JP2021158237A - Thermoelectric conversion module - Google Patents

Abstract

To provide a thermoelectric conversion module that improves heat transfer efficiency by efficiently transferring heat applied from the outside and obtains high electromotive force.SOLUTION: A thermoelectric conversion module includes a support, and a thermoelectric element layer in which P-type thermoelectric elements and N-type thermoelectric elements formed on a support are alternately arranged, and adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically arranged such that electrons move in the direction of the arrangement, and the thermoelectric element layer is made of a coating film, and the thickness difference tdif in the cross section of at least one of the P-type thermoelectric element and the N-type thermoelectric element along the direction perpendicular to the direction of the arrangement is 50 um or less.SELECTED DRAWING: Figure 5

Description

The present invention relates to a thermoelectric conversion module, and more particularly to a flexible thermoelectric conversion module.

Thermoelectric power generation technology and Perche cooling technology are known as energy conversion technologies using thermoelectric conversion. Thermoelectric power generation technology is a technology that utilizes the conversion of thermal energy to electrical energy by the Seebeck effect. Since this technology does not require a large cost to operate the thermoelectric conversion element for realizing thermoelectric conversion, unused waste generated from fossil fuel resources used in facilities such as buildings and factories in particular. It is in the limelight as an energy-saving technology that can recover thermal energy as electrical energy. The Perche cooling technology is a technology that utilizes the conversion of electrical energy to thermal energy by the Perche effect, as opposed to thermoelectric power generation. This technique is used, for example, in wine coolers and small portable refrigerators. This technique is also used as a cooling means for a CPU used in a computer and as a temperature control means for parts and devices (for example, a semiconductor laser oscillator for optical communication) that require precise temperature control.

For example, Patent Document 1 includes a support substrate and a plurality of thermoelectric elements arranged on the support substrate for the purpose of improving thermoelectric performance, yield, reliability, and productivity. It is composed of an N-type thermoelectric element and a P-type thermoelectric element composed of a sintered body, which are arranged in pairs with each other. A thermoelectric module (so-called π-type thermoelectric module) having a height difference (difference in height between thermoelectric elements) of 20 μm or less is disclosed.

Further, for example, in Patent Document 2, the first electrode layer and the first electrode layer and the first electrode layer are described for the purpose of suppressing the force by which the bonding material pooling portion spreads the thermoelectric conversion element and ensuring the conductive cross-sectional area between the thermoelectric conversion elements. The two electrode layers are provided with a plurality of thermoelectric conversion elements made of a thermoelectric conversion material bonded by a bonding material, and the heights of the plurality of thermoelectric conversion elements (heights between the thermoelectric elements) are set to a maximum value and a minimum value. A thermoelectric conversion element (so-called π-type thermoelectric conversion element) in which the difference is set to 0.02 mm or less is disclosed.

On the other hand, a thermoelectric conversion element called an in-plane type has also been proposed. The in-plane type thermoelectric conversion element is a thermoelectric conversion element having a configuration capable of converting thermal energy into electrical energy by causing a temperature difference in the surface direction of the thermoelectric element layer. Since the in-plane type thermoelectric conversion element can expand the length of the temperature difference in the plane direction, it can efficiently generate thermoelectromotive force even if the thermoelectric conversion layer is thin, and the element can be made thin by making the thermoelectric conversion layer thin. The whole can be made thin and flexible.

Japanese Unexamined Patent Publication No. 2003-34605 Japanese Unexamined Patent Publication No. 2006-30307

In recent years, as thermoelectric conversion elements have become widespread, their use in various environments is required. In particular, since the in-plane type thermoelectric conversion element is generally thin, the usage environment is further expanded, and it is required that the in-plane type thermoelectric conversion element can be used in various environments.
However, in terms of improving the electromotive force, there is still room for improvement in the thermoelectric conversion module having an in-plane type thermoelectric conversion element.

In view of the above problems, it is an object of the present invention to provide a thermoelectric conversion module capable of improving heat transfer efficiency by efficiently transferring heat applied from the outside and obtaining a high electromotive force.

The present inventors have made intensive studies to solve the above problems, in the thermoelectric conversion element of in-plane, rather than the difference in thickness between the elements, the thickness of the thermoelectric element difference t _dif, in particular, P We have found that the above problems can be solved by adjusting the _{thickness difference t div} in the element of the thermoelectric element having the larger _{gauge element thickness t ga} among the type thermoelectric element and the N type thermoelectric element within a predetermined range. The present invention has been completed.
That is, the present invention provides the following [1] to [4].
[1] A support and P-type thermoelectric elements and N-type thermoelectric elements formed on the support are alternately arranged, and adjacent P-type thermoelectric elements and N are arranged so that electrons move in the direction of the arrangement. The thermoelectric element has a thermoelectric element layer to which the type thermoelectric element is electrically connected, and the thermoelectric element layer is made of a coating film, and the thermoelectric element of at least one of the P-type thermoelectric element and the N-type thermoelectric element. in cross section along the direction perpendicular to the direction of the arrangement, the following (1) to the thickness difference _{t dif} defined by (4) is equal to or less than 50um, the thermoelectric conversion module.
(1) The thickness profile of the thermoelectric element in the cross section is measured by a stylus type surface shape measuring device.
(2) From the measured thickness profile, the average thickness in the central portion excluding both ends of the thermoelectric element is calculated, and the average of the calculated thickness is defined as the element average thickness _tav . However, with respect to the central portion, the length of the boundary line between the thermoelectric element and the support in the cross section is L, and from the boundary line of the length L to 1/6 L inward from one end of the boundary line. Of the thermoelectric elements, the center line is defined as a line segment having a length of 2/3 L, excluding the line segment of 1 and the line segment of 1/6 L inward from the other end of the boundary line. A region portion sandwiched by a line segment extending in the vertical direction of the main surface of the support from both ends of the segment.
(3) From the measured thickness profile, the maximum value of the thickness of the thermoelectric element is detected, and the maximum value of the detected thickness is defined as the maximum thickness t _max .
(4) The thickness difference t _div is defined as the difference between the maximum thickness t _max and the element average thickness t _av (t _div = t _max −t _av ).
[2] A support and P-type thermoelectric elements and N-type thermoelectric elements formed on the support are alternately arranged, and adjacent P-type thermoelectric elements and N are arranged so that electrons move in the direction of the arrangement. The thermoelectric element layer has a thermoelectric element layer to which the type thermoelectric element is electrically connected, and the thermoelectric element layer is made of a thermoelectric semiconductor composition containing thermoelectric semiconductor particles and a resin, and is composed of the P-type thermoelectric element and the N-type thermoelectric. at least one of the thermoelectric elements of the device in cross section along the direction perpendicular to the direction of the arrangement, the thickness difference t _dif is defined by the following (1) to (4), it is less than 50um, thermoelectric Conversion module.
(1) The thickness profile of the thermoelectric element in the cross section is measured by a stylus type surface shape measuring device.
(2) From the measured thickness profile, the average thickness in the central portion excluding both ends of the thermoelectric element is calculated, and the average of the calculated thickness is defined as the element average thickness _tav . However, with respect to the central portion, the length of the boundary line between the thermoelectric element and the support in the cross section is L, and from the boundary line of the length L to 1/6 L inward from one end of the boundary line. Of the thermoelectric elements, the center line is defined as a line segment having a length of 2/3 L, excluding the line segment of 1 and the line segment of 1/6 L inward from the other end of the boundary line. A region portion sandwiched by a line segment extending in the vertical direction of the main surface of the support from both ends of the segment.
(3) From the measured thickness profile, the maximum value of the thickness of the thermoelectric element is detected, and the maximum value of the detected thickness is defined as the maximum thickness t _max .
(4) The thickness difference t _div is defined as the difference between the maximum thickness t _max and the element average thickness t _av (t _div = t _max −t _av ).
[3] the different and P-type thermoelectric gauge elements thickness t _ga of the gauge element thickness t _ga and the N-type thermoelectric element of the device of the P-type thermoelectric elements and the N-type thermoelectric element, the gauge elements thickness t _ga The thermoelectric conversion module according to the above [1] or [2], wherein the thickness difference t _{div of the larger thermoelectric element is 50 μm or less.}
[4] gauge elements thickness t _ga and equals the gauge element thickness t _ga of the P-type thermoelectric element and the N-type thermoelectric elements, both of the P-type thermoelectric elements and the N-type thermoelectric element, the thickness difference t _dif The thermoelectric conversion module according to the above [1] or [2], wherein the temperature is 50 μm or less.

According to the present invention, it is possible to provide a thermoelectric conversion module capable of improving heat transfer efficiency by efficiently transferring heat applied from the outside and obtaining a high electromotive force.

It is a partial cross-sectional view which shows the structure of the thermoelectric conversion module which concerns on embodiment of this invention. It is a schematic plan view of the support provided with electrodes in a predetermined arrangement pattern. It is a top view which shows the arrangement pattern of the P-type thermoelectric element and the N-type thermoelectric element provided on one main surface side of the support provided with an electrode. It is a top view which shows the arrangement pattern of the 1st high thermal conduction layer provided on the main surface side of the support including P type thermoelectric element and N type thermoelectric element. It is a partial cross-sectional view of the thermoelectric conversion module along the line indicated by reference numeral III-III of FIG. It is a figure for demonstrating an example of the process of forming a thermoelectric element layer (the 1). It is a figure for demonstrating an example of the process of forming a thermoelectric element layer (the 2). It is a perspective view for demonstrating the printing plate in FIG. 6A and FIG. 6B. It is a figure for demonstrating the printing plate for forming an N-type thermoelectric element used in Comparative Examples 2-4. It is a perspective view for demonstrating the printing plate for forming an N-type thermoelectric element in FIG. 7A.

Hereinafter, embodiments of the present invention (hereinafter, may be referred to as “the present embodiment”) will be described.
In the present specification, "the thickness of A and the thickness of B are different" means that the thickness of one of A and B is 0.900 times or less or 1.111 times or more of the thickness of the other. means.
Further, in the present specification, "the thickness of A and the thickness of B are equal" means that the thickness of one of A and B is more than 0.900 times and less than 1.111 times the thickness of the other. means.
Further, in the present specification, "the thickness of A is larger than the thickness of B" means that the thickness of A is 1.111 times or more the thickness of B.
Further, in the present specification, "the thickness of A is smaller than the thickness of B" means that the thickness of A is 0.900 times or less the thickness of B.

