sb 2-XThose represented by [formula] are preferably used. 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 or equal to 0.8, the Seebeck coefficient and the electrical conductivity increase, and the characteristics as a P-type thermoelectric conversion material are maintained, which is preferable. Further, the N-type bismuth telluride has electrons as carriers and a negative Seebeck coefficient. For example, Bi2Te 3-Y Se Y Those represented by [formula] are preferably used. In this case, Y is preferably 0 ≤ Y ≤ 3 (when Y = 0: Bi2Te3), more preferably 0 < Y ≤ 2.7. When Y is 0 to 3, the Seebeck coefficient and the electrical conductivity increase, and the characteristics as an N-type thermoelectric conversion material are maintained, which is preferable.

[0042] The blending amount of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass, more preferably 70 to 95% by mass. If the blending amount of the thermoelectric semiconductor particles is within the above range, the Seebeck coefficient (the absolute value of the Peltier coefficient) is large, the decrease in electrical conductivity is suppressed, and only the thermal conductivity decreases, so it exhibits high thermoelectric performance, and a film with sufficient film strength and flexibility can be obtained, which is preferable.

[0043] The average particle size of the thermoelectric semiconductor particles is preferably 10 nm to 200 μm, more preferably 50 nm to 10 μm. If it is within the above range, uniform dispersion becomes easy and the electrical conductivity can be increased. The method for obtaining thermoelectric semiconductor particles by pulverizing the thermoelectric semiconductor material is not particularly limited, and it may be pulverized to a predetermined size by a known fine pulverization device such as a jet mill, ball mill, bead mill, colloid mill, conical mill, disk mill, edge mill, powder mill, hammer mill, pellet mill, Willy mill, roller mill, etc. The average particle size of the thermoelectric semiconductor particles is obtained by measuring with a laser diffraction particle size analyzer (Model 1064, manufactured by CILAS) and taking the median value of the particle size distribution.

[0044] The thermoelectric semiconductor particles are preferably annealed (hereinafter, sometimes referred to as "annealing treatment A"). Annealing treatment A improves the crystallinity of the thermoelectric semiconductor particles and removes the surface oxide film of the thermoelectric semiconductor particles, thereby increasing the Seebeck coefficient (absolute value of the Peltier coefficient) of the thermoelectric conversion material and further improving the thermoelectric figure of merit. Annealing treatment A is not particularly limited, but is preferably performed before preparing the thermoelectric semiconductor composition in an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere such as hydrogen, or a vacuum condition with a controlled gas flow rate, so as not to adversely affect the thermoelectric semiconductor particles. Annealing treatment A is more preferably performed in a mixed gas atmosphere of an inert gas and a reducing gas. The specific temperature conditions depend on the thermoelectric semiconductor particles used, but it is usually preferable to perform the treatment at a temperature below the melting point of the particles, at 100 to 1500°C, for several minutes to several tens of hours.

[0045] (Heat-resistant resin) The heat-resistant resin used in the present invention acts as a binder between thermoelectric semiconductor particles to enhance the flexibility of the thermoelectric conversion material. There are no particular limitations on the heat-resistant resin, but a heat-resistant resin is used that maintains its mechanical strength, thermal conductivity, and other physical properties as a resin when the thermoelectric semiconductor particles are crystallized by annealing a thin film made of the thermoelectric semiconductor composition. Examples of the heat-resistant resin include polyamide resin, polyamideimide resin, polyimide resin, polyetherimide resin, polybenzoxazole resin, polybenzimidazole resin, epoxy resin, and copolymers having the chemical structure of these resins. The heat-resistant resins may be used alone or in combination of two or more. Among these, polyamide resin, polyamideimide resin, polyimide resin, and epoxy resin are preferred because they have higher heat resistance and do not adversely affect the crystal growth of thermoelectric semiconductor particles in the thin film. Polyamide resin, polyamideimide resin, and polyimide resin are more preferred because they have excellent flexibility. When a polyimide film is used as the substrate, polyimide resin is more preferred as the heat-resistant resin because of its adhesion to the polyimide film. In the present invention, polyimide resin collectively refers to polyimide and its precursor.

[0046] The heat-resistant resin preferably has a decomposition temperature of 300° C. or higher. If the decomposition temperature is within the above range, the resin will not lose its function as a binder and the flexibility of the thermoelectric element layer can be maintained even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0047] Furthermore, the heat-resistant resin preferably has a mass loss rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less at 300°C as measured by thermogravimetry (TG).If the mass loss rate is within the above range, as will be described later, even when a thin film made of the thermoelectric semiconductor composition is annealed, the resin does not lose its function as a binder and the flexibility of the thermoelectric element layer can be maintained.

