JP7196940B2 - Thermoelectric conversion element and manufacturing method thereof - Google Patents

Description

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

A thermoelectric conversion element is an element capable of mutually converting thermal energy and electrical energy. By installing the thermoelectric conversion element in an environment where a temperature difference occurs between both ends thereof, electric power can be extracted from the thermoelectric conversion element without requiring a movable part. For example, electrical energy can be produced from waste heat. Therefore, power generation technology using thermoelectric conversion elements is highly expected as an energy harvesting technology for recovering and utilizing unused energy around us.
If a thermoelectric conversion element can be used as, for example, a distributed self-sustaining power source, it will be possible to use it 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 substance is used, the thermoelectric conversion layer can be formed in a printed pattern, which makes it possible to reduce the weight, reduce the cost, and increase the output due to the large area. In this case, in order to maintain the flatness of the thermoelectric conversion element unit, the temperature difference is generally applied in the direction perpendicular to the substrate of the unit.

As an example of a thermoelectric conversion element having a thermoelectric conversion layer as a printed pattern, there is a thermoelectric generation element disclosed in Patent Document 1. In the thermoelectric conversion element (thermoelectric power generation element) of Patent Document 1, a plurality of thermoelectric conversion layers (thermoelectric conversion units) made up of printed patterns are formed on a corrugated substrate (base material) in which bottom portions and top portions 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 slopes of one projection or depression that constitutes the corrugation of the substrate, and is not formed on the other.
In the thermoelectric conversion element of Patent Document 1, the bottom is on the heat absorption side and the top is on the heat dissipation side, and electricity is generated by the temperature difference between the bottom side and the top side. Further, since the substrate is formed in a corrugated shape, the distance between the heat absorption side and the heat dissipation side is increased, so a large temperature difference can be obtained. On the other hand, in a thermoelectric conversion element having a substrate without unevenness, a sufficient temperature difference cannot be obtained when the substrate is held horizontally.

International publication 2013/114854 pamphlet

In the thermoelectric conversion element of Patent Document 1, the cross-sectional shape of the entire substrate including not only the portion where the thermoelectric conversion layer is formed but also the portion where the thermoelectric conversion element is not formed is wavy. Therefore, when a large difference in height is to be provided between the bottom and top, it is necessary to provide a reinforcing member for maintaining the shape in the space below the protrusion of the substrate. In addition, in order to stably install the substrate on a flat heating device such as a hot plate, a support base for placing and fixing a plurality of bottom portions of the substrate is further required.
An object of the present invention is to form a plurality of thermoelectric conversion units connected in series on a substrate, have a height difference greater than the thickness of the thermoelectric conversion layer between the heat absorption side and the heat dissipation side, and be high even when used without being erected. To provide a thermoelectric conversion element capable of obtaining power generation performance and stably installed on a flat heating device only with a substrate on which thermoelectric conversion units are 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 formation portion of the substrate where the thermoelectric conversion units are formed is composed of a convex portion and first and second low surface portions lower than the convex portion on both sides of the convex portion. A non-formation portion of the substrate where the thermoelectric conversion unit is not formed is located at a position lower than the top portion of the protrusion.
(3) The thermoelectric conversion unit has a first layer extending from the first low surface portion of the unit forming portion to the top portion of the convex portion, and a second layer extending from the top portion 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 wiring connecting the first layer and the second layer of the adjacent thermoelectric conversion units formed on the first and second low surface portions. It is connected. Connection terminals are provided at both ends of the series connection.

A second aspect of the present invention is a method for manufacturing a thermoelectric conversion element having the above structures (1) to (4), characterized by comprising steps of the following structures (11) to (13).
(11) A first printing step of forming, on a substrate, a thermoelectric conversion pattern composed of the first layer and the second layer constituting the plurality of thermoelectric conversion units.
(12) A second printing step of forming a conductive layer pattern composed of the wiring and the connection terminal on the thermoelectric conversion pattern.
(13) A protrusion forming step of forming the protrusion by stretching and deforming the first layer, the second layer, and the portion of the substrate on which 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 printed patterns.
(22) The wiring and the connection terminals are printed patterns.

According to this invention, a plurality of thermoelectric conversion units are formed in series connection on the substrate, and the difference in height between the heat absorption side and the heat dissipation side is equal to or greater than the thickness of the thermoelectric conversion layer. Provided is a thermoelectric conversion element that can be stably installed on a planar heating device with only a substrate on which thermoelectric conversion units are formed, and which has power generation performance.

