JP2018067567A - Thermoelectric transducer and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric transducer with which a plurality of thermoelectric conversion units are formed in series connection on a substrate, and which has a height difference equal to or greater than thickness of a thermoelectric conversion layer between a heat absorption side and a heat radiation side, is capable of obtaining a high power generation performance even if used without being stood, and can be stably installed on a planar heating device only with a substrate on which the thermoelectric conversion units are formed.SOLUTION: A thermoelectric transducer 1 comprises a substrate 2 and a plurality of thermoelectric conversion units 10. A cross-sectional shape of a unit formed part 21 is formed from a projection 211, a first low surface part 212 and a second low surface part 213 at both sides of the projection. A non-formed part 22 in which no thermoelectric conversion unit is formed is located at a position lower than an apex 211a of the projection 211. The thermoelectric conversion unit 10 includes a first layer 31 from the first low surface part 212 of the unit formed part 21 to the apex 211a, and a second layer 32 from the apex 211a to the second low surface part 213. At least one of the first layer 31 and the second layer 32 are formed from a thermoelectric conversion material.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermoelectric conversion element and a manufacturing method thereof.

A thermoelectric conversion element is an element which can mutually convert heat energy and electric energy. By installing the thermoelectric conversion element in an environment where a temperature difference occurs between both ends, electric power can be extracted from the thermoelectric conversion element without the need for a movable part. For example, electrical energy can be generated from exhaust heat. Therefore, the power generation technology using the thermoelectric conversion element is highly expected as an energy harvesting technology for recovering and using unused energy around us.
If the thermoelectric conversion element can be used as, for example, a distributed self-supporting power source, it can be used as a power source for large-scale sensor networks, wearable electronics, and the like. In particular, when a thermoelectric conversion material made of an organic material is used, the thermoelectric conversion layer can be formed with a printed pattern, so that weight reduction, cost reduction, and high output due to a large area are possible. In this case, in order to maintain the flatness of the thermoelectric conversion element unit, the temperature difference is generally given in a direction perpendicular to the unit substrate.

As an example of a thermoelectric conversion element having a thermoelectric conversion layer as a print pattern, a thermoelectric power generation element disclosed in Patent Document 1 can be given. In the thermoelectric conversion element (thermoelectric power generation element) of Patent Document 1, a plurality of thermoelectric conversion layers (thermoelectric conversion units) formed of a print pattern are formed on a corrugated substrate (base material) in which a bottom portion and a top portion are alternately repeated. A plurality of thermoelectric conversion layers are connected in series. Each thermoelectric conversion layer is formed on one of a pair of inclined surfaces of one convex portion or concave portion constituting the corrugation of the substrate, and is not formed on the other.
In the thermoelectric conversion element of Patent Document 1, the bottom is the heat absorption side and the top is the heat dissipation side, and power is generated by the temperature difference between the bottom and the top. Further, since the substrate is formed in a corrugated shape, a large temperature difference can be obtained as the distance between the heat absorption side and the heat dissipation side increases. On the other hand, in a thermoelectric conversion element having a substrate without unevenness, a sufficient temperature difference cannot be obtained in a state where the substrate is held horizontally.

International Publication 2013/114854 Pamphlet

In the thermoelectric conversion element of Patent Document 1, not only the portion where the thermoelectric conversion layer is formed, but also the portion where the thermoelectric conversion element is not formed, the cross-sectional shape of the entire substrate is a waveform. For this reason, when a large height difference is provided between the bottom and the top, it is necessary to provide a reinforcing material for maintaining the shape in the lower space of the convex portion of the substrate. In addition, in order to stably install on a flat heating device such as a hot plate, a support base material for mounting and fixing a plurality of bottom portions of the substrate is further required.
An object of the present invention is that a plurality of thermoelectric conversion units are formed in series connection on a substrate, have a difference in height over the thickness of the thermoelectric conversion layer between the heat absorption side and the heat dissipation side, and are high even when used without standing It is an object to provide a thermoelectric conversion element that has a power generation performance and can be stably installed on a planar heating device only by a substrate on which a thermoelectric conversion unit is formed.

In order to solve the above problems, a first aspect of the present invention provides a thermoelectric conversion element having the following configurations (1) to (4).
(1) It has a substrate and a plurality of thermoelectric conversion units formed on the upper surface or the lower surface of the substrate.
(2) The cross-sectional shape of the unit forming portion on which the thermoelectric conversion unit of the substrate is formed includes a convex portion and a first low surface portion and a second low surface portion that are lower than the convex portions on both sides thereof. The non-formation part in which the said thermoelectric conversion unit of the said board | substrate is not formed exists in the position lower than the top part of the said convex part.
(3) The thermoelectric conversion unit has a first layer extending from the first low surface portion of the unit forming portion to the top of the convex portion, and a second layer extending from the top to the second low surface portion. At least one of the first layer and the second layer is made of a thermoelectric conversion material.
(4) The plurality of thermoelectric conversion units are connected in series by the wiring connecting the first layer and the second layer of the adjacent thermoelectric conversion units formed on the first low surface portion and the second low surface portion. It is connected. Connection terminals are provided at both ends of the series connection.

According to a second aspect of the present invention, there is provided a method for manufacturing a thermoelectric conversion element having the above configurations (1) to (4), which includes the following steps of the following configurations (11) to (13).
(11) A first printing step of forming a thermoelectric conversion pattern comprising the first layer and the second layer constituting the plurality of thermoelectric conversion units on a substrate.
(12) A second printing step of forming a conductive layer pattern including the wiring and the connection terminal on the thermoelectric conversion pattern.
(13) A projecting portion forming step of forming the projecting portion by stretching and deforming the first layer and the second layer and a portion of the substrate where the first layer and the second layer are formed.

The thermoelectric conversion element manufactured by the method of the second aspect has the above configurations (1) to (4) and the following configurations (21) and (22).
(21) The plurality of thermoelectric conversion unit substrates are formed of a printing pattern.
(22) The wiring and the connection terminal are formed of a printed pattern.