[0048] The amount of the heat-resistant resin in the thermoelectric semiconductor composition is preferably 0.1 to 40% by mass, more preferably 1 to 20% by mass. When the amount of the heat-resistant resin in the thermoelectric semiconductor composition is within the above range, a film having both high thermoelectric performance and high film strength can be obtained.

[0049] (ionic liquid) The ionic liquid used in the present invention is a molten salt formed by combining a cation and anion, and refers to a salt that can exist in liquid form at any temperature range from -50°C to less than 400°C. In other words, an ionic liquid is an ionic compound having a melting point in the range of -50°C to less than 400°C. The melting point of the ionic liquid is preferably 0°C to 150°C. Ionic liquids are characterized by extremely low vapor pressure, nonvolatility, excellent thermal stability and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive additive, they can effectively suppress a decrease in electrical conductivity between thermoelectric semiconductor particles. Furthermore, ionic liquids exhibit high polarity due to their aprotic ionic structure and excellent compatibility with heat-resistant resins, thereby enabling the electrical conductivity of the thermoelectric element layer to be uniform.

[0050] The ionic liquid may be a known or commercially available one. For example, a nitrogen-containing cyclic cationic compound such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, or imidazolium, or a derivative thereof; a tetraalkylammonium-based amine-based cation and a derivative thereof; a phosphine-based cation such as phosphonium, trialkylsulfonium, or tetraalkylphosphonium, or a derivative thereof; a lithium cation and a derivative thereof; or a mixture of a cation component and a Cl cation. - , 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 - and an anion component such as the above.

[0051] The electrical conductivity of the ionic liquid is preferably 10 -7 S / cm or more, preferably 10 -6 If the electrical conductivity is in the above range, the conductive additive can effectively suppress the decrease in electrical conductivity between thermoelectric semiconductor particles.

[0052] The ionic liquid preferably has a decomposition temperature of 300° C. or higher. If the decomposition temperature is within the above range, the ionic liquid can maintain its effect as a conductive additive even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0053] Furthermore, the ionic liquid preferably has a mass loss rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less at 300°C as measured by thermogravimetry (TG). If the mass loss rate is within the above range, the ionic liquid can maintain its effectiveness as a conductive additive even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0054] The amount of the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 1.0 to 20% by mass. When the amount of the ionic liquid is within the above range, a decrease in electrical conductivity is effectively suppressed, and a film having high thermoelectric performance is obtained.

[0055] (inorganic ionic compounds) The inorganic ionic compound used in the present invention is a compound composed of at least a cation and an anion. The inorganic ionic compound is solid at room temperature, has a melting point somewhere in the temperature range of 400 to 900°C, and has characteristics such as high ionic conductivity, so that it can suppress a decrease in electrical conductivity between thermoelectric semiconductor particles as a conductive additive.

[0056] As the cation, a metal cation is used. Examples of metal cations include alkali metal cations, alkaline earth metal cations, typical metal cations and transition metal cations, with alkali metal cations and alkaline earth metal cations being more preferred. Examples of alkali metal cations include Li + , Na + , K. + , Rb + , Cs + and Fr + etc. Examples of alkaline earth metal cations include Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ etc.

[0057] Examples of anions include F - , Cl - , Br - , I - , O.H. - , C.N. - , NO 3- , NO 2- , ClO - , ClO 2- , ClO 3- , ClO 4- , CrO4 2- , HSO4 - , SCN - , BF4 - , PF6 - etc.

[0058] The inorganic ionic compound may be a known or commercially available one. For example, a compound containing a cationic component such as potassium cation, sodium cation, or lithium cation and Cl - , AlCl4 - , Al2Cl7 - , ClO4 - Chloride ions such as Br - bromide ions, such as I - Iodide ions such as BF4 - , PF6 - Fluoride ions such as F(HF) n - Halide anions such as NO3 - , O.H. - , C.N. - and an anion component such as the above.