FIG. 2 is a partial cross-sectional view showing the thermoelectric conversion element of the first embodiment, showing a unit formation portion of a substrate corresponding to one thermoelectric conversion unit and non-formation portions on both sides thereof. FIG. 2 is a plan view for explaining a pre-stage step of a first printing step that constitutes the method for manufacturing the thermoelectric conversion element shown in FIG. 1; FIG. 3 is a plan view for explaining a post-process of a first printing process that constitutes the method for manufacturing the thermoelectric conversion element shown in FIG. 1; 2 is a plan view for explaining a second printing step that constitutes the method for manufacturing the thermoelectric conversion element shown in FIG. 1. FIG. 3 is a plan view for explaining a through-hole forming step that constitutes the method for manufacturing the thermoelectric conversion element shown in FIG. 1. FIG. FIG. 6 is a cross-sectional view taken along the line AA of FIG. 5; FIG. 10 is a partial cross-sectional view showing the thermoelectric conversion element of the second embodiment, showing a unit formation portion of the substrate corresponding to one thermoelectric conversion unit within the substrate surface and non-formation portions on both sides thereof. FIG. 7 is a plan view showing the state of the thermoelectric conversion element shown in FIG. 7 before the process of forming the projections, and a cross-sectional view taken along line A'-A' after the formation of the projections corresponds to FIG. FIG. 10 is a partial cross-sectional view showing the thermoelectric conversion element of the third embodiment, showing a unit formation portion of the substrate corresponding to one thermoelectric conversion unit in the substrate plane and non-formation portions on both sides thereof. FIG. 10 is a plan view for explaining an insulating layer forming step that constitutes the method for manufacturing the thermoelectric conversion element shown in FIG. 9; FIG. 10 is a plan view for explaining a coating layer forming step that constitutes the method for manufacturing the thermoelectric conversion element shown in FIG. 9; FIG. 12 is a cross-sectional view taken along the line AA of FIG. 11; It is a perspective view explaining an example of the wireless sensor transmission device using the thermoelectric conversion element of the first embodiment. FIG. 10 is a front view illustrating a cow collar, which is an example of a wearable device power supply using the thermoelectric conversion element of the third embodiment. FIG. 15 is a schematic diagram showing a state in which the cow collar of FIG. 14 is wrapped around a cow; FIG. 16 is a schematic diagram corresponding to the BB cross section of FIG. 15; FIG. 4A is a front view showing an example of a shape different from that of the first and second embodiments, relating to the convex portion of the substrate that constitutes the thermoelectric conversion element of the embodiment.

Embodiments of the present invention will be described below. In the embodiments shown below, technically preferable limitations are made for carrying out the present invention, but the present invention is not limited to the embodiments shown below.

[First embodiment]
The thermoelectric conversion element of this embodiment is a thermoelectric conversion element manufactured by performing each step shown in FIGS. FIG. 1 shows a cross section of one thermoelectric conversion unit 10 that constitutes the thermoelectric conversion element 1 of this embodiment.
The thermoelectric conversion element 1 is formed in the first step of the first printing step shown in FIG. 2, the latter step of the first printing step shown in FIG. 3, the second printing step shown in FIG. 4, and the through hole forming step shown in FIG. , and a step of forming projections from the state shown in FIG. 6 to the state shown in FIG.

The thermoelectric conversion element 1 has a substrate 2 having flexibility and a plurality of thermoelectric conversion units 10 each having a printed pattern formed on the upper surface of the substrate 2 . The cross-sectional shape of the unit formation portion 21 on which the thermoelectric conversion units 10 of the substrate 2 are formed is composed of a convex portion 211 , a first low surface portion 212 and a second low surface portion 213 . The first low surface portion 212 and the second low surface portion 213 are lower than the convex portions on both sides of the convex portion 211 and have the same height as the non-forming portion 22 where the thermoelectric conversion units 10 are not formed.
The thermoelectric conversion unit 10 has a first layer 31 extending 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 extending 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). A layer made of an n-type conductive polymer (thermoelectric conversion material) may be provided as the second layer 32, but at present there is no one with stable performance, so in this embodiment, silver paste is used as an alternative. A second layer 32 of hardened material is provided.

As shown in FIG. 5, on the upper surface of the substrate 2, 14 thermoelectric conversion units 10 are formed in 2 columns and 7 rows. Rectangular through holes 25 are formed over the entire range of the projections 211 between the adjacent thermoelectric conversion units 10 between rows of the substrate 2 . In other words, the thermoelectric conversion units 10 adjacent to each other between the rows of the substrate 2 are separated within the range of the protrusions 211 .
Then, the lower wiring 41 connecting the first layer 31 and the second layer 32 of the thermoelectric conversion units 10 adjacent between rows and columns is formed on the first lower surface portion 212 and the second lower surface portion 213, and the first layer 31 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 connecting the first layer 31 and the second layer 32 in the thermoelectric conversion unit 10 is located at the top portion 211a of the convex portion 211. formed. Furthermore, both ends of the series connection exist at one edge of the upper surface of the substrate 2, and connection terminals 43 with the outside are formed at each position.
In the method for manufacturing the thermoelectric conversion element 1 of this embodiment, first, as a pre-stage step of the first printing step, one first layer 31 is formed in one thermoelectric conversion unit 10 in the arrangement shown in FIG. form with That is, the first layers 31 adjacent to each other in the two rows of 14 thermoelectric conversion units 10 and between the rows are arranged on opposite sides in the long side direction of the rectangle.

Next, as a subsequent step of the first printing step, as shown in FIG. They are formed with the same planar shape and thickness.
In this way, a thermoelectric conversion pattern consisting of all the first layers 31 and the second layers 32 constituting the two rows of 14 thermoelectric conversion units 10 is formed on the upper surface of the substrate 2 . In the state of FIG. 3, the portion where the first layer 31 and the second layer 32 of the substrate 2 are present is the unit formation portion.
Next, as a second printing step, as shown in FIG. 4, a conductive layer pattern composed of lower wiring 41, connection terminals 43, and upper wiring 42 is formed on the thermoelectric conversion pattern shown in FIG.

