WO2013065856A1

WO2013065856A1 - Thermoelectric conversion element and thermoelectric conversion module

Info

Publication number: WO2013065856A1
Application number: PCT/JP2012/078547
Authority: WO
Inventors: 雅芳角野; 規之殿内
Original assignee: 日本電気株式会社
Priority date: 2011-11-01
Filing date: 2012-10-29
Publication date: 2013-05-10
Also published as: JPWO2013065856A1

Abstract

A thermoelectric conversion element of the invention is provided with a substrate, an insulator film positioned opposite the substrate, a conductive film thermally coupled to the substrate and the insulator film, and a heat-insulating material for supporting the conductive film; the conductive film includes a conductive polymer which is a thermoelectric material, and the conductive polymer is positioned in a direction almost perpendicular to the substrate. Further, a thermoelectric conversion module of the invention is provided with a plurality of thermoelectric conversion elements, and a plurality of parts positioned on the conductive film substrate side and a plurality of parts positioned on the conductive film insulator film side adjacent to the conductive film are continuously connected in series using conductive wires.

Description

Thermoelectric conversion element and thermoelectric conversion module

The present invention relates to a thermoelectric conversion element and a thermoelectric conversion module using a conductive polymer material.

A thermoelectric conversion element is an element which mutually converts heat energy and electric energy. An electromotive force can be obtained by applying a temperature difference to both ends of the thermoelectric conversion element. As an index for evaluating the characteristics of the thermoelectric material used for the thermoelectric conversion element, for example, a figure of merit Z shown in Formula 1 as described in Patent Document 1 (Japanese Patent No. 4351504) is used.
Z = S ² σ / κ (1)
However, S: Seebeck coefficient, (sigma): Electrical conductivity, (kappa): Thermal conductivity.
The Seebeck coefficient S represents the magnitude of an electromotive force generated by a temperature difference of 1K. The dimensionless figure of merit ZT, which is the product of the figure of merit Z and the absolute temperature T indicating the value, is also an index for evaluating the characteristics of the thermoelectric material.
Thermoelectric materials have a unique Seebeck coefficient S, and are roughly classified into p-type thermoelectric materials having a positive Seebeck coefficient S and n-type thermoelectric materials having a negative Seebeck coefficient S. Rather than forming an element with only a p-type or n-type thermoelectric material, a structure in which p-type and n-type thermoelectric materials are joined in series via a conductive portion serving as an electrode, that is, a structure called a π-type element. As a result, a large output power can be obtained.
For example, as described in Patent Document 2 (JP-A-8-316532), a thermoelectric conversion module having a structure in which a plurality of π-type elements are joined in series can be used to increase the output voltage. A thermoelectric conversion module composed of a π-type element, for example, as in Patent Document 2, electrically connects p-type and n-type thermoelectric conversion elements processed into a rectangular parallelepiped block shape in series on a ceramic substrate such as alumina. It is common to take a structure arranged in Examples of thermoelectric materials used for such thermoelectric conversion elements include Bi—Te, Pb—Te, and Si—Ge.
Compound semiconductors such as oxides, oxide ceramics such as Na _x CoO ₂ (0.3 ≦ x ≦ 0.8), (ZnO) mIn ₂ O ₃ (1 ≦ m ≦ 19), Ca ₃ Co ₄ O _2, etc. is there.
A maximum electromotive force P obtained from a thermoelectric conversion module including N thermoelectric conversion elements is obtained from Equation 2.
P = V ² / (4NR) (2)
Where V is the voltage of the entire module, and R is the electrical resistance of one thermoelectric conversion element.
When the waste heat generated from an electric device or the like is used by thermoelectric conversion, the waste heat can be efficiently converted into electricity by directly attaching the thermoelectric conversion element to the electric device. In order to convert waste heat into electric energy without waste, it is desirable to directly install a thermoelectric conversion module in a waste heat duct or pipe where waste heat of electrical equipment is concentrated. However, since it has a structure in which a rigid thermoelectric conversion element is mounted on a rigid ceramic substrate, there is no flexibility. In such a thermoelectric conversion module, it is difficult to attach directly to a heat dissipation surface of an electronic device having a curved surface portion or an uneven portion.
In Patent Document 3 (Japanese Patent No. 3927784), a thermoelectric conversion element is formed on a flexible substrate. However, since the thermoelectric conversion element is composed of an inorganic material such as ceramics, there is a problem that the flexibility of the thermoelectric conversion module is insufficient.
Patent Document 1 and Patent Document 4 (Japanese Patent Laid-Open No. 2010-95688) describe the use of a conductive polymer, that is, a conductive polymer as a thermoelectric material. Since a conductive polymer functions as a thermoelectric material due to the Seebeck effect as in a semiconductor, when a temperature difference is given to both ends of a film made of a conductive polymer, electromotive force is generated at both ends. For example, the Seebeck coefficient of polyaniline is 40 μV / K, which is a sufficient value as a thermoelectric material.
If a conductive polymer can be formed as a thermoelectric conversion element by a coating method, mass production of thermoelectric conversion modules can be facilitated, and manufacturing costs can be reduced. However, at present, an n-type conductive polymer that can be coated and formed in the atmosphere has not been obtained. Therefore, in the case of producing a thermoelectric conversion element by forming a conductive polymer film by coating, there is a restriction that it must be composed only of a p-type thermoelectric material.
For example, Patent Document 5 (Japanese Patent Laid-Open No. 2010-205883) and Patent Document 6 (Japanese Patent Laid-Open No. 2006-319119) describe thermoelectric conversion elements composed only of p-type thermoelectric materials. Patent Document 5 describes a thermoelectric element in which only a p-type thermoelectric material or only an n-type thermoelectric material is joined in series. Patent Document 6 describes a thermoelectric conversion element using only p-type polythiophene as a conductive polymer.
Patent Document 1 and Patent Document 4 also have a description related to a thermoelectric conversion element using a conductive polymer. However, the dimensionless figure of merit ZT of the conductive polymers described in Patent Document 1 and Patent Document 4 is 0.1 or less at room temperature, and is 10% or less of the dimensionless figure of merit ZT of general inorganic materials. is there. Therefore, when the conductive polymer is configured with a general π-type element structure, it is difficult to obtain an output power of 50 μW or more that can drive a general sensor or a wireless tag.
A general conductive polymer sheet has a thickness of about 50 μm, and even if a thermoelectric conversion element is installed in a waste heat duct of an electronic device of about 40 ° C., the temperature difference between the high temperature portion and the low temperature portion is 0.5 ° C. There was also a problem that it was difficult to obtain an output power of 50 μW or more.
When a film-like thermoelectric conversion module is configured using the conductive polymer described in Patent Document 1 and Patent Document 4 described above, a temperature difference of several degrees Celsius is caused on both surfaces of the film in a general element structure. Since it cannot even be generated, there is a problem that sufficient output power cannot be obtained.
In the thermoelectric conversion module including the p-type thermoelectric conversion element having the structure described in Patent Document 6 described above, the temperature difference between the heat absorption surface and the exhaust heat surface is small, so that the output power is small. There was a problem that the required voltage could not be obtained.
The object of the present invention is to solve the problem that a sufficient temperature difference cannot be generated on both sides of the film in the film-like thermoelectric conversion element and thermoelectric conversion module, which are the problems described above, and the thermoelectric conversion element and thermoelectric conversion To provide a module.
The object of the present invention is also a thermoelectric conversion element and a thermoelectric conversion that solve the above-mentioned problem that sufficient output power and output voltage cannot be obtained only with a conductive polymer that is a p-type thermoelectric material. To provide a module.