[0059] Among the above inorganic ionic compounds, from the viewpoints of high-temperature stability, compatibility with thermoelectric semiconductor particles and resin, and suppression of a decrease in the electrical conductivity of the gaps between thermoelectric semiconductor particles, it is preferable that the cation component of the inorganic ionic compound contains at least one selected from potassium, sodium, and lithium. Also, it is preferable that the anion component of the inorganic ionic compound contains a halide anion, and Cl - , Br - , and I - It is more preferable that the composition contains at least one selected from the following:

[0060] The above inorganic ionic compounds have an electrical conductivity of 10 -7 S / cm or more is preferable, and 10 -6 If the electrical conductivity is in the above range, the conductive additive can effectively suppress a decrease in electrical conductivity between thermoelectric semiconductor particles.

[0061] The inorganic ionic compound preferably has a decomposition temperature of 400° C. or higher. If the decomposition temperature is within the above range, the effect as a conductive additive can be maintained even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0062] Furthermore, the inorganic ionic compound preferably exhibits a mass loss rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less at 400°C as measured by thermogravimetry (TG). If the mass loss rate is within the above range, the compound can maintain its effectiveness as a conductive additive even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0063] The amount of the inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 1.0 to 10% by mass. When the amount of the inorganic ionic compound is within the above range, a decrease in electrical conductivity can be effectively suppressed, resulting in a film with improved thermoelectric performance. When an inorganic ionic compound and an ionic liquid are used in combination, the total content of the inorganic ionic compound and the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50 mass %, more preferably 1.0 to 10 mass %.

[0064] The thickness of the thermoelectric element layer consisting of the P-type thermoelectric element layer and the N-type thermoelectric element layer is not particularly limited, and may be the same thickness or different thicknesses (leading to a step at the connection portion). From the viewpoints of flexibility and material cost, the thickness of the P-type thermoelectric element and the N-type thermoelectric element is preferably 0.1 μm to 300 μm, more preferably 1 μm to 140 μm, and particularly preferably 30 μm to 100 μm.

[0065] The thermoelectric element layer used in the present invention is preferably formed from the thermoelectric semiconductor composition on one surface of the substrate. Methods for applying the thermoelectric semiconductor composition to the substrate include known methods such as screen printing, flexographic printing, gravure printing, spin coating, dip coating, die coating, spray coating, bar coating, and doctor blade coating, and are not particularly limited. When forming a coating film in a pattern, screen printing, slot die coating, and the like are preferably used, which allow for easy pattern formation using a screen plate having a desired pattern. The resulting coating film is then dried to form a thin film, and any conventionally known drying method can be used, such as hot air drying, heated roll drying, infrared irradiation, etc. The heating temperature is usually 80 to 150°C, and the heating time, which varies depending on the heating method, is usually several seconds to several tens of minutes. When a solvent is used in preparing the thermoelectric semiconductor composition, the heating temperature is not particularly limited as long as it is within a temperature range that allows the solvent used to be dried. After forming the thin film, it is preferable to further perform an annealing treatment (hereinafter, sometimes referred to as annealing treatment B). By performing annealing treatment B, the thermoelectric performance can be stabilized and the thermoelectric semiconductor particles in the thin film can undergo crystal growth, thereby further improving the thermoelectric performance. Although there are no particular limitations on annealing treatment B, it is usually performed in an inert gas atmosphere such as nitrogen or argon, in a reducing gas atmosphere, or under vacuum conditions with a controlled gas flow rate, and is performed at 100 to 500°C for several minutes to several tens of hours, depending on the heat resistance temperature of the resin and ionic liquid used.

[0066] <Insulating layer> The thermoelectric conversion module of the present invention may include an insulating layer. The insulating layer is not particularly limited, but is preferably made of a resin or an inorganic material, and from the viewpoint of flexibility, a resin is more preferable.

[0067] The resin is not particularly limited, but examples thereof include resin films. The inorganic material is not particularly limited, and examples thereof include silicon oxide, aluminum oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide, boron nitride, aluminum nitride, silicon carbide, etc. Among these, silicon oxide and aluminum oxide are preferred from the viewpoints of cost, stability, and ease of availability. The thickness of the insulating layer is preferably 1 to 150 μm, and particularly preferably 5 to 100 μm. The insulating layer can be formed by a known method. For example, it may be formed directly on the surface of the thermoelectric element layer, or may be attached via an adhesive layer or the like. Alternatively, an insulating layer previously formed on a release sheet may be attached to the thermoelectric element layer, and the insulating layer may be transferred to the thermoelectric element layer. Two or more types of insulating layers may be laminated, or a covering layer may be interposed.

[0068] <Coating layer> The thermoelectric conversion module of the present invention may include a coating layer. The coating layer is not particularly limited, but examples thereof include a sealing layer and a gas barrier layer.