[Structure of thermoelectric conversion module]
In the thermoelectric conversion module according to the embodiment of the present invention, the support and the P-type thermoelectric element and the N-type thermoelectric element formed on the support are alternately arranged so that electrons move in the direction of the arrangement. , A thermoelectric element layer in which adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically connected, and if necessary, a P-type thermoelectric element and an N-type thermoelectric element constituting the thermoelectric element layer. It further has an electrode for electrical connection, a coating layer covering the surface of the thermoelectric element layer, and a high thermal conductivity layer provided on the surface of the coating layer opposite to the thermoelectric element layer.
Here, the thermoelectric element layer satisfies at least one of (1) made of a coating film and (2) made of a thermoelectric semiconductor composition containing thermoelectric semiconductor particles and a resin, and is screen-printed. It is formed by coating such as.

Hereinafter, the configuration of the thermoelectric conversion module according to the embodiment of the present invention will be described with reference to the drawings. All drawings are schematic and may be exaggerated for ease of understanding.
FIG. 1 is a partial cross-sectional view showing the configuration of the thermoelectric conversion module according to the embodiment of the present invention, and is a partial cross-sectional view near the center of the thermoelectric conversion module 1A along the line indicated by reference numeral IV-IV in FIG. 4, which will be described later. Is. As shown in FIG. 1, the thermoelectric conversion module 1A has a support 2 on which an electrode 3 having a predetermined pattern is formed, and is formed on one main surface of the support 2 (main surface side on the electrode 3 side). A thermoelectric element layer 6 composed of the P-type thermoelectric element 5 and an N-type thermoelectric element 4, a first coating layer 81 and a first coating laminated on a surface of the thermoelectric element layer 6 opposite to the support 2. The first high thermal conductive layer 91 provided on the surface of the layer 81 opposite to the thermoelectric element layer 6, the second coating layer 82 laminated on the other main surface of the support 2, and the second coating layer 82. It has a second high thermal conductive layer 92 provided on a surface opposite to the thermoelectric element layer 6 of the above. In this embodiment, the support is a substrate that remains when the thermoelectric conversion module is mounted.
In the following description, the first coating layer and the second coating layer may be collectively referred to as a "coating layer". Further, the first high thermal conductive layer and the second high thermal conductive layer may be collectively referred to as a "high thermal conductive layer".

FIG. 2 is a schematic plan view of a support in which electrodes are provided in a predetermined arrangement pattern. As shown in FIG. 2, the electrodes 3 provided on one main surface of the rectangular support 2 are for electrically connecting each row of the thermoelectric element layers 6 provided in a plurality of rows to each other. A plurality of first electrode portions 3a (connecting electrode portions) and two external connection terminals serving as terminals for extracting thermoelectromotive force from the thermoelectric element layer 6 or applying a voltage to the thermoelectric element layer 6. A large number of second electrodes for electrically connecting the two electrode portions 3b (electromotive force extraction electrode portions) and the P-type thermoelectric elements 5 and the N-type thermoelectric elements 4 arranged in a row so as to be alternately adjacent to each other. It has 3 electrode portions 3c and. The electrode portions 3a to 3c are arranged separately in an island shape.

FIG. 3 is a plan view showing an arrangement pattern of a P-type thermoelectric element and an N-type thermoelectric element provided on one main surface side of a support having electrodes.
As shown in FIG. 3, a plurality of rows of the thermoelectric element layer 6 composed of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 are arranged side by side. In each row of the thermoelectric element layer 6, the third electrode portion 3c is arranged so as to overlap the joint portions of the adjacent thermoelectric elements 4 and 5 other than the end portions. The first electrode portion 3a is arranged so as to be in contact with one end of each row of the thermoelectric element layer 6. The first electrode portion 3a includes a P-type thermoelectric element 5 or an N-type thermoelectric element 4 at one end of a row of a certain thermoelectric element layer 6 and an N-type thermoelectric element at one end of a row of the next thermoelectric element layer 6. The element 4 or the P-type thermoelectric element 5 is electrically bonded. The other end of each row of the thermoelectric element layer 6 is also electrically joined to the end of the next row of the thermoelectric element layer 6 by the first electrode portion 3a. The thermoelectric elements 4 and 5 at one end of the row of thermoelectric element layers 6 located at both ends are connected to the second electrode portion 3b, respectively. In this way, the P-type thermoelectric element 5 and the N-type thermoelectric element 4 two-dimensionally arranged on the support 2 are electrically connected in series by the electrode portions 3a to 3c, and as a result, the main support 2 is main. The energization path is formed so as to meander on the surface.

The shapes of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 are not particularly limited, but the P-type thermoelectric element 5 and the N-type thermoelectric element 4 are alternately arranged while electrically connecting the adjacent thermoelectric element layers 6. From the viewpoint of easy operation, it is preferably rectangular. The rectangular thermoelectric elements 4 and 5 preferably have a short side in the direction Y of the arrangement of the thermoelectric elements 4 and 5, and a long side in the direction Z perpendicular to the direction Y of the arrangement of the thermoelectric elements 4 and 5. Since the thermoelectric elements 4 and 5 have such a shape, the P-type thermoelectric element 5 and the N-type thermoelectric element 4 are arranged while increasing the number of repetitions per area of the P-type thermoelectric element 5 and the N-type thermoelectric element 4. The width of the strip-shaped row can be increased to improve the thermoelectric efficiency. The length of the short side of the rectangular thermoelectric elements 4 and 5 is preferably 0.3 to 3 mm, more preferably 0.5 to 2 mm. The length of the long side is preferably 2 to 20 mm, more preferably 4 to 15 mm.
Here, the "direction Z perpendicular to the direction Y of the arrangement of the thermoelectric elements 4 and 5" is perpendicular to the direction Y of the arrangement of the thermoelectric elements 4 and 5 in the plan view according to the plan view of FIG. This is the coating direction Z when the thermoelectric semiconductor composition (coating liquid) is applied onto the support in the "step of forming the thermoelectric element layer 6" described later.

FIG. 4 is a diagram showing an arrangement pattern of a first high thermal conductive layer provided on the main surface side of a support including a P-type thermoelectric element and an N-type thermoelectric element.
In FIG. 4, the first coating layer 81 is not shown for ease of understanding.
As shown in FIG. 4, the first high thermal conductive layer 91 is formed in a plurality of stripes arranged so as to intersect the rows of the respective thermoelectric element layers 6. The first high thermal conductive layer 91 covers every other joint portion between the P-type thermoelectric element 5 and the N-type thermoelectric element 4. The second high thermal conductive layer 92 is also formed in a plurality of stripes intersecting the rows of each thermoelectric element layer 6, and although not shown in FIG. 4, it is viewed from a direction perpendicular to the main surface of the support 2. The second high thermal conductive layer 92 is arranged at a position corresponding to the joint portion of the thermoelectric elements 4 and 5 not covered by the first high thermal conductive layer 91. As a result, the first high thermal conductive layer 91 and the second high thermal conductive layer 92 are alternately arranged with respect to the thermoelectric element layer 6 in the vertical cross section in the arrangement direction of the striped high thermal conductive layers 91 and 92. .. In the direction perpendicular to the main surface of the support 2, the widthwise end of the first high heat conductive layer 91 and the widthwise end of the second high heat conductive layer 92 may coincide with or overlap each other. It may be separated or it may be separated.

In FIGS. 2 and 3, the number of the third electrode portions 3c is 42 (= 7 × 6 rows), the number of the first electrode portions 3a is 5, and the P-type thermoelectric element 5 and the N-type thermoelectric element 4 The number is 24 (= 4 × 6 rows), and in FIG. 4, the number of the first high thermal conductive layer 91 is 4, but these numbers can be changed as appropriate. The size and position of each electrode portion 3 can be changed as appropriate. Further, in FIG. 2, the two second electrode portions 3b are arranged so as to be in contact with one side of the support 2, but the present invention is not limited to this, and the thermoelectric conversion module is adapted to the application field and usage environment. The two second electrode portions 3b may be arranged so as to be in contact with the separate sides of the support 2.

In the above embodiment, no layer is provided in the region on the coating layer where the high thermal conductive layer is not provided, but for example, a member such as a low thermal conductive layer may be provided. In this case, the coating layer can function not only as a high thermal conductive layer but also as a fixing material for a member such as a low thermal conductive layer. From the viewpoint of improving the thermoelectric conversion performance of the thermoelectric conversion module, the thermal conductivity of the low thermal conductive layer is preferably lower than that of the high thermal conductive layer.
In addition, as in the above-described embodiment, when no layer is provided in the region on the coating layer where the high thermal conductivity layer is not provided and the coating layer is exposed, the atmosphere is used instead of the low thermal conductivity layer. Since it exists and the thermal conductivity of the atmosphere is very low, for example, about 0.02 W / (m · K), it is possible to exhibit thermoelectric conversion performance equal to or higher than that when the low thermal conductive layer is provided. ..

FIG. 5 is a partial cross-sectional view of the thermoelectric conversion module along the line indicated by reference numerals III-III in FIG.
The cross section 50 shown in FIG. 5 is a support 2 along a direction (that is, a direction of movement of electrons in the thermoelectric element layer 6) perpendicular to the direction of arrangement of the thermoelectric elements 4 and 5 (the coating direction Z in FIG. 3). It is a cross section about a thermoelectric element 4 and 5.
The line shown by reference numeral III-III in FIG. 3 is a line along the center of the length in the direction Y of the second thermoelectric element 4 and 5 from the right in FIG. That is, the cross section of the thermoelectric elements 4 and 5 in FIG. 5 is a cross section when the thermoelectric elements 4 and 5 are cut in the Z direction so as to pass through the center in the length of the direction Y (FIG. 3).