The thermoelectric conversion element of the present invention includes a substrate, an insulating film disposed so as to face the substrate, a conductive film thermally connected to the substrate and the insulating film, and an insulating heat insulator that supports the conductive film. The conductive film includes a conductive polymer that is a thermoelectric material, and the conductive polymer is oriented in a direction substantially perpendicular to the substrate.
Moreover, the thermoelectric conversion module of this invention arrange | positions two or more above-mentioned thermoelectric conversion elements, and isolate | separates the site | part located in the board | substrate side of several electroconductive film, and the electroconductive film adjacent to several electroconductive film mentioned above. The part located in the film side is continuously connected in series by the conductive wire.

It is a perspective view of the thermoelectric conversion module of 1st Embodiment. It is a side view of the thermoelectric conversion module of 1st Embodiment. It is a top view of the module of a 1st embodiment. It is a 1st explanatory view of a manufacturing process of a thermoelectric conversion module of a 1st embodiment. It is 2nd explanatory drawing of the manufacturing process of the thermoelectric conversion module of 1st Embodiment. It is 3rd explanatory drawing of the manufacturing process of the thermoelectric conversion module of 1st Embodiment. It is a perspective view of the thermoelectric conversion module of 2nd Embodiment. It is a side view of the thermoelectric conversion module of 2nd Embodiment. It is a top view of the thermoelectric conversion module of 2nd Embodiment. It is the figure which installed the thermoelectric conversion module of Example 1. FIG. 5 is a graph showing the dependency of the temperature difference generated in the conductive film of Example 2 on the occupation ratio. It is the graph which showed the occupation rate dependence of the output power density of the thermoelectric conversion module of Example 3. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the preferred embodiments described below are technically preferable for carrying out the present invention, but the scope of the invention is not limited to the following.
[First Embodiment] FIG. 1 is a perspective view of a thermoelectric conversion module according to a first embodiment. FIG. 2 shows a side view of the thermoelectric conversion module according to the first embodiment. FIG. 3 shows a top view of the thermoelectric conversion module according to the first embodiment. FIG. 1 is a perspective view of a part of a module cut along line AB in FIG. FIG. 2 is a side view of a part of the module cut along the line AB, which is drawn on the same object as FIG. In FIG. 3, the upper conductive wire 3, the upper electrode 6, the first electrode 7, and the insulating film 8 are omitted in order to facilitate explanation of the inside of the module.
The thermoelectric conversion module according to the first embodiment includes a substrate 1, a lower electrode 2, a conductive wire 3, an insulating heat insulator 4, a conductive film 5, an upper electrode 6, a first electrode 7, an insulating film 8, and a second electrode 9. Consists of. The conductive film 5 functions as a thermoelectric conversion element. Most of the conductive polymer in one conductive film 5 is oriented in one direction. In the thermoelectric conversion element of the first embodiment, all the conductive films 5 are arranged so that the conductive polymer is oriented in the direction of the arrow 10.
In FIG. 2, the upper electrode 6 and the conductive film 5, the conductive wire 3 and the lower electrode 2, and the conductive film 5 and the lower electrode 2 are electrically connected to each other, and a plurality of thermoelectric elements disposed on the substrate 1. In the conversion element, the first electrode 7 to the second electrode 9 are electrically connected in series. In the first embodiment, it is assumed that the substrate 1 is installed on the high temperature side and the insulating film 8 is installed on the low temperature side. In the case of a p-type thermoelectric material, the low temperature side is the positive electrode and the high temperature side is the negative electrode. In the thermoelectric conversion module of the first embodiment, the first electrode 7 drawn from the low temperature side is the positive electrode, and the second electrode 9 drawn from the high temperature side is the negative electrode. When the high temperature side and the low temperature side are switched, the polarity of the electrode is reversed. Similarly, when the p-type thermoelectric material is replaced with an n-type thermoelectric material, the polarity of the electrode is reversed.
In FIG. 3, blocks 13 made of a plurality of thermoelectric conversion elements are arranged on a substrate 1 so as to form a row, and each block 13 is electrically connected via an electrode 20. Electrically connected in series. The actual number of elements is set so that the output power necessary for driving the sensor or the like can be obtained according to the temperature difference obtained at the installation location.
In the first embodiment, the blocks 13 are formed in which the conductive films 5 and the insulating heat insulators 4 are alternately adjacent to each other. Therefore, the conductive film 5 is held in a direction perpendicular to the substrate 1. By taking such a form, the occupation ratio of the conductive film 5 can be increased. Note that the occupation ratio η of the conductive film 5 is defined by the ratio of the area occupied by the cross section of the conductive film 5 in the cut surface obtained by cutting the thermoelectric conversion element in a plane parallel to the substrate 1. Thus, by filling a module having a certain area with a large number of conductive films, an output voltage necessary for driving a sensor or the like can be obtained.
Further, the orientation direction of the conductive polymer constituting the conductive film 5 is set so as to face the direction perpendicular to the substrate 1. Since current flows selectively along the orientation direction of the conductive polymer, by orienting the conductive polymer as in the first embodiment, the electric resistance of the thermoelectric conversion element can be reduced, and the output power can be reduced. Can be bigger.
In the thermoelectric conversion module according to the first embodiment, the insulating heat insulator 4 and the thin conductive wire 3 are used. The heat insulation between the substrate 1 and the insulating film 8 can be reduced by the insulating heat insulator 4. Further, by reducing the cross-sectional area of the conductive wire 3, the movement of heat from the substrate 1 toward the insulating film 8 through the conductive wire 3 can be reduced. As a result, the temperature difference generated in the conductive film 5 can be increased, and the output power can be increased.
In the first embodiment, a thermoelectric conversion element including the substrate 1, the insulating film 8, the insulating heat insulating body 4, and the conductive film 5 is used as a minimum structural unit for power generation. Therefore, when taking out and using a single thermoelectric conversion element, the conductive wire 3 does not become an essential structure. Usually, in order to obtain a sufficient voltage, the thermoelectric conversion elements are electrically connected in series by the conductivity 3 and used as a thermoelectric conversion module.
Examples of the material of the conductive film 5 according to the first embodiment include polythiophene known as a conductive polymer, polyethylene dioxythiophene (PEDOT: Poly (3,4-ethylenedioxythiophene)), polyaniline, polyacetylene, polypyrrole, and polyphenylene. Vinylene and derivatives thereof can be used. Alternatively, materials in which metal nanoparticles are dispersed in these materials can also be used.
The conductive polymer has a main chain having a π-conjugated structure in which double bonds and single bonds are alternately arranged, and conductivity is obtained by doping a carrier that is a mobile charge that can move freely. This doping is performed by adding iodine, arsenic pentafluoride, or the like to the polymer, and the additive functions as an acceptor.