Next, as shown in FIG. 5 , through holes 25 are formed by punching or cutting in portions between adjacent thermoelectric conversion units 10 between rows of the substrate 2 in the entire range where the projections 211 are to be formed in a post-process. to form In this state, the thermoelectric conversion unit 10 is formed in a flat shape on the flat substrate 2, as shown in FIG.
Next, as a convex portion forming step, a mold having a male portion and a female portion corresponding to the convex portion 211 in FIG. Apply pressure while heating (perform heat and pressure molding). As a result, 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 . At that time, by using a mold having male and female portions corresponding to the convex portions 211 of all the unit forming portions 21, the convex portions 211 are formed in all the thermoelectric conversion units 10 at once.

In the thermoelectric conversion element 1 manufactured in this way, in all the thermoelectric conversion units 10, the lower portion 31a which is the portion on the first lower surface portion 212 of the first layer 31 and the second lower surface portion 213 of the second layer 32 Between the lower portion 32a, which is the upper portion, and the high portions 31b, 32b, which are portions above the top portions 211a of the first layer 31 and the second layer 32, there is a thickness equal to or greater than the thickness of the first layer 31 and the second layer 32. has a height difference of
Therefore, the thermoelectric conversion element 1 is placed on, for example, a hot plate while holding the non-formation portion 22 of the substrate 2 horizontally, and the lower portion 31 a of the first layer 31 and the lower portion of the second layer 32 are placed through the substrate 2 . Even when the portion 32a is heated and used, high power generation performance can be obtained. Also, the substrate 2 on which the print pattern is formed can be stably placed on the hot plate.

Furthermore, due to the formation of the through holes 25 , the adjacent thermoelectric conversion units 10 between the rows of the substrate 2 are separated from each other over the entire range of the protrusions 211 in all the unit forming portions 21 . That is, as shown in FIG. 1, all the unit forming portions 21 have cut surfaces 214 separated independently for each thermoelectric conversion unit 10 over the entire range of the convex portions 211, and the cut surfaces 214 adjacent between the rows. The space (through-hole 25) formed by and the lower space K of the convex part 211 are communicating. Therefore, every 10 thermoelectric conversion units are in contact with the surrounding air.
Therefore, if the top portion 211a is cooled by circulating air through the flow path formed by the lower space K during heating by the hot plate described above, the lower portions 31a and 32a and the higher portions 31b and 32b of the thermoelectric conversion unit 10 It can be expected that a larger temperature difference will be generated between them.
In addition, in the manufacturing method of 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 order in which these layers are printed can be changed arbitrarily.

[Second embodiment]
As shown in FIG. 7, the thermoelectric conversion element 101 of the second embodiment not only has two columns and seven rows of thermoelectric conversion units 10 on the upper surface of the substrate 2, like the thermoelectric conversion element 1 of the first embodiment. , 2 columns and 7 rows of thermoelectric conversion units 10A on the lower surface of the substrate 2 .
Each thermoelectric conversion unit 10A is arranged at a position overlapping with each thermoelectric conversion unit 10 with the substrate 2 interposed therebetween. The first layer 31 of the thermoelectric conversion unit 10A is formed so as 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 so as to overlap the first layer 31 of the thermoelectric conversion unit 10. It is In addition, all the unit forming portions 21 have cut surfaces 214 separated independently for each of the thermoelectric conversion units 10 and 10A over the entire range of the convex portions 211, and the space between the cut surfaces 214 adjacent between rows and the convex portions It communicates with the lower space K of the part 211 .

Further, as shown in FIG. 8, the connection terminals 43a on the upper surface and the connection terminals 43a on the lower surface overlapping with the substrate 2 are connected by electrodes provided on the end surfaces of the substrate 2, for example. Thus, the thermoelectric conversion units 10 arranged in 2 columns and 7 rows on the upper surface and the thermoelectric conversion units 10A arranged in 2 columns and 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 with the outside.
In addition, 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 formed so as to overlap the second layer 32 of the thermoelectric conversion unit 10. , and the connection terminals 43a on the upper and lower surfaces and the connection terminals 43b on the upper surface and the lower surface may be connected to each other. In this case, the thermoelectric conversion units 10 of 2 columns and 7 rows on the upper surface and the thermoelectric conversion units 10A of 2 columns and 7 rows on the lower surface are connected in parallel, and the connection terminals 43a and 43b in a state of being connected vertically are connected to the outside. become a terminal.

The thermoelectric conversion element 101 is produced by performing the first printing step and the second printing step on the upper surface and the lower surface of the substrate 2 in the same method as the method for manufacturing the thermoelectric conversion element 1 of the first embodiment, and then the thermoelectric conversion element 101 of the first embodiment. It can be manufactured by performing a through-hole forming process and a projection forming process on the substrate 2 in the same method as the manufacturing method of the conversion element 1 .
According to the thermoelectric conversion element 101 of this embodiment, in addition to the effects of the thermoelectric conversion element 1 of the first embodiment, by having thermoelectric conversion units on both sides of the substrate 2, a single substrate can generate a high electromotive force. It also has the effect of being obtained.

