JP2016187008A - Thermoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly efficient thermoelectric conversion device capable of externally absorbing thermal energy sufficiently, and externally dissipating thermal energy sufficiently.SOLUTION: A plurality of electrodes are electrically insulated from each other, respectively, one or both of first and second film substrates are provided, respectively, with a plurality of through holes arriving at every other electrode, out of the plurality of electrodes arranged in series, and one or a plurality of heat conductors include a portion provided in at least one of the plurality of through holes, and a portion exposed to the outer surface of the first or second film substrate, respectively, in a thermoelectric conversion device.SELECTED DRAWING: Figure 1

Description

The present invention relates to a thermoelectric conversion device. More specifically, the present invention relates to a thermoelectric conversion device that can be used for energy harvesting such as various exhaust heat power generation as a film-like thermoelectric power generation sheet.

Thermoelectric conversion devices use various exhaust heat such as industrial exhaust heat and daily life exhaust heat, and can be used for power generation due to the temperature difference, and are expected to be used for energy harvesting.

As shown in FIG. 13, the conventional thermoelectric conversion device generally has a π-type structure, and the P-type thermoelectric material p and the N-type thermoelectric material n are electrodes 501 and 501a made of a metal material. Are electrically connected in series alternately. Then, one side of each thermoelectric material is set to the high temperature side and the other side is set to the low temperature side, and a temperature difference is provided at both ends of each thermoelectric material to generate a voltage difference at both ends of the thermoelectric conversion device 520 to generate power.

In a conventional general thermoelectric conversion device, each thermoelectric material has a bulky block shape and is made of a metal material in order to ensure a temperature difference between a low temperature side and a high temperature side. Since the conventional general thermoelectric conversion device is configured by arranging such thermoelectric materials and electrodes so as to have a π-type structure, the device becomes thick and heavy. Moreover, since each thermoelectric material is a block shape and a rigid body, there is no flexibility.
On the other hand, in recent years, thermoelectric conversion devices that are flexible and easy to handle have attracted attention and various proposals have been made (for example, see Patent Documents 1 to 4).

In the invention described in Patent Document 1, Bi ₂ Te ₃ as an N-type thermoelectric material and Sb ₂ Te ₃ (added by a small amount of Se) as a P-type thermoelectric material are dispersed and kneaded in each emulsified butadiene-styrene resin (SBR). Then, they are connected alternately in a planar shape. Furthermore, a sheet-like thermoelectric conversion device is configured by arranging foamed polyurethane sheets alternately on the front side and the back side of each connection portion between thermoelectric materials to generate a temperature difference in a plane (for example, Patent Documents). 1 (see FIG. 3).

In the invention described in Patent Document 2, a P-type thermoelectric material and an N-type thermoelectric material are formed on a film substrate with a thickness of 1 to 100 μm by a method such as vapor deposition or sputtering (see, for example, FIG. 1 of Patent Document 2). .

In the invention described in Patent Document 3, both sides of a thermoelectric conversion module of a thin film P-type thermoelectric element and a thin film N-type thermoelectric element are covered with a material having low thermal conductivity, and a heat conductor is disposed on a part of the outer surface. It has a structure (for example, see FIG. 1 of Patent Document 3). Thereby, the inner surface temperature difference of the thermoelectric conversion module occurs.

In the invention described in Patent Document 4, in a structure in which a plurality of P-type thermoelectric conversion elements and N-type thermoelectric conversion elements arranged alternately on a film substrate are connected in series via electrodes, both ends of each thermoelectric conversion element A heat conductor is vertically arranged in the vicinity of the portion, one reaches the surface of the high-temperature side substrate and the other reaches the surface of the low-temperature side substrate to generate a temperature difference between both ends of the thermoelectric conversion element. Furthermore, the moisture on the heat generating surface is led to the moisture absorbing layer disposed on the low temperature side substrate surface through the moisture passage hole penetrating in the thickness direction of the substrate, and the temperature on the low temperature side can be lowered by the heat of vaporization during the evaporation of moisture. (For example, refer to FIG. 2 of Patent Document 4).

Japanese Patent Laid-Open No. 7-111345 JP 2003-133600 A JP 2006-186255 A JP 2012-79841 A

Each of the patent documents described above relates to a film-like thermoelectric conversion device having flexibility, but the film-like thermoelectric conversion device has the following problems.
As described above, in the thermoelectric conversion device, one surface side of the substrate is the high temperature side, and the other surface side is the low temperature side, and the temperature difference between the P-type thermoelectric material and the N-type thermoelectric material alternately in the substrate surface. It is converted into electric energy by thermoelectric conversion elements arranged in series.

In a conventional general thermoelectric conversion device (for example, the thermoelectric conversion device shown in FIG. 13), one end to the other end of each thermoelectric material is arranged in a direction parallel to a direction having a temperature difference. There is a natural temperature difference between the ends of each thermoelectric material. On the other hand, in the film-like thermoelectric conversion device described in the above-mentioned patent document, since each thermoelectric material is arranged in a plane, the direction from one end of each thermoelectric material to the other end is perpendicular to the direction in which there is a temperature difference. Is arranged. Efficiently generating a temperature difference between both ends of each thermoelectric material is a problem of the film-like thermoelectric conversion device. In this specification, the end of the thermoelectric material refers to the end of the thermoelectric material that is connected to the electrode.