_{When the gauge element thickness t ga of the} P-type thermoelectric element 5 and the N-type thermoelectric element 4 are different, the heat from the outside of the thermoelectric conversion module 1B is preferentially transferred to the thicker thermoelectric element, and thus the inside of the thicker thermoelectric element. It is preferable to reduce the thickness difference t _dif of the thermoelectric element layer 6 in that the electromotive force of the thermoelectric element layer 6 can be further improved. On the other hand, when the gauge element thickness _tga of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 are the same, there is no preferential heat transfer as described above, so that any of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 It is preferable that the thickness difference t _{dif of the above is also reduced.}
Here, the gauge element thickness t _ga is the thickness of the thermoelectric element obtained by measuring the thickness of the thermoelectric element at one point with a thickness gauge and subtracting the thickness of the support from the measured thickness. Here, the gauge element thickness t _ga of the thermoelectric element is calculated as follows, for example, as shown in Examples described later. _{First, the gauge element thickness tga} is measured for five thermoelectric elements randomly selected from a plurality of thermoelectric elements in one support with a thermoelectric element layer, and the average of the measured values of the five thermoelectric elements is measured. The first average value is calculated. Such a thickness measurement is performed on three supports with a thermoelectric element layer, and the average of the first average values of three three supports with a thermoelectric element layer is calculated and used as the second average value. _{Let the} average value be the gauge element thickness t ga.
The thickness gauge used for measuring the gauge element thickness t _ga is not particularly limited, and examples thereof include commercially available products such as Digital Indicator PC-465J manufactured by Teclock Co., Ltd.

_{The value of the gauge element thickness t ga} of the P-type thermoelectric element and the N-type thermoelectric element is not particularly limited, and as described above, both may have the same thickness or different thicknesses. Flexibility, in terms of material costs, the gauge element thickness _{t ga} of P-type thermoelectric elements and N-type thermoelectric element is preferably 0.1 to 300, more preferably 1 to 200 [mu] m.

When the thermoelectric element layer is formed by the screen printing method as follows, the thermoelectric element (P-type thermoelectric element 5 in FIGS. 6A and 6B) formed earlier than the previously formed thermoelectric element (P-type thermoelectric element 5). In FIGS. 6A and 6B, the N-type thermoelectric element 4) usually has a larger _{gauge element thickness t ga.}
Hereinafter, the formation of the thermoelectric element layer by the screen printing method will be described.
First, as shown in FIG. 6A, the printing plate 60 is arranged above the support 2, and the thermoelectric semiconductor composition (coating liquid) is placed on the support 2 through the opening (hole) 61 of the printing plate 60. By applying and drying, one of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 (P-type thermoelectric element 5 in FIG. 6A) is formed on the support 2. Next, as shown in FIG. 6B, the printing plate 60 is arranged above the support 2 so as not to crush the thermoelectric element (P-type thermoelectric element 5 in FIG. 6B) already formed on the support 2. , The thermoelectric semiconductor composition (coating liquid) is applied onto the support 2 through the opening (hole) 61 of the printing plate 60, and dried to obtain the P-type thermoelectric element 5 and the N-type thermoelectric element 4. The other thermoelectric element (N-type thermoelectric element 4 in FIG. 6B) is formed on the support 2. After that, annealing treatment is performed. Here, the direction in which the thermoelectric semiconductor composition is applied (coating direction Z) is preferably the direction Z perpendicular to the direction Y of the arrangement of the thermoelectric elements 4 and 5. As described above, when the thermoelectric element is rectangular, it is preferable that the thermoelectric element has a long side in the direction Z perpendicular to the direction Y of the arrangement of the thermoelectric elements 4 and 5. In this case, if the thermoelectric semiconductor composition is applied in the direction Y of the arrangement of the thermoelectric elements 4 and 5, the squeegee is likely to be caught on the long side of the rectangular pattern of the printing plate, which may hinder the application. By setting the coating direction Z to the long side direction of the thermoelectric elements 4 and 5, that is, the direction Z perpendicular to the direction Y of the arrangement of the thermoelectric elements 4 and 5, such a problem can be avoided and coating is facilitated. be able to.

Hereinafter, the _{wording necessary for defining the thickness difference t dif} will be described with reference to FIG.
In FIG. 5, the interface between the thermoelectric elements 4 and 5 and the support 2 is defined as the boundary line 51, and the length of the boundary line 51 is defined as L. Further, a line segment 52 from one end P of the boundary line 51 to 1/6 L inward and a line segment 53 from the other end Q of the boundary line 51 to 1/6 L inward are formed from the boundary line 51 having a length L. The excluded line segment having a length of 2/3 L is defined as the center line segment 54. Further, among the thermoelectric elements 4 and 5, the region portion sandwiched by the line segments 55 and 56 extending in the vertical direction from both ends 54a and 54b of the central line segment 54 to the support main surface 2a is defined as the central portion 57. Further, the region from the line segment 55 to one end P is defined as the end portion 58, and the region from the line segment 56 to one end Q is defined as the end portion 59.

_{Hereinafter, the calculation of the thickness difference t div} specified in the present invention will be described with reference to FIG.
(1) First, the thickness profiles of the thermoelectric elements 4 and 5 in the cross section of FIG. 5 are measured by a stylus type surface shape measuring device.
Here, the thickness profile is measured for the entire region of the cross section (ie, central 57 and both ends 58, 59).
The stylus type surface shape measuring instrument used for measuring the thickness profile is not particularly limited, and examples thereof include commercially available products such as the Vectorak 150 manufactured by ULVAC.
The frequency of measuring the thickness in the thickness profile is not particularly limited, but is preferably higher than the frequency of every 1 μm (frequency of every less than 1 μm) in that a more accurate thickness profile can be obtained.
The thickness profile is measured, for example, as shown in Examples described later. First, thickness profile measurement is performed on five thermoelectric elements randomly selected from a plurality of thermoelectric elements in one substrate with a thermoelectric element layer, and such thickness profile measurement is performed on a substrate with three thermoelectric element layers. Do about. That is, 15 thickness profiles are obtained.
In addition, in this specification, "the substrate with a thermoelectric element layer" is a unit which includes a substrate as a support and a thermoelectric element layer, and corresponds to "the thermoelectric conversion module" of this invention.
(2) Next, from the measured thickness profile, the average thickness of the central portion 57 excluding both ends 58 and 59 of the thermoelectric elements 4 and 5 is calculated for each thickness profile, and the average of the calculated thicknesses is calculated. _Let be the element average thickness tav, respectively.
(3) Further, the maximum value of the thickness of the thermoelectric elements 4 and 5 is detected for each thickness profile from the measured thickness profile, and the maximum value of the detected thickness is defined as the maximum thickness t _max .
(4) Finally, the difference between _{the maximum thickness t max} and the element average thickness t _{av (t dif} = t _max −t _av ) was calculated for each thickness profile, and first, the above five randomly selected thermoelectric elements were calculated. The average of the differences between the maximum thickness t _max and the element average thickness t _av (that is, the average of the five differences obtained from the five thickness profiles) was calculated and used as the first average value. The average of the first average values of the three substrates with the thermoelectric element layer (that is, the average of the 15 differences obtained from the 15 thickness profiles) was calculated and used as the second average value. _Let the second average value be the thickness difference t dim.
Here, the thickness profiles of the three thermoelectric element layered substrates were measured, but if only two thermoelectric element layered substrates can be obtained, the thickness profiles of the two thermoelectric element layered substrates are used. The second average value is calculated in the same manner as described above by measurement, and when only one substrate with a thermoelectric element layer can be obtained, the first average value is set as the second average value.

In the thermoelectric element layer in the thermoelectric conversion module of the present invention, that is, the inplane type thermoelectric element layer in which P-type thermoelectric elements and N-type thermoelectric elements are alternately formed by coating such as screen printing, the P-type thermoelectric element and the N-type thermoelectric element. of that thickness difference t _dif becomes less 50um in at least one in one of the elements, it is efficiently transferred by heat thermoelectric element layer which is applied from the outside, the heat transfer between the thermoelectric element layer and the thermoelectric module external The efficiency can be improved and the electromotive force can be improved.

The thickness difference _{t dif,} as long as it is less 50um, is not particularly limited, preferably 40μm or less, more preferably 30μm or less, more preferably 20μm or less.
Here, in order to make the thickness difference t _dif smaller, the thickness of the thermoelectric element may be reduced, or the thickness difference t _dif generated at the time of formation may be corrected by pressing, polishing, or the like (that is, the maximum thickness). may be reduced t _max), it may reduce the maximum thickness t _max thermoelectric semiconductor composition viscosity (coating liquid) was prepared.
Further, from the viewpoint of further improving the electromotive force, it is usually preferable to increase the absolute values of _{the gauge element thickness t ga} and the element average thickness t _{av of the thermoelectric elements 4 and 5.}

The thermoelectric element layer in the thermoelectric conversion module of the present invention is formed by coating, but as in the examples described later, coating is performed by a screen printing method using a printing plate having a rectangular opening (hole). When this is done, the cross section of the thermoelectric element usually has a shape in which the _{maximum thickness t max} exists at the end portion 59 on the end point side of the coating, as shown in FIG. Such a tendency is remarkable when the length of the rectangular opening in the coating direction is as long as 2 mm or more, for example.

Hereinafter, each part constituting the thermoelectric conversion module 1A will be described in detail.
<Support>
The support supports at least the thermoelectric element layer. The support may be a support for temporary fixing that is removed after applying the thermoelectric element layer to another member, or may be a substrate that finally remains in the thermoelectric conversion module. The support may support an electrode or the like in addition to the thermoelectric element layer, and the substrate may further support a coating layer, a high thermal conductive layer or the like.
As the support, it is possible to use a plastic film that does not affect the decrease in the electric conductivity and the increase in the thermal conductivity of the thermoelectric element layer, is easy to remove even when used for temporary fixing, and has excellent flexibility. preferable. When the support is used as a substrate, the performance of the thermoelectric element layer can be maintained without thermal deformation of the substrate even when the thin film made of the thermoelectric semiconductor composition described later is annealed, and the heat resistance and dimensions can be maintained. A polyimide film, a polyamide film, a polyetherimide film, a polyaramid film, and a polyamideimide film are preferable from the viewpoint of high stability, and a polyimide film is particularly preferable from the viewpoint of high versatility. The substrate may have an adhesive layer for joining with the thermoelectric element layer on the surface facing the thermoelectric element layer.

The thickness of the plastic film used as the support is preferably 1 to 1,000 μm, more preferably 10 to 500 μm, and even more preferably 20 to 100 μm from the viewpoint of flexibility, heat resistance and dimensional stability.
Further, the film preferably has a decomposition temperature of 300 ° C. or higher.