  According to the present invention, a plurality of thermoelectric conversion units are formed on the substrate in series connection, and have a difference in height over the thickness of the thermoelectric conversion layer between the heat absorption side and the heat dissipation side, which is high even when used without standing. There is provided a thermoelectric conversion element that has a power generation performance and can be stably installed on a planar heating device only by a substrate on which a thermoelectric conversion unit is formed.

It is a fragmentary sectional view showing the thermoelectric conversion element of a first embodiment, and shows the unit formation part of a substrate corresponding to one thermoelectric conversion unit, and the non-formation part of the both sides. It is a top view explaining the front | former stage process of the 1st printing process which comprises the manufacturing method of the thermoelectric conversion element shown in FIG. It is a top view explaining the back | latter stage process of the 1st printing process which comprises the manufacturing method of the thermoelectric conversion element shown in FIG. It is a top view explaining the 2nd printing process which comprises the manufacturing method of the thermoelectric conversion element shown in FIG. It is a top view explaining the through-hole formation process which comprises the manufacturing method of the thermoelectric conversion element shown in FIG. It is AA sectional drawing of FIG. It is a fragmentary sectional view which shows the thermoelectric conversion element of 2nd embodiment, Comprising: The unit formation part of the board | substrate corresponding to one thermoelectric conversion unit in a substrate surface, and the non-formation part of the both sides are shown. FIG. 8 is a plan view showing a state before the convex portion forming step of the thermoelectric conversion element shown in FIG. 7, and an A′-A ′ cross-sectional view after the convex portion is formed corresponds to FIG. 7. It is a fragmentary sectional view which shows the thermoelectric conversion element of 3rd embodiment, Comprising: The unit formation part of the board | substrate corresponding to one thermoelectric conversion unit in a board | substrate surface, and the non-formation part of the both sides are shown. It is a top view explaining the insulating layer formation process which comprises the manufacturing method of the thermoelectric conversion element shown in FIG. It is a top view explaining the coating layer formation process which comprises the manufacturing method of the thermoelectric conversion element shown in FIG. It is AA sectional drawing of FIG. It is a perspective view explaining an example of the wireless sensor transmitter using the thermoelectric conversion element of a first embodiment. It is a front view explaining the collar for cattle which is an example of the power supply for wearable apparatus using the thermoelectric conversion element of 3rd embodiment. It is a schematic diagram which shows the state by which the cow collar of FIG. 14 was wound around the cow. It is a schematic diagram corresponding to the BB cross section of FIG. It is a front view which shows the example of the shape different from 1st thru | or 2nd embodiment regarding the convex part of the board | substrate which comprises the thermoelectric conversion element of embodiment.

  Embodiments of the present invention will be described below. In the embodiment described below, a technically preferable limitation is made for carrying out the present invention, but the present invention is not limited to the embodiment described below.

[First embodiment]
The thermoelectric conversion element of this embodiment is a thermoelectric conversion element manufactured by performing each process shown in FIGS. FIG. 1 shows a cross section of one thermoelectric conversion unit 10 constituting the thermoelectric conversion element 1 of this embodiment.
The thermoelectric conversion element 1 includes a pre-process of the first printing process shown in FIG. 2, a post-process of the first printing process shown in FIG. 3, a second printing process shown in FIG. 4, and a through-hole forming process shown in FIG. And the convex part formation process which changes from the state of FIG. 6 to the state of FIG. 1 is manufactured.

The thermoelectric conversion element 1 includes a flexible substrate 2 and a plurality of thermoelectric conversion units 10 each having a print pattern formed on the upper surface of the substrate 2. The cross-sectional shape of the unit forming portion 21 on which the thermoelectric conversion unit 10 of the substrate 2 is formed includes a convex portion 211, a first low surface portion 212, and a second low surface portion 213. The 1st low surface part 212 and the 2nd low surface part 213 are parts lower than the convex part of the both sides of the convex part 211, and are the same height as the non-formation part 22 in which the thermoelectric conversion unit 10 is not formed.
The thermoelectric conversion unit 10 includes a first layer 31 that extends from the first low surface portion 212 of the unit forming portion 21 to the top portion 211 a of the convex portion 211, and a second layer 32 that extends from the top portion 211 a to the second low surface portion 213. The first layer 31 is made of a p-type conductive polymer (thermoelectric conversion material), and the second layer 32 is made of a cured silver paste (conductive material). Although a layer made of an n-type conductive polymer (thermoelectric conversion material) may be provided as the second layer 32, since there is no material that has stable performance at present, in this embodiment, as an alternative, a silver paste is used. A second layer 32 made of a cured product is provided.

As shown in FIG. 5, 14 thermoelectric conversion units 10 are formed on the upper surface of the substrate 2 in two columns and seven rows. Between the thermoelectric conversion units 10 adjacent between the rows of the substrates 2, rectangular through holes 25 are formed in the entire range of the convex portions 211. That is, the adjacent thermoelectric conversion units 10 between the rows of the substrates 2 are separated within the range of the convex portions 211.
And the lower wiring 41 which connects the 1st layer 31 and the 2nd layer 32 of the thermoelectric conversion unit 10 adjacent between row | line | columns and between columns is on the 1st layer 31 on the 1st low surface part 212 and the 2nd low surface part 213. And the second layer 32.

In addition, since the first layer 31 and the second layer 32 are made of different materials, the upper wiring 42 that connects the first layer 31 and the second layer 32 in the thermoelectric conversion unit 10 is located at the top 211a of the convex portion 211. Is formed. Further, both ends of the series connection exist at one edge portion of the upper surface of the substrate 2, and connection terminals 43 to the outside are formed at each position.
In the manufacturing method of the thermoelectric conversion element 1 of this embodiment, first, as the pre-stage process of the first printing process, one first layer 31 is arranged in one rectangular shape in the arrangement shown in FIG. Form with. In other words, the adjacent first layers 31 are arranged at positions opposite to each other in the long-side direction of the rectangle, within and between the two rows of the 14 thermoelectric conversion units 10.