Examples of the conductive polymer obtained by coating include polythiophene, polyaniline, etc., all of which have p-type conductivity. At present, the technology for forming an n-type conductive film by a coating method has not been put to practical use. Therefore, in the film-like thermoelectric conversion element and thermoelectric conversion module according to the first embodiment, a p-type thermoelectric material is assumed. Yes. However, when obtaining an n-type thermoelectric material by a method other than coating, the n-type thermoelectric material can also be applied to this embodiment. In addition, when using an n-type thermoelectric material, the 1st electrode 7 becomes a negative electrode and the 2nd electrode 9 becomes a positive electrode.
As a method for forming the conductive film 5, there are a spin coating method in which the above-described conductive polymer is dissolved in an organic solvent and spin-coated on the substrate, and a roller method in which the solution is thinly extended with a roller immediately after the solution is applied to the substrate. . The conductive polymer can be oriented in the direction of centrifugal force by the spin coating method and in the direction of pulling the substrate by the roller method. By repeating the above steps, the film oriented in the in-plane direction can be thickened. In addition, even if the conductive film 5 is formed by other film forming methods, the same effect can be obtained by adopting the same structure as that of the first embodiment.
When the length L of the conductive film 5 is 2 mm or less, a sufficient temperature difference between both ends of the conductive film 5 cannot be obtained, so that sufficient output power cannot be obtained. Further, if the thickness of the conductive film 5 is 30 mm or more, the flexibility of the module is reduced.
Therefore, the length L of the conductive film 5 is appropriately 2 mm or more and 30 mm or less. The length L of the conductive film 5 is more preferably 5 mm or more and 20 mm or less. The reason for providing a guideline for the length L is to adapt to the required flexibility and output power.
When the film thickness d of the conductive film 5 is 30 μm or less, the cross-sectional area of the conductive film 5 becomes small, so that the contact resistance and electrical resistance increase, and the output power decreases. In addition, when the cross-sectional area S of the conductive film 5 is thicker than 500 μm, the manufacturing time increases.
Therefore, the film thickness d of the conductive film 5 is desirably 30 μm or more and 500 μm or less. Further, considering the flexibility of the thermoelectric conversion module and the manufacturing efficiency, the film thickness d of the conductive film 5 is optimally 50 μm or more and 200 μm or less.
The cross-sectional area S of the conductive wire 3 is preferably 40 square micrometers or more and 400 square micrometers or less. If it is 40 square micrometers or less, there is a drawback that the electrical resistance increases and the mechanical strength decreases. If it is 400 square micrometers or more, since the thermal resistance is small, the temperature difference between the high temperature part and the low temperature part of the thermoelectric conversion module is reduced. It is desirable to use a material having a large thermal resistance and a small electrical resistance for the conductive wire 3. For example, materials made of gold, silver, and copper are applicable, but the embodiments of the present invention are not limited to these materials.
The substrate 1 is optimally polyimide or polyethylene naphthalate. Other materials for the substrate 1 include ionomer, polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polypropylene, polyester, polycarbonate, polystyrene, polyacrylonitrile, ethylene vinyl acetate copolymer, ethylene-vinyl alcohol copolymer. , Ethylene-methacrylic acid copolymer, polyamide, fluororesin and the like can be used. However, the material mentioned here is only an example, and the material of the substrate 1 is not limited. Moreover, the material similar to a board | substrate can be selected also as the material of the insulating film 8. FIG.
From the viewpoint of durability, the thickness d of the substrate 1 is desirably 50 μm or more. Further, from the viewpoint of flexibility, the thickness d of the substrate 1 is desirably 5 mm or less. When the thickness of the substrate 1 is in the range of 50 μm to 5 mm, the substrate 1 can be deformed to function as a flexible substrate, and the thermoelectric conversion module can be installed in contact with an installation surface having a certain curvature.
The insulating heat insulating body 4 is made of a polymer material having excellent heat insulating properties and insulating properties. In particular, a foamed polymer made from polyurethane, phenol resin, or the like exhibits excellent heat insulation performance and insulation performance because it contains a large amount of air in ultrafine bubbles. The thermal conductivity of the polyurethane foam polymer is 0.033 W / mK, the thermal conductivity of the phenol foam polymer is 0.020 W / mK, which is the same value as the thermal conductivity of air, 0.024 W / mK. As the foaming agent, carbon dioxide gas generated by mixing a polyol containing isocyanate and water can be used. In addition to polyurethane and phenol resin, polystyrene, polyolefin, polyvinyl chloride, urea resin, silicone, polyimide, melamine resin, and the like can be used as the foamed polymer. In addition, the above-mentioned polymer material is an example, and does not limit the insulating heat insulator 4 according to the first embodiment.
In the following, in order to describe the first embodiment, a specific numerical value is applied to some members for explanation. Note that the first embodiment is not limited to the numerical values shown here.
The conductive polymer of the conductive film 5 according to the first embodiment is oriented in a direction perpendicular to the substrate 1. The length L in the direction perpendicular to the substrate of the conductive film 5 is 10 mm, the width W is 10 mm, and the thickness d of the film is 100 μm. The length of the insulating insulator 4 in the direction perpendicular to the substrate is 10 mm, the width is 10 mm, and the thickness is 150 μm. The conductive wire 3 has a length of about 10 mm, a width of 40 μm, and a thickness of 5 μm. The conductive wire 3 has a thermal conductivity higher than that of the conductive film 5 by about three digits. The lower electrode 2 has a length of 10 mm, a width of 200 μm, and a thickness of 10 μm. The upper electrode 6 is also the same size as the lower electrode 2. The conductive wire 3, the lower electrode 2, and the upper electrode 6, and the conductive film 5, the lower electrode 2, and the upper electrode 6 are electrically connected with a conductive adhesive.
An example of a method for manufacturing a thermoelectric conversion element and a thermoelectric conversion module will be described below with reference to the drawings.
In FIG. 4, the multilayer film 11 formed in the process of manufacturing the thermoelectric conversion element which concerns on 1st Embodiment is illustrated. The multilayer film 11 has a structure in which the conductive film 5 and the insulating heat insulator 4 are laminated.
On the base material 12 having a thickness of 2 mm, the insulating heat insulators 4 and the conductive films 5 are alternately overlapped in a state in which the polymer orientation directions 10 of all the conductive films 5 are aligned in a certain direction. When the entire laminated film is pressurized and heated at 150 ° C., an integrated multilayer film 11 is obtained. In addition, although the base material 12 is used when manufacturing the multilayer film 11, the base material 12 isolate | separates from the block 13 at a next process.
FIG. 5 illustrates a block 13 formed in the process of manufacturing the thermoelectric conversion element according to the first embodiment.
First, the multilayer film is cut and divided in a direction along the polymer orientation direction 10 with a width of 10 mm by a mechanical cutting method or a cutting method using laser light. The striped conductive lines 3 shown in FIG. 5 are formed at the center of the insulating heat insulator 4 on the cut surface of the divided multilayer film. The conductive line 3 and the polymer orientation direction 10 are parallel to each other.
