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 having a thermoelectric effect such as the Seebeck effect or the Peltier effect. As a thermoelectric conversion module, a configuration of a so-called in-plane type thermoelectric conversion element is known. From the viewpoint of thermoelectric performance, the in-plane type thermoelectric conversion element is usually configured by alternately arranging P-type thermoelectric elements and N-type thermoelectric elements in the in-plane direction of a substrate, and, for example, connecting the upper or lower parts of adjacent or abutting P-type thermoelectric elements and N-type thermoelectric elements in series via electrodes. In this situation, various demands remain for in-plane type thermoelectric conversion modules, such as further improvement in thermoelectric performance, thinning, 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 type thermoelectric conversion module, and no consideration is given to the placement of another specific insulating layer on the in-plane type thermoelectric conversion module from the viewpoint of improving thermoelectric performance, or the relationship between the thermal resistance value of the other specific insulating layer and the thermal resistance value of the components that constitute the in-plane type 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 a thermally conductive interface material (hereinafter sometimes simply referred to as "TIM") having a thermal resistance value at a specific ratio to a total thermal resistance value, which is the sum of the thermal resistance values ​​of each component constituting the in-plane type thermoelectric conversion module, on the top and bottom surfaces of the in-plane type thermoelectric conversion module, the thermal conductivity of the interface between the components constituting the in-plane type 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, 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 above R M R AB Ratio of (RAB / R M ) is 1.40 or less. [2] The thermoelectric conversion module according to the above item [1], further comprising a high thermal conductive layer A and a high thermal conductive layer B, the high thermal conductive layer A constituting the outermost layer of the in-plane type thermoelectric conversion module on the thermal conductive interface member A side, and the high thermal conductive layer B constituting the outermost layer of the in-plane type thermoelectric conversion module on the thermal conductive interface member B side. [3] The thermoelectric conversion module according to the above item [2], wherein the high thermal conductivity layer A is composed of a plurality of high thermal conductivity layers a arranged at intervals, with a portion of the thermal conductive interface member A embedded in the gaps between adjacent high thermal conductivity layers a, and the high thermal conductivity layer B is composed of a plurality of high thermal conductivity layers b arranged at intervals, with a portion of the thermal 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 an embedding depth of the part of the thermally conductive interface member A to a thickness of the high thermal conductivity layer A is 0.01 to 1.00, and a ratio N of an embedding depth of the part of the thermally conductive interface member B to a 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. Effect 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 conductivity at the interface between members. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing an embodiment of a thermoelectric conversion module of the present invention. [Diagram 2]FIG. 2 is a plan view showing an example of an arrangement of electrodes and a thermoelectric element layer on a substrate constituting a part of a thermoelectric conversion module used in an example of the present invention. [Diagram 3] FIG. 2 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 PREFERRED EMBODIMENTS

[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 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 above R M R AB Ratio of (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 The thermal resistance value R of TIMA A and the thermal resistance value R of TIMB B The total thermal resistance R AB Ratio of (R AB / R M) to 1.40 or less, the heat transfer properties at the interfaces between the members constituting the in-plane type thermoelectric conversion module can be improved, resulting in higher thermoelectric performance.

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

[0011] In this specification, preferred definitions may be selected arbitrarily, and combinations of preferred definitions may be considered more preferred. In this specification, the expression "XX to YY" means "at least XX and at most YY." In this specification, the lower limit and upper limit described in stages for the preferred numerical range (e.g., range of content, etc.) 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] Hereinafter, the thermoelectric conversion module of the present invention will be described with reference to the drawings.