This will be described in more detail below with reference to conceptual diagrams. FIG. 14 is a conceptual diagram showing a conventional general thermoelectric conversion device using a block-shaped thermoelectric material. FIG. 15 is a conceptual diagram showing a film-like thermoelectric conversion device. 14 and 15, one surface side of the substrate is a high temperature surface side, and the other surface side is a low temperature surface side. ΔT represents a temperature difference between one end and the other end of the thermoelectric material n (p) for generating a thermoelectromotive force.

In the case of FIG. 14, the direction from the high temperature surface side to the low temperature surface side (open thick arrow) and the direction from one end of the thermoelectric material n (p) to the other end are aligned in parallel. A temperature difference naturally occurs at both ends of the thermoelectric material n (p). On the other hand, in the case of FIG. 15, the direction from the high temperature surface side to the low temperature surface side (open thick arrow) and the direction from one end of the thermoelectric material n (p) to the other end are orthogonal (perpendicular). There is a relationship, and if one device is not devised, one end and the other end of the thermoelectric material n (p) will be at the same temperature (intermediate temperature between the high temperature side and the low temperature side), and a thermoelectromotive force may be generated. Can not. Therefore, in the film-like thermoelectric conversion device shown in FIG. 15, it is possible to convert the temperature difference energy in the vertical direction between the high temperature side and the low temperature side of the film substrate into the temperature difference energy in the horizontal direction as efficiently as possible. It is considered important for improving the characteristics. The above Patent Literatures 1 to 4 will be reviewed based on the above concept.

In the invention described in Patent Document 1, from the high temperature side or the low temperature side by a heat insulating material (foamed polyurethane) that covers the connection portion of the P-type thermoelectric material and the N-type thermoelectric material alternately on one surface side and the other surface side. The supplied thermal energy is blocked. Therefore, the thermal energy in the portion where the heat insulating material is disposed cannot contribute to the thermoelectromotive force. Further, in the portion where the heat insulating material is not disposed, both the P-type thermoelectric material and the N-type thermoelectric material are supplied with thermal energy from both the high temperature side and the low temperature side, and the temperature of the thermoelectric material is the intermediate temperature. Fixed to. Therefore, it cannot be utilized as the temperature difference or energy of the portion where the heat insulating material is disposed, and the generation of the thermoelectromotive force is inhibited efficiently.

In the invention described in Patent Document 2, in order to generate a temperature difference between both ends of the thermoelectric material, the high-temperature portion and the low-temperature portion are striped in the same plane on the low-temperature side and the high-temperature side, and the P-type thermoelectric material and the N-type thermoelectric It arrange | positions according to the period of the connection part of material. Even if the thermoelectric conversion device described in Patent Document 2 is used in contact with a surface having a heat source having a constant temperature, a temperature difference does not occur at both ends of each thermoelectric material, and a thermoelectromotive force cannot be generated.

In the invention described in Patent Document 3, since a material having a low thermal conductivity of 10 μm or more is sandwiched between the thermal conductor and the thermoelectric material, the thermal energy cannot be efficiently transmitted. Furthermore, since the thermal conductor is arranged only on a part of the outer surface of the substrate, the thermal energy can be absorbed in a part where the thermal conductor is arranged, but the thermal conductivity is not arranged. In the low part, heat energy cannot be absorbed sufficiently and cannot contribute to the thermoelectromotive force.

In the invention described in Patent Document 4, columnar heat conductors are arranged adjacent to both ends of a thermoelectric conversion element made of each thermoelectric material. Thus, the heat conductor is in contact with the end of the thermoelectric conversion element through the insulating film in the lateral direction (in the substrate plane). However, since the distance between the thermal conductor and the thermoelectric conversion element changes depending on the alignment accuracy in the lateral direction, it is greatly increased by a slight change in the distance of the insulating film having low thermal conductivity between the thermal conductor and the thermoelectric conversion element. The thermal conductivity will fluctuate, making it difficult to obtain stable thermoelectric conversion characteristics. The absolute value of the alignment accuracy in the lateral direction (in the substrate plane) itself is also relatively large (usually on the order of microns or more), and it is not easy to reduce the distance between the heat conductor and the thermoelectric conversion element to an optimum distance. In addition, since the area of the heat conductor exposed on the outer surface of the film substrate is only the columnar upper or lower surface, it is very small compared to the entire area of the outer surface of the film substrate, and most of the area on the outer surface of the film substrate has a thermal conductivity. It is an insulating film substrate with low resistance. Therefore, it is difficult to collect heat energy in the heat conductor.

As described above, the inventions described in Patent Documents 1 to 4 described above have room for improvement in sufficiently absorbing the heat energy on the high temperature side and the low temperature side and transmitting the heat energy to both ends of the thermoelectric conversion element.

The present invention has been made in view of the above-described present situation, and provides a highly efficient thermoelectric conversion device that can sufficiently absorb heat energy from the outside or sufficiently dissipate heat energy to the outside. It is for the purpose.