The method of forming the stripe-shaped conductive wire 3 is, for example, a method of spraying a solution containing metal nanoparticles such as gold, silver, copper or the like onto the cut surface by an ink jet method to form a stripe and baking it with light or heat. Can be used. Furthermore, the stripe of the conductive wire 3 having a thickness of several μm can be formed by overwriting. As another method for forming the conductive wire 3, there is a method in which a gold wire having a diameter of 20 μm or less is adhered with an epoxy adhesive.
Next, the multilayer film is mechanically cut and divided into a width of 10 mm in a direction perpendicular to the conductive wire 3 to obtain the block 13 shown in FIG.
Further, a pattern of the lower electrode 2 and the second electrode 9 is formed on the substrate 1. As a forming method, a method of patterning by vapor deposition / exposure, a method of ink-jet printing or screen printing a solution containing metal nanoparticles, and a method of plating are possible.
For example, as a method by plating, a method of forming a lower electrode 2 by patterning polypyrrole resin on a substrate 1 by a printing method in accordance with the shape of the lower electrode 2 and then immersing it in a gold plating solution using Pd particles as a catalyst. is there. A pattern of the upper electrode 6 and the first electrode 7 can be formed on the insulating film 8 by the same method.
FIG. 6 illustrates a process of joining the block 13 to the lower electrode 2 and the upper electrode 6 in the manufacture of the thermoelectric conversion module according to the first embodiment.
A conductive adhesive 14 is applied on the pattern of the lower electrode 2 of the substrate 1 and the pattern of the upper electrode 6 of the insulating film 8 by a dispenser. As the conductive adhesive 14, an epoxy-based conductive adhesive composed of 84% silver powder, 15% liquid epoxy resin, and 1% amine-based curing agent can be used.
Using an alignment joining apparatus having a microscope and a CCD camera, as shown in FIG. 6, the block 13 is directed in a direction in which the conductive line 3 is perpendicular to the substrate 1, and the conductive line 3 and the conductive film 5 are aligned. The pair is bonded so as to contact the lower electrode 2. Similarly, the insulating film 8 on which the pattern of the upper electrode 6 is formed is bonded so that the pair of the conductive wire 3 and the conductive film 5 is in contact with the upper electrode 6 so that all the conductive films 5 are connected in series. To do. Lightly hold the upper and lower films with a fixing jig and place them on a heater at 150 ° C. to solidify and fix the adhesive.
The above is description of the thermoelectric conversion module manufacturing process of 1st Embodiment. However, the method for manufacturing the thermoelectric conversion module of the first embodiment is not limited to the above-described method.
[Second Embodiment] FIG. 7 is a perspective view of a thermoelectric conversion module according to a second embodiment. FIG. 8 is a side view of the thermoelectric conversion module according to the second embodiment. In addition, the member and material which comprise the thermoelectric conversion module which concerns on 2nd Embodiment are the same as that of 1st Embodiment unless there is particular notice.
The thermoelectric conversion module according to the second embodiment includes a substrate 21, a heat insulating film 211, a lower electrode 22, a conductive wire 23, an insulating heat insulator 24, a conductive film 25, an upper electrode 26, a first electrode 27, and an insulating film. 28 and the second electrode 29. The polymer orientation direction 30 in the conductive film 25 is indicated by an arrow. In the second embodiment, the heat insulating film 211 is pasted on the substrate 21 in order to reduce the conduction of radiant heat from the substrate 21 to the insulating film 22.
In FIG. 7, a plurality of thermoelectric conversion elements are arranged on the substrate 21 and are electrically coupled in series. In the second embodiment, it is assumed that the substrate 21 is installed on the high temperature side and the insulating film 28 is installed on the low temperature side. In this case, in the thermoelectric conversion module made of the p-type thermoelectric material, the first electrode 27 drawn from the high temperature side is the negative electrode, and the second electrode 29 drawn from the low temperature side is the positive electrode. When the high temperature side and the low temperature side are switched, the polarity of the electrode is reversed. Similarly, when the p-type thermoelectric material is replaced with an n-type thermoelectric material, the polarity of the electrode is reversed.
In the following, in order to specifically describe the second embodiment, a description will be given by applying numerical values to some members. However, the second embodiment is not limited to the numerical values shown here.
The length of the insulating heat insulator 24 in the direction perpendicular to the substrate 21 is 8 mm, the width is 16 mm, the thickness is 2 mm, and the conductive film 25 is supported so as to be substantially perpendicular to the substrate 21. Yes. Note that “substantially perpendicular” means that most of the film surface of the conductive film 25 is oriented in a direction perpendicular to the substrate, but the entire film surface is not strictly perpendicular.
In the structure of the second embodiment, since the end portion of the conductive film 25 is bonded to the end portion of the insulating heat insulator 24, the film surface is not a uniform plane. Also, it is not exactly vertical as in the first embodiment. Therefore, the conductive film 5 is supported so as to be substantially perpendicular to the substrate 1.
The conductive polymer of the conductive film 25 is oriented in a direction substantially perpendicular to the substrate 21, and is shown as a polymer orientation direction 30.
The length L of the conductive film 25 in the direction perpendicular to the substrate 21 is about 8 mm, the width W is 16 mm, and the thickness d of the film is 150 μm. In addition, since the margin for adhering with the lower electrode 22 and the upper electrode 26 is provided in the both ends of the length L direction of the electroconductive film 25, the length L is an approximate length.
The conductive wire 23 is a gold wire having a diameter of 20 μm and a length of about 10 mm. The diameter of the gold wire was reduced in order to reduce the heat transfer from the high temperature side to the low temperature side and maintain the temperature difference of the elements. The lower electrode 22 has a length of 16 mm, a width of 4 mm, and a thickness of 10 μm. The upper electrode 26 has a length of 16 mm, a width of 2 mm, and a thickness of 10 μm.
The conductive film 25 is electrically connected to the lower electrode 22 and the upper electrode 26 with a conductive adhesive. The length of the conductive film 25 is reduced for applications that require flexibility, and is increased for applications that require output power.
FIG. 9 shows a top view of the thermoelectric conversion module according to the second embodiment. In FIG. 9, the illustration of the upper insulating film 28 is omitted in order to make the inside of the module easier to see. A plurality of thermoelectric conversion elements are arranged in a row on the substrate 21, and each row is electrically connected in series via the electrode 40. In 2nd Embodiment, since the space | interval of a thermoelectric conversion element is wide, compared with 1st Embodiment, the occupation rate of the electroconductive film 25 is small. The actual number of elements is adjusted so as to obtain the output power necessary for driving the sensor or the like according to the temperature difference obtained depending on the installation location.
In the second embodiment, the insulating heat insulator 24 supports the conductive film 25 so that at least a part of the surface of the conductive film 25 is substantially perpendicular to the substrate 21. In 2nd Embodiment, since it wired with a margin with gold | metal | money wire, a disconnection does not occur easily with respect to a deformation | transformation of the whole thermoelectric conversion module. Further, in the second embodiment, since the area where the conductive film 25 is in contact with the lower electrode 22 and the upper electrode 26 is larger than that in the first embodiment, the contact resistance can be reduced and the output power can be increased. it can.