[0013] 1 is a cross-sectional view showing an embodiment of a thermoelectric conversion module of the present invention. The thermoelectric conversion module 1 includes a thermally conductive interface member A10a and a heat dissipation member 11 on one surface of an in-plane type thermoelectric conversion module 9, and further includes a thermally conductive interface member B10b on the other surface of the in-plane type thermoelectric conversion module 9. The in-plane type thermoelectric conversion module 9 includes a high thermal conductivity layer A8A consisting of a plurality of high thermal conductivity layers a8a arranged at intervals via a coating layer 7 on one surface of a thermoelectric element layer 6 formed by alternately adjacent (contacting) a P-type thermoelectric element layer 4 and an N-type thermoelectric element layer 5 in the in-plane direction of a substrate 2 and arranged in series via a common electrode 3, and further includes a high thermal conductivity layer B8B consisting of an electrode 3 and a plurality of high thermal conductivity layers b8b arranged at intervals via the substrate 2 on the other surface of the thermoelectric element layer 6. 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 generated 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 generated 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 members 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 Ratio (R AB / R M ) to 1.40 or less, the heat transfer properties at the interfaces between the members constituting the in-plane type thermoelectric conversion module can be improved, resulting in higher thermoelectric performance.

[0014] The total thermal resistance R is the sum of the thermal resistances of the individual components that make up the in-plane thermoelectric conversion module. M The thermal resistance value R of TIMA A and the thermal resistance value R of TIMB B The total thermal resistance R AB 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 When the ratio (R) is within this range, the heat transfer at the interface between the members is more easily improved, and the thermoelectric performance is improved.

[0015] <Thermal conductive interface member A and the thermal conductive interface member B> In the thermoelectric conversion module of the present invention, a thermally conductive interface member A is provided between the upper surface of the in-plane type thermoelectric conversion module and the heat dissipation member, and a thermally conductive interface member B is provided 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 type 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 type thermoelectric conversion module and, for example, a heat source, the contact thermal resistance occurring therebetween can be reduced. In this way, by using the thermally conductive interface member A and the thermally conductive interface member B, the thermal conduction within the in-plane type thermoelectric conversion module is easily improved, which can lead to an improvement in the thermoelectric performance of the thermoelectric conversion module.

[0016] It is preferable that the thermally conductive interface member A and the thermally conductive interface member B are 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 and the like. Examples of the resin material include thermosetting resins, thermoplastic resins, photocurable resins, etc. Examples of the resin material 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, 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 products 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 viewpoints 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 conformability 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 any of an emulsion type, a solvent type, or a solventless type, and may be any of a crosslinked type or a non-crosslinked type. Among them, an acrylic adhesive or a silicone adhesive is preferred.

[0021] From the viewpoint of improving the thermal conductivity, the resin layer may be filled with a thermally conductive filler. The thermally conductive filler is not particularly limited, and 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, further 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 appropriately adjusted according to the desired thermal conductivity, and is preferably 40 to 99 mass %, more preferably 50 to 95 mass %, and particularly preferably 50 to 80 mass % in the resin composition. When the content of the thermally conductive filler is within this range, the heat dissipation characteristics, folding resistance, and flex resistance are excellent, and the strength of the thermally conductive interface member is maintained.

[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 further preferably 0.10 to 1.00 mm. When 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, product number: Manion50α, thickness: 0.50 mm, thermal conductivity: 17 W / (m·K)), heat dissipation sheet TIMLIGHT (manufactured by Sekisui Polymatech, product number: PT-V, thickness: 0.50 mm, thermal conductivity: 12 W / (m·K)), thermally conductive double-sided tape (manufactured by 3M, product number: 8926, thickness: 0.20 mm, thermal conductivity: 1.5 W / (m·K)), thermally conductive double-sided tape (manufactured by 3M, 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 capable of conducting generated heat and dissipating it to the outside, and is not particularly limited, but examples thereof include a heat sink, a heat spreader, etc. Examples of materials for the heat sink and the heat spreader include copper, aluminum, etc. In addition to the heat spreader and the heat sink, examples of the heat dissipation member include a radiator, a cooler, a cooling fan, a heat pipe, a vapor chamber, a metal cover, a housing, etc. The heat pipe is, for example, a hollow structure having a cylindrical, approximately cylindrical, or flattened tubular shape.

[0025] (High thermal conductive layer A and high thermal conductive 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 on the thermally conductive interface member A side of the in-plane type thermoelectric conversion module, and the high thermal conductivity layer B constitutes the outermost layer on the thermally conductive interface member B side of the in-plane type thermoelectric conversion module.