By using a plastic film as the substrate and forming other layers thinly, the entire thermoelectric conversion module can be made into a thin and flexible sheet shape.

<Thermoelectric element layer>
In the thermoelectric element layer, P-type thermoelectric elements and N-type thermoelectric elements are alternately arranged, and adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically connected so that electrons move in the direction of the arrangement. There is. Here, it is preferable that the adjacent P-type thermoelectric element and N-type thermoelectric element are electrically connected on the side surface of the element, for example, as shown in FIG.
Further, the thermoelectric element layer satisfies at least one of (1) made of a coating film and (2) made of a thermoelectric semiconductor composition containing thermoelectric semiconductor particles and a resin.
The thermoelectric semiconductor composition preferably contains thermoelectric semiconductor particles, a resin, and one or both of an ionic liquid and an inorganic ionic compound.

(Thermoelectric semiconductor particles)
For the thermoelectric semiconductor particles used in the thermoelectric element layer, it is preferable that the thermoelectric semiconductor material is pulverized to a predetermined size by a fine pulverizer or the like.

The material constituting the P-type thermoelectric element and the N-type thermoelectric element is not particularly limited as long as it is a material capable of generating a thermoelectric force by applying a temperature difference. For example, P-type bismasterlide, N. Bismas-tellu thermoelectric semiconductor materials such as type bismastellide; telluride thermoelectric semiconductor materials such as GeTe and PbTe; antimon-tellu thermoelectric semiconductor materials; zinc-antimon thermoelectrics such as ZnSb, Zn ₃ Sb ₂ , Zn ₄ Sb ₃ Semiconductor material; Silicon-germanium-based thermoelectric semiconductor material such as SiGe; Bismus selenide-based thermoelectric semiconductor material _{such as Bi 2} Se ₃ ; VDD-based thermoelectric semiconductor such as β-FeSi ₂ , CrSi ₂ , MnSi _1.73 , Mg ₂ Si Materials; oxide-based thermoelectric semiconductor materials; Whistler materials such as FeVAL, FeVALSi, and FeVTiAl; sulfide-based thermoelectric semiconductor materials such as _{TiS 2; scutterdite materials; and the like are used.} These may be used alone or in combination of two or more. Among these, silicide-based thermoelectric semiconductor materials are preferable from the viewpoint of not containing rare metals whose supply is unstable due to geopolitical problems, and it is possible to facilitate the functioning of the thermoelectric conversion module in a high temperature environment. From the viewpoint, the scuterdite material is preferable.

Further, from the viewpoint of high thermoelectric conversion performance in a low temperature environment, the thermoelectric semiconductor material is preferably a bismuth-tellurium-based thermoelectric semiconductor material such as P-type bismuthellide or N-type bismuthellide.
As the P-type bismuth telluride, one having a hole as a carrier and a positive Seebeck coefficient, for example, _{represented by Bi X} Te ₃ Sb _2-X is preferably used. In this case, X is preferably 0 <X ≦ 0.8, more preferably 0.4 ≦ X ≦ 0.6. When X is larger than 0 and 0.8 or less, the Seebeck coefficient and the electric conductivity become large, and the characteristics as a P-type thermoelectric conversion material are maintained, which is preferable.
Further, as the N-type bismuth telluride, those having an electron carrier and a negative Seebeck coefficient, for example, _{represented by Bi 2} Te _3-Y Se _Y , are preferably used. In this case, Y is preferably 0 ≦ Y ≦ 3 (when Y = 0: Bi ₂ Te ₃ ). When Y is 0 or more and 3 or less, the Seebeck coefficient and the electric conductivity become large, and the characteristics as an N-type thermoelectric conversion material are maintained, which is preferable.

The blending amount of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass. It is more preferably 50 to 98% by mass, and even more preferably 70 to 97% by mass. When the blending amount of the thermoelectric semiconductor particles is within the above range, the Seebeck coefficient (absolute value of the Perche coefficient) is large, the decrease in the electric conductivity is suppressed, and only the thermal conductivity is decreased, so that high thermoelectric performance is exhibited. At the same time, a film having sufficient film strength and flexibility can be obtained, which is preferable.

The average particle size of the thermoelectric semiconductor particles is preferably 10 nm to 200 μm, more preferably 10 nm to 30 μm, still more preferably 50 nm to 10 μm, and particularly preferably 1 to 6 μm. Within the above range, uniform dispersion can be facilitated and the electrical conductivity can be increased.
The method of crushing a thermoelectric semiconductor material to obtain thermoelectric semiconductor particles is not particularly limited, and is a jet mill, a ball mill, a bead mill, a colloid mill, a conical mill, a disc mill, an edge mill, a milling mill, a hammer mill, a pellet mill, a willy mill, and a roller mill. It may be pulverized to a predetermined size by a known fine pulverizer or the like.
The average particle size of the thermoelectric semiconductor particles was obtained by measuring with a laser diffraction type particle size analyzer (Mastersizer 3000 manufactured by Malvern), and was used as the median value of the particle size distribution.

Further, the thermoelectric semiconductor particles are preferably annealed (hereinafter, may be referred to as "annealing treatment A"). By performing the annealing treatment A, the crystallinity of the thermoelectric semiconductor particles is improved, and the surface oxide film of the thermoelectric semiconductor particles is removed, so that the Seebeck coefficient (absolute value of the Perche coefficient) of the thermoelectric conversion material is increased. , The thermoelectric performance index can be further improved. The annealing treatment A is not particularly limited, but before preparing the thermoelectric semiconductor composition, the gas flow rate is controlled so as not to adversely affect the thermoelectric semiconductor particles, and the atmosphere is an inert gas such as nitrogen or argon. Similarly, it is preferably carried out in a reducing gas atmosphere such as hydrogen or under vacuum conditions, and more preferably in a mixed gas atmosphere of an inert gas and a reducing gas. The specific temperature condition depends on the thermoelectric semiconductor particles used, but it is usually preferable to carry out the temperature at a temperature equal to or lower than the melting point of the particles and at 100 to 1500 ° C. for several minutes to several tens of hours.

(resin)
The resin contained in the thermoelectric element layer acts as a binder between the thermoelectric semiconductor particles, and is for enhancing the printability and the film strength of the thermoelectric conversion material. The resin is not particularly limited, but when a thin film made of a thermoelectric semiconductor composition is subjected to crystal growth of thermoelectric semiconductor particles by annealing or the like, various physical properties such as mechanical strength and thermal conductivity of the resin are exhibited. It is preferable to use a resin that is maintained without being damaged.
Examples of the resin include polyamide resin, polyamideimide resin, polyimide resin, polyetherimide resin, polybenzoxazole resin, polybenzoimidazole resin, epoxy resin, and copolymers having a chemical structure of these resins. .. The resin may be used alone or in combination of two or more. Among these, polyamide resin, polyamide-imide resin, polyimide resin, and epoxy resin are preferable from the viewpoint of high heat resistance and not adversely affecting the crystal growth of thermoelectric semiconductor particles in the thin film, and are superior in heat resistance. Polyamide resin, polyamideimide resin, and polyimide resin are more preferable. When a polyimide film is used as the above-mentioned support, a polyimide resin is more preferable as the resin from the viewpoint of adhesion to the polyimide film and the like. In the specification of the present application, the polyimide resin is a general term for polyimide and its precursor (for example, polyamic acid).

The resin preferably has a decomposition temperature of 300 ° C. or higher. When the decomposition temperature is within the above range, the film strength of the thermoelectric conversion material can be maintained without losing the function as a binder even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

Further, the mass reduction rate of the resin at 300 ° C. by thermogravimetric analysis (TG) is preferably 10% or less, more preferably 5% or less, and further preferably 1% or less. As long as the mass reduction rate is within the above range, the film strength of the thermoelectric conversion material can be maintained without losing the function as a binder even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later. ..

The blending amount of the resin in the thermoelectric semiconductor composition is preferably 0.1 to 40% by mass, more preferably 0.5 to 20% by mass, and further preferably 0.7 to 20% by mass. When the blending amount of the resin is within the above range, it is easy to obtain a film having high thermoelectric performance, printability, and film strength.

(Ionic liquid)
The ionic liquid contained in the thermoelectric element layer is a molten salt formed by combining a cation and an anion, and refers to a salt that can exist as a liquid in a wide temperature range of -50 or more and less than 400 ° C. Ionic liquids have features such as extremely low vapor pressure, non-volatility, excellent thermostability and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive auxiliary agent, it is possible to effectively suppress the reduction of the electrical conductivity between the thermoelectric semiconductor particles. Further, since the ionic liquid exhibits high polarity based on the aprotic ionic structure and has excellent compatibility with the resin, the electric conductivity of the thermoelectric conversion material can be made uniform.

As the ionic liquid, known or commercially available ones can be used. For example, nitrogen-containing cyclic cation compounds such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, imidazolium and their derivatives; tetraalkylammonium-based amine-based cations and their derivatives; phosphonium, trialkylsulfonium, tetraalkylphosphonium and the like. Hosphin-based cations and their derivatives; cation components such as lithium cations and their derivatives, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (FSO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , F (HF) _n ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) Examples thereof include those composed of anionic components such as ₂ N ⁻ , C ₃ F ₇ ^{COO −} , and (CF ₃ SO ₂ ) (CF ₃ CO) N ^−.

Among the above ionic liquids, the cation component of the ionic liquid is a pyridinium cation and its derivatives from the viewpoints of high temperature stability, compatibility with thermoelectric semiconductor particles and resins, and suppression of decrease in electrical conductivity between thermoelectric semiconductor particle gaps. , It is preferable to contain at least one selected from the imidazolium cation and its derivatives.

Specific examples of ionic liquids in which the cation component contains a pyridinium cation and a derivative thereof include 4-methyl-butylpyridinium chloride, 3-methyl-butylpyridinium chloride, 4-methyl-hexylpyridinium chloride, and 3-methyl-hexylpyridinium. Chloride, 4-methyl-octylpyridinium chloride, 3-methyl-octylpyridinium chloride, 3,4-dimethyl-butylpyridinium chloride, 3,5-dimethyl-butylpyridinium chloride, 4-methyl-butylpyridiniumtetrafluoroborate, 4- Examples thereof include methyl-butylpyridinium hexafluorophosphate, 1-butylpyridinium bromide (N-butylpyridinium bromide), 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium hexafluorophosphate and the like. These may be used alone or in combination of two or more. Among these, 1-butylpyridinium bromide, 1-butyl-4-methylpyridinium bromide, and 1-butyl-4-methylpyridinium hexafluorophosphate are preferable.