Next, as a subsequent step of the first printing step, as shown in FIG. 3, one second layer 32 for one thermoelectric conversion unit 10 is in contact with the first layer 31 next to the first layer 31. They are formed with the same planar shape and thickness.
Thus, the thermoelectric conversion pattern which consists of all the 1st layers 31 and the 2nd layers 32 which comprise the 14 rows of thermoelectric conversion units 10 in the upper surface of the board | substrate 2 is formed. In the state of FIG. 3, a portion where the first layer 31 and the second layer 32 of the substrate 2 exist is a unit forming portion.
Next, as a second printing step, as shown in FIG. 4, a conductive layer pattern composed of the lower wiring 41, the connection terminal 43, and the upper wiring 42 is formed on the thermoelectric conversion pattern shown in FIG. 3.

Next, as shown in FIG. 5, a through hole 25 is formed by a punching method or a cutting method in a portion between the adjacent thermoelectric conversion units 10 between the rows of the substrate 2 in the entire range in which the convex portions 211 are formed in the subsequent process. Form. In this state, the thermoelectric conversion unit 10 is formed in a flat plate shape on the flat plate substrate 2 as shown in FIG.
Next, as a convex forming step, a mold having a male part and a female part corresponding to the convex part 211 in FIG. 1 is prepared, and the male part is pressed against the back side of the substrate 2 and the female part is pressed against the front side. Pressurizing while heating (heat-press molding is performed). Thereby, the first layer 31 and the second layer 32 and the portion of the substrate 2 where the first layer 31 and the second layer 32 are formed are stretched and deformed to form the convex portion 211. In that case, the convex part 211 is formed in all the thermoelectric conversion units 10 at once by using the metal mold | die which has the male part and female part corresponding to the convex part 211 of all the unit formation parts 21. FIG.

Thus, the manufactured thermoelectric conversion element 1 is the low part 31a which is a part on the 1st low surface part 212 of the 1st layer 31, and the 2nd low surface part 213 of the 2nd layer 32 in all the thermoelectric conversion units 10. More than the thickness of the 1st layer 31 and the 2nd layer 32 between the low part 32a which is an upper part, and the high parts 31b and 32b which are the parts on the top part 211a of the 1st layer 31 and the 2nd layer 32 There is a difference in height.
Therefore, the thermoelectric conversion element 1 is placed on, for example, a hot plate while holding the non-formed portion 22 of the substrate 2 horizontally, and the low portion 31 a of the first layer 31 and the low portion of the second layer 32 are interposed via the substrate 2. Even when the part 32a is heated and used, high power generation performance can be obtained. Further, the substrate 2 on which the printed pattern is formed can be stably placed on the hot plate.

Further, the thermoelectric conversion units 10 adjacent between the rows of the substrates 2 are separated by the entire range of the convex portions 211 in all the unit forming portions 21 by forming the through holes 25. That is, as shown in FIG. 1, all the unit forming portions 21 have the cut surfaces 214 that are separated independently for each thermoelectric conversion unit 10 in the entire range of the convex portions 211, and the cut surfaces 214 that are adjacent between the rows. The space (through hole 25) made of and the lower space K of the convex portion 211 communicate with each other. Therefore, for each thermoelectric conversion unit 10, the atmosphere is in contact with the surroundings.
Therefore, when the top portion 211a is cooled by circulating the air through the flow path formed of the lower space K during the heating by the hot plate described above, the low portions 31a and 32a and the high portions 31b and 32b of the thermoelectric conversion unit 10 are cooled. In the meantime, it can be expected that a larger temperature difference is generated.
In the method of manufacturing the thermoelectric conversion element 1 of this embodiment, the printing process is performed in the order of the first layer 31, the second layer 32, and the conductive layer pattern (the lower wiring 41, the connection terminal 43, and the upper wiring 42). However, the printing order of these layers can be arbitrarily changed.

[Second Embodiment]
As shown in FIG. 7, the thermoelectric conversion element 101 according to the second embodiment not only has the thermoelectric conversion units 10 in two columns and seven rows on the upper surface of the substrate 2, similarly to the thermoelectric conversion element 1 according to the first embodiment. Two columns and seven rows of thermoelectric conversion units 10 </ b> A are provided on the lower surface of the substrate 2.
Each thermoelectric conversion unit 10A is arranged at a position overlapping each thermoelectric conversion unit 10 with the substrate 2 interposed therebetween. The first layer 31 of the thermoelectric conversion unit 10A is formed to overlap the second layer 32 of the thermoelectric conversion unit 10, and the second layer 32 of the thermoelectric conversion unit 10A is formed to overlap the first layer 31 of the thermoelectric conversion unit 10. Has been. Moreover, all the unit formation parts 21 have the cut surface 214 cut | disconnected independently for every thermoelectric conversion unit 10 and 10A in the whole range of the convex part 211, and the space and the space between the adjacent cut surfaces 214 between rows are convex. The lower space K of the part 211 is in communication.

Further, as shown in FIG. 8, the connection terminal 43 a on the upper surface and the connection terminal 43 a on the lower surface that overlaps with the substrate 2 are connected by, for example, electrodes provided on the end surface of the substrate 2. Thereby, the thermoelectric conversion unit 10 of 2 columns 7 rows on the upper surface and the thermoelectric conversion unit 10A of 2 columns 7 rows on the lower surface are connected in series. In this case, the connection terminals 43b on the upper surface and the lower surface serve as connection terminals to the outside.
The first layer 31 of the thermoelectric conversion unit 10A is formed so as to overlap the first layer 31 of the thermoelectric conversion unit 10, and the second layer 32 of the thermoelectric conversion unit 10A is overlapped with the second layer 32 of the thermoelectric conversion unit 10. The connection terminals 43a on the upper surface and the lower surface and the connection terminals 43b may be connected to each other. In this case, the thermoelectric conversion unit 10 of 2 columns and 7 rows on the upper surface and the thermoelectric conversion unit 10A of 2 columns and 7 rows on the lower surface are connected in parallel, and the connection terminal 43a and the connection terminal 43b in the state of being connected vertically are connected to the outside. It becomes a terminal.

The thermoelectric conversion element 101 is the same method as the manufacturing method of the thermoelectric conversion element 1 of the first embodiment, and after performing the first printing process and the second printing process on the upper surface and the lower surface of the substrate 2, the thermoelectric conversion element 101 of the first embodiment. It can manufacture by performing the through-hole formation process and convex part formation process with respect to the board | substrate 2 by the same method as the manufacturing method of the conversion element 1. FIG.
According to the thermoelectric conversion element 101 of this embodiment, in addition to the effects that the thermoelectric conversion element 1 of the first embodiment has, a high electromotive force can be obtained on a single substrate by having thermoelectric conversion units on both sides of the substrate 2. It also has the effect of being obtained.