[0026] From the viewpoint of suppressing the contact thermal resistance at the interfaces between each component of the in-plane type thermoelectric conversion module and further improving the heat transfer, it is preferable that the high thermal conductivity layer A is composed of a plurality of high thermal conductivity layers a arranged at intervals, and that a part of the thermally conductive interface member A is embedded in the gaps between adjacent high thermal conductivity layers a. Similarly, the highly thermally conductive layer B is preferably composed of a plurality of highly thermally conductive layers b arranged at intervals, with a portion of the thermally conductive interface member B embedded in the gaps between adjacent highly thermally conductive 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 further preferably 0.60 to 0.90. The 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 preferably 0.01 to 1.00, more preferably 0.10 to 0.95, and further preferably 0.60 to 0.90. When the ratios M and N are within these ranges, the heat transfer properties at the interfaces between the members are more likely to be improved, and the thermoelectric performance is more improved. Here, "the embedding depth of a part of the thermally conductive interface member A" means, for example, the maximum distance in the thickness direction starting from the upper surface of the high thermal conductivity layer a8a when a part of the thermally conductive interface member A10a in contact with the upper surface of the high thermal conductivity layer a8a in FIG. 1 enters partially into a 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, 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 in FIG. 1 enters partially into 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 highly thermally conductive layer A, the highly thermally conductive layer a, the highly thermally conductive layer B, and the highly thermally conductive layer b may be simply referred to as "highly thermally conductive layers".

[0029] The arrangement of the highly thermally conductive layer used in the present invention is not particularly limited, but must be appropriately adjusted depending on the arrangement and shapes 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 the high thermal conductive layer b8b or the high thermal conductive layer a8a is repeatedly arranged at a predetermined interval on the surface of the substrate 2 or the covering layer 7 opposite to the thermoelectric element layer 6 side so as to straddle the extension line of the boundary surface joining the P-type thermoelectric element layer 4 and the N-type thermoelectric element layer 5. It is also preferable that the high thermal conductive layer a8a and the high thermal conductive layer b8b straddle only one extension line of the boundary surface, and that the high thermal conductive layer a and the high thermal conductive layer b are arranged alternately when viewed in a cross section in the thickness direction as shown in Figure 1. It is presumed that by arranging the high thermal conductive layer a and the high thermal conductive layer b in this way, high temperature regions and low temperature regions are continuously formed in order inside the thermoelectric element layer 6 in a direction parallel to the plane of the substrate 2 and the plane of the covering layer 7, and power generation efficiency is improved. 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 applied in the in-plane direction of the thermoelectric element layer 6. The ratio of the highly thermally conductive layer to the total width in the series direction consisting of a pair of P-type thermoelectric element layer 4 and N-type thermoelectric element layer 5 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 highly thermally conductive layer is within this range, heat can be selectively dissipated in a specific direction, and a temperature difference can be efficiently applied in the in-plane direction of the thermoelectric element layer 6. Furthermore, it is preferable that the above is satisfied and that the highly thermally conductive layer is symmetrically disposed at the abutting portion consisting of a pair of P-type thermoelectric element layer 4 and N-type thermoelectric element layer 5 in the series direction.

[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 includes 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 a photolithography method, 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 fibers, or mixtures of these materials with resins. Among these, the high thermal conductivity layer is preferably at least one 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 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. Ceramic materials include barium titanate, aluminum nitride, boron nitride, aluminum oxide, silicon carbide, silicon nitride, and the like. 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 above-mentioned resins can be used. Representative metal materials having high thermal conductivity that can be used in the present invention are shown below. Oxygen-free copper Oxygen-free copper (OFC) generally refers to high purity copper with a purity of 99.95% (3N) or more that does not contain 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 applied in the in-plane direction of the thermoelectric element layer in which the P-type thermoelectric element layer and the N-type thermoelectric element layer are alternately adjacent to each other in the in-plane direction and arranged in series with the 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 preferable because they have excellent flexibility, and even when a thin film made of a thermoelectric semiconductor composition described later is annealed, the substrate does not thermally deform, and the performance of the thermoelectric element layer can be maintained, and they have high heat resistance and dimensional stability, and further, polyimide films are particularly preferable because they are highly versatile.