Further, as specific examples of the ionic liquid in which the cation component contains an imidazolium cation and a derivative thereof, [1-butyl-3- (2-hydroxyethyl) imidazolium bromide], [1-butyl-3- (2) -Hydroxyethyl) imidazolium tetrafluoroborate], 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium chloride, 1-hexyl-3 − Methyl imidazolium chloride, 1-octyl-3-methyl imidazolium chloride, 1-decyl-3-methyl imidazolium chloride, 1-decyl-3-methyl imidazolium bromide, 1-dodecyl-3-methyl imidazolium chloride, 1-Tetradecyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium tetrafluoroborolate, 1-butyl-3-methylimidazolium tetrafluoroborobolate, 1-hexyl-3-methylimidazolium tetraflolate Orobolate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-methyl-3-butylimidazolium methylsulfate, 1,3-dibutylimidazolium methyl Sulfate and the like can be mentioned. These may be used alone or in combination of two or more. Among these, [1-butyl-3- (2-hydroxyethyl) imidazolium bromide] and [1-butyl-3- (2-hydroxyethyl) imidazolium tetrafluoroborate] are preferable.

The above ionic liquid preferably has an electrical conductivity of ^10-7 S / cm or more. When the ionic conductivity is within the above range, the reduction of the electrical conductivity between the thermoelectric semiconductor particles can be effectively suppressed as a conductivity auxiliary agent.

Further, the above-mentioned ionic liquid preferably has a decomposition temperature of 300 ° C. or higher. As long as the decomposition temperature is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

Further, the above-mentioned ionic liquid preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and further preferably 1% or less at 300 ° C. by thermogravimetric analysis (TG). .. As long as the mass reduction rate is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

The blending amount of the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 20% by mass. When the blending amount of the ionic liquid is within the above range, the decrease in electrical conductivity is effectively suppressed, and a film having high thermoelectric performance can be obtained.

(Inorganic ionic compound)
The inorganic ionic compound contained in the thermoelectric element layer is a compound composed of at least cations and anions. Since the inorganic ionic compound exists as a solid in a wide temperature range of 400 to 900 ° C. and has characteristics such as high ionic conductivity, it can be used as a conductivity auxiliary agent to reduce the electrical conductivity between thermoelectric semiconductor particles. Can be suppressed.

As the cation constituting the inorganic ionic compound, a metal cation is used.
Examples of the metal cation include alkali metal cations, alkaline earth metal cations, typical metal cations and transition metal cations, and alkali metal cations or alkaline earth metal cations are more preferable.
Examples of the alkali metal cation include Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ^+, Fr ^{+ and the} like.
Examples of the alkaline earth metal cation include Mg ²⁺ , Ca ²⁺ , Sr ²⁺ and Ba ²⁺ .

Examples of the anions constituting the inorganic ionic compound include F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , OH ⁻ , CN ⁻ , NO ₃ ⁻ , NO ₂ ⁻ , ClO ⁻ , ClO ₂ ⁻ , and ClO ₃ ^{−. _{, ClO 4 -, CrO 4 2-}} , HSO 4 -, SCN -, BF 4 -, PF 6 - , and the like.

As the inorganic ionic compound contained in the thermoelectric element layer, known or commercially available ones can be used. For example, cation components such as potassium cation, sodium cation, or lithium cation, chloride ion such as ^{Cl −} , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , ClO ₄ ⁻ , bromide ion such as ^{Br − , I − and the} like. iodide _ion, ^BF 4 -, PF ₆ ^- fluoride ions, F _{(HF) n,} such as ^- such as halide anions _{^{of, NO 3 -, OH -,}} CN - and the ones mentioned consists the anion component of such Be done.

Among the above-mentioned inorganic ionic compounds, the cationic component of the inorganic ionic compound is potassium from the viewpoints of high temperature stability, compatibility with thermoelectric semiconductor particles and resins, and suppression of decrease in electrical conductivity between thermoelectric semiconductor particle gaps. , Sodium, and lithium are preferably included. Further, the anion component of the inorganic ionic compound preferably contains a halide anion, and more preferably contains at least one selected from ^{Cl −} , Br ⁻ , and I ^−.

Cationic component is, as a specific example of the inorganic ionic compound containing a potassium cation, KBr, KI, KCl, KF , KOH, K 2 CO 3 and the like. These may be used alone or in combination of two or more. Among these, KBr and KI are preferable.
Specific examples of the inorganic ionic compound whose cation component contains a sodium cation include NaBr, NaI, NaOH, NaF, Na ₂ CO _{3 and the} like. These may be used alone or in combination of two or more. Among these, NaBr and NaI are preferable.
Specific examples of the inorganic ionic compound whose cation component contains a lithium cation include LiF, LiOH, and LiNO ₃ . These may be used alone or in combination of two or more. Among these, LiF and LiOH are preferable.

The above-mentioned inorganic ionic compound ^{preferably has an electric conductivity of 10-7} S / cm or more, and more preferably ^10-6 S / cm or more. When the electric conductivity is within the above range, the reduction of the electric conductivity between the thermoelectric semiconductor particles can be effectively suppressed as a conductivity auxiliary agent.

Further, the decomposition temperature of the above-mentioned inorganic ionic compound is preferably 400 ° C. or higher. As long as the decomposition temperature is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

Further, the above-mentioned inorganic ionic compound preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and preferably 1% or less at 400 ° C. by thermogravimetric analysis (TG). More preferred. As long as the mass reduction rate is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

The blending amount of the inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 10% by mass. When the blending amount of the inorganic ionic compound is within the above range, the decrease in electrical conductivity can be effectively suppressed, and as a result, a film having improved thermoelectric performance can be obtained.
When the inorganic ionic compound and the ionic liquid are used in combination, the total content of the inorganic ionic compound and the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably. Is 0.5 to 30% by mass, more preferably 1.0 to 10% by mass.

<Electrode>
The electrodes are provided for electrically connecting the P-type thermoelectric element and the N-type thermoelectric element constituting the thermoelectric element layer, or for electrically connecting the thermoelectric element layer and the outside. Various electrode materials can be used for the electrodes. From the viewpoint of connection stability and thermoelectric performance, it is preferable to use a highly conductive metal material. Preferred electrode materials include gold, silver, nickel, copper, alloys of these metals, and laminates of these metals and alloys.
The thickness of the electrode is preferably 1 μm to 50 μm, more preferably 2.5 μm to 30 μm, and even more preferably 3 μm to 20 μm. When the thickness of the electrode is within the above range, the electric conductivity is high and the resistance is low, and the total electric resistance value of the thermoelectric element layer can be suppressed low. Moreover, sufficient strength can be obtained as an electrode. Further, the volume of the electrode can be increased, and even if the metal element constituting the electrode diffuses into the thermoelectric element during use, the deterioration of the electrode performance can be suppressed. Furthermore, the electrodes are easily embedded in the thermoelectric element layer, the smoothness of the surface of the thermoelectric conversion module is maintained, and the thermoelectric performance is also easily stabilized.

<High thermal conductivity layer>
As the high thermal conductivity layer, a layer having excellent thermal conductivity and whose thermal conductivity is larger than that of the coating layer is used. As the high thermal conductive layer, those having a thermal conductivity of 5 to 500 W / (m · K) are preferably used, those having a thermal conductivity of 15 to 420 W / (m · K) are more preferable, and those having a thermal conductivity of 300 to 420 W / (m · K) are more preferable. Is more preferable.
The material constituting the high thermal conductivity layer is not particularly limited as long as it has a high thermal conductivity, but is preferably a metal, and more preferably any one of copper, aluminum, silver, and nickel. More preferably, it is any one of copper, aluminum, and silver, and even more preferably, it is any one of copper and aluminum.
The high thermal conductive layer is arranged in a pattern such as a stripe shape, a grid shape, a honeycomb shape, a comb shape, or a matrix shape. This makes it easier to generate a temperature difference in the surface direction of the thermoelectric conversion module, and by exposing the boundary between the P-type thermoelectric element and the N-type thermoelectric element, heat exchange with the outside is efficiently performed. .. As a result, the electromotive force performance, heat generation performance, and endothermic performance of the thermoelectric conversion module can be improved.
As described in FIG. 4, the first high thermal conductive layer is arranged on one surface side of the thermoelectric element layer so as to cover every other joint portion between the P-type thermoelectric element and the N-type thermoelectric element. The high thermal conductive layer 2 is arranged at a position corresponding to the joint portion of the thermoelectric element not covered by the first high thermal conductive layer when viewed from the direction perpendicular to the main surface of the support (substrate), and the high thermal conductive layer is arranged. It is preferable that the first high heat conductive layer and the second high heat conductive layer are alternately arranged with respect to the thermoelectric element layer in the vertical cross section in the arrangement direction of.
The thickness of the high thermal conductive layer is preferably 40 to 550 μm, more preferably 60 to 530 μm, and even more preferably 80 to 510 μm from the viewpoint of flexibility, heat dissipation and dimensional stability. When two high thermal conductive layers, a first high thermal conductive layer 91 and a second high thermal conductive layer 92, are provided, they may be made of the same material or different materials, and they may have the same thickness. It may have different thicknesses.

<Coating layer>
The coating layer is arranged so as to cover the thermoelectric element layer. When the coating layer is arranged in this way, it is not necessary to pattern and form the coating layer, so that the productivity is excellent. Further, when a member such as a low thermal conductive layer is not provided in the region where the high thermal conductive layer is not provided in the thermoelectric element layer, the thermoelectric element layer is exposed unless the coating layer covers the thermoelectric element layer. By covering the thermoelectric element layer with the coating layer, the coating layer can protect the thermoelectric element layer in a region where the high thermal conductivity layer does not exist.

When two coating layers are provided, such as the first coating layer 81 and the second coating layer 82 described above, they may be made of the same material or different materials.