[0069] The sealing layer may be laminated directly on the thermoelectric element layer, or via a substrate, or via a gas barrier layer or insulating layer, which will be described later. The main component constituting the sealing layer used in the present invention is preferably a polyolefin resin, an epoxy resin, or an acrylic resin. Furthermore, it is preferable that the sealing layer is made of a sealant (hereinafter, sometimes referred to as a "sealant composition") having adhesive properties. In this specification, "having adhesive properties" means that the sealant has adhesive properties, is adhesive, or has adhesive properties in the normal state when attached, and then adheres and hardens upon the application of energy. The use of a sealing layer makes it easy to laminate on the thermoelectric element layer. It also makes it easy to attach to the insulating layer, the high thermal conductivity layer, the gas barrier layer described below, etc. The sealing layer may be one layer or two or more layers stacked together. When two or more layers are stacked together, they may be the same or different. The thickness of the sealing layer is preferably 0.5 to 300 μm, more preferably 10 to 100 μm, and even more preferably 30 to 80 μm. Within this range, when the sealing layer is laminated on the surface of the thermoelectric element layer of the thermoelectric conversion module, the water vapor transmission rate can be reduced and the durability of the thermoelectric conversion module can be improved. Furthermore, as described above, it is preferable that the thermoelectric element layer and the sealing layer are in direct contact with each other, since direct contact between the thermoelectric element layer and the sealing layer prevents water vapor from being directly present between the thermoelectric element layer and the sealing layer, thereby suppressing the penetration of water vapor into the thermoelectric element layer and improving the sealing property of the sealing layer. The sealing layer can be formed by a known method, for example, it may be formed directly on the surface of the thermoelectric element layer and / or on the substrate, or it may be formed by laminating a sealing layer previously formed on a release sheet to the thermoelectric element layer and transferring the sealing layer to the thermoelectric element layer. In addition, two or more sealing layers may be laminated, or an insulating layer or other covering layer may be interposed therebetween.

[0070] The gas barrier layer may be laminated directly on the thermoelectric element layer, or may be composed of a layer containing the main component described below on a substrate, with either side laminated directly on the thermoelectric element layer, or may be laminated via a sealing layer or an insulating layer. The gas barrier layer used in the present invention contains one or more materials selected from the group consisting of metals, inorganic compounds, and polymer compounds as its main component, and the gas barrier layer can improve the durability of the thermoelectric conversion module. Examples of metals include aluminum, magnesium, nickel, zinc, gold, silver, copper, and tin, and these are preferably used as vapor-deposited films. Inorganic compounds include inorganic oxides (MO x ), inorganic nitrides (MN y ), inorganic carbide (MC z ), inorganic oxide carbide (MO x C z ), inorganic carbide nitrides (MN y C z ), inorganic oxide nitrides (MO x N y ), and inorganic oxynitride carbide (MO x N y C z ) and the like. Here, x, y, and z represent the composition ratio of each compound. Examples of M include metal elements such as silicon, zinc, aluminum, magnesium, indium, calcium, zirconium, titanium, boron, hafnium, and barium. Examples of the polymer compound include silicon-containing polymer compounds such as polyorganosiloxane and polysilazane compounds, polyimide, polyamide, polyamideimide, polyphenylene ether, polyether ketone, polyether ether ketone, polyolefin, polyester, etc. These polymer compounds can be used alone or in combination of two or more. The thickness of the layer containing a metal, an inorganic compound, and a polymer compound varies depending on the compounds used, but is usually 0.01 to 50 μm, and preferably 0.03 to 10 μm. If the thickness of the layer containing a metal, an inorganic compound, and a resin is within this range, the water vapor transmission rate can be effectively suppressed.

[0071] The thickness of the gas barrier layer having a substrate of the metal, inorganic compound, or polymer compound is preferably 10 to 80 μm, more preferably 15 to 50 μm. When the thickness of the gas barrier layer is in this range, excellent gas barrier properties can be obtained, and both flexibility and coating strength can be achieved. The gas barrier layer may be a single layer or a laminate of two or more layers, and when two or more layers are laminated, they may be the same or different. The gas barrier layer can be formed by a known method, and may be formed directly on the surface of the thermoelectric element layer and / or on a substrate, or may be formed by attaching a gas barrier layer previously formed on a release sheet to the thermoelectric element layer and transferring the gas barrier layer to the thermoelectric element layer, or may be laminated by opposing a base material having a gas barrier layer to the thermoelectric element layer. Furthermore, two or more types of gas barrier layers may be laminated, and an insulating layer or other covering layer may be interposed therebetween. [Example]

[0072] Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples in any way.