[0035] From the viewpoints of flexibility, heat resistance, and dimensional stability, the thickness of the substrate is preferably from 1 μm to 1000 μm, more preferably from 10 μm to 500 μm, and even more preferably from 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 constituting the thermoelectric element layer described below. Examples of the electrode material 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 further preferably 50 nm to 120 μm. If 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 having no pattern is provided on a film substrate, and then processing the electrode layer 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. Methods for forming an electrode layer on which no pattern is formed 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 methods, electrolytic plating, electroless plating, and lamination of metal foils, and are appropriately selected 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 layer and the N-type thermoelectric element layer are alternately adjacent to each other in the in-plane direction and arranged in series, and are electrically connected in series. Furthermore, the connection between the P-type thermoelectric element layer and the N-type thermoelectric element layer may be via the above-mentioned electrode layer formed 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, the layer 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 a thermoelectromotive force 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, Zn3Sb 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, in the N-type bismuth telluride, the carriers are electrons and the Seebeck coefficient is a negative value. 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 in the range of 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 that high thermoelectric performance is exhibited, and a film having 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, a ball mill, a bead mill, a colloid mill, a conical mill, a disk mill, an edge mill, a powder mill, a hammer mill, a pellet mill, a Willy mill, a 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 the median value of the particle size distribution is used.

[0044] In addition, the thermoelectric semiconductor particles are preferably annealed (hereinafter, sometimes referred to as "annealing treatment A"). By carrying out the annealing treatment A, the crystallinity of the thermoelectric semiconductor particles is improved, and further, the surface oxide film of the thermoelectric semiconductor particles is removed, so that the Seebeck coefficient (absolute value of the Peltier coefficient) of the thermoelectric conversion material increases, and the thermoelectric figure of merit can be further improved. The annealing treatment A is not particularly limited, but is preferably carried out under an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere such as hydrogen, or under vacuum conditions with a controlled gas flow rate, before preparing the thermoelectric semiconductor composition, so as not to adversely affect the thermoelectric semiconductor particles, and more preferably under 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 carry out the annealing treatment at a temperature below the melting point of the particles and 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 various physical properties such as mechanical strength and thermal conductivity as a resin without being impaired when the thermoelectric semiconductor particles are crystal-grown by annealing a thin film made of a 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 resin 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, and 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 adhesion to the polyimide film. In the present invention, polyimide resin is a general term for 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 thermoelectric semiconductor composition does not lose its function as a binder and can maintain the flexibility of the thermoelectric element layer, even when the thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0047] 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, the thermoelectric element layer can maintain its flexibility without losing its function as a binder, even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0048] The amount of the heat-resistant resin in the thermoelectric semiconductor composition is preferably 0.1 to 40% by mass, and more preferably 1 to 20% by mass. When the amount of the heat-resistant resin 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 an anion, and refers to a salt that can exist in a liquid state in any temperature range of -50°C or more and less than 400°C. In other words, the ionic liquid is an ionic compound having a melting point in the range of -50°C or more and less than 400°C. The melting point of the ionic liquid is more preferably 0°C to 150°C. The ionic liquid has characteristics such as extremely low vapor pressure, non-volatility, excellent thermal stability and electrochemical stability, low viscosity, and high ionic conductivity, and therefore can effectively suppress the reduction in electrical conductivity between thermoelectric semiconductor particles as a conductive auxiliary. In addition, the ionic liquid exhibits high polarity based on an aprotic ionic structure and has excellent compatibility with heat-resistant resins, so that the electrical conductivity of the thermoelectric element layer can be made uniform.

[0050] The ionic liquid may be a known or commercially available one. For example, a mixture of a cationic component such as a pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, imidazolium, etc., and a derivative thereof; a tetraalkylammonium-based amine-based cation and a derivative thereof; a phosphine-based cation such as a phosphonium, trialkylsulfonium, tetraalkylphosphonium, etc., and a derivative thereof; a lithium cation and a derivative thereof; and a mixture of a Cl cation and ... - , 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, more preferably 10 -6 If the electrical conductivity is within 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 effect as a conductive auxiliary agent can be maintained even when a thin film made of the thermoelectric semiconductor composition is annealed, as described below.