The second coating layer 82 laminated on the surface of the support 2 (board) opposite to the surface on the thermoelectric element layer 6 side may be a single layer or a multilayer structure. good. Further, the second coating layer 82 may be removed from the thermoelectric conversion module, and the second high thermal conductive layer may be provided directly on the back surface of the support 2.

When a single-layer coating layer is used, it is preferable that the coating layer itself has adhesiveness and the high thermal conductive layer can be adhered to and fixed to the thermoelectric element layer. Further, when the single-layer coating layer itself is a sealing layer, and as will be described later, it is a layer having a water vapor transmittance within a predetermined range or a layer composed of a composition containing a polyolefin resin. The coating layer covers the thermoelectric element layer, and is more preferable because the coating layer functions as a member for sealing the thermoelectric element layer. When a single-layer coating layer is used, the number of layers in the thermoelectric conversion module is small, so that the configuration of the thermoelectric conversion module can be simplified and the manufacturing process of the thermoelectric conversion module can be simplified. Further, since the overall thickness of the coating layer can be reduced, the efficiency of heat exchange between the high thermal conductive layer and the thermoelectric element layer can be improved.

When the thermoelectric conversion module has a coating layer including a plurality of layers, there is an advantage that a plurality of functions such as a function of adhering a high thermal conductive layer and a thermoelectric element layer and a sealing function can be easily shared by each layer. For example, by imparting gas barrier properties to the auxiliary substrate layer described later as an intermediate layer and providing an inner layer and an outer layer as adhesive layers on both sides of the auxiliary substrate layer, the function of the gas barrier and the function of adhesion can be obtained. Can be easily compatible with each other. In this case, if at least one of the inner layer and the outer layer also serves as a sealing layer, due to the gas barrier property of the auxiliary substrate layer and the sealing property of the inner layer and / or the outer layer which is the sealing layer, The durability of the thermoelectric conversion module can be expected to improve. When the thermoelectric conversion module has the first coating layer 81, it is considered that the decrease in thermoelectric efficiency becomes more remarkable due to the large _{thickness difference t div of the thermoelectric element.} It is presumed that the reason is _{that the large thickness difference t div} reduces the adhesiveness between the coating layer and the thermoelectric element layer, and hinders the heat conduction between the thermoelectric element layer and the outside air.

The overall thickness of the coating layer is preferably 1 to 200 μm, more preferably 5 to 175 μm, from the viewpoint of efficiently conducting heat conduction between the high thermal conductive layer and the thermoelectric element layer. preferable.

The thermoelectric conversion module according to the present embodiment can improve the heat transfer efficiency by efficiently transferring the heat applied from the outside, and can obtain a high electromotive force.
Further, in the present embodiment, by providing two high thermal conductive layers, a first high thermal conductive layer 91 and a second high thermal conductive layer 92, a temperature difference can be efficiently generated in the plane of the thermoelectric conversion module, which is preferable. It is a composition. However, for example, when the area of the thermoelectric conversion module can be increased or the configuration of the thermoelectric conversion module is required to be simplified as much as possible, the second high thermal conductive layer 92 can be omitted.

[Manufacturing method of thermoelectric conversion module]
As an example of the method for manufacturing the thermoelectric conversion module of the present embodiment, a coating layer is formed on the thermoelectric element layer, and a high thermal conductive layer is formed in a pattern on a part of one surface of the coating layer. To give a more specific example, as shown in FIG. 2, a step of preparing a support 2 in which the electrodes 3 are arranged in a pattern, and as shown in FIG. 3, a P-shape is formed on one surface of the support 2. A step of forming a thermoelectric element layer 6 composed of a thermoelectric element 5 and an N-type thermoelectric element 4, a step of forming a first coating layer 81 on the surface of the thermoelectric element layer 6, a first coating layer 81 as shown in FIG. A step of forming the first high thermal conductive layer 91 on at least a part of the surface of the support 2 and a step of forming a second high thermal conductive layer 92 on the other surface of the support 2 are included.
Hereinafter, each step will be sequentially described with reference to the drawings.

<Step of preparing the support on which the electrodes are formed>
In the method for manufacturing a thermoelectric conversion module, for example, as shown in FIG. 2, first, a support 2 in which electrodes 3 having a predetermined pattern are formed on one main surface is prepared. In order to prepare the support on which the electrode 3 is formed, the electrode may be formed on the support 2 by using the electrode material or the like described above. As a method of forming an electrode on a support, after providing an electrode having no pattern formed on the support, a known physical treatment or chemical treatment (for example, wet etching) mainly composed of a photolithography method is performed. , Or a method of processing into a predetermined pattern by using them in combination, or a method of directly forming an electrode pattern by a screen printing method, an inkjet method, or the like.
As a method for forming an electrode in which a pattern is not formed, PVD (Physical Vapor Deposition Method) such as vacuum deposition method, sputtering method, ion plating method, or CVD (Chemical Vapor Deposition) such as thermal CVD, atomic layer deposition (ALD), etc. Dry process such as vapor deposition method), various coating methods such as dip coating method, spin coating method, spray coating method, gravure coating method, die coating method, doctor blade method, wet process such as electrodeposition method, silver salt method , Electrolytic plating method, electroless plating method, lamination of metal foil and the like, and are appropriately selected according to the material of the electrode.

<Step of forming a thermoelectric element layer>
Next, as shown in FIG. 3, a thermoelectric semiconductor composition is used on one main surface of the support 2 in which the electrodes 3 are arranged in a pattern, and the thermoelectric element is composed of a P-type thermoelectric element 5 and an N-type thermoelectric element 4. The element layer 6 is formed. The thermoelectric element layer 6 is formed, for example, by applying a varnish, ink, or the like in which each material of the thermoelectric semiconductor composition described above is dissolved or dispersed in a solvent onto a support. Examples of the method for applying the thermoelectric semiconductor composition onto the support include known methods such as screen printing, flexographic printing, gravure printing, spin coating, dip coating, die coating, spray coating, bar coating, and doctor blade. Not limited. When the coating film is formed into a pattern, screen printing capable of easily forming a pattern using a screen plate (printing plate) having a desired pattern is preferably used. Specific embodiments of the formation of the thermoelectric element layer by the screen printing method are as described above.
Next, a thin film is formed by drying the obtained coating film. As a method for drying the coating film, conventionally known drying methods such as hot air drying, hot roll drying, and infrared irradiation can be adopted. The heating temperature during drying can be in the range of 80 to 150 ° C. The heating time during drying varies depending on the heating method, but can be several seconds to several tens of minutes.
When a thermoelectric semiconductor composition is prepared using a solvent, the heating temperature for drying the coating film of this composition is not particularly limited as long as the temperature range in which the solvent used can be dried.
Further, the obtained coating film may be annealed. The annealing treatment can be performed under the same conditions as the annealing treatment A described above.
After forming the thermoelectric element layer, the thermoelectric element layer may be peeled off from the support 2 and replaced with, for example, another support (substrate) having low heat resistance.

<Step of forming the first coating layer>
Next, the first coating layer 81 is formed on the surface of the thermoelectric element layer 6 opposite to the support 2. The coating layer can be formed by a known method. The coating layer may be formed directly on the surface of the thermoelectric element layer, or may be formed by bonding the coating layer previously formed on the release sheet to the thermoelectric element layer and transferring the coating layer to the thermoelectric element layer. You may.

When the coating layer is composed of a plurality of layers, a coating layer including the plurality of layers may be prepared in advance and attached to the thermoelectric element layer, or each layer constituting the plurality of layers may be sequentially thermoelectric. A coating layer composed of a plurality of layers may be formed on the thermoelectric element layer by being laminated on the element layer.

<Step of forming the first high thermal conductive layer>
The first high thermal conductive layer 91 is formed on at least a part of the surface of the first coating layer 81. The first high thermal conductive layer 91 may be provided on the coating layer 81 formed on the thermoelectric element layer 6, or the first high thermal conductive layer 91 may be provided on the coating layer 81 and then the first high thermal conductive layer 91 is attached. The coating layer 81 can also be provided on the support 2.

<Step of forming the second high thermal conductive layer>
A second high thermal conductive layer 92 is formed on a part of the other surface of the support 2. In this case, the second coating layer 82 may be provided on the support 2, and then the second high thermal conductive layer 92 may be provided, or the second coating layer 82 provided with the second high thermal conductive layer 92 may be provided on the other side of the support 2. It may be provided on the surface. If a support in which the second high thermal conductive layer 92 is directly formed by vapor deposition, sputtering, printing, or the like is used, a thermoelectric conversion module in which the high thermal conductive layer is provided in direct contact with the support can be obtained.

Next, specific examples of the present invention will be described, but the present invention is not limited to these examples.
The thickness difference evaluation and the electromotive force evaluation in the examples and comparative examples described later were carried out by the following procedure.

[Thickness difference evaluation]
Thickness gauge (manufactured by TECLOCK Co., Ltd., Digital Indicator PC-465J) for the thermoelectric element formed on the substrate with the thermoelectric element after arranging the P-type thermoelectric element and the N-type thermoelectric element and before performing the annealing treatment. ), And the thickness of the thermoelectric element was determined by subtracting the thickness of the substrate (50 μm) from the measured thickness. In determining the thickness of the thermoelectric element, first, the thickness of five thermoelectric elements randomly selected from a plurality of thermoelectric elements on a substrate with one thermoelectric element layer is measured, and the measured values of the five thermoelectric elements are measured. The first average value, which is the average of, was calculated. Such thickness measurement is performed on three substrates with thermoelectric element layers, and the average of the first average values of three three substrates with thermoelectric element layers is calculated and used as the second average value, and the second average value is obtained. _{Was defined} as the gauge element thickness t ga.