That is, the thermoelectric conversion element 101 of the second embodiment has the same area of the substrate 2 as the thermoelectric conversion element 1 of the first embodiment, but the thermoelectric conversion units 10 and 10A having the same pattern are arranged in the thickness direction of the substrate 2. Since it has two layers, the output voltage is twice that of the thermoelectric conversion element 1 in the case of series connection, and the output current is twice that of the thermoelectric conversion element 1 in the case of parallel connection.
Further, by increasing the number of thermoelectric conversion units 10 in the thickness direction of the substrate 2 to three layers, four layers, or more, the output current of the thermoelectric conversion element can be increased without changing the area of the substrate 2. .
Moreover, it is preferable that the thermoelectric conversion element 101 of 2nd embodiment is covering all the thermoelectric conversion units 10, the lower wiring 41, and the upper wiring 42 with a weather resistant material. In that case, the formation of the covering layer made of the weather resistant material may be performed at any timing before and after the formation of the convex portion 211.

[Third embodiment]
As shown in FIG. 9, the thermoelectric conversion element 102 of the third embodiment has only two columns and seven rows of thermoelectric conversion units 10 in the plane of the substrate 2, as in the thermoelectric conversion element 1 of the first embodiment. The same two columns and seven rows of thermoelectric conversion units 10 are provided on the upper surface of the substrate 2. FIG. 9 shows a cross section of a portion where the thermoelectric conversion units 10 and 10B of the thermoelectric conversion element 102 overlap. As shown in FIG. 9, the thermoelectric conversion element 102 has an insulating layer 44 between the two thermoelectric conversion units 10 and 10 </ b> B, and has a coating layer 45 made of a weather resistant material on the surface opposite to the substrate 2.
The thermoelectric conversion element 102 is manufactured by the following method.

  First, each process shown in FIGS. 2 to 5 is performed in the same manner as the thermoelectric conversion element 1 of the first embodiment, and the pattern of the first thermoelectric conversion unit 10 (thermoelectric conversion pattern and conductive layer pattern) is formed on the substrate 2. And a through hole 25 is formed. Next, an insulating layer 44 is formed on the entire surface excluding the connection terminal 43 on the substrate 2 in the state shown in FIG. FIG. 10 shows this state. Next, the steps shown in FIGS. 2 to 4 are performed by the same method, and the pattern (thermoelectric conversion pattern and conductive layer pattern) of the thermoelectric conversion unit 10B of the second layer is formed on the substrate 2 in the state shown in FIG. After the formation, a coating layer 45 is formed on the entire surface of the substrate 2 to obtain the state shown in FIG.

The thermoelectric conversion element 102 in this state has a flat plate shape, and the thermoelectric conversion units 10 and 10B have a flat plate shape as shown in FIG. Next, the convex part 211 is formed in all the thermoelectric conversion units 10 and 10B by performing the same convex part formation process as 1st embodiment.
The thermoelectric conversion element 102 manufactured in this way has the low portion 31a and the second low level of the second layer 32 that are portions on the first low surface portion 212 of the first layer 31 in all the thermoelectric conversion units 10 and 10B. The thickness of the first layer 31 and the second layer 32 between the low part 32a that is a part on the surface part 213 and the high parts 31b and 32b that are parts on the top part 211a of the first layer 31 and the second layer 32. It has a height difference of more than that.

Therefore, the thermoelectric conversion element 102 is placed on, for example, a hot plate while holding the non-forming portion 22 of the substrate 2 horizontally, and the low portion 31 a of the first layer 31 and the low portion of the second layer 32 are interposed via the substrate 2. Even when the part 32a is heated and used, high power generation performance can be obtained. Further, the substrate 2 on which the printed pattern is formed can be stably placed on the hot plate.
Further, the thermoelectric conversion units 10 and 10B adjacent between the rows of the substrate 2 are separated by the entire range of the convex portions 211 in all the unit forming portions 21 by forming the through holes 25. That is, as shown in FIG. 9, all the unit forming portions 21 have cutting surfaces 214 that are separated independently for each thermoelectric conversion unit 10, 10 </ b> B in the entire range of the convex portion 211, and are adjacent to each other between rows. The space between the surfaces 214 and the lower space K of the convex portion 211 communicate with each other.

Therefore, when the top portion 211a is cooled by circulating the air through the flow path formed by the lower space K during the heating by the hot plate described above, the low portions 31a and 32a and the high portions 31b and 32b of the thermoelectric conversion units 10 and 10B. It can be expected that a larger temperature difference will occur between the two.
Moreover, the thermoelectric conversion element 102 of 3rd embodiment has the same area of the thermoelectric conversion element 1 and board | substrate 2 of 1st embodiment, However, The thermoelectric conversion units 10 and 10B of the same pattern are the thickness direction of the board | substrate 2. Since it has two layers, the output current is larger than that of the thermoelectric conversion element 1.
In the thermoelectric conversion element 102 of the third embodiment, the conductive layer patterns (lower wiring 41, upper wiring 42, and connection terminal 43) of the two-layer thermoelectric conversion units 10 and 10B are the same, and the second layer When the conductive layer pattern is formed, the second-layer connection terminal 43 is printed on the first-layer connection terminal 43 so that the two-layer thermoelectric conversion units 10 and 10B are connected in parallel.

Further, if the two-layer thermoelectric conversion units 10 and 10B are connected in series by setting the print pattern of the conductive layer and the insulating layer, the output voltage of the thermoelectric conversion element 102 can be increased. Moreover, the output of the thermoelectric conversion element 102 can also be freely adjusted by connecting the two-layer thermoelectric conversion units 10 and 10B by combining parallel connection and series connection in each layer and between layers.
Further, by increasing the number of thermoelectric conversion units 10 in the thickness direction of the substrate 2 to three layers, four layers, or more, the output current of the thermoelectric conversion element can be increased without changing the area of the substrate 2. .
Further, in the third embodiment, the convex portion 211 is formed after the coating layer 45 is formed. However, after the convex portion 211 is formed after the uppermost thermoelectric conversion unit 10B is formed, the covering portion 45 is formed. Layer 45 may be formed.