[0053] 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 effect as a conductive auxiliary 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 a solid at room temperature, has a melting point at any temperature in the temperature range of 400 to 900°C, and has characteristics such as high ionic conductivity, so that it can suppress the decrease in electrical conductivity between thermoelectric semiconductor particles as a conductive auxiliary.

[0056] As the cation, a metal cation is used. Examples of the metal cation 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] The anion may be, for example, 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 any known or commercially available inorganic ionic compound. For example, a cationic component such as potassium cation, sodium cation, or lithium cation and a 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 cationic component of the inorganic ionic compound contains at least one selected from potassium, sodium, and lithium. In addition, it is preferable that the anionic component of the inorganic ionic compound contains a halide anion, and Cl is preferably 0.01 to 0.01. - , 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 the 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 auxiliary agent can be maintained even when a thin film made of the thermoelectric semiconductor composition is annealed, as described later.

[0062] The inorganic ionic compound preferably has 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 effect as a conductive auxiliary 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, the decrease in electrical conductivity can be effectively suppressed, and as a result, a film with improved thermoelectric performance can be obtained. In addition, 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 %, and 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 (a step is generated at the connection portion). From the viewpoint 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 onto the substrate include known methods such as screen printing, flexographic printing, gravure printing, spin coating, dip coating, die coating, spray coating, bar coating, doctor blade, etc., and are not particularly limited. When forming a coating film in a pattern, screen printing, slot die coating, etc., which can easily form a pattern using a screen plate having a desired pattern, are preferably used. The coating film thus obtained is then dried to form a thin film, and the drying method may be any conventionally known method such as hot air drying, hot roll drying, infrared irradiation, etc. The heating temperature is usually 80 to 150° C., and the heating time varies depending on the heating method, but is usually several seconds to several tens of minutes. 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 a temperature range in which the solvent used can be dried. After the thin film is formed, it is preferable to further perform an annealing treatment (hereinafter, sometimes referred to as annealing treatment B). By performing the annealing treatment B, the thermoelectric performance can be stabilized and the thermoelectric semiconductor particles in the thin film can be crystallized, thereby further improving the thermoelectric performance. Although there are no particular limitations, the annealing treatment B is usually performed under an inert gas atmosphere such as nitrogen or argon with a controlled gas flow rate, under a reducing gas atmosphere, or under vacuum conditions, 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 it may be attached via an adhesive layer or the like. Alternatively, the insulating layer may be formed by attaching an insulating layer previously formed on a release sheet to the thermoelectric element layer, and transferring the insulating layer to the thermoelectric element layer. Also, 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 may be laminated via a gas barrier layer or an insulating layer, which will be described later. The main component constituting the sealing layer used in the present invention is preferably a polyolefin-based resin, an epoxy-based resin, or an acrylic-based resin. In addition, it is preferable that the sealing layer is made of a sealant having adhesive properties (hereinafter, sometimes referred to as a "sealant composition"). In this specification, having adhesive properties means that the sealant has adhesive properties, adhesion properties, and adhesion in the normal state when applied, and then adheres and hardens by the addition of energy. By using the sealing layer, it is possible to easily laminate it on the thermoelectric element layer. It is also easy to apply it to the insulating layer, the high thermal conductive layer, the gas barrier layer described later, etc. The sealing layer may be one layer or two or more layers laminated together. When two or more layers are laminated 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 further preferably 30 to 80 μm. If the thickness is 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 suppressed 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. By directly contacting the thermoelectric element layer and the sealing layer, water vapor in the atmosphere is not directly present between the thermoelectric element layer and the sealing layer, so that the penetration of water vapor into the thermoelectric element layer is suppressed, and the sealing property of the sealing layer is improved. 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 attaching a sealing layer formed in advance on a release sheet to the thermoelectric element layer and transferring the sealing layer to the thermoelectric element layer. In addition, two or more kinds of 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 a main component described later on a substrate, with either side of the layer 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 at least one material selected from the group consisting of metals, inorganic compounds, and polymer compounds as a main component. 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 it is preferable to use these as a vapor-deposited film. 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 Here, x, y, and z represent the composition ratio of each compound. The M may be a metal element such as silicon, zinc, aluminum, magnesium, indium, calcium, zirconium, titanium, boron, hafnium, or 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 the metal, inorganic compound, and polymer compound varies depending on the compound used, but is usually 0.01 to 50 μm, preferably 0.03 to 10 μm. If the thickness of the layer containing the metal, inorganic compound, and resin is within this range, the water vapor transmission rate can be effectively suppressed.