That is, in the thermoelectric conversion element 101 of the second embodiment, the area of the substrate 2 is the same as that of the thermoelectric conversion element 1 of the first embodiment, but the thermoelectric conversion units 10 and 10A of the same pattern are arranged in the thickness direction of the substrate 2. Since there are two layers, the output voltage is double that of the thermoelectric conversion element 1 in the case of series connection, and the output current is double 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, in the thermoelectric conversion element 101 of the second embodiment, all the thermoelectric conversion units 10, the lower wirings 41 and the upper wirings 42 are preferably covered with a weather resistant material. In that case, the coating layer made of the weather-resistant material may be formed either before or after the formation of the projections 211 .

[Third embodiment]
As shown in FIG. 9, the thermoelectric conversion element 102 of the third embodiment only has thermoelectric conversion units 10 of 2 columns and 7 rows in the plane of the substrate 2 in the same manner as the thermoelectric conversion element 1 of the first embodiment. Instead, two layers of thermoelectric conversion units 10 of the same 2 columns and 7 rows are provided on the upper surface of the substrate 2 . FIG. 9 shows a cross section of the 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 layers of thermoelectric conversion units 10 and 10B, and a coating layer 45 made of a weather-resistant material on the surface opposite to the substrate 2 .
Thermoelectric conversion element 102 is manufactured by the following method.

First, each step 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 thermoelectric conversion unit 10 of the first layer (thermoelectric conversion pattern and conductive layer pattern) is formed on the substrate 2. and through holes 25 are formed. Next, an insulating layer 44 is formed on the entire surface of the substrate 2 in the state shown in FIG. FIG. 10 shows this state. Next, each step shown in FIGS. 2 to 4 is performed in the same manner to form a second-layer thermoelectric conversion unit 10B pattern (thermoelectric conversion pattern and conductive layer pattern) 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 is flat, and as shown in FIG. 12, the thermoelectric conversion units 10 and 10B are also flat. Next, by performing the same protrusion forming step as in the first embodiment, protrusions 211 are formed on all the thermoelectric conversion units 10 and 10B.
The thermoelectric conversion element 102 manufactured in this manner has a lower portion 31a which is a portion above the first lower surface portion 212 of the first layer 31 and a second lower portion of the second layer 32 in all the thermoelectric conversion units 10 and 10B. The thickness of the first layer 31 and the second layer 32 is between the lower portion 32a which is the portion on the face portion 213 and the high portions 31b and 32b which are the portions on the top portion 211a of the first layer 31 and the second layer 32. It has a height difference of more than

Therefore, the thermoelectric conversion element 102 is placed on, for example, a hot plate while holding the non-formation portion 22 of the substrate 2 horizontally, and the lower portion 31 a of the first layer 31 and the lower portion of the second layer 32 are placed through the substrate 2 . Even when the portion 32a is heated and used, high power generation performance can be obtained. Also, the substrate 2 on which the print pattern is formed can be stably placed on the hot plate.
Furthermore, due to the formation of the through holes 25 , the adjacent thermoelectric conversion units 10 and 10B between the rows of the substrate 2 are separated from each other over the entire range of the protrusions 211 in all the unit forming portions 21 . That is, as shown in FIG. 9, all the unit forming portions 21 have cut surfaces 214 that are independently separated for each of the thermoelectric conversion units 10 and 10B over the entire range of the convex portions 211, and cut surfaces that are adjacent to each other between the rows. The space between the surfaces 214 and the space K below the projection 211 communicate with each other.

Therefore, when heating by the hot plate described above, if the top portion 211a is cooled by circulating air through the flow path formed by the lower space K, the lower portions 31a and 32a and the higher portions 31b and 32b of the thermoelectric conversion units 10 and 10B It can be expected that a larger temperature difference will be generated between
Further, in the thermoelectric conversion element 102 of the third embodiment, the area of the substrate 2 is the same as that of the thermoelectric conversion element 1 of the first embodiment. Since it has two layers, the output current is larger than that of the thermoelectric conversion element 1 .
In addition, 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 thermoelectric conversion units 10 and 10B of the two layers are the same, and the second layer When the conductive layer pattern is formed, the connection terminals 43 of the second layer are printed on the connection terminals 43 of the first layer, so that the two layers of thermoelectric conversion units 10 and 10B are connected in parallel.

Moreover, by setting the printed patterns of the conductive layer and the insulating layer, the output voltage of the thermoelectric conversion element 102 can be increased by connecting the two layers of the thermoelectric conversion units 10 and 10B in series. In addition, by connecting two layers of thermoelectric conversion units 10 and 10B in a combination of parallel connection and series connection within each layer and between layers, the output of thermoelectric conversion element 102 can be freely adjusted.
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 portions 211 are formed after the formation of the coating layer 45, but after forming the thermoelectric conversion units 10B of the uppermost layer, the convex portions 211 are formed, and then the coating A layer 45 may be formed.