In FIG. 10, the example of installation of the thermoelectric conversion module of Example 1 is shown. In order to take out the generated output power to the outside, the lead wire (positive electrode) 17 was connected to the second electrode 9, and the lead wire (negative electrode) 19 was connected to the second electrode 7. In Example 1, in the thermoelectric conversion module according to the first embodiment, the effect of making the conductive film 5 perpendicular to the substrate 1 was verified. In addition, the basic composition of the thermoelectric conversion module in Example 1 is the same as that of 1st Embodiment.
As the conductive film 5, a film made of polyaniline was used. In Example 1, the occupation ratio η of the conductive film 5 was set to about 40%. In Example 1, the height L of the conductive film 5 is 10 mm.
The temperature of the installation surface of the thermoelectric conversion module was set to 40 ° C. on the assumption that the electronic device is disposed on the side surface of the waste heat duct. When the heating stage 15 was held at 40 ° C. and the environmental temperature was controlled at 25 ° C. and the temperature of the module surface portion 16 was measured, the module surface portion 16 was at a temperature of 32.6 ° C. That is, a temperature difference of 7.4 ° C. (= 40.0−32.6) was obtained.
For comparison experiments, the conductive film 5 was placed horizontally with respect to the substrate 1 and the temperature of the module surface portion 16 was measured. Note that placing the conductive film 5 horizontally with respect to the substrate 1 is equivalent to the case where the height L of the conductive film 5 is 1 mm. As a result, the temperature difference between the high temperature part and the low temperature part was 0.7 ° C.
That is, in Example 1, it was confirmed that a temperature difference 10 times that of the comparative experiment could be maintained. Since the conductive film 5 of Example 1 was installed perpendicularly to the substrate 1, a temperature difference larger by one digit or more was obtained than when the conductive film 5 was installed horizontally.
The temperature difference generated at both ends of the conductive film 5 increases in proportion to the length L of the conductive film 5, and the output power obtained increases. From this verification, it was proved that the output voltage can be increased by setting the length L of the insulating heat insulator 4 and the conductive film 5 even in the thermoelectric conversion module formed in a film shape.