[0071] The thickness of the gas barrier layer having a base material of the metal, inorganic compound, or polymer compound is preferably 10 to 80 μm, and 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 flexibility and film strength can be both achieved. The gas barrier layer may be one layer or two or more layers laminated. 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 the 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. In addition, two or more types of gas barrier layers may be laminated, and may be laminated via an insulating layer or other covering layer. EXAMPLES

[0072] The present invention will now 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 embedded amount of 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] was installed on the surface of one of the thermally conductive interface members 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 (manufactured by VICS, product name: Peltier temperature controller set VTH1.8-70S) was installed on the surface of the other thermally conductive interface member B 33b, and the temperature controller (heat source) 34 was set to 60°C to apply a temperature difference from the outside. In order to ensure the adhesion of each member, a heat insulating material 36 [polycarbonate hollow board, manufactured by Hikarisha, 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 )] was used to calculate the value from the following formula (1). Thermal resistance of TIM = thickness of TIM / (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 type 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 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 R M R AB 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 conductive 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 conductive layers to the thickness of the high thermal conductive layers (embedding ability) was calculated.

[0075] Example 1 (Method of 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. In addition, 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 having 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) The P-type bismuth telluride Bi 0.4 Te3Sb 1.6 A coating liquid (P) was prepared comprising 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 arrangement) FIG. 2 is a plan view showing the configuration of the thermoelectric element layer used in the embodiment, 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: 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 arranged corresponding to the arrangement of the P-type thermoelectric element layer 24 and the N-type thermoelectric element layer 25 described later. The main electrode 23a was formed with a size of 550 μm × 800 μm so as to straddle each boundary between the adjacent P-type thermoelectric element layer 24 and N-type thermoelectric element layer 25 in the arrangement of the thermoelectric element layer 26 described later. Here, 23b indicates an electromotive force extraction electrode portion (size: 3 mm × 5 mm), and 23c indicates a connection electrode portion (size: 550 μm × 2.4 mm) that connects the thermoelectric element layers 26 of each row. 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 an electrode pattern (laminate) 23Q.

[0078] (Manufacturing of thermoelectric element layer) 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 plate 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, the coating liquid (P) prepared above was similarly applied onto the electrode pattern (laminate) 23Q on the polyimide film substrate 22 using a printing plate with a plate 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 each heated at a heating 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 the formation of the thin films, 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 obtained P-type thermoelectric element layer 24 of 1 mm×0.8 mm×80 μm thickness and N-type thermoelectric element layer 25 of 1 mm×0.8 mm×90 μm thickness are alternately arranged, and are adjacent to each other so as to be in contact with each other alternately along a side having a length of 0.8 mm, forming one pair. In the thermoelectric element layer 26, 408 pairs of the P-type thermoelectric element layer 24 and the N-type thermoelectric element layer 25 are formed, and are provided in electrical series within the surface of the polyimide film substrate 22 to constitute the thermoelectric element layer 26, and the P-type thermoelectric element layer 24 and the N-type thermoelectric element layer 25 are electrically connected by the main electrode 23a. The thermoelectric element layer 26 has a folded structure. Specifically, 17 pairs of the P-type thermoelectric element layer 24 and the N-type thermoelectric element layer 25 are connected to each other to form one row, and 24 rows are provided via the connecting electrode portion 23c that connects 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 may 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 an insulating layer, and an adhesive layer (manufactured by Somar, product name: EP-0002EF-01MB, thickness: 25 μm) was laminated on both sides to create a covering layer. The lamination was performed at a temperature of 80°C. The top surface (surface of the thermoelectric element layer) of the prepared substrate with thermoelectric element layer was covered with the above-mentioned covering layer, and the bottom surface (the surface opposite to the surface on which the thermoelectric element layer is provided) was covered with a single covering layer of an adhesive layer (manufactured by Somar, product name: EP-0002EF-01MB, thickness: 25 μm). A high thermal conductivity layer made of a high thermal conductivity material (copper foil) [C1020, thickness: 200 μm, width: 1 mm, length: 100 mm, spacing: 1 mm, thermal conductivity: 398 (W / (m K))] was intermittently arranged above and below the area where the P-type thermoelectric element layer and the N-type thermoelectric element layer were adjacent to each other. In this case, the covering layer provided on the top surface of the substrate with thermoelectric element layer was arranged so that the aluminum-deposited surface of the aluminum-deposited PET film was distant 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 at a temperature of 80°C under vacuum conditions. Thereafter, the thermoelectric conversion module was left to stand in an environment of 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 satisfying the thermal conductivity of 0.12 (manufactured by Sekisui Polymerec Co., Ltd., product number: PT-V, thickness: 0.50 mm, thermal conductivity: 12 W / (m K)) 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 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 in the thermoelectric conversion modules obtained in Examples 1 to 3 and Comparative Examples 1 and 2.

