Thermoelectric conversion module

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

Technical Field

[0001] The present invention relates to a thermoelectric conversion module, and more particularly to a flexible thermoelectric conversion module.

Background Art

[0002] As energy conversion technologies using thermoelectric conversion, a thermoelectric power generation technology and a Peltier cooling technology are known. The thermoelectric power generation technology is a technology that utilizes the conversion of thermal energy into electrical energy by the Seebeck effect. Since this technology does not require a great deal of cost to operate a thermoelectric conversion element for realizing thermoelectric conversion, it has attracted great attention as an energy-saving technology that can recover unused waste heat energy generated from fossil fuel resources and the like used in facilities such as buildings and factories as electrical energy. The Peltier cooling technology, contrary to thermoelectric power generation, is a technology that utilizes the conversion of electrical energy into thermal energy by the Peltier effect. This technology is used, for example, in wine coolers and portable small refrigerators. In addition, this technology is also used as a cooling means for a CPU used in a computer and as a temperature control means for components and devices that require precise temperature control (for example, a semiconductor laser oscillator for optical communication).

[0003] For example, Patent Document 1 discloses a thermoelectric module (so-called π-type thermoelectric module) including 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, wherein the thermoelectric elements are arranged in pairs, and are composed of N-type thermoelectric elements and P-type thermoelectric elements made of a sintered body, and among the plurality of thermoelectric elements, the difference in height between the thermoelectric element with the maximum height and the thermoelectric element with the minimum height (the difference in height between thermoelectric elements) is 20 μm or less.

[0004] Further, for example, Patent Document 2 discloses a thermoelectric conversion element in which a bonding material reservoir portion can suppress the force that expands the thermoelectric conversion element, and a plurality of thermoelectric conversion elements made of a thermoelectric conversion material bonded to a first electrode layer and a second electrode layer by a bonding material for the purpose of securing a conductive cross-sectional area between the thermoelectric conversion elements. Regarding the height of the plurality of thermoelectric conversion elements (the height between the thermoelectric elements), a thermoelectric conversion element (so-called π-type thermoelectric conversion element) is disclosed in which the difference between the maximum value and the minimum value is set to 0.02 millimeters or less.

[0005] 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 generating a temperature difference in the plane direction of the thermoelectric element layer. Since the in-plane type thermoelectric conversion element can expand the length in which the temperature difference occurs in the plane direction, it can efficiently generate a thermoelectromotive force even if the thermoelectric conversion layer is thin, and by making the thermoelectric conversion layer thin, the entire element can be made thin and flexible.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] In recent years, as thermoelectric conversion elements have become more popular, their use in various environments has been demanded. In particular, since in-plane type thermoelectric conversion elements are generally thin, the range of use environments has further expanded, and it is required that they can be used in various environments. However, in terms of improving the electromotive force, there is still room for improvement in thermoelectric conversion modules having in-plane type thermoelectric conversion elements.

[0008] In view of the above problems, an object of the present invention is to provide a thermoelectric conversion module that improves the heat transfer efficiency by efficiently transferring heat applied from the outside and can obtain a high electromotive force.