[application]
An application example of the thermoelectric conversion element 1 of the first embodiment and the thermoelectric conversion element 101 of the second embodiment includes a self-sustaining power supply for a wireless sensor transmitter.
The wireless sensor transmitter 5 shown in FIG. 13 includes an antenna circuit 52 and a sensor terminal 53 formed on a circuit board 51, a self-sustaining power supply composed of the thermoelectric conversion element 1, a signal processing/transmission circuit 54, a voltage amplifier/battery 55 and .
As described above, in the thermoelectric conversion element 1 of the embodiment, the thermoelectric conversion layers (first layer 31 and Since the height difference is 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 transmitter 5 using the thermoelectric conversion element 1 of the embodiment as a power source can be used as a self-supporting wireless sensor transmitter that can always operate even in places without lighting where solar cells cannot be used.
As an application example of the thermoelectric conversion element 102 of the third embodiment, there is an independent power supply for a wearable wireless sensor transmitter.

The cattle collar 6 shown in FIG. 14 has a self-sustaining power supply composed of a thermoelectric conversion element 102 fixed to the inner surface of a collar body (attachment) 61 . The coating 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 wrapped around the neck 71 of a cow (warm-blooded animal) 7 with the thermoelectric conversion element 102 side facing inward, and the wearable wireless sensor transmitter is connected to the connection terminal 43 of the thermoelectric conversion element 102 . Used in connection. As shown in FIG. 16 , the space K below the thermoelectric conversion element 102 exists on the neck 71 side of the cow 7 when the cow collar 6 is wrapped around the cow 7 . In other words, between the neck 71 of the cow 7 and the collar main body 61, there is an atmospheric flow path in which the lower spaces K for each row of the thermoelectric conversion units 10 and 10B are connected.

Further, since the substrate 2 of the thermoelectric conversion element 102 has flexibility, the cow collar 6 can be easily attached to the neck 71 of the cow 7 and has the thin thermoelectric conversion element 102 as an independent power supply. The behavior of the cow 7 is not hindered in the attached state. Moreover, the thermoelectric conversion element 102 can supply electric power capable of driving the wearable wireless sensor transmission device due to the temperature difference between the body surface of the cow 7 and the environment in which the cow 7 exists.
In addition, since the air passes through the air flow path associated with the lower space K, the temperature between the low parts 31a, 32a and the high parts 31b, 32b of the thermoelectric conversion units 10, 10B can be adjusted without using a heat sink. difference can be guaranteed. As a result, the thickness of the cattle collar 6 can be reduced by the thickness of the radiator plate.

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 period of time even when used outdoors. For indoor use or short-term use, the thermoelectric conversion element 1 of the first embodiment without the coating layer 45 may be used instead of the thermoelectric conversion element 102 of the third embodiment.
Although the cow collar 6 shown in FIG. 14 is an example of a wearable device power source, the shape and material of the wearable device power source are not limited, and the body surface such as the limbs, neck, and body of a warm-blooded animal can be used. It is sufficient that it can be attached to a part of the thermoelectric conversion element, does not significantly hinder the circulation of air around the thermoelectric conversion element, and does not easily come off from the attachment position.

[Regarding the shape of the convex part]
FIG. 17 shows a plurality of examples of the shape of the convex portion that constitutes the cross-sectional shape of the unit forming portion 21 of the substrate 2. As shown in FIG.
17(a) includes a top portion 27 formed of an arc surface facing the same plane 26 as the back surface of the substrate 2, and a pair of inclined surfaces connecting both ends of the straight line forming the plane 26 and both ends of the arc forming the top portion 27. 28 and . A boundary between the top portion 27 and the inclined surface 28 is formed round.
17(b) has a top portion 27 formed of a plane facing parallel to the plane 26 which is the same as the back surface of the substrate 2, and a pair of slopes connecting both ends of the straight line forming the plane 26 and both ends of the straight line forming the top portion 27. a surface 28; A boundary between the top portion 27 and the inclined surface 28 is formed round.

17(c) has a top portion 27 formed of a plane parallel to the plane 26 which is the same as the back surface of the substrate 2, and both ends of the straight line forming the plane 26 and both ends of the straight line forming the top portion 27. and a pair of vertical surfaces 29 perpendicular to the . The boundary between the top portion 27 and the vertical surface 29 is rounded.
The convex portion in FIG. 17(d) is composed of an arcuate surface 27A that faces the same plane 26 as the back surface of the substrate 2 and that is joined to both ends of a straight line that forms the plane 26. As shown in FIG. The position of the arc surface 27A farthest from the plane 26 is the top.

[About materials]
<Thermoelectric conversion material>
As the thermoelectric conversion material, a conductive polymer or CNT (carbon nanotube) can be preferably used. CNT (carbon nanotube) dispersions to increase the polar high boiling point solvents such as ethylene glycol, dimethyl sulfoxide, n-methylpyrrolidone or dimethylformamide, polyethylene glycol, diethylene glycol monomethyl ether can be added.
The thermoelectric conversion material is not limited in kind as long as it 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. In general, when the breaking strain of the thermoelectric conversion material is 10% or more, it easily follows 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 properties), 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, breaking strain after 150 ° C heat stretching treatment 5%), poly (p-phenyleneethynylene) compound (breaking strain 2.5%), poly(p-fluorenylene vinylene) compounds (breaking strain 2.5%), polyacene compounds (breaking strain 1%), and polyphenanthrene compounds (breaking strain 1%).
Further, a conjugated polymer having a repeating unit composed of a derivative in which a substituent is introduced into the monomer of the polymer compound is also included.
Examples of n-type conductive polymers (conductive polymers having n-type semiconductor properties) include polymer compounds having a conjugated molecular structure, but many of them are unstable substances.