[application]
As an application example of the thermoelectric conversion element 1 of the first embodiment and the thermoelectric conversion element 101 of the second embodiment, there is a self-supporting power source of a wireless sensor transmission device.
A wireless sensor transmission device 5 shown in FIG. 13 includes an antenna circuit 52 and a sensor terminal 53 formed on a circuit board 51, a self-supporting power source including a thermoelectric conversion element 1, a signal processing / transmission circuit 54, a voltage amplification unit, and a battery. 55.
As described above, the thermoelectric conversion element 1 of the embodiment includes the thermoelectric conversion layer (the first layer 31 and the first layer 31 and the heat absorption portion) 31a and 32a and the high portions (heat dissipation portions) 31b and 32b of the thermoelectric conversion unit 10. Since it has a height difference equal to or greater than the thickness of the second layer 32), it is possible to supply sufficient power to drive the wireless sensor even when the thermal energy applied to the heat absorbing portion is small. Therefore, the wireless sensor transmission device 5 using the thermoelectric conversion element 1 of the embodiment as a power source can be used as a self-supporting wireless sensor transmission device that can always operate even in a place where there is no illumination where a solar cell cannot be used.
As an application example of the thermoelectric conversion element 102 of the third embodiment, there is a self-supporting power source of a wearable wireless sensor transmission device.

A cow collar 6 shown in FIG. 14 has a self-supporting power source composed of a thermoelectric conversion element 102 fixed to an inner surface of a collar body (attachment) 61. The cover layer 45 side of the thermoelectric conversion element 102 is attached to the collar body 61, and the substrate 2 side is exposed.
As shown in FIG. 15, the cow collar 6 is wound around the neck 71 of the cow (constant animal) 7 with the thermoelectric conversion element 102 side inward, and a wearable wireless sensor transmission device is connected to the connection terminal 43 of the thermoelectric conversion element 102. Used in connection. As shown in FIG. 16, the lower space K of the thermoelectric conversion element 102 exists on the neck 71 side of the cow 7 in a state where the cow collar 6 is wound around the cow 7. That is, there is an air flow path between the neck 71 of the cow 7 and the collar body 61 where the lower space K for each row of the thermoelectric conversion units 10 and 10B is connected.

And since the board | substrate 2 of the thermoelectric conversion element 102 has flexibility, while the cow collar 6 can be easily attached to the neck 71 of the cow 7, and has the thermoelectric conversion element 102 formed thinly as a self-supporting power source, It does not interfere with the behavior of the cow 7 in the mounted state. In addition, the thermoelectric conversion element 102 can supply power that can drive the wearable wireless sensor transmission device based on a temperature difference between the body surface of the cow 7 and the environment in which the cow 7 exists.
Furthermore, the temperature between the low portions 31a and 32a and the high portions 31b and 32b of the thermoelectric conversion units 10 and 10B can be obtained without using a heat sink because the air passes through the air flow path associated with the lower space K. A difference can be secured. As a result, the thickness of the cow collar 6 can be reduced by the amount of the heat sink.

Moreover, since the thermoelectric conversion element 102 has the coating layer 45 made of a weather resistant material, the thermoelectric conversion element 102 can be used for a long time even when used outdoors. Note that the thermoelectric conversion element 1 according to the first embodiment without the coating layer 45 may be used instead of the thermoelectric conversion element 102 according to the third embodiment for indoor or short-term use.
The cow collar 6 shown in FIG. 14 is an example of a wearable device power supply, but the shape and material of the wearable device power supply are not limited, and the body surface such as the limb, neck, and torso of a thermostat animal is not limited. It can be attached to a part, does not significantly disturb the circulation of air around the thermoelectric conversion element, and does not have to be easily removed from the attachment position.

[About convex shape]
FIG. 17 shows a plurality of examples of the shape of the convex portion constituting the cross-sectional shape of the unit forming portion 21 of the substrate 2.
17A is a pair of inclined surfaces that connect a top portion 27 formed of an arc surface facing the same plane 26 as the back surface of the substrate 2, and both ends of a straight line forming the plane 26 and both ends of the arc forming the top portion 27. 28. The boundary between the top 27 and the inclined surface 28 is rounded.
The convex portion in FIG. 17B is a pair of slopes connecting a top portion 27 formed of a plane facing the same plane 26 as the back surface of the substrate 2, and both ends of a straight line forming the plane 26 and both ends of a straight line forming the top portion 27. Surface 28. The boundary between the top 27 and the inclined surface 28 is rounded.

The convex part of FIG. 17 (c) connects the top part 27 formed of a plane facing the same plane 26 as the back surface of the substrate 2 in parallel with both ends of the straight line forming the plane 26 and both ends of the straight line forming the top part 27. And a pair of vertical surfaces 29 perpendicular to each other. The boundary between the top 27 and the vertical surface 29 is rounded.
The convex portion in FIG. 17D is formed of an arcuate surface 27A that faces the same plane 26 as the back surface of the substrate 2 and is joined to both ends of a straight line that forms the plane 26. The position farthest from the flat surface 26 of the circular arc surface 27A is the top.

[About materials]
<Thermoelectric conversion material>
As the thermoelectric conversion material, a conductive polymer or CNT (carbon nanotube) can be preferably used. Depending on the type of the conductive polymer, a binder such as a thermosetting resin necessary for molding, a conductive material A CNT (carbon nanotube) dispersion for increasing the viscosity and a polar high-boiling solvent such as ethylene glycol, dimethyl sulfoxide, n-methylpyrrolidone or dimethylformamide, polyethylene glycol, diethylene glycol monomethyl ether can be added.
Note that the thermoelectric conversion material is not limited as long as the material can follow the deformation of the substrate, and an inorganic material or a mixed material of an organic substance and an inorganic substance can also be used. Generally, when the breaking strain of the thermoelectric conversion material is 10% or more, it is easy to follow the deformation of the substrate.