The present inventor has focused on a film-like thermoelectric conversion device, and absorbs heat energy using a thermoelectric conversion device that can efficiently absorb and radiate heat energy, that is, a wide surface on the high temperature side and low temperature side of the film substrate. -Various thermoelectric conversion devices that diverge and can efficiently generate a temperature difference between both ends of the P-type thermoelectric material and the N-type thermoelectric material were studied. And this inventor provides the through-hole which penetrates a film substrate and reaches an electrode for every other electrode arranged in series with P type and N type thermoelectric materials, and on the outer surface of the film substrate and A heat conductor is arranged in the through hole. Furthermore, the inventor patterned the heat conductor on the outer surface of the film substrate so as not to electrically short-circuit each electrode, or separated the heat conductor and the electrode in the through hole via an insulating film. The heat conductor is made electrically insulating. Accordingly, the inventor can efficiently absorb the heat energy from the outside into the heat conductor or efficiently dissipate the heat energy to the outside, and the heat conductivity between the heat conductor and the electrode. It has also been found that a film-like thermoelectric conversion device can be obtained. Such a film-like thermoelectric conversion device can also suppress heat conduction in a portion other than the through hole by the film substrate made of a low heat conductive material. As described above, the thermoelectric conversion device of the present invention can efficiently generate a temperature difference between both ends of a thermoelectric material, and can efficiently generate a thermoelectromotive force. The present inventor has arrived at the present invention by conceiving that the above problems can be solved with the thermoelectric conversion device.

That is, according to one embodiment of the present invention, a first film substrate, a plurality of P-type thermoelectric material films alternately arranged in series on the first film substrate, a plurality of electrodes, and a plurality of N-types are provided. A second film substrate covering the plurality of P-type thermoelectric material films, the plurality of electrodes, and the plurality of N-type thermoelectric material films, the first film substrate, and the second film. One or more thermal conductors covering at least one outer surface of the substrate and connected to the plurality of electrodes, each of the plurality of P-type thermoelectric material films and the plurality of N-type thermoelectric materials Each of the films is connected to each other via one of the plurality of electrodes, and each of the plurality of electrodes is electrically insulated from each other, and the first film substrate and the second film substrate One or each of the electrodes reaches every other electrode of the plurality of electrodes arranged in series. A plurality of through holes, and each of the one or more heat conductors includes a portion provided inside at least one of the plurality of through holes, the first film substrate, or the first film substrate. The thermoelectric conversion device containing the part exposed to the outer surface of 2 film substrates may be sufficient.

The plurality of P-type thermoelectric material films, the plurality of electrodes, and the plurality of N-type thermoelectric material films alternately arranged in series on the first film substrate are a P-type thermoelectric material film and an electrode. The N-type thermoelectric material film and the electrode are repeatedly connected in series in this order. Such a circuit composed of a plurality of P-type thermoelectric material films, a plurality of electrodes, and a plurality of N-type thermoelectric material films is also referred to as a thermoelectric conversion module in this specification. Usually, both ends of the thermoelectric conversion module are electrodes, and wiring for taking out electromotive force is electrically connected to each of the electrodes at both ends.

As described later, one or more thermal conductors connected to the plurality of electrodes, as long as each of the plurality of electrodes is electrically insulated from each other, It may be directly connected to a plurality of electrodes, or may be indirectly connected via an insulating film.

In the present specification, “each of the plurality of electrodes is electrically insulated from each other” also means that the plurality of electrodes are not electrically connected to each other via a heat conductor. . The configuration in which the plurality of electrodes are not electrically connected to each other via the heat conductor includes, for example, a configuration in which the heat conductor on the outer surface of the film substrate is patterned, and heat in the through hole of the film substrate, as will be described later. Examples include a configuration in which the conductor and the electrode are separated via an insulating film, and a configuration in which the heat conductor is electrically insulating. As long as each of the plurality of electrodes is electrically insulated from each other, these structures can be appropriately combined.

For example, in the thermoelectric conversion device of the present invention, the one or more heat conductors are a plurality of heat conductors, and a plurality of heat conductions covering at least one outer surface of the first film substrate and the second film substrate. The body is preferably patterned so that each of the plurality of electrodes is electrically insulated from each other.

The thermoelectric conversion device of the present invention further includes an insulating film, and the one or more heat conductors and the plurality of electrodes are in at least one through-hole of the first film substrate and the second film substrate. It is preferable that the insulating film is electrically insulated from each other through the insulating film.

For example, in the thermoelectric conversion device of the present invention, it is preferable that the thermal conductor is electrically insulating.

Moreover, in the thermoelectric conversion device of the present invention, the thermoelectric conversion device includes a plurality of heat conductors that cover both outer surfaces of the first film substrate and the second film substrate and are connected to the plurality of electrodes, Each of the second film substrates is provided with a plurality of through holes reaching every other electrode of the plurality of electrodes arranged in series, and the plurality of through holes are arranged in series. It is preferable that the electrodes are alternately provided on the first film substrate side or the second film substrate side.

The plurality of through holes are alternately provided on the first film substrate side or the second film substrate side of the plurality of electrodes arranged in series, as shown in FIG. The through-holes penetrating the first film substrate or the through-holes penetrating the second film substrate are alternately reached.

In the thermoelectric conversion device of the present invention, it is preferable that the first film substrate and the second film substrate have the same average thickness. The average thickness may be anything that can be said to be substantially the same in the technical field of the present invention.

In the thermoelectric conversion device of the present invention, each electrode may be disposed in different layers as long as the effects of the present invention can be exhibited, but it is preferable that the respective electrodes be disposed in the same layer. That each electrode is provided in the same layer means that each electrode is in contact with a common member (first film substrate, second film substrate, etc.) on the upper layer side and / or the lower layer side. Say that.

The configuration of the thermoelectric conversion device of the present invention is not particularly limited by other components, and other configurations normally used for thermoelectric conversion devices (for example, wiring for extracting electromotive force) are appropriately applied. be able to.