<Regarding the first and second layers>
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, a wiring (upper wiring) connecting the first layer and the second layer in the thermoelectric conversion unit is formed on the top of the projection.
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 made of conductive polymers (n-type conductive polymers) are unstable substances.

<Substrate>
The type of substrate is not particularly limited, but it is preferable to use a substrate (breaking strain of 50% or more) that is less likely to be affected during the formation of the electrodes and the thermoelectric conversion layer and that is less likely to crack when deformed. From the viewpoint of cost and flexibility, plastic films are preferable, and polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene terephthalate, poly(1,4-cyclohexylene dimethylene terephthalate), polyethylene-2,6-phthalenedicarboxy polycycloolefin films, polyimide films, polycarbonate films, polyether ether ketone films, polyphenyl sulfide films and the like.
Among these, commercially available polyethylene terephthalate (PET), polyethylene naphthalate (PEN), various polyimides and polycarbonate films are preferred from the viewpoint of availability, heat resistance of 100° C. or more, workability, economy and effect. Considering the printing process, for example, a sheet having one side treated for easy adhesion is preferable.

[Regarding preferred embodiments]
The thermoelectric conversion element of 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 separated independently for each thermoelectric conversion unit within the range of the convex portion.
In this case, each thermoelectric conversion unit can be brought into contact with the atmosphere around the thermoelectric conversion unit.

(5') The unit formation portion is separated from the non-formation portion within the range of the convex portion. In this case, the substrate surface including the non-formation portion between the thermoelectric conversion units adjacent in parallel exists within one surface (a surface including the first and second low surface portions). Therefore, by having the configuration (5'), the effect of being able to be stably installed on a flat heating device is higher than when the configuration (5') is not provided.
In addition to having the configuration (5′), a plurality of thermoelectric conversion units are arranged in a matrix of X columns and Y rows (X≧1, Y≧2), and adjacent thermoelectric conversion units are arranged between rows of the substrate. However, if they are separated within the range of all the projections, the spaces below all the projections are connected on the top side of the projections for each row of the thermoelectric conversion units to form air passages.

Therefore, when the thermoelectric conversion element of the first aspect has the configuration (5) or (5'), when the thermoelectric conversion element is placed on a flat heating device and heated, air is allowed to flow through the flow path formed by the space below the convex portion. By cooling the top part, a larger temperature difference can be generated between the lower part and the upper part of the thermoelectric conversion unit.
In addition, in the thermoelectric element of Patent Document 1, since the surroundings of each thermoelectric conversion unit cannot be brought into contact with the atmosphere, there is also a problem in that the top of the convex portion is effectively cooled. This problem can be solved by the thermoelectric conversion element of the first aspect having the configuration (5) or (5').

The thermoelectric conversion element of 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 upper and lower surfaces of the substrate. The connection terminals on the top surface and the bottom surface are connected to each other at least one end of the series connection.
The thermoelectric conversion element of 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 wiring is formed on the top portion to connect the first layer and the second layer in the thermoelectric conversion unit.

The thermoelectric conversion element of 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 thermoelectric conversion units are provided in the thickness direction of the substrate via an insulating layer.

Preferably, the thermoelectric conversion element of the first aspect of the present invention further has at least one of the following structures (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 polythiophene-based compound, polypyrrole-based compound, polyaniline-based compound, polyacetylene-based compound, poly(p-phenylene)-based compound, poly(p-phenylene vinylene); -based compounds, poly(p-phenyleneethynylene)-based compounds, poly(p-fluorenylenevinylene)-based compounds, polyacene-based compounds, polyphenanthrene-based compounds, and derivatives in which substituents are introduced into the monomers of these compounds at least one selected from conjugated polymers having repeating units of

(c) The thermoelectric conversion material is a p-type conductive polymer.
(d) The substrate is polyethylene terephthalate film, polyethylene isophthalate film, polyethylene naphthalate film, polybutylene terephthalate film, poly(1,4-cyclohexylene dimethylene terephthalate) film, polyethylene-2,6-phthalene dicarboxylate. At least one selected from a film, a polyimide film, a polycarbonate film, a polyetheretherketone film, and a polyphenylsulfide film.
(e) The printed pattern of the thermoelectric conversion element is covered with a protective layer (for example, a layer formed by applying and curing a coating agent made of a synthetic resin, a layer made of a weather-resistant material).