Next, a substrate with a thermoelectric element similar to the substrate with a thermoelectric element layer is attached to a glass plate (length 100 mm × width 100 mm × thickness 0.7 mm), and among the P-type thermoelectric element and the N-type thermoelectric element, gauges are attached. An element having a larger element thickness t _ga (hereinafter, an element having a larger gauge element thickness t _ga is also referred to as a "thicker element") (Examples 1 to 5 and Comparative Examples 1 to 4: N-type thermoelectric element, implementation. Example 6: A stylus of the thickness profile of the cross section of the P-type thermoelectric element) along the direction perpendicular to the arrangement direction of the thermoelectric element (the coating direction of the coating liquid (P) and the coating liquid (N) described later). The measurement was performed using a formula surface shape measuring device (Electrok150 manufactured by ULVAC). The measurement frequency was every 0.4 μm. The measurement site was a portion where no electrode was provided. The average thickness of the central portion excluding both ends of the thermoelectric element was calculated, and the average of the calculated thickness was defined as the element average thickness _tav . The central portion is an area defined as described above. The thickness profile was first measured on five thermoelectric elements randomly selected from a plurality of thermoelectric elements on a single thermoelectric layered substrate. As a result, the average thickness _tav of 5 elements was obtained. Such thickness profile measurements were performed on three substrates with thermoelectric element layers. As a result, an average thickness _tav of 15 elements was obtained. Further, from the 15 measured thickness profiles, the maximum value of the thickness of the thermoelectric element (thickness of the thickest portion) was detected for each thickness profile, and the maximum value of the detected thickness was defined as the maximum thickness t _max . As a result, 15 maximum thicknesses t _max were obtained. Further, the average of the difference between the maximum thickness t _max and the element average thickness t _av was calculated for the above five randomly selected thermoelectric elements, and the first average value (that is, 5 obtained from the five thickness profiles) was calculated. The average of the differences between the pieces). Such a calculation is performed on the three substrates with the thermoelectric element layer, and the average of the first average values of three three substrates with the thermoelectric element layer is calculated to calculate the second average value (that is, the thickness of 15 pieces). The average of 15 differences obtained from the profile), and the second average value was defined as the thickness difference t _dim . The results are shown in Table 1.

[Electromotive force evaluation]
A state in which a temperature difference of 20 ° C is applied between the hot plate and the water-cooled chiller to the thermoelectric conversion modules produced in the examples and the comparative examples (the temperature difference between the hot plate and the water-cooled chiller is set to 20 ° C. (Adjustment), the electromotive force between the extraction electrodes was measured using a digital high tester (manufactured by Hioki Electric Co., Ltd., model name: 3801-50). The case where the electromotive force between the extraction electrodes was 0.4 V or more was defined as (◯: allowable), and the case where it was less than 0.4 V was defined as (x: defective).
The electromotive force was measured by installing thermocouples on both sides of the manufactured thermoelectric conversion module and measuring the measured value of the temperature difference between the high temperature side and the low temperature side. If the measured value of the temperature difference does not match 20 ° C and a difference within ± 5 ° C occurs, the electromotive force measured as described above is equivalent to 20 ° C based on the proportional relationship between the electromotive force and the temperature difference. The correction calculation was made so as to be. The results are shown in Table 1.

[Manufacturing of thermoelectric conversion module]
<Example 1>
(Manufacture of thermoelectric semiconductor particles)
_{P-type bismuth tellurium Bi 0.4} Te ₃ Sb _1.6 (manufactured by High Purity Chemical Laboratory, particle size: 90 μm), which is a bismuth-tellurium thermoelectric semiconductor material, is used in a planetary ball mill (manufactured by Fritsch Japan, Premium line P). By pulverizing in a nitrogen gas atmosphere using −7), thermoelectric semiconductor fine particles T1 having an average particle size of 2.5 μm as thermoelectric semiconductor particles were produced.
_{Further, N-type bismuth tellurium Bi 2} Te ₃ (manufactured by High Purity Chemical Laboratory, particle size: 90 μm), which is a bismuth-tellurium-based thermoelectric semiconductor material, is pulverized in the same manner as described above, and the average particle size as the thermoelectric semiconductor particles is 2. 5 μm thermoelectric semiconductor fine particles T2 were produced.
The average particle size of T1 and T2 was obtained by measuring the particle size distribution of the thermoelectric semiconductor particles obtained by pulverization with a laser diffraction type particle size analyzer (Mastersizer 3000 manufactured by Malvern).

(Preparation of thermoelectric semiconductor composition)
94.6 parts by mass of fine particles T1 of the obtained P-type bismuth-tellu thermoelectric semiconductor material, polyamide imide solution as a resin (manufactured by Arakawa Chemical Industry Co., Ltd., product name: Compolasen AI301, solvent: N-methylpyrrolidone, solid content) A coating liquid (P) consisting of a thermoelectric semiconductor composition in which 2.9 parts by mass (concentration: 18% by mass) (in terms of solid content) and 2.5 parts by mass of N-butylpyridinium bromide as an ionic liquid are mixed and dispersed is prepared. bottom.
Further, 95.0 parts by mass of the obtained fine particles T2 of the N-type bismuth-tellu thermoelectric semiconductor material, a polyamide-imide solution as a resin (manufactured by Arakawa Chemical Industry Co., Ltd., product name: Compolasen AI301, solvent: N-methylpyrrolidone, Coating liquid (N) consisting of a thermoelectric semiconductor composition in which 2.7 parts by mass (solid content equivalent) of solid content concentration: 18% by mass and 2.3 parts by mass of N-butylpyridinium bromide as an ionic liquid are mixed and dispersed. Was prepared.

(Formation and placement of electrodes)
By the following procedure, a substrate provided with electrodes was produced in an arrangement pattern according to FIGS. 2 and 3 described above. Note that FIGS. 2 and 3 conceptually show the arrangement of the electrodes and the thermoelectric element, and the number of the electrodes and the thermoelectric element is different from that of the actually manufactured electrodes and the thermoelectric element.
First, a polyimide film substrate to which a copper foil was attached (manufactured by Ube Exsymo Co., Ltd., product name: Iupicel N, thickness of polyimide substrate: 50 μm, copper foil: 9 μm) was prepared. Then, the copper foil on the polyimide film substrate was wet-etched with a ferric chloride solution to form electrodes arranged in an arrangement pattern corresponding to the arrangement of P-type and N-type thermoelectric elements described later. The electrodes were formed in a size of 550 μm × 6 mm so as to straddle the boundaries between the adjacent P-type thermoelectric elements and N-type thermoelectric elements in the arrangement of the thermoelectric elements described later. A nickel layer (thickness: 3 μm) is selectively laminated on a patterned copper foil by electroless plating, and then a gold layer (thickness: 400 nm) is selectively laminated on the nickel layer by electroless plating. To form an electrode.

(Formation of thermoelectric element layer)
Using the coating liquid (P) prepared above using a printing plate for forming a P-type thermoelectric element having a plate thickness of 30 um and an opening of 1 mm × 6 mm, the thermoelectric element is arranged in the direction Y perpendicular to the screen printing method. Was applied to the polyimide film on which the electrodes were formed, and dried at a temperature of 150 ° C. for 10 minutes in an argon atmosphere to form a thin film (FIGS. 6A and 6C (the printing plate 60 of FIG. 6C). , Although it has three openings (holes) 61 for the sake of clarity in the illustration, the number of openings (holes) 61 is not limited to this.)). Next, similarly, the coating liquid (N) prepared above was subjected to the arrangement of the thermoelectric elements by the screen printing method using a printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um and an opening of 1 mm × 6 mm. The film was coated on the polyimide film with the direction Z perpendicular to the direction Y as the coating direction, and dried at a temperature of 150 ° C. for 10 minutes in an argon atmosphere to form a thin film (see FIGS. 6B and 6C).
Further, for each of the obtained thin films, the temperature was raised at a heating rate of 5 K / min in an atmosphere of a mixed gas of hydrogen and argon (hydrogen: argon = 3% by volume: 97% by volume), and the temperature was raised at 325 ° C. for 30 minutes. By holding and annealing after forming the thin film, fine particles of the thermoelectric semiconductor material were crystallized to produce a P-type thermoelectric element and an N-type thermoelectric element.

(Arrangement of thermoelectric elements)
By applying the coating liquid (P) and the coating liquid (N) onto the electrodes on the polyimide film substrate, a 1 mm × 6 mm P-type thermoelectric element and a 1 mm × 6 mm N-type thermoelectric element are alternately applied. Formed in. The P-type thermoelectric element and the N-type thermoelectric element are adjacent to each other so as to be in contact with each other on a side having a length of 6 mm and form a pair. In this way, the thermoelectric element layer in which the P-type thermoelectric element and the N-type thermoelectric element 380 pairs are provided in series electrically in the plane of the polyimide film substrate is similar to the arrangement of the thermoelectric elements in FIG. It was made in the arrangement of. As a result, electrons move in the direction of arrangement of the thermoelectric element inside the thermoelectric element layer composed of the P-type thermoelectric element and the N-type thermoelectric element. The thermoelectric element layer has a folded structure. At this time, 38 pairs of P-type thermoelectric elements and N-type thermoelectric elements were connected in a row, and 10 rows were provided. The distance between each row of the thermoelectric element layer is 1 mm, the connecting electrode of each row of the thermoelectric element layer is 0.55 mm × 13 mm, and the electromotive force extraction electrode is 12.775 mm × 6 mm.
_{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

(Formation of coating layer and high thermal conductivity layer)
An aluminum-deposited PET film (manufactured by Mitsubishi Shindoh Co., Ltd., thickness: 12 μm) is used as an insulating layer, and an adhesive layer (manufactured by Somar Corporation, trade name: EP-0002EF-01MB, thickness: 25 μm) is laminated on both sides thereof. A coating layer was prepared. Lamination was performed at a temperature of 50 ° C.
Opposite to the case where the upper surface of the produced substrate with a thermoelectric element layer (the surface of the thermoelectric element layer) is provided with the above-mentioned coating layer and the lower surface of the substrate with a thermoelectric element layer (the thermoelectric element layer in the substrate). On the side surface), a striped high thermal conductive material (copper) is provided via a coating layer (manufactured by Somer, trade name: EP-0002EF-01MB, thickness: 25 μm) composed of a single adhesive layer. A high thermal conductive layer (C1020, thickness: 200 μm, width: 1 mm, length: 100 mm, spacing: 1 mm, thermal conductivity: 398 (W / m · K)) made of a foil) was arranged. At this time, the striped high thermoelectric layer is the opposite of the upper part (the surface of the thermoelectric element) and the lower part (the thermoelectric element layer on the substrate) of the portion where the P-type thermoelectric element and the N-type thermoelectric element are adjacent to each other. Arranged alternately on the side surface). Further, the coating layer provided on the surface of the substrate with the thermoelectric element layer was arranged so that the aluminum vapor deposition forming surface of the aluminum vapor deposition PET film was distal to the thermoelectric element layer.
Laminating the coating layer on the thermoelectric element layer, laminating the adhesive layer on the substrate, and laminating the high heat conductive layer on the coating layer and the adhesive layer were all performed at a temperature of 80 ° C.
Then, the thermoelectric conversion module was allowed to stand in an environment of 150 ° C. for 30 minutes to cure the adhesive layer, and a thermoelectric conversion module was obtained.