The height L of the conductive film 5 was adjusted to 10 mm, and verification to change the occupation ratio was performed. In Example 2, the temperature difference generated in the conductive film 5 was measured in the same evaluation environment as in Example 1. The occupation ratio was controlled by fixing the thickness d of the conductive film 5 to 100 μm and changing the thickness of the insulating heat insulator 4.
FIG. 11 shows the occupancy dependency of the temperature difference generated in the conductive film 5. Those having an occupation ratio of 0 are all temperature differences in the case of an insulating heat insulator, and those having an occupation ratio of 1 are all temperature differences in the case of the conductive film 5.
The insulating heat insulator 4 has a thermal conductivity that is nearly an order of magnitude smaller than that of the conductive film 5. Therefore, it has been confirmed that the temperature difference decreases as the occupation ratio of the conductive film 5 increases.
The verification of Example 2 confirmed that the temperature difference between the high temperature part and the low temperature part can be controlled by setting the occupation ratio. When the thermoelectric conversion module is put to practical use, it can be confirmed that the temperature difference and the output power can be set by setting the electric resistance and thermal conductivity of the thermoelectric conversion element composed of the conductive film 5 and the insulating heat insulator 4. That's right.

Except changing the length of the conductive film 5, the output power of the thermoelectric conversion module when the length of the conductive film was changed to 2 mm, 5 mm, 10 mm, and 15 mm in the same environment as in Example 1 was measured. As the thermoelectric conversion module, 10 cm square and 15 cm square modules were used. In Example 3, the output power necessary to drive the sensor or the like was set to 50 μW, and it was determined that the sensor or the like could be driven if an output power of 50 μW or more was obtained by power generation.
FIG. 12 shows the output power of the thermoelectric conversion module when the heating stage 15 is controlled to 40 ° C. and the environmental temperature is controlled to 25 ° C. and the length of the conductive film is changed in a 10 cm square thermoelectric conversion module. The occupancy rate η dependence of density Pa is shown. The curve in FIG. 12 is a theoretical curve.
The peak of the output power is in the vicinity of the occupation ratio of the conductive film of 0.6, and the output power decreased at 0.6 or more.
When the length of the conductive film was 10 mm, a value of 8.8 microwatt square meters was obtained as the output power density Pa. That is, an output power of 88 μW can be obtained from the 10 cm square thermoelectric conversion module. Since the electric power necessary for driving the sensor or the like is set to 50 μW, it can be determined that the sensor or the like can be driven.
From FIG. 12, it can be read that when the length of the conductive film 5 is 10 mm, an output power of 50 μW or more necessary for driving the sensor can be obtained if the occupation ratio is 0.16 or more. Moreover, when the length of the conductive film 5 was 5 mm or less, the output power required for sensor driving could not be obtained.
In the 15 cm square thermoelectric conversion module, an output power of 100 μW was obtained even when the occupation ratio was 0.1. That is, in the case of a 15 cm square thermoelectric conversion module, it has been confirmed that the output power required for driving the sensor can be obtained even when the occupation ratio is as small as 10%.
From the above result, it has confirmed that the thermoelectric conversion module which can be used as power supplies, such as a sensor, was obtained by the structure which concerns on embodiment of this invention. In addition, embodiment of this invention is not limited to the content described as mentioned above.
According to the present invention, even a film-like thermoelectric conversion module can generate a sufficient temperature difference on both sides of the film, and can generate electric power and voltage necessary to drive a sensor or the like. become.
Although the present invention has been described with reference to the exemplary embodiments and examples, the present invention is not limited to the above exemplary embodiments and examples. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2011-240282 for which it applied on November 1, 2011, and takes in those the indications of all here.