The thermoelectric conversion elements having the configurations (1) to (5) can be produced, for example, by a method having the configurations (11) to (13) and the configuration (14) below.
(14) A step of forming a through hole in a portion of the substrate, which is located between the adjacent thermoelectric conversion units between the rows within the range where the convex portion is formed, before the convex portion forming step.
A third aspect of the present invention includes a wireless sensor power supply including the thermoelectric conversion element of the first aspect.
As a fourth aspect of the present invention, a self-sustaining power supply comprising the thermoelectric conversion element of the first aspect, a signal processing/transmitting circuit, a voltage amplifying section/battery, and a circuit board on which an antenna circuit and a sensor terminal are formed. wireless sensors with

As a fifth aspect of the present invention, an attachment that is attached to a part of the body surface of a warm-blooded animal such as limbs, neck, body, etc.; the thermoelectric conversion element of the first aspect fixed to the surface of the attachment; A power supply for wearable devices having
Since the power supply for wearable devices of the fifth aspect uses the body temperature of warm-blooded animals including humans as an energy source, the electric power does not significantly decrease as long as the vital activity of the warm-blooded animals worn is maintained. Further, since the thermoelectric conversion element of the first aspect has the configuration (8), it can be expected to continue supplying electric power over a long period of time even when used outdoors.
On the other hand, in energy harvesting technology using electromagnetic waves or mechanical energy, the power is significantly attenuated depending on conditions such as location and time. In other words, the wearable wireless sensor transmitter using the power source of the fifth aspect is excellent as an independent wireless sensor transmitter that can always operate.

[About thermoelectric conversion materials]
As a material for the first layer 31, "Clevios PH1000 (aqueous dispersion)" manufactured by Heraeus Co., Ltd., which is a coating agent containing a polythiophene-based compound, was used. A polythiophene-based compound is a p-type conductive polymer, and the main component of this coating agent is "poly(3,4-ethylenedioxythiophene): polystyrene sulfide".
Cellulose nanofiber (manufactured by Chuetsu Pulp Co., Ltd., maximum width 500 nm or less, average width 50 nm or less, average fiber length 0.5 μm, degree of polymerization 350) is added 10% by mass to the active ingredient of PH 1000, and ethylene glycol is added to PH 1000. After adding so as to be 5% by volume, the mixture was heated with stirring to evaporate the water content, thereby obtaining a gel-like p-type thermoelectric conversion material.
Silver paste was used as the material for the second layer 32 , the lower wiring 41 , the connection terminal 43 , and the upper wiring 42 . The lower wiring 41, the connection terminals 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. Moreover, in order to suppress the oxidation of silver, carbon paste may be printed on the silver paste.

[Manufacture of thermoelectric conversion element]
<Sample No.1>
A thermoelectric conversion element having 312 thermoelectric conversion units arranged 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, 7 rows and 14 thermoelectric conversion units 10 was described. did in the same way.
First, a metal mask having a thickness of 0.1 mm was prepared in which opening patterns of the first layer 31 of 16 columns and 24 rows were alternately formed in each column and each row in the same manner as in FIG. Using this metal mask, the gel p-type thermoelectric conversion material was printed on the upper surface of the substrate 2 made of PET film with a thickness of 100 μm. As a result, the printed pattern of the first layer 31 made of the p-type thermoelectric conversion material was formed on each thermoelectric conversion unit 10 in the same layout as in FIG.

Next, the p-type thermoelectric conversion material was dried by heating the substrate 2 in this state at 120° C. for 2 hours. The thickness of the first layer 31 after drying was 10 μm.
Next, the second layer 32 made of silver paste was printed next to the first layer 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 dried second layer 32 had a thickness of 10 μm. As a result, 312 thermoelectric conversion patterns composed of the first layer 31 and the second layer 32 similar to those shown in FIG. 3 were formed.
Next, on all the thermoelectric conversion patterns, a conductive layer pattern including lower wirings 41, connection terminals 43, and upper wirings 42 was formed in the same manner as in FIG. The conductive layer pattern was formed by screen-printing a silver paste and drying it by heating at 120° C. for 2 hours.

Next, through holes 25 were formed in the same arrangement as in FIG. 5 by a cutting method using laser processing. In this state, the thermoelectric conversion unit 10 is formed in a flat shape on the flat substrate 2, as shown in FIG.
Next, using a mold having male and female portions corresponding to all 312 convex portions 211, the step of forming convex portions by heat and pressure molding described in the first embodiment is performed at 120° C. for 120 minutes. was performed under the conditions of As a result, all 312 thermoelectric conversion units 10 were brought into the state shown in FIG. The protrusion height T of the protrusion 211 was set to 1.7 mm. Also, the first layer 31 and the second layer 32 were stretched and deformed together with the substrate 2 .
As shown in FIG. 1, the thermoelectric conversion element 1 obtained in this manner has an air flow path in which the spaces K below the projections 211 are connected to each of the thermoelectric conversion units 10 in each row.

<Sample No.2>
A thermoelectric conversion element having 312 thermoelectric conversion units arranged in a matrix of 13 columns and 24 rows (642 units in total on both sides) on each of the upper and lower surfaces of the substrate 2 was 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 respectively was described, but the number of thermoelectric conversion units 10 and 10A is different. , each step was performed in the same manner as each step described in the second embodiment.
First, a conductive layer pattern including lower wiring 41, connection terminal 43, and upper wiring 42 was formed on both the upper and lower surfaces of substrate 2 by the same method as for sample No. 1. FIG. The pattern of each layer was arranged in the same manner on the upper surface and the lower surface of the substrate 2 (arrangement overlapping with the substrate interposed therebetween).