According to the thermoelectric conversion device of the present invention, it is possible to sufficiently absorb and / or dissipate heat energy, and to realize a highly efficient thermoelectric conversion device.

3 shows the thermoelectric conversion device of Embodiment 1, and is a schematic cross-sectional view showing a cross section of a portion corresponding to a one-dot chain line indicated by aa ′ in FIG. 2. FIG. 1 is a schematic plan view showing a thermoelectric conversion device of Embodiment 1. FIG. 5 is a schematic cross-sectional view for explaining a manufacturing process of the thermoelectric conversion device of Embodiment 1. FIG. 5 is a schematic cross-sectional view for explaining a manufacturing process of the thermoelectric conversion device of Embodiment 1. FIG. 5 is a schematic cross-sectional view for explaining a manufacturing process of the thermoelectric conversion device of Embodiment 1. FIG. 5 is a schematic cross-sectional view for explaining a manufacturing process of the thermoelectric conversion device of Embodiment 1. FIG. 6 is a schematic cross-sectional view showing a thermoelectric conversion device of Embodiment 2. FIG. 6 is a schematic cross-sectional view for explaining a manufacturing process of the thermoelectric conversion device of Embodiment 2. FIG. 6 is a schematic cross-sectional view for explaining another manufacturing process of the thermoelectric conversion device of Embodiment 2. FIG. 6 is a schematic cross-sectional view showing a thermoelectric conversion device of Embodiment 3. FIG. 6 is a schematic cross-sectional view showing a thermoelectric conversion device of Embodiment 4. FIG. 6 is a schematic cross-sectional view showing a thermoelectric conversion device of Reference Example 1. FIG. It is a cross-sectional schematic diagram which shows the conventional thermoelectric conversion device of a pi-type structure. It is a conceptual diagram which shows the conventional general thermoelectric conversion device using a block-shaped thermoelectric material. It is a conceptual diagram which shows a film-form thermoelectric conversion device.

Embodiments will be described below, and the present invention will be described in more detail with reference to the drawings. However, the present invention is not limited only to these embodiments. In the present specification, the average thickness means the average thickness of the whole.

In addition, in each embodiment, the member and part which exhibit the same function are attached | subjected the same code | symbol. In the figure, unless otherwise specified, n indicates an N-type thermoelectric material film, p indicates a P-type thermoelectric material film, H indicates a through hole, and L indicates an adjacent electrode to electrode. An interval (minimum interval) is indicated, and d indicates an average thickness of the first film substrate and the second film substrate having a smaller average thickness. The average thickness of the substrate, electrode, thermoelectric material, etc. can be determined by averaging the overall thickness of the substrate, electrode, thermoelectric material, etc.

(Embodiment 1)
FIG. 1 is a schematic cross-sectional view illustrating a thermoelectric conversion device according to the first embodiment and illustrating a cross section of a portion corresponding to a one-dot chain line indicated by aa ′ in FIG. 2. FIG. 2 is a schematic plan view showing the thermoelectric conversion device of the first embodiment.
As shown in FIG. 1, the thermoelectric conversion device according to the first embodiment includes a thermal conductor 17; a film substrate 15; a circuit unit composed of an N-type thermoelectric material n, an electrode 1, and a P-type thermoelectric material p; 3; a film substrate 5; a heat conductor 7 is laminated in this order from the back surface side to the front surface side of the thermoelectric conversion device.
Here, on the film substrate 15, the film substrate 5 is arranged via the adhesive layer 3 on the upper part of the circuit portion composed of the N-type thermoelectric material n and the P-type thermoelectric material p connected in series via the electrode 1. In the structure, through holes H are alternately opened from the outer surfaces of the film substrates 5 and 15 on the front and back surfaces to the electrode 1, and the heat conductors 7 and 17 covering almost the entire outer surface of the film are connected to the electrode 1 through the through holes H. Connected directly to.