<Example of thermoelectric conversion material made of conductive polymer>
As the p-type conductive polymer (conductive polymer having p-type semiconductor characteristics), a polymer compound having a conjugated molecular structure (conjugated polymer) can be used.
Conjugated polymers include polythiophene compounds (breaking strain 10-20%), polypyrrole compounds (breaking strain 20%), polyaniline compounds (breaking strain 35%), polyacetylene compounds (breaking strain 800%). , Poly (p-phenylene) compound, poly (p-phenylene vinylene) compound (PPV compound, 5% strain at break after 150 ° C. heat-stretching treatment), poly (p-phenylene ethynylene) compound (break strain) 2.5%), poly (p-fluorenylene vinylene) compound (breaking strain 2.5%), polyacene compound (breaking strain 1%), and polyphenanthrene compound (breaking strain 1%).
Moreover, the conjugated polymer which has a repeating unit which consists of a derivative | guide_body in which the substituent was introduce | transduced into the monomer of the said high molecular compound is also mentioned.
As the n-type conductive polymer (conductive polymer having n-type semiconductor characteristics), a polymer compound having a conjugated molecular structure can be given, but many unstable substances are present.

<About the first layer and the second layer>
At least one of the first layer and the second layer is made of a thermoelectric conversion material, and the first layer and the second layer are made of the same material or different materials. When the first layer and the second layer are made of different materials, wiring (upper wiring) that connects the first layer and the second layer in the thermoelectric conversion unit is formed at the top of the convex portion.
That is, when the first layer and the second layer are made of different materials, the combination of materials is p-type thermoelectric material and n-type thermoelectric material, p-type thermoelectric material and conductive material (no thermoelectric conversion function), n-type thermoelectric material. And conductive materials (without thermoelectric conversion function). However, as described above, many n-type thermoelectric materials (n-type conductive polymers) made of conductive polymers are unstable.

<Board>
The type of the substrate is not particularly limited, but it is preferable to use a substrate (breaking strain of 50% or more) that is not easily affected by the formation of the electrode or the thermoelectric conversion layer and that is not easily broken during deformation. From the viewpoint of cost and flexibility, a plastic film is preferable. Polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene terephthalate, poly (1,4-cyclohexylenedimethylene terephthalate), polyethylene-2,6-phthalenedicarboxy Examples thereof include polyester film such as polyester film obtained by polymerization of rate, bisphenol A with iso and terephthalic acid, polycycloolefin film, polyimide film, polycarbonate film, polyether ether ketone film, polyphenyl sulfide film and the like.
Of these, commercially available polyethylene terephthalate (PET), polyethylene naphthalate (PEN), various polyimides and polycarbonate films are preferred from the viewpoints of availability, heat resistance of 100 ° C. or higher, processability, economy and effects. Considering the printing process, for example, a sheet subjected to one-side easy adhesion processing is preferable.

[About preferred embodiments]
The thermoelectric conversion element according to the first aspect of the present invention can have the following configuration (5) or (5 ′) in addition to the above configurations (1) to (4).
(5) The unit forming portion has a plurality of cut surfaces that are independently cut for each thermoelectric conversion unit within the range of the convex portion.
In this case, for each thermoelectric conversion unit, the atmosphere can be brought into contact with the surroundings of the thermoelectric conversion unit.

(5 ′) The unit forming portion is separated from the non-forming portion within the range of the convex portion. In this case, the substrate surface, including the non-formed portion between the thermoelectric conversion units adjacent in parallel, exists in one surface (a surface including the first low surface portion and the second low surface portion). Therefore, by having the configuration (5 ′), the effect of being able to be stably installed on a planar heating device is higher than in the case without the configuration (5 ′).
The thermoelectric conversion unit having the configuration (5 ′) is arranged in a matrix of X columns and Y rows (X ≧ 1, Y ≧ 2), and between adjacent thermoelectric conversion units between the rows of the substrate. However, if it is separated within the range of all the convex portions, the lower space of all the convex portions is connected on the top side of the convex portion for each row of thermoelectric conversion units, thereby forming an air flow path.

Therefore, when the thermoelectric conversion element of the first aspect has the configuration (5) or (5 ′), the air is circulated through the flow path formed by the space below the convex portion when the thermoelectric conversion element is heated on the flat heating device. By cooling the top part, a larger temperature difference can be generated between the low part and the high part of the thermoelectric conversion unit.
In addition, in the thermoelectric element of patent document 1, since it cannot be made the state which air | atmosphere touches the circumference | surroundings of a thermoelectric conversion unit for every thermoelectric conversion unit, there also exists a subject also in the point of cooling the top part of a convex part effectively. This problem can be solved when the thermoelectric conversion element of the first aspect has the configuration (5) or (5 ′).

The thermoelectric conversion element according to the first aspect of the present invention can have the following configuration (6) in addition to the above configurations (1) to (4).
(6) The plurality of thermoelectric conversion units and the wiring are formed on both the upper surface and the lower surface of the substrate. The connection terminals on the upper surface and the lower surface are connected to each other at at least one end of the series connection.
The thermoelectric conversion element according to the first aspect of the present invention can have the following configuration (7) in addition to the above configurations (1) to (4).
(7) The first layer and the second layer are made of different materials, and a wiring connecting the first layer and the second layer in the thermoelectric conversion unit is formed on the top.

The thermoelectric conversion element according to the first aspect of the present invention can have the following configuration (8) in addition to the above configurations (1) to (4).
(8) The plurality of thermoelectric conversion units and the wiring are covered with a weather resistant material.
The thermoelectric conversion element of the first aspect can have the following configuration (9) in addition to the above configurations (1) to (4).
(9) A plurality of the thermoelectric conversion units are provided via an insulating layer in the thickness direction of the substrate.

The thermoelectric conversion element according to the first aspect of the present invention preferably further has at least one of the following configurations (a) to (e).
(a) At least one of the first layer and the second layer is made of a conductive polymer.
(b) At least one of the first layer and the second layer is a polythiophene compound, a polypyrrole compound, a polyaniline compound, a polyacetylene compound, a poly (p-phenylene) compound, or poly (p-phenylene vinylene). Compounds, poly (p-phenyleneethynylene) compounds, poly (p-fluorenylene vinylene) compounds, polyacene compounds, polyphenanthrene compounds, and derivatives in which substituents are introduced into the monomers of these compounds And having at least one selected from conjugated polymers having a repeating unit.