[0073] The electromotive force and the amount of embedded TIM of the thermoelectric conversion modules produced in the examples and comparative examples were evaluated by the following methods.

[0074] (a) Electromotive force evaluation (output evaluation) FIG. 3 is a cross-sectional view showing an example of a configuration for evaluating the electromotive force of a thermoelectric conversion module of the present invention. In the thermoelectric conversion module electromotive force evaluation configuration 31, a heat dissipation member 35 [folding fin OPFF, manufactured by Mogami Inks Co., Ltd.] was installed on the surface of one thermally conductive interface member A 33a on the in-plane type thermoelectric conversion module 32 obtained in the examples and comparative examples, and a temperature controller (heat source) 34 (product name: Peltier temperature controller set VTH1.8-70S, manufactured by VICS Co., Ltd.) was installed on the surface of the other thermally conductive interface member B 33b. The temperature controller (heat source) 34 was set to 60°C, and a temperature difference was applied from the outside. In order to ensure adhesion between the respective members, a heat insulating material 36 [polycarbonate hollow board, manufactured by Hikarisha Co., Ltd., product number: KTP4534W] was placed on the heat dissipation member 35, and a load member 37 [precision weight, stainless steel, 27 gf / cm, manufactured by Murakami Scale Co., Ltd.] was placed on the heat dissipation member 35. 2 ] was used to apply the load. With the temperature difference applied, the electromotive force between the extraction electrodes was measured using a Digital HiTester (manufactured by Hioki E.E. Corporation, model number: 3801-50). (b) Thermal resistance evaluation The thermal resistance (K / W) of the TIM used in the examples and comparative examples was calculated based on the thermal conductivity [W / (m K)], thickness (m), and effective area [0.07 (m) × 0.065 (m) = 4.5 × 10 -3 (m 2 )] and calculated using the following formula (1). Thermal resistance of TIM = TIM thickness / (thermal conductivity of TIM x effective area) (1) Similarly, the thermal conductivity, thickness, and effective area of ​​each of the following layers constituting the in-plane thermoelectric conversion module were calculated. Polyimide film substrate: Thermal conductivity 0.29 [W / (m K)]; Thickness 5.0 × 10 -5 (m); effective area 4.5×10 -3 (m 2 ) Electrode layer: Thermal conductivity 398 [W / (m K)]; Thickness 1.2 × 10 -5 (m); effective area 2.48×10 -3 (m 2 ) Thermoelectric element layer: Thermal conductivity 0.5 [W / (m K)]; Thickness 8.0 × 10 -5 (m); effective area 1.86×10 -3 (m 2 ) Adhesive layer: Thermal conductivity 0.17 [W / (m·K)]; Thickness 5.0×10 -6 (m); effective area 4.5×10 -3 (m 2 ) Coating layer (Al / PET sealing layer): Thermal conductivity 0.3 [W / (m K)]; Thickness 1.2 × 10 -5 (m); effective area 4.5×10 -3 (m 2 ) High thermal conductivity layer: Thermal conductivity 398 [W / (m K)]; Thickness 2.0 × 10 -4 (m); effective area 2.28×10 -3 (m 2 ) From the above, the thermal resistance value R of the thermally conductive interface material A is A (mK / W), thermal resistance value R of thermally conductive interface material B B (mK / W) AB (mK / W), and the total thermal resistance R of the in-plane thermoelectric conversion module M (mK / W) and then R M R AB The ratio (R AB / R M ) was calculated. (c) Embeddability evaluation The embedding depth of the thermally conductive interface material TIM embedded between the high thermal conductivity layers was measured by cross-sectional observation using a digital microscope (Keyence Corporation, model name: VHX-5000), and the ratio of the embedding depth of the thermally conductive interface material TIM embedded between the high thermal conductivity layers to the thickness of the high thermal conductivity layers (embedding ability) was calculated.