The heat conductors 7 and 17 are patterned so that the adjacent electrodes 1 are not electrically connected to each other. Since the outer surfaces of the film substrates 5 and 15 on the front surface and the back surface are almost covered with the heat conductors 7 and 17, when the outer surface of one of the film substrates 5 and 15 is low temperature and the other is high temperature, The heat energy of the outer surfaces of the high temperature side film substrates 5 and 15 can be almost exchanged by the heat conductors 7 and 17 disposed on the outer surfaces. For example, it is preferable that 60% or more of the area of the outer surface of the film substrate (the area of the film substrate when the main surface of the film substrate is viewed in plan) is covered with the heat conductor. And the said thermal energy can be efficiently transmitted to the electrode 1 which is a connection part of the N-type thermoelectric material film | membrane n and the P-type thermoelectric material film | membrane p through the through-hole H in which the heat conductors 7 and 17 were similarly formed. (In Embodiment 1, since the heat conductors 7 and 17 and the electrode 1 are directly connected, the efficiency of heat conduction is good.) On the other hand, between the thermal conductors 7 and 17 disposed on the outer surfaces of the film substrates 5 and 15 and the N-type thermoelectric material n and the P-type thermoelectric material p, the film substrates 5 and 15 made of a low thermal conductivity material are provided. Has been placed. The average thickness of the electrode 1 is preferably 50 to 400 nm, for example. The electrode 1 is usually made of a metal material having high conductivity such as aluminum, copper, or silver. Examples of the N-type thermoelectric material n and the P-type thermoelectric material p include Bi—Te, Pb—Te, Mg—Si, Si—Ge, etc. Especially when the exhaust heat temperature is around room temperature, Bi-Te system is preferred. For example, Bi ₂ Te ₃ is preferable as the N-type thermoelectric material n, and Sb ₂ Te ₃ (Se trace addition) is preferable as the P-type thermoelectric material p. The average thickness of the N-type thermoelectric material n and the P-type thermoelectric material p is preferably, for example, 50 to 1000 nm. The average thickness of the heat conductors 7 and 17 is preferably 50 to 400 nm, for example. Examples of the heat conductors 7 and 17 include metal materials such as copper, aluminum, and silver. The thermal conductivity of the thermal conductor is preferably 100 to 400 [W / mK]. The average thickness of the film substrate 5 and the average thickness of the film substrate 15 are the same, and are 20 to 200 μm. Examples of the material (low thermal conductivity material) of the film substrate include polystyrene, polyimide, polyvinylphenol, fluoropolymer, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polyethylene, acrylic, polyether sulfone, polypropylene, polyester, and the like. The thermal conductivity of the film substrate is 0.1 to 0.4 [W / mK], and the organic insulating film has a thermal conductivity of about 1/1000 of the thermal conductors 7 and 17.
In addition, about the electrode 1 and the heat conductors 7 and 17, metals other than the above, for example, tungsten, molybdenum, etc. may be sufficient. Further, in order to improve the adhesion between the electrode 1 and the heat conductors 7 and 17 and the film substrates 5 and 15, the electrode 1 and the heat conductors 7 and 17 are made of Ti, TiN, TaN or the like with a film thickness of 5 to 30 nm, for example. It may be used (arranged) in the lower layer.

The distance between the electrodes 1 is set in consideration of the average thickness of the film substrate 15 and the thermal conductivity. That is, the electrode interval (minimum interval) between both ends of each thermoelectric material is L, and the average thickness of the film substrates 5 and 15 with the smaller average thickness (in FIG. 1, the average thickness of the film substrate 5 and the average thickness of the film substrate 15 are Since it is the same, any average thickness may be used.) When d is d, L <300d is preferable, and L <100d is more preferable. It is also preferable that d <L. The electrode interval (minimum interval) L between both ends of each thermoelectric material depends on the processing accuracy of the electrodes, but considering the formation interval of the through holes, it is equal to or more than the average thickness of the film substrate, that is, 20 to 200 μm or more. It is considered preferable. Thereby, compared with the thermal energy supplied through the through-hole H, it is thought that the influence on the thermoelectric material from the outer surface of a film substrate becomes very small. Therefore, it becomes possible to more efficiently and uniformly apply the thermal energy of the outer surface of the film substrate to both ends of the N-type thermoelectric material and the P-type thermoelectric material.
In the first embodiment, since the heat conductors 7 and 17 on the outer surfaces of the film substrates 5 and 15 are patterned, the distortion applied to the heat conductors 7 and 17 when the film substrates 5 and 15 are curved. Can be dispersed, and the generation of cracks can be further prevented. Furthermore, since the heat conductors 7 and 17 and the electrode 1 are directly connected via the through hole H, the efficiency of heat conduction is good.

(Specific Example and Production Example of Thermoelectric Conversion Device of Embodiment 1)
3 to 6 are schematic cross-sectional views for explaining the manufacturing process of the thermoelectric conversion device according to the first embodiment.
In FIG. 3, the electrode 1 is formed on the film substrate 15. The film substrate 15 is flexible and is made of a low thermal conductivity material. The electrode is formed by etching or the like using a photolithography method after depositing a metal material on the entire surface of the film substrate by vapor deposition or sputtering. The electrode may be formed by mask vapor deposition or printing a conductive metal material.

In the thermoelectric conversion device shown in FIG. 4, the N-type thermoelectric material n and the P-type thermoelectric material p are formed by patterning so as to connect the electrodes 1.

A method for producing the N-type thermoelectric material n and the P-type thermoelectric material p is a vapor deposition method, a sputtering method, or screen printing using a paste obtained by mixing a thermoelectric material with a dispersion solvent.

In FIG. 5, the film substrate 5 is attached to the entire surface through the adhesive layer 3. The adhesive material layer 3 can be formed using, for example, a liquid thermosetting adhesive or a photocurable adhesive. In addition, members other than the film substrate 5 formed by vapor deposition, sputtering, film formation, or the like are usually sufficiently bonded to the base without using an adhesive. The film substrate 5 to be attached is made of the same material as the film substrate 15 used first, and preferably has the same average thickness. Thereby, since the layer in which the N-type thermoelectric material n, the electrode 1, and the P-type thermoelectric material p are formed is located at a substantially central portion of the entire thickness of the thermoelectric conversion device finally obtained, the thermoelectric conversion device When the film is bent, the film substrate is positioned on the neutral plane, so that bending stress can be minimized.

In FIG. 6, through holes (opening portions) H are formed from the outer surfaces of the film substrates 5 and 15 toward the electrode 1. Through holes H can be formed by wet etching or dry etching using a mask obtained by patterning a photosensitive dry film. A mask obtained by previously patterning a metal mask such as copper may be used as the mask (in this case, the process proceeds to the next step while leaving copper or the like used as the mask).