(c) The thermoelectric conversion material is a p-type conductive polymer.
(d) The substrate is made of polyethylene terephthalate film, polyethylene isophthalate film, polyethylene naphthalate film, polybutylene terephthalate film, poly (1,4-cyclohexylenedimethylene terephthalate) film, polyethylene-2,6-phthalenedicarboxylate. It consists of at least one selected from a film, a polyimide film, a polycarbonate film, a polyether ether ketone film, and a polyphenyl sulfide film.
(e) The printed pattern of the thermoelectric conversion element is covered with a protective layer (for example, a layer formed by applying a coating agent made of a synthetic resin and cured, or a layer made of a weather resistant material).

The thermoelectric conversion elements having the above configurations (1) to (5) can be produced, for example, by a method having the above configurations (11) to (13) and the following configuration (14).
(14) A step of providing a through hole in a portion of the substrate between the adjacent thermoelectric conversion units between the rows within the range of forming the convex portion before the convex portion forming step.
As a third aspect of the present invention, there is a power supply for a wireless sensor provided with the thermoelectric conversion element of the first aspect.
As a fourth aspect of the present invention, a self-supporting power source comprising the thermoelectric conversion element of the first aspect, a signal processing / transmission circuit, a voltage amplification unit / battery, and a circuit board on which an antenna circuit and a sensor terminal are formed, The wireless sensor which has is mentioned.

As a fifth aspect of the present invention, an attachment attached to a part of a body surface such as a limb, neck, torso, etc. of a thermostat animal, and the thermoelectric conversion element of the first aspect fixed to a surface of the attachment, A power source for wearable devices having
Since the power source for the wearable device according to the fifth aspect uses the body temperature of a constant temperature animal including a human as an energy source, the power is not significantly attenuated as long as the life activity of the constant temperature animal is maintained. In addition, since the thermoelectric conversion element of the first aspect has the configuration (8), it can be expected that electric power will continue to be supplied for a long time even when used outdoors.
On the other hand, in the energy harvesting technology using electromagnetic waves and mechanical energy, power is significantly attenuated depending on conditions such as location and time. That is, the wearable wireless sensor transmission device using the power supply of the fifth aspect is excellent as a self-supporting wireless sensor transmission device that can always operate.

[About thermoelectric conversion materials]
As a material for the first layer 31, “Clevios PH1000 (aqueous dispersion)” of Heraeus Co., Ltd., which is a coating agent containing a polythiophene compound, was used. The polythiophene compound is a p-type conductive polymer, and the main component of this coating agent is “poly (3,4-ethylenedioxythiophene): polystyrene sulfide”.
Cellulose nanofibers (manufactured by Chuetsu Pulp Co., Ltd., maximum width of 500 nm or less, average width of 50 nm or less, average fiber length of 0.5 μm, polymerization degree of 350) are added at 10 mass% with respect to the active ingredient of PH1000, and ethylene glycol is added to PH1000. After adding to 5% by volume, the mixture was heated with stirring to evaporate the water, thereby obtaining a gel-like p-type thermoelectric conversion material.
As a material for the second layer 32, the lower wiring 41, the connection terminal 43, and the upper wiring 42, silver paste was used. The lower wiring 41, the connection terminal 43, and the upper wiring 42 were formed by screen printing. As the silver paste, for example, “Dotite FA-333” manufactured by Fujikura Kasei Co., Ltd. can be used. Further, in order to suppress silver oxidation, a carbon paste may be printed over the silver paste.

[Manufacture of thermoelectric conversion elements]
<Sample No.1>
A thermoelectric conversion element having 312 thermoelectric conversion units in a matrix of 13 columns and 24 rows was manufactured by the following method. In the first embodiment, the thermoelectric conversion element 1 having 2 columns and 7 rows and 14 thermoelectric conversion units 10 has been described. However, each process is the same as that described in the first embodiment except that the number of thermoelectric conversion units 10 is different. Was done in the same way.
First, a metal mask having a thickness of 0.1 mm was prepared in which the opening pattern of the first layer 31 of 16 columns and 24 rows was alternately formed in each column and each row as in FIG. Using this metal mask, the gel p-type thermoelectric conversion material described above was printed on the upper surface of the substrate 2 made of a PET film having a thickness of 100 μm. Thereby, the printing pattern of the 1st layer 31 which consists of p-type thermoelectric conversion material was formed in each thermoelectric conversion unit 10 by the arrangement | positioning similar to FIG.

Next, the substrate 2 in this state was heated at 120 ° C. for 2 hours to dry the p-type thermoelectric conversion material. The thickness of the first layer 31 after drying was 10 μm.
Next, the second layer 32 made of a silver paste was printed next to the first layers 31 of all the thermoelectric conversion units 10, and the silver paste was dried by heating at 120 ° C. for 2 hours. This printing was performed by screen printing. The silver paste was printed so that the second layer 32 after drying was 10 μm. Thereby, 312 thermoelectric conversion patterns composed of the first layer 31 and the second layer 32 similar to those in FIG. 3 were formed.
Next, a conductive layer pattern composed of the lower wiring 41, the connection terminal 43, and the upper wiring 42 was formed on all the thermoelectric conversion patterns as in FIG. The conductive layer pattern was formed by screen-printing a silver paste, followed by heating at 120 ° C. for 2 hours and drying.

Next, the through holes 25 were formed in the same arrangement as in FIG. 5 by a laser cutting method. In this state, the thermoelectric conversion unit 10 is formed in a flat plate shape on the flat plate substrate 2 as shown in FIG.
Next, using a mold having a male part and a female part corresponding to all 312 convex parts 211, the convex part forming step by heating and pressing described in the first embodiment is performed at 120 ° C. for 120 minutes. It went on condition of. Thereby, all 312 thermoelectric conversion units 10 were brought into the state shown in FIG. The protrusion height T of the convex portion 211 was 1.7 mm. The first layer 31 and the second layer 32 were also stretched and deformed together with the substrate 2.
As shown in FIG. 1, the thermoelectric conversion element 1 obtained in this way has an air flow path in which the lower space K of the convex portion 211 is connected for each row of thermoelectric conversion units 10.