[0075] Example 1 (Method for producing thermoelectric semiconductor particles) p-type bismuth telluride Bi, a bismuth-tellurium-based thermoelectric semiconductor material 0.4Te3Sb 1.6 (manufactured by Kojundo Chemical Laboratory, maximum particle size: 90 μm or less) was pulverized using a planetary ball mill (manufactured by Fritsch Japan, Premium line P-7) to produce thermoelectric semiconductor particles T1 with an average particle size of 2.0 μm. Furthermore, n-type bismuth telluride Bi2Te3 (manufactured by Kojundo Chemical Laboratory, maximum particle size: 90 μm or less), which is a bismuth-tellurium based thermoelectric semiconductor material, was pulverized in the same manner as above to produce thermoelectric semiconductor particles T2 with an average particle size of 4.0 μm. The average particle size of each of the thermoelectric semiconductor particles T1 and the thermoelectric semiconductor particles T2 was obtained by measuring the particle size distribution using a laser diffraction particle size analyzer (Malvern, Mastersizer 3000).

[0076] (Preparation of Thermoelectric Semiconductor Composition) Coating liquid (P) P-type bismuth telluride Bi 0.4 Te3Sb 1.6 A coating liquid (P) was prepared, which consisted of a thermoelectric semiconductor composition in which 75.7 parts by mass of particles, 2.41 parts by mass of polyamideimide as a binder resin, 8.8 parts by mass of N-octylpyridinium bromide as an ionic liquid, and 13.09 parts by mass of N-methylpyrrolidone as a solvent were mixed and dispersed. Coating fluid (N) A coating liquid (N) consisting of a thermoelectric semiconductor composition was prepared by mixing and dispersing 82.3 parts by mass of the obtained N-type bismuth telluride Bi2Te3 particles, 2.51 parts by mass of polyamideimide as a binder resin, 4.5 parts by mass of N-octylpyridinium bromide as an ionic liquid, and 10.69 parts by mass of N-methylpyrrolidone as a solvent.

[0077] (Electrode formation and placement) Figure 2 is a plan view showing the configuration of the thermoelectric element layer used in the example, where (a) shows a conceptual diagram of the arrangement of electrodes formed on a film substrate, and (b) shows a conceptual diagram of the arrangement of P-type and N-type thermoelectric element layers formed on the electrodes. A polyimide film substrate with copper foil attached (manufactured by Ube Exsymo Co., Ltd., product name: Upicel N, polyimide substrate thickness: 50 μm, copper foil thickness: 9 μm) was prepared, and the copper foil on the polyimide film substrate 22 was wet-etched using a ferric chloride solution to form an electrode pattern (single layer) 23P made of copper foil in an arrangement corresponding to the arrangement of P-type thermoelectric element layers 24 and N-type thermoelectric element layers 25 described below. Main electrode 23a was formed with a size of 550 μm × 800 μm so as to straddle the boundaries between adjacent P-type thermoelectric element layers 24 and N-type thermoelectric element layers 25 in the arrangement of thermoelectric element layers 26 described below. Here, 23b denotes an electromotive force extraction electrode portion (size: 3 mm × 5 mm), and 23c denotes a connecting electrode portion (size: 550 μm × 2.4 mm) connecting each row of thermoelectric element layers 26. A nickel layer (thickness: 3 μm) was laminated on the patterned copper foil by electroless plating, and then a gold layer (thickness: 40 nm) was laminated on the nickel layer by electroless plating to form electrode pattern (laminate) 23Q.

[0078] (Manufacturing of thermoelectric element layers) The coating liquid (N) prepared above was applied onto the electrode pattern (laminate) 23Q on the polyimide film substrate 22 by screen printing using a printing plate with a thickness of 80 μm and an opening of 1 mm × 0.8 mm, and dried in the atmosphere for 10 minutes at a temperature of 125° C. Next, similarly, the coating liquid (P) prepared above was applied onto the electrode pattern (laminate) 23Q on the polyimide film substrate 22 using a printing plate with a thickness of 30 μm and an opening of 1 mm × 0.8 mm, and dried in the atmosphere for 10 minutes at a temperature of 125° C. Furthermore, the obtained thin films were heated at a rate of 5 K / min in an atmosphere of a mixed gas of hydrogen and argon (hydrogen:argon = 3 vol%:97 vol%) and held at 310°C for 30 minutes, performing an annealing treatment after thin film formation, thereby causing crystal growth of the particles of the thermoelectric semiconductor material, and producing a P-type thermoelectric element layer 24 and an N-type thermoelectric element layer 25. The obtained N-type thermoelectric element layer had a thickness of 80 μm, and the P-type thermoelectric element layer had a thickness of 90 μm.