Since the thermoelectric conversion module according to the embodiment of the present invention has a thin film shape and is configured of a flexible member, the thermoelectric conversion module can be installed on various curved surfaces such as pipes and ducts of electronic devices, and the surface of a human body. Therefore, electric power can be extracted not only from high-temperature waste heat generated from factories and cars, but also from low-temperature waste heat generated from electrical equipment such as office air conditioners, servers, personal computers, and lighting.
Since the thermoelectric conversion module according to the embodiment of the present invention can be easily manufactured as a module with a large area, it can be applied to mass production and can be reduced in cost. Therefore, a large amount of thermoelectric conversion modules according to the embodiment of the present invention can be manufactured and installed in a large amount in the living environment. If environmental information such as temperature obtained from sensors installed in the living environment can be transmitted to the server using an active wireless tag and the electronic devices in the office can be controlled from the server, it is possible to save wasteful electric energy. You can build a system.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Lower electrode 3 Conductive wire 4 Insulating heat insulator 5 Conductive film 6 Upper electrode 7 First electrode 8 Insulating film 9 Second electrode 10 Polymer orientation direction 11 Multilayer film 12 Base material 13 Block 14 Conductive adhesive 15 Heating stage 16 Module surface part 17 Lead wire (positive electrode)
19 Lead wire (negative electrode)
20 electrode 21 substrate 211 heat insulating film 22 lower electrode 23 conductive wire 24 insulating heat insulating body 25 conductive film 26 upper electrode 27 first electrode 28 insulating film 29 second electrode 30 polymer orientation direction 40 electrode