<Sample No.2>
Thermoelectric conversion elements having 312 thermoelectric conversion units on a top surface and a bottom surface of the substrate 2 in a matrix of 13 columns and 24 rows (642 in total on both surfaces) were manufactured by the following method. In the second embodiment, the thermoelectric conversion element 101 having 2 columns and 7 rows and 14 thermoelectric conversion units 10 and 10A on the upper surface and the lower surface of the substrate 2 has been described, but the number of thermoelectric conversion units 10 and 10A is different. Each process was performed by the same method as each process explained in the second embodiment.
First, a conductive layer pattern composed of the lower wiring 41, the connection terminal 43, and the upper wiring 42 was formed on both the upper and lower surfaces of the substrate 2 by the same method as Sample No. 1. The pattern of each layer was the same arrangement on the upper surface and lower surface of the substrate 2 (arrangement with the substrate sandwiched therebetween).

Next, the through hole forming step and the convex portion forming step were performed by the same method as Sample No. 1. That is, the protrusion height T of the convex portion 211 is 1.7 mm, which is the same as that of the sample No. 1.
Next, the connection terminals 43a on the upper surface and the lower surface that overlap each other with the substrate 2 interposed therebetween were electrically connected. Thereby, the thermoelectric conversion element 101 in which 642 thermoelectric conversion units were connected in series was obtained.
As shown in FIG. 7, the thermoelectric conversion element 101 obtained in this manner has an air flow path in which the lower space K of the convex portion 211 is connected to each row of the thermoelectric conversion units 10 and 10 </ b> A.

[Breaking strain test]
The fracture strains of the thermoelectric conversion layers constituting the thermoelectric conversion elements of samples No. 1 and No. 2 were tested by the following method.
In both samples, since the thermoelectric conversion material constituting the first layer 31 is “poly (3,4-ethylenedioxythiophene): polystyrene sulfide”, “poly (3,4-ethylenedioxythiophene) is formed on the PET film. ): A test piece on which “polystyrene sulfide” was formed was prepared, and a tensile fracture test was performed. As a result, the breaking strain of the thermoelectric conversion layer was 10%. That is, in the thermoelectric conversion elements of samples No. 1 and No. 2, the first layer 31 easily follows the deformation of the substrate 2.

[Evaluation of thermoelectric conversion element]
Samples No. 1 and No. 2 were placed on a hot plate at 80 ° C. while holding the non-formed portion 22 of the substrate 2 horizontally in an environment of room temperature of 25 ° C. The lower part 31a of the first layer 31 and the lower part 32a of the second layer 32 were heated. In this state, the voltage generated between both terminals 43 was measured with a tester.
The measured voltage was 80 mV for sample No. 1 and 150 mV for sample No. 2, and an electromotive force that can be used as a power source for a wireless sensor was obtained with any thermoelectric conversion element.
The above results are summarized in Table 1 below.

DESCRIPTION OF SYMBOLS 1 Thermoelectric conversion element 10 Thermoelectric conversion unit of board | substrate upper surface 10A Thermoelectric conversion unit of board | substrate lower surface 10B Thermoelectric conversion unit of 2nd layer 2 Board | substrate 21 Unit formation part 211 Projection part 211a Top part of projection part 212 1st low surface part 213 2nd low surface part 214 Cut surface 22 Non-formed part 25 Through hole 31 1st layer 31a 1st layer low part 31b 1st layer high part 32 2nd layer 32b 2nd layer high part 32a 2nd layer low part 41 Lower wiring 42 upper wiring 43 connection terminal 44 insulating layer 45 coating layer made of weathering material 5 wireless sensor transmission device 51 circuit board 52 antenna circuit 53 sensor terminal 54 signal processing / transmission circuit 55 voltage amplifier / battery 6 cattle collar 61 collar body (Wearing thing)
7 cattle (constant animals)
71 neck

Claims (6)

A substrate,
A plurality of thermoelectric conversion units formed on the upper or lower surface of the substrate;
Have
The cross-sectional shape of the unit forming part in which the thermoelectric conversion unit of the substrate is formed is composed of a first low surface part and a second low surface part lower than the convex part and the convex part on both sides thereof,
The non-formation part in which the thermoelectric conversion unit of the substrate is not formed is in a position lower than the top part of the convex part,
The thermoelectric conversion unit has a first layer from the first low surface portion of the unit forming portion to the top of the convex portion, and a second layer from the top to the second low surface portion,
At least one of the first layer and the second layer is made of a thermoelectric conversion material,
The plurality of thermoelectric conversion units are connected in series by wiring connecting the first layer and the second layer of the adjacent thermoelectric conversion units formed on the first low surface portion and the second low surface portion,
A thermoelectric conversion element having connection terminals at both ends of the series connection.   2. The thermoelectric conversion element according to claim 1, wherein the unit forming portion has a cut surface that is independently cut for each thermoelectric conversion unit within the range of the convex portion. The plurality of thermoelectric conversion units and the wiring are formed on both the upper surface and the lower surface of the substrate,
The thermoelectric conversion element according to claim 1 or 2, wherein the connection terminals on the upper surface and the lower surface are connected at at least one end of the series connection.   The thermoelectric conversion element according to any one of claims 1 to 3, wherein the plurality of thermoelectric conversion units and the wiring are covered with a weather resistant material. A method for producing the thermoelectric conversion element according to claim 1,
A first printing step for forming a thermoelectric conversion pattern comprising the first layer and the second layer constituting the plurality of thermoelectric conversion units on a substrate;
A second printing step of forming a conductive layer pattern composed of the wiring and the connection terminal on the thermoelectric conversion pattern;
A projecting portion forming step of forming the projecting portion by stretching and deforming the first layer and the second layer, and a portion of the substrate where the first layer and the second layer are formed;
The manufacturing method of the thermoelectric conversion element which has this.   6. The method according to claim 5, further comprising a step of providing a through hole in a portion of the substrate that is between the thermoelectric conversion units adjacent to each other between the rows within a range in which the convex portion is formed, before the convex portion forming step. The manufacturing method of the thermoelectric conversion element of description.

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