[0079] (Arrangement of thermoelectric element layers) The resulting P-type thermoelectric element layers 24, each measuring 1 mm × 0.8 mm × 80 μm, and N-type thermoelectric element layers 25, each measuring 1 mm × 0.8 mm × 90 μm, were alternately arranged, adjacent to each other along 0.8 mm sides, forming pairs. In the thermoelectric element layer 26, 408 pairs of P-type thermoelectric element layers 24 and N-type thermoelectric element layers 25 were formed, and were arranged electrically in series within the surface of the polyimide film substrate 22 to form the thermoelectric element layer 26. The P-type thermoelectric element layers 24 and N-type thermoelectric element layers 25 were electrically connected by main electrodes 23 a. The thermoelectric element layer 26 had a folded structure. Specifically, 24 rows were arranged, each consisting of 17 pairs of P-type thermoelectric element layers 24 and N-type thermoelectric element layers 25, with connecting electrodes 23 c connecting the rows. It should be noted that FIG. 3 shows a conceptual arrangement of the electrodes and thermoelectric element layers, and the dimensions, number, etc. of the electrodes and thermoelectric element layers that are actually fabricated will differ.

[0080] (Arrangement of coating layer and high thermal conductive layer) An aluminum-deposited PET film (manufactured by BAX, thickness: 12 μm) was used as the insulating layer, and an adhesive layer (manufactured by Somar, product name: EP-0002EF-01MB, thickness: 25 μm) was laminated on both sides to form a covering layer. The lamination was performed at a temperature of 80°C. The top surface of the thermoelectric element layer-attached substrate (the surface of the thermoelectric element layer) was covered with the above-mentioned coating layer, and the bottom surface (the side opposite the thermoelectric element layer) was covered with a single adhesive layer (manufactured by Somar, product name: EP-0002EF-01MB, thickness: 25 μm). High-thermal-conductivity layers (C1020, thickness: 200 μm, width: 1 mm, length: 100 mm, spacing: 1 mm, thermal conductivity: 398 (W / (m K))) made of a high-thermal-conductivity material (copper foil) were intermittently placed above and below the adjacent P-type and N-type thermoelectric element layers. The coating layer on the top surface of the thermoelectric element layer-attached substrate was positioned so that the aluminum-coated surface of the aluminum-coated PET film was far from the thermoelectric element layer. The coating layer was laminated onto the thermoelectric element layer and the adhesive layer was laminated onto the substrate under vacuum conditions at a temperature of 80°C and a pressure of 0.2 MPa for 10 seconds. The high thermal conductivity layer was laminated onto the coating layer and adhesive layer under vacuum conditions at a temperature of 80°C. Thereafter, the thermoelectric conversion module was left standing in an environment at 150° C. for 30 minutes to harden the adhesive layer, thereby obtaining an in-plane type thermoelectric conversion module.

[0081] (TIM placement) The in-plane thermoelectric module was fabricated with R AB / R M A TIM (manufactured by Sekisui Polymatech Co., Ltd., product number: Manion50α, thickness: 0.50 mm, thermal conductivity: 17 W / (m K)) with a thermal conductivity of 0.08 was installed, and the electromotive force between the extraction electrodes of the obtained thermoelectric conversion module was measured based on the above-mentioned (a) electromotive force evaluation (output evaluation).

[0082] Example 2 In Example 1, R AB / R M The electromotive force between the extraction electrodes was measured in the same manner as in Example 1, except that a TIM (manufactured by Sekisui Polymatech Co., Ltd., product number: PT-V, thickness: 0.50 mm, thermal conductivity: 12 W / (m K)) satisfying a coefficient of thermal conductivity of 0.12 was installed.

[0083] Example 3 In Example 1, R AB / R M The electromotive force between the extraction electrodes was measured in the same manner as in Example 1, except that a TIM [manufactured by 3M, product number: 8926, thickness: 0.20 mm, thermal conductivity: 1.5 W / (m·K)] satisfying a thermal conductivity of 0.38 was installed.

[0084] (Comparative Example 1) In Example 1, the electromotive force between the extraction electrodes was measured in the same manner as in Example 1, except that no TIM was provided on the top and bottom surfaces of the in-plane type thermoelectric conversion module.

[0085] (Comparative Example 2) In Example 1, R AB / R M The electromotive force between the extraction electrodes was measured in the same manner as in Example 1, except that a TIM [manufactured by 3M, product number: VHR0601, thickness: 0.30 mm, thermal conductivity: 0.6 W / (m·K)] satisfying a thermal conductivity of 1.44 was installed.