Subsequently, the heat conductors 7 and 17 are formed on the outer surfaces of the front and back film substrates 5 and 15 (FIG. 1). A metal material is formed on the entire outer surfaces of the film substrates 5 and 15 by vapor deposition, sputtering, or the like, and then formed by pattern etching or the like using a photolithography method. Moreover, you may form the heat conductors 7 and 17 by mask vapor deposition or printing a conductive metal material. Patterning is performed so that the heat conductors corresponding to the electrodes do not contact each other so that the electrodes are not electrically short-circuited. In the first embodiment, the heat conductors 7 and 17 are also formed inside the through hole H and are electrically connected to the electrodes. The inside of the through hole H does not necessarily need to be filled with the heat conductor, but is formed on the side wall of the through hole H, and the heat conductivity between the heat conductor layer on the outer surface of the film substrates 5 and 15 and the electrode can be obtained. If so, there is no problem.

(Embodiment 2)
FIG. 7 is a schematic cross-sectional view showing the thermoelectric conversion device of the second embodiment.
FIG. 7 shows another example. The difference from FIG. 1 (Embodiment 1) is that insulating films 102 and 112 are sandwiched between contact portions of the heat conductors 107 and 117 and the electrode 101 in the through hole H. It has a structure. As described later, the insulating films 102 and 112 include a film made of an organic insulating film material, a metal oxide film, an inorganic insulating film, and the like. With the above structure, the heat conductors 107 and 117 on the outer surfaces of the film substrates 105 and 115 and the electrode 101 are electrically insulated. Therefore, the P-type thermoelectric material p and the N-type thermoelectric material n are also electrically insulated. Even if the heat conductor on the high temperature side or low temperature side region on the outer surface of the film substrate 105 or 115 is conductive, it is possible to prevent a short circuit between the electrodes 101.
In the thermoelectric conversion device 120 of the second embodiment, the heat conductors 107 and 117 on the outer surfaces of the film substrates 105 and 115 are patterned in the same manner as in the first embodiment so that the electrodes 101 are not electrically short-circuited. In addition, since the heat conductors 107 and 117 and the electrode 101 in the through-hole H are insulated through the insulating films 102 and 112, the insulation between the electrodes 101 can be more sufficiently secured to increase the yield. be able to. In addition, since the heat conductors 107 and 117 on the outer surfaces of the film substrates 105 and 115 are patterned, distortion applied to the heat conductors 107 and 117 when the film substrates 105 and 115 are curved can be dispersed. The occurrence of cracks can be more sufficiently prevented.

(Specific Example and Production Example of Thermoelectric Conversion Device of Embodiment 2)
FIG. 8 is a schematic cross-sectional view for explaining a manufacturing process of the thermoelectric conversion device of the second embodiment. After performing the steps shown in FIGS. 3 to 6 of the first embodiment in the same manner as in the first embodiment, an insulating film 102 is formed on the electrode 101 on the bottom surface of the through hole H as shown in FIG. Examples of a method for forming the insulating film 102 include application and baking of an organic insulating film material. Firing is performed, for example, at a temperature of 100 to 150 ° C. for several minutes to several tens of minutes (in this case, although not shown, an insulating film is formed on the entire outer surface of the film substrate). Examples of the organic insulating film material include polyimide, polystyrene, polyvinylphenol, and fluoropolymer. The average thickness of the organic insulating film is, for example, 50 to 1000 nm. Another method for forming the insulating film 102 is to oxidize the electrode surface to form an oxide film. A metal oxide film is formed on the electrode surface on the bottom surface of the through hole H by performing a heat treatment in the atmosphere, an atmospheric pressure plasma treatment, or the like. The average thickness of the metal oxide film is about 100 nm (for example, 80 to 120 nm).
The subsequent steps (film formation steps of the heat conductors 107 and 117) are the same as those described in the first embodiment.

FIG. 9 is a schematic cross-sectional view for explaining another manufacturing process of the thermoelectric conversion device of the second embodiment. After the steps shown in FIGS. 3 and 4 of the first embodiment are performed in the same manner as in the first embodiment, an insulating film 102 is formed on the entire outer surface of the film substrate as shown in FIG. The insulating film 102 is an inorganic insulating film in one of the preferred embodiments in the present invention. Examples of the inorganic insulating film include a silicon oxide film and a silicon nitride film formed by vapor deposition or sputtering. The average thickness of the inorganic insulating film is, for example, 50 to 400 nm. By using the inorganic insulating film, the etching selectivity can be ensured when the through hole is formed in a later step.
The subsequent steps (the step of attaching the film substrate 105 via the adhesive layer 103, the step of forming the through holes H, the step of forming the thermal conductors 107 and 117) are the same as the steps described above in the first embodiment. It is.
By setting it as such a structure, even if the heat conductor of a high temperature side or a low temperature side is an electroconductivity thing, between electrodes does not electrically short-circuit.

The second embodiment has an advantage that the thickness of the insulating films 102 and 112 can be finely adjusted. That is, by setting the film thickness to the minimum necessary for maintaining electrical insulation, it is possible to minimize the adverse effect of the decrease in thermal conductivity caused by the insulating films 102 and 112. In order to maintain electrical insulation, it is considered sufficient that the insulating films 102 and 112 have a thickness of several tens to several hundreds of nanometers. For example, the average thickness of the insulating films 102 and 112 is preferably 10 nm or more and 1 μm or less.