Claims

A substrate,
An insulating film arranged to face the substrate;
A conductive film thermally connected to the substrate and the insulating film;
An insulating heat insulator that supports the conductive film,
The conductive film includes a conductive polymer that is a thermoelectric material,
The thermoelectric conversion element, wherein the conductive polymer is oriented in a direction substantially perpendicular to the substrate.
The thermoelectric conversion element according to claim 1, wherein the substrate is a flexible substrate.
The thermoelectric conversion element according to claim 2, wherein main surfaces of the conductive film and the insulating heat insulating material are in contact with each other.
The thermoelectric conversion element according to claim 3, wherein the conductive polymer is a p-type thermoelectric material.
5. The conductive film is a conductive polymer containing any one of polyaniline, polythiophene, polyethylene dioxy thiophene, polypyrrole, polyphenylene vinylene, polythienylene vinylene, and derivatives thereof. The thermoelectric conversion element according to 1.
6. The thermoelectric conversion element according to claim 5, wherein the insulating heat insulator includes any one of polyurethane, phenol resin, polystyrene, polyolefin, polyvinyl chloride, urea resin, silicone, polyimide, and melamine resin.
A thermoelectric conversion module in which a plurality of the thermoelectric conversion elements according to any one of claims 1 to 6 are arranged,
A portion located on the substrate side of the plurality of conductive films and a portion located on the insulating film side of the conductive film adjacent to the plurality of conductive films are continuously connected in series by a conductive wire. A thermoelectric conversion module characterized by comprising:
The thermoelectric conversion module according to claim 7, wherein the conductive wire is attached to a side surface of the insulating heat insulator.
The thermoelectric conversion module according to claim 7, wherein main surfaces of the conductive film and the insulating heat insulator are separated from each other.
In a cut surface obtained by cutting the thermoelectric conversion element in a plane parallel to the substrate,
The thermoelectric conversion module according to claim 7, wherein an area occupation ratio occupied by a cross section of the conductive film is in a range of 0.1 to 0.6 with respect to a total area of the cut surface.