Next, a through-hole forming step and a projection forming step were performed in the same manner as for sample No.1. That is, the protrusion height T of the protrusion 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, which overlap with each other with the substrate 2 interposed therebetween, were electrically connected. As a result, a thermoelectric conversion element 101 having 642 thermoelectric conversion units 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 spaces K below the projections 211 are connected to each of the thermoelectric conversion units 10 and 10A in each row.

[Breaking strain test]
The breaking strain of the thermoelectric conversion layers forming the thermoelectric conversion elements of Samples No. 1 and No. 2 was tested by the following method.
In both samples, the thermoelectric conversion material constituting the first layer 31 is "poly(3,4-ethylenedioxythiophene):polystyrene sulfide", so that "poly(3,4-ethylenedioxythiophene ): A test piece in which polystyrene sulfide was formed was prepared and subjected to a tensile breaking test. 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 followed the deformation of the substrate 2 .

[Evaluation of thermoelectric conversion element]
The thermoelectric conversion elements of Samples No. 1 and No. 2 were placed on a hot plate at 80° C. in an environment of room temperature 25° C. while holding the non-formation portion 22 of the substrate 2 horizontally. The lower portion 31a of the first layer 31 and the lower portion 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 values were 80 mV for sample No. 1 and 150 mV for sample No. 2, and both thermoelectric conversion elements provided an electromotive force that could be used as a power supply for wireless sensors.
The above results are summarized in Table 1 below.

REFERENCE SIGNS LIST 1 thermoelectric conversion element 10 thermoelectric conversion unit on upper surface of substrate 10A thermoelectric conversion unit on lower surface of substrate 10B thermoelectric conversion unit in second layer 2 substrate 21 unit forming portion 211 convex portion 211a top portion of convex portion 212 first lower surface portion 213 second lower surface portion 214 cut surface 22 non-forming portion 25 through hole 31 first layer 31a first layer lower portion 31b first layer higher portion 32 second layer 32b second layer higher portion 32a second layer lower portion 41 lower wiring 42 Upper Wiring 43 Connection Terminal 44 Insulating Layer 45 Coating Layer Made of Weather Resistant Material 5 Wireless Sensor Transmitter 51 Circuit Board 52 Antenna Circuit 53 Sensor Terminal 54 Signal Processing/Transmitting Circuit 55 Voltage Amplifier/Battery 6 Cattle Collar 61 Collar Body (Equipment)
7 Cattle (warm-blooded animals)
71 neck

Claims (6)

a substrate;
a plurality of thermoelectric conversion units formed on the substrate at intervals in a matrix;
has
The cross-sectional shape along the row direction of the matrix of the unit forming portions in which the thermoelectric conversion units of the substrate are formed is from the first lower surface portion and the second lower surface portion lower than the convex portion and the convex portions on both sides of the convex portion. and the first lower surface portion and the second lower surface portion are at the same height,
All non-formed portions of the substrate where the thermoelectric conversion units are not formed are at the same height as the first and second low surface portions,
The thermoelectric conversion unit has a first layer extending from the first bottom surface portion of the unit forming portion to the top portion of the convex portion, and a second layer extending from the top portion to the second bottom surface portion,
all of the unit forming portions have cut surfaces separated independently for each of the thermoelectric conversion units throughout the range of the convex portion;
a through hole including the cut surface as an inner wall surface is formed in the substrate between the unit forming portions adjacent to each other between rows in the entire range of the convex portion;
For each column of the matrix of the thermoelectric conversion units, the space formed by the adjacent cut surfaces between rows communicates with the space below the convex portion,
There is no through hole in the non-formation portion at the end in the row direction and the non-formation portion between the columns,
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 and second low surface portions,
A thermoelectric conversion element having connection terminals at both ends of the series connection. The plurality of thermoelectric conversion units and the wiring are formed on both the top surface and the bottom surface of the substrate,
2. The thermoelectric conversion element according to claim 1, wherein said connection terminals on said upper surface and said lower surface are connected to each other at least one end of said series connection. 2. The thermoelectric conversion element according to claim 1, wherein said plurality of thermoelectric conversion units are provided in plurality in the thickness direction of said substrate via an insulating layer. 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 on the outermost surface opposite to the substrate. A method for manufacturing the thermoelectric conversion element according to claim 1,
a first printing step of forming a thermoelectric conversion pattern composed of the first layer and the second layer for forming the plurality of thermoelectric conversion units arranged at intervals in a matrix 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 protrusion forming step of forming the protrusion by stretching and deforming the first layer, the second layer, and a portion of the substrate on which the first layer and the second layer are formed;
and
Before the convex portion forming step,
The method of manufacturing a thermoelectric conversion element, further comprising the step of forming through holes in portions of the substrate that are between the adjacent thermoelectric conversion units between the rows in the entire range where the convex portions are formed. It comprises an attachment that is attached to a part of the body surface of a warm-blooded animal such as limbs, neck, body, etc., and a thermoelectric conversion element fixed to the surface of the attachment, wherein the thermoelectric conversion element is according to claims 1- 5. A power supply for wearable equipment, which is the thermoelectric conversion element according to any one of items 4.

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