The reason why the thickness of the insulating films 102 and 112 can be finely adjusted is as follows. Controllability in the film thickness direction (longitudinal direction) can be achieved with deposition accuracy (nanometer order) by vapor deposition or sputtering. On the other hand, the controllability in the in-plane direction depends on the precision of the microfabrication apparatus such as a photolithography method or a printing method, and an expensive exposure apparatus is required even for controlling on the order of microns. From the above, by insulating the heat conductors 107 and 117 and the electrode 101 in the through-hole H shown in FIG. 7 through the insulating films 102 and 112, the insulating films 102 and 112 in the film thickness direction. The control can be adjusted to optimize the thermal conductivity while maintaining the electrical insulation. Such advantages are the same in the third embodiment described later.

(Embodiment 3)
FIG. 10 is a schematic cross-sectional view showing the thermoelectric conversion device of the third embodiment. The difference from FIG. 7 (Embodiment 2) is that in Embodiment 3, the heat conductors 207 and 217 on the outer surfaces of the film substrates 205 and 215 are not patterned. As a result, it is possible to efficiently exchange heat energy in all portions of the high temperature side or low temperature side region of the thermoelectric conversion device, thereby minimizing waste of heat energy. In addition, since the patterning step is not necessary, the number of manufacturing steps can be reduced, leading to a reduction in cost and manufacturing period.

(Specific Example and Production Example of Thermoelectric Conversion Device of Embodiment 3)
In the manufacturing example of the thermoelectric conversion device of the second embodiment, the thermoelectric conversion device 220 as shown in FIG. 10 can be manufactured by not performing the final thermal conductor patterning step. In this case, since the last patterning step is not necessary, the cost and the manufacturing period can be shortened. Further, it becomes possible to generate a temperature difference between the electrodes 201 at both ends of the P-type thermoelectric material p and the N-type thermoelectric material n by using all portions of the high temperature side or low temperature side region of the thermoelectric conversion device. Efficiency can be further improved.

Moreover, since the insulating film is formed on the electrode surface at the bottom of the through hole H as in the second embodiment, even if the heat conductor on the high temperature side or the low temperature side is electrically conductive, there is a gap between the electrodes. There is no electrical short circuit.

(Embodiment 4)
FIG. 11 is a schematic cross-sectional view illustrating the thermoelectric conversion device of the fourth embodiment. The difference from FIG. 1 (Embodiment 1) is that the heat conductors 307 and 317 on the outer surfaces of the film substrates 305 and 315 are not patterned, and the heat conductors 307 and 317 are electrically insulating. is there. Examples of electrically insulating thermal conductor materials include BeO (beryllium oxide), SiC (silicon carbide), AlN (aluminum nitride), BN (boron nitride), SiN (silicon nitride), diamond, and the like. Is mentioned. Thereby, it becomes possible to transfer heat energy in all parts of the high temperature side or low temperature side region, and waste of heat energy is minimized. In addition, since the patterning step is not necessary, the number of manufacturing steps can be reduced, leading to a reduction in cost and manufacturing period. Furthermore, since the heat conductors 307 and 317 and the electrode 301 are directly connected through the through-hole H, the efficiency of heat conduction is good.

(Specific Example and Production Example of Thermoelectric Conversion Device of Embodiment 4)
In the manufacturing example of the thermoelectric conversion device of the first embodiment, the last heat conductor patterning step is not performed, and the above-described electrical insulation is used as the material of the heat conductor, so that the thermoelectric as shown in FIG. A conversion device 320 can be formed. In this case, since the last patterning step is not necessary, cost reduction and production time can be shortened. Moreover, it becomes possible to generate a temperature difference between the electrodes 301 at both ends of the P-type thermoelectric material p and the N-type thermoelectric material n by using all portions of the high temperature side or low temperature side region of the thermoelectric conversion device. Efficiency can be further improved.

The configurations of Embodiments 1 to 4 described above can be combined as appropriate. For example, in one film substrate, as in the first embodiment, the heat conductor on the outer surface is patterned so that the electrodes are not electrically short-circuited, and the heat conductor and the electrode in the through hole In the other film substrate, the heat conductor on the outer surface is not patterned as in the third embodiment, and the heat conductor in the through hole and the electrode are insulated through an insulating film. May be. Moreover, in Embodiment 1-4 mentioned above, although the through-hole and the heat conductor are each provided in both the film substrates, and this is a preferable form, a through-hole and a heat conductor are provided only in any one film substrate. A thermoelectric conversion device may be configured, and even with such a thermoelectric conversion device, a temperature difference is generated at both ends of the thermoelectric material, and the effects of the present invention can be exhibited.

(Reference Example 1)
FIG. 12 is a schematic cross-sectional view showing the thermoelectric conversion device of Reference Example 1. The difference from FIG. 1 (Embodiment 1) is that no electrode is present. Also by this, heat energy can be sufficiently absorbed from the outside, or heat energy can be sufficiently dissipated to the outside, and a highly efficient thermoelectric conversion device can be provided.

(Specific example and fabrication example of thermoelectric conversion device of Reference Example 1)
In Embodiment 1, the N-type thermoelectric material n and the P-type thermoelectric material p are patterned so as to be in direct contact with each other without performing the electrode forming step, whereby the thermoelectric conversion device 420 as shown in FIG. 12 can be manufactured. it can.