[0086] Table 1 shows the evaluation results of the embeddability of the TIM and the electromotive force of the thermoelectric conversion modules obtained in Examples 1 to 3 and Comparative Examples 1 and 2.

[0087] [Table 1]

[0088] High embeddability and R M R AB The ratio (R AB / R M The electromotive force obtained from the thermoelectric conversion modules of Examples 1 to 3, in which R M R AB The ratio (R AB / R M ) is higher than the electromotive forces obtained from the thermoelectric conversion modules of Comparative Examples 1 and 2, which do not satisfy the requirements of the present invention, and it is clear that the thermoelectric performance is improved. [Industrial Applicability]

[0089] The thermoelectric conversion module of the present invention provides a thermoelectric conversion module with improved electromotive force, and is therefore potentially applicable to power generation applications such as converting exhaust heat from various combustion furnaces, such as factories, waste incineration furnaces, and cement combustion furnaces, exhaust heat from automobile combustion gases, and exhaust heat from electronic devices into electricity. Conceivable cooling applications include temperature control of various sensors, such as CPUs (Central Processing Units) used in smartphones and various computers, image sensors, such as CMOS (Complementary Metal Oxide Semiconductors) and CCD (Charge Coupled Devices), and MEMS (Micro Electro Mechanical Systems), light-receiving elements, etc., in the field of electronic devices. [Explanation of symbols]

[0090] 1: Thermoelectric conversion module 2: Circuit board 3: Electrode 4: P-type thermoelectric element layer 5: N-type thermoelectric element layer 6: Thermoelectric element layer 7: Covering layer 8A: High thermal conductivity layer A 8B: High thermal conductivity layer B 8a: High thermal conductivity layer a 8b: High thermal conductivity layer b 9: In-plane thermoelectric conversion module 10a: Thermally conductive interface member A 10b: Thermally conductive interface member B 11: Heat dissipation material 22: Polyimide film substrate 23P: Electrode pattern (single layer) 23Q: Electrode pattern (lamination) 23a: Main electrode 23b: Electrode part for taking out electromotive force 23c: Connection electrode part 24: P-type thermoelectric element layer 25: N-type thermoelectric element layer 26: Thermoelectric element layer 31: Thermoelectric conversion module electromotive force evaluation configuration 32: In-plane thermoelectric conversion module 33a: Thermally conductive interface member A 33b: Thermally conductive interface member B 34: Temperature controller (heat source) 35: Heat dissipation material 36: Heat insulating material 37: Load-bearing member

Claims

1. A thermoelectric conversion module including a thermally conductive interface member A and a heat dissipation member on one surface of the in-plane type thermoelectric conversion module, and further including a thermally conductive interface member B on the other surface of the in-plane type thermoelectric conversion module, The in-plane thermoelectric conversion module further includes a high thermal conductive layer A and a high thermal conductive layer B, the high thermal conductivity layer A constitutes the outermost layer of the in-plane thermoelectric conversion module on the thermally conductive interface member A side, the high thermal conductivity layer B constitutes the outermost layer of the in-plane type thermoelectric conversion module on the thermally conductive interface member B side, The high thermal conductivity layer A is composed of a plurality of high thermal conductivity layers a arranged at intervals, and a portion of the thermally conductive interface member A is embedded as a continuous layer in the gaps between adjacent high thermal conductivity layers a, and the high thermal conductive layer B is composed of a plurality of high thermal conductive layers b arranged at intervals, and a portion of the thermally conductive interface member B is embedded as a continuous layer in the gaps between adjacent high thermal conductive layers b; a ratio M of the embedding depth of the portion of the thermally conductive interface member A to the thickness of the high thermal conductivity layer A is 0.01 to 1.00, and a ratio N of the embedding depth of the portion of the thermally conductive interface member B to the thickness of the high thermal conductivity layer B is 0.01 to 1.00; The thermal resistance value of the thermally conductive interface member A is R Ａ (mK / W), the thermal resistance value of the thermally conductive interface member B is R Ｂ (mK / W), and the sum of these, the total thermal resistance, is R ＡＢ (mK / W), and the total thermal resistance of the in-plane thermoelectric conversion module is R Ｍ (mK / W), the R Ｍ The R ＡＢ The ratio (R ＡＢ / R Ｍ ) is 0.01 or more and 1.40 or less.

2. The thermoelectric conversion module according to claim 1 , wherein the thermally conductive interface member A and the thermally conductive interface member B are each independently a resin layer or an organic layer.

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