[0087] [Table 1]

[0088] High embeddability, R M R AB 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 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] According to the thermoelectric conversion module of the present invention, a thermoelectric conversion module with improved electromotive force can be obtained, and therefore it is possible to apply it to power generation applications such as converting exhaust heat from various combustion furnaces such as factories, waste combustion furnaces, and cement combustion furnaces, exhaust heat from automobile combustion gases, and exhaust heat from electronic devices into electricity. As cooling applications, in the field of electronic devices, it is possible to apply it to 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 further, MEMS (Micro Electro Mechanical Systems), light receiving elements, etc. [Explanation of symbols]

[0090] 1: Thermoelectric conversion module 2: Substrate 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 type thermoelectric conversion module 10a: Thermally conductive interface member A 10b: Thermally conductive interface material 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 type thermoelectric conversion module 33a: Thermally conductive interface material A 33b: Thermally conductive interface material B 34: Temperature controller (heat source) 35: Heat dissipation material 36: Thermal insulation material 37: Loading member

Claims

1. A thermoelectric conversion module including a thermal conductivity interface member A and a heat dissipation member on one surface of an in-plane type thermoelectric conversion module, and further including a thermal conductivity interface member B on the other surface of the in-plane type thermoelectric conversion module, 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 constitutes the outermost layer on the thermal conductivity interface member A side of the in-plane type thermoelectric conversion module, the high thermal conductivity layer B constitutes the outermost layer on the thermal conductivity interface member B side of the in-plane type thermoelectric conversion module, the high thermal conductivity layer A is composed of a plurality of high thermal conductivity layers a arranged at intervals, and a part of the thermal conductivity interface member A is embedded as a continuous layer without interruption in the gap between adjacent high thermal conductivity layers a, and the high thermal conductivity layer B is composed of a plurality of high thermal conductivity layers b arranged at intervals, and a part of the thermal conductivity interface member B is embedded as a continuous layer without interruption in the gap between adjacent high thermal conductivity layers b, the ratio M of the embedding depth of a part of the thermal conductivity interface member A to the thickness of the high thermal conductivity layer A is 0.01 to 1.00, and the ratio N of the embedding depth of a part of the thermal conductivity interface member B to the thickness of the high thermal conductivity layer B is 0.01 to 1.00, Let the thermal resistance value of the thermal conductive interface member A be R Ａ (mK / W), and let the thermal resistance value of the thermal conductive interface member B be R Ｂ (mK / W). Let the total thermal resistance value, which is the sum of these, be R ＡＢ (mK / W). Further, when the total thermal resistance value of the in-plane type thermoelectric conversion module is R Ｍ (mK / W), when the ratio (R Ｍ with respect to R ＡＢ (R ＡＢ / R Ｍ ) is 1.40 or less, a thermoelectric conversion module.

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

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