Another embodiment of the present invention includes a first film substrate, a plurality of P-type thermoelectric material films alternately arranged in series on the first film substrate, and a plurality of N-type thermoelectric material films, Covering the plurality of P-type thermoelectric material films, the second film substrate covering the plurality of N-type thermoelectric material films, and covering at least one outer surface of the first film substrate and the second film substrate; One or more thermal conductors connected to a plurality of connection points of each of the mold type thermoelectric material films and each of the plurality of N-type thermoelectric material films, the connection points being electrically connected to each other One or each of the first film substrate and the second film substrate is provided with a plurality of through-holes that reach every other connecting portion arranged in series. Each of the one or more thermal conductors includes at least one of the plurality of through holes. A portion disposed in part, may be a thermoelectric device including a portion exposed to the outer surface of the first film substrate or the second film substrate.
A plurality of heat conductors covering both outer surfaces of the first film substrate and the second film substrate and connected to the plurality of connection points, and each of the first film substrate and the second film substrate; Is provided with a plurality of through-holes reaching every other plurality of connection points arranged in series, and the plurality of through-holes are arranged on the first film substrate side of the plurality of connection points arranged in series. Or it is preferable to be provided in the 2nd film board | substrate side alternately.
Also in another form of the present invention, the heat conductor on the outer surface of the film substrate is patterned so that the connection points are not electrically short-circuited with each other, or the heat conductor and the electrode are interposed in the through hole with an insulating film interposed therebetween. It is preferable to separate the thermal conductors or to make the thermal conductor electrically insulating.
The preferable aspect of another form of this invention is the same as that of the preferable aspect of this invention mentioned above.

Although not shown, the wiring is electrically connected to the outside from the electrodes at both ends of a series of circuits in which the P-type thermoelectric material and the N-type thermoelectric material are connected in series via the electrodes. The electromotive force can be taken out.

In addition, the shape of the P-type thermoelectric material and the N-type thermoelectric material shown in the above-described drawings is an example, and is not limited to this shape, and thermoelectric materials having various structures can be used.

The thermoelectric conversion device of the present invention is suitably deformed along a curved surface (which may be a curved surface that does not have a certain curvature) as a lightweight and flexible film-like thermoelectric power generation sheet when incorporated into a product. Can do. Moreover, once the thermoelectric conversion device of the present invention is once assembled into a certain place of the product, it can be replaced with another part of the product or another product. Furthermore, the thermoelectric conversion device of the present invention can be expected to have high thermoelectric conversion efficiency in principle, exhaust heat from piping in factories, exhaust heat from automobile engines, mufflers, etc., backlights of liquid crystal panels, and other electronic devices It can be suitably used for various types of exhaust heat generation, energy harvesting, and the like.

In addition, the electrode structure etc. which concern on the thermoelectric conversion device of this invention can be confirmed by microscope observation, such as SEM (Scanning Electron Microscope: Scanning electron microscope).

1, 101, 201, 301, 501, 501a: Electrode 3: Adhesive layer 5, 15, 105, 115, 205, 215, 305, 315, 405, 415: Film substrate 7, 17, 107, 117, 207, 217, 307, 317, 407, 417: thermal conductor 20, 120, 220, 320, 420, 520: thermoelectric conversion device 102, 112, 202, 212: insulating film p: P-type thermoelectric material (film)
n: N-type thermoelectric material (film)
n (p): Thermoelectric material H: Through hole

Claims (6)

A first film substrate;
A plurality of P-type thermoelectric material films, a plurality of electrodes, and a plurality of N-type thermoelectric material films alternately arranged in series on the first film substrate;
A second film substrate covering the plurality of P-type thermoelectric material films, the plurality of electrodes, and the plurality of N-type thermoelectric material films;
One or a plurality of thermal conductors covering at least one outer surface of the first film substrate and the second film substrate and connected to the plurality of electrodes,
Each of the plurality of P-type thermoelectric material films and each of the plurality of N-type thermoelectric material films are connected to each other via one of the plurality of electrodes,
Each of the plurality of electrodes is electrically insulated from each other;
One or each of the first film substrate and the second film substrate is provided with a plurality of through holes reaching every other electrode of the plurality of electrodes arranged in series,
Each of the one or more thermal conductors includes a portion provided inside at least one of the plurality of through holes, and a portion exposed to the outer surface of the first film substrate or the second film substrate. A thermoelectric conversion device characterized by that. A plurality of thermal conductors covering both outer surfaces of the first film substrate and the second film substrate and connected to the plurality of electrodes;
Each of the first film substrate and the second film substrate is provided with a plurality of through holes reaching every other electrode of the plurality of electrodes arranged in series,
2. The thermoelectric conversion device according to claim 1, wherein the plurality of through holes are alternately provided on the first film substrate side or the second film substrate side of the plurality of electrodes arranged in series. 3. . The one or more thermal conductors are a plurality of thermal conductors;
The plurality of heat conductors covering at least one outer surface of the first film substrate and the second film substrate are patterned so that each of the plurality of electrodes is electrically insulated from each other. The thermoelectric conversion device according to claim 1 or 2. In addition, including an insulating film,
The one or more thermal conductors and the plurality of electrodes are separated from each other through the insulating film in at least one through-hole of the first film substrate and the second film substrate, and are electrically insulated. The thermoelectric conversion device according to claim 1, wherein the thermoelectric conversion device is provided. The thermoelectric conversion device according to claim 1, wherein the one heat conductor or the plurality of heat conductors are electrically insulating. 6. The thermoelectric conversion device according to claim 1, wherein an average thickness of the first film substrate and an average thickness of the second film substrate are the same.

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