<Example 2>
In the first embodiment, the same as in the first embodiment except that the printing plate for forming an N-type thermoelectric element having a plate thickness of 50 um was used instead of using the printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um. A thermoelectric conversion module was prepared and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

<Example 3>
In the first embodiment, the same as in the first embodiment except that the printing plate for forming an N-type thermoelectric element having a plate thickness of 110 um was used instead of using the printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um. A thermoelectric conversion module was prepared and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

<Example 4>
In Example 1, the same as in Example 1 except that a printing plate for forming a P-type thermoelectric element having a plate thickness of 80 um was used instead of using a printing plate for forming a P-type thermoelectric element having a plate thickness of 30 um. A thermoelectric conversion module was prepared and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

<Example 5>
In Example 1, instead of using the printing plate for forming a P-type thermoelectric element having a plate thickness of 30 um and the printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um, the printing plate for forming a P-type thermoelectric element having a plate thickness of 80 um is used. A thermoelectric conversion module was produced in the same manner as in Example 1 except that a printing plate for forming an N-type thermoelectric element having a plate thickness of 50 um was used, and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

<Example 6>
In the first embodiment, the thermoelectric element is printed in the same manner as in the first embodiment except that the P-type thermoelectric element is printed after the N-type thermoelectric element is printed instead of printing the N-type thermoelectric element after printing the P-type thermoelectric element. A conversion module was prepared and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the P-type thermoelectric element was larger than _{the gauge element thickness t ga} of the N-type thermoelectric element.

<Comparative example 1>
In Example 1, instead of using the printing plate for forming a P-type thermoelectric element having a plate thickness of 30 um and the printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um, the printing plate for forming a P-type thermoelectric element having a plate thickness of 150 um is used. A thermoelectric conversion module was produced in the same manner as in Example 1 except that a printing plate for forming an N-type thermoelectric element having a plate thickness of 50 um was used, and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

<Comparative example 2>
In Example 1, instead of using the printing plate for forming a P-type thermoelectric element having a plate thickness of 30 um and the printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um, the printing plate for forming a P-type thermoelectric element having a plate thickness of 150 um is used. , And FIGS. 7A and 7B (However, the printing plate 70 for forming an N-type thermoelectric element in FIG. 7B has three gaps (grooves) 70A and openings (holes) 70B for convenience of illustration. Although there are two, the number of voids (grooves) 70A and openings (holes) 70B is not limited to this. Further, the printing plate 70 for forming an N-type thermoelectric element in FIG. 7B is coated. As shown in (used by reversing 180 ° with respect to the direction Z), a gap (groove) 70A having a plate thickness T of 180 um and a height H of 130 um is formed so that the already formed P-type thermoelectric element can be fitted. A thermoelectric conversion module was produced in the same manner as in Example 1 except that the printing plate 70 for forming an N-type thermoelectric element was used, and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

<Comparative example 3>
In Example 1, instead of using a printing plate for forming a P-type thermoelectric element having a plate thickness of 30 um and an opening of 1 mm × 6 mm and a printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um, the plate thickness is 150 um. A printing plate for forming a P-type thermoelectric element having an opening of 0.8 mm × 6 mm, and a plate thickness T of 180 um as shown in FIGS. 7A and 7B, which is high enough to fit the already formed P-type thermoelectric element. A thermoelectric conversion module was produced in the same manner as in Example 1 except that the printing plate 70 for forming an N-type thermoelectric element in which a gap (groove) 70A having a H of 130 um was formed, and the same measurement and measurement were performed. Evaluation was performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

<Comparative example 4>
In Example 1, instead of using a printing plate for forming a P-type thermoelectric element having a plate thickness of 30 um and an opening of 1 mm × 6 mm and a printing plate for forming an N-type thermoelectric element having a plate thickness of 30 um and an opening of 1 mm × 6 mm. A printing plate for forming a P-type thermoelectric element having a plate thickness of 150 um and an opening of 0.8 mm × 6 mm, and a plate thickness T of 180 um and an opening (hole) 70B as shown in FIGS. 7A and 7B are 0. Except for the use of the N-type thermoelectric element forming printing plate 70, which is 8 mm × 6 mm and has a gap (groove) 70A having a height H of 130 um so that the already formed P-type thermoelectric element can be fitted. , A thermoelectric conversion module was produced in the same manner as in Example 1, and the same measurement and evaluation were performed. _{The gauge element thickness t ga} of the N-type thermoelectric element was larger than _{the gauge element thickness t ga} of the P-type thermoelectric element.

From Table 1, in the thermoelectric conversion modules of Comparative Examples 1 to 4 _{, high electromotive force could not be obtained in any of the comparative examples because the thickness difference t dif} was more than 50 um (less than 0.40 V: evaluation ×). On the other hand, in the thermoelectric conversion modules of Examples 1 to 6 _{, a high electromotive force was obtained because the thickness difference t dif} was 50 um or less in all the examples (0.40 V or more: evaluation 〇).

1A, 1B: Thermoelectric conversion module 2: Support 2a: Support main surface 3: Electrode 3a: First electrode portion (connecting electrode portion)
3b: Second electrode part (electrode part for taking out electromotive force)
3c: Third electrode portion 4: N-type thermoelectric element 5: P-type thermoelectric element 6: Thermoelectric element layer 50: Cross section 51: Boundary line 52: Line segment 53: Line segment 54: Central line segment 54a: End 54b: End 55 : Line segment 56: Line segment 57: Central part 58: End part 59: End part 60: Printing plate (screen plate)
61: Aperture (hole)
70: Print plate (screen version)
70A: Void part (groove)
70B: Aperture (hole)
81: 1st coating layer 82: 2nd coating layer 91: 1st high thermal conductive layer 92: 2nd high thermal conductive layer H: height P: one end Q: other end T: plate thickness t _av : element average thickness t _max : Maximum thickness Y: Direction of arrangement of thermoelectric element Z: Coating direction

Claims (4)

With the support
P-type thermoelectric elements and N-type thermoelectric elements formed on the support are alternately arranged, and adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically arranged so that electrons move in the direction of the arrangement. With a connected thermoelectric element layer,
The thermoelectric element layer is made of a coating film.
The thickness difference defined by the following (1) to (4) in the cross section of at least one of the P-type thermoelectric element and the N-type thermoelectric element along the direction perpendicular to the direction of the arrangement. t _dif is less 50um, the thermoelectric conversion module.
(1) The thickness profile of the thermoelectric element in the cross section is measured by a stylus type surface shape measuring device.
(2) From the measured thickness profile, the average thickness in the central portion excluding both ends of the thermoelectric element is calculated, and the average of the calculated thickness is defined as the element average thickness _tav . However, with respect to the central portion, the length of the boundary line between the thermoelectric element and the support in the cross section is L, and from the boundary line of the length L to 1/6 L inward from one end of the boundary line. Of the thermoelectric elements, the center line is defined as a line segment having a length of 2/3 L, excluding the line segment of 1 and the line segment of 1/6 L inward from the other end of the boundary line. A region portion sandwiched by a line segment extending in the vertical direction of the main surface of the support from both ends of the segment.
(3) From the measured thickness profile, the maximum value of the thickness of the thermoelectric element is detected, and the maximum value of the detected thickness is defined as the maximum thickness t _max .
(4) The thickness difference t _div is defined as the difference between the maximum thickness t _max and the element average thickness t _av (t _div = t _max −t _av ). With the support
P-type thermoelectric elements and N-type thermoelectric elements formed on the support are alternately arranged, and adjacent P-type thermoelectric elements and N-type thermoelectric elements are electrically arranged so that electrons move in the direction of the arrangement. With a connected thermoelectric element layer,
The thermoelectric element layer is made of a thermoelectric semiconductor composition containing thermoelectric semiconductor particles and a resin.
The thickness difference defined by the following (1) to (4) in the cross section of at least one of the P-type thermoelectric element and the N-type thermoelectric element along the direction perpendicular to the direction of the arrangement. t _dif is less 50um, the thermoelectric conversion module.
(1) The thickness profile of the thermoelectric element in the cross section is measured by a stylus type surface shape measuring device.
(2) From the measured thickness profile, the average thickness in the central portion excluding both ends of the thermoelectric element is calculated, and the average of the calculated thickness is defined as the element average thickness _tav . However, with respect to the central portion, the length of the boundary line between the thermoelectric element and the support in the cross section is L, and from the boundary line of the length L to 1/6 L inward from one end of the boundary line. Of the thermoelectric elements, the center line is defined as a line segment having a length of 2/3 L, excluding the line segment of 1 and the line segment of 1/6 L inward from the other end of the boundary line. A region portion sandwiched by a line segment extending in the vertical direction of the main surface of the support from both ends of the segment.
(3) From the measured thickness profile, the maximum value of the thickness of the thermoelectric element is detected, and the maximum value of the detected thickness is defined as the maximum thickness t _max .
(4) The thickness difference t _div is defined as the difference between the maximum thickness t _max and the element average thickness t _av (t _div = t _max −t _av ). Gauge elements is different from the thickness t _ga of the gauge element thickness t _ga and the N-type thermoelectric element of the P-type thermoelectric element,
The thermoelectric conversion module according to claim 1 or 2, wherein the thickness difference t _{dif of the thermoelectric element having a larger gauge element thickness t ga} among the P-type thermoelectric element and the N-type thermoelectric element is 50 μm or less. Gauge elements thickness t _ga are equal gauge element thickness t _ga and the N-type thermoelectric element of the P-type thermoelectric element,
The thermoelectric conversion module according to claim 1 or 2 _{, wherein the thickness difference t div} of both the P-type thermoelectric element and the N-type thermoelectric element is 50 μm or less.

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