Means for Solving the Problems

[0009] As a result of intensive studies to solve the above problems, the present inventors have found that in an in-plane type thermoelectric conversion element, it is not the difference in thickness between elements, but the thickness difference t dif in the thermoelectric element, particularly in the gauge element thickness t ga of the thermoelectric element with the larger thickness among the P-type thermoelectric element and the N-type thermoelectric element dif is adjusted within a predetermined range, and the present invention has been completed by finding that the above problems can be solved. That is, the present invention provides the following [1] to [4]. [1] A support, a thermoelectric element layer in which 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 connected so that electrons move in the direction of the arrangement, wherein the thermoelectric element layer is composed of a coating film, and at least one of the P-type thermoelectric element and the N-type thermoelectric element has a thickness difference t dif defined by the following (1) to (4) in a cross section along the direction perpendicular to the direction of the arrangement, which is 50 μm or less, a thermoelectric conversion module. (1) Measure the thickness profile of the thermoelectric element in the cross section with a stylus surface profiler. (2) Calculate the average thickness at the central portion excluding both ends of the thermoelectric element from the measured thickness profile, and set the calculated average thickness as the element average thickness t av . However, the central portion means a region portion sandwiched by line segments extending in the direction perpendicular to the main surface of the support from both ends of the central line segment of the thermoelectric element when a line segment with a length of 2 / 3L is defined as the central line segment, excluding a line segment from one end of the boundary line to the inside by 1 / 6L and a line segment from the other end of the boundary line to the inside by 1 / 6L, where the length of the boundary line between the thermoelectric element and the support in the cross section is L. (3) Detect the maximum value of the thickness of the thermoelectric element from the measured thickness profile, and define the detected maximum value of the thickness as the maximum thickness t max . (4) Define the thickness difference t dif as the difference (t max ) between the maximum thickness t av and the average element thickness t dif = t max - t av ). [2] A thermoelectric conversion module having a support, a thermoelectric element layer in which 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 connected so that electrons move in the direction of the arrangement, wherein the thermoelectric element layer is made of a thermoelectric semiconductor composition containing thermoelectric semiconductor particles and a resin, and the thickness difference t dif defined by the following (1) to (4) in a cross section along the direction perpendicular to the direction of the arrangement of at least one of the P-type thermoelectric elements and the N-type thermoelectric elements is 50 μm or less. (1) Measure the thickness profile of the thermoelectric element in the cross section with a stylus surface profilometer. (2) Calculate the average of the thicknesses in the central portion excluding both ends of the thermoelectric element from the measured thickness profile, and define the calculated average of the thicknesses as the average element thickness t av . However, the central portion refers to a region portion of the thermoelectric element sandwiched by line segments extending in the direction perpendicular to the main surface of the support from both ends of the central line segment when the central line segment is a line segment with a length of 2 / 3L obtained by excluding line segments from one end of the boundary line to the inside by 1 / 6L and from the other end of the boundary line to the inside by 1 / 6L of the boundary line having a length L of the boundary line between the thermoelectric element and the support in the cross section. (3) Detect the maximum value of the thickness of the thermoelectric element from the measured thickness profile, and define the detected maximum value of the thickness as the maximum thickness t max . (4) Define the thickness difference t dif as the difference (t max ) between the maximum thickness t av and the average element thickness tdif =t max -t av ) shall be used. [3] The gauge element thickness t of the P-type thermoelectric element ga and the gauge element thickness t of the N-type thermoelectric element ga are different, and among the P-type thermoelectric element and the N-type thermoelectric element, for the thermoelectric element with the larger gauge element thickness t ga the thickness difference t dif is 50 μm or less. The thermoelectric conversion module according to [1] or [2] above. [4] The gauge element thickness t of the P-type thermoelectric element ga and the gauge element thickness t of the N-type thermoelectric element ga are equal, and for both the P-type thermoelectric element and the N-type thermoelectric element, the thickness difference t dif is 50 μm or less. The thermoelectric conversion module according to [1] or [2] above.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a thermoelectric conversion module that improves the heat transfer efficiency by efficiently transferring the heat applied from the outside and obtains a high electromotive force.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6A

Figure 6B

Figure 6C

Figure 7A

Figure 7B

[0012] Hereinafter, embodiments of the present invention (hereinafter sometimes referred to as "the present embodiments") will be described. In this 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. Also, in this 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 of the thickness of the other. Also, in this specification, "the thickness of A is greater than the thickness of B" means that the thickness of A is 1.111 times or more of the thickness of B. Furthermore, in this specification, "the thickness of A is less than the thickness of B" means that the thickness of A is 0.900 times or less of the thickness of B.

[0013] [Configuration of Thermoelectric Conversion Module] The thermoelectric conversion module according to an embodiment of the present invention includes a support, a thermoelectric element layer in which 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 connected so that electrons move in the direction of the arrangement. Optionally, it further includes an electrode for electrically connecting the P-type thermoelectric element and the N-type thermoelectric element constituting the thermoelectric element layer, 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) being composed of a coating film and (2) being composed of a thermoelectric semiconductor composition containing thermoelectric semiconductor particles and a resin, and is formed by coating such as screen printing.

[0014] Hereinafter, the configuration of the thermoelectric conversion module according to an embodiment of the present invention will be described with reference to the drawings. All the drawings are schematic and may be exaggerated for easy understanding. FIG. 1 is a partial cross-sectional view showing the configuration of the thermoelectric conversion module according to an 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 the reference IV-IV in FIG. 4 described later. 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, a thermoelectric element layer 6 composed of a P-type thermoelectric element 5 and an N-type thermoelectric element 4 formed on one main surface of the support 2 (the main surface side on the electrode 3 side), a first coating layer 81 laminated on the surface of the thermoelectric element layer 6 opposite to the support 2, a first high thermal conductivity layer 91 provided on the surface of the first coating layer 81 opposite to the thermoelectric element layer 6, a second coating layer 82 laminated on the other main surface of the support 2, and a second high thermal conductivity layer 92 provided on the surface of the second coating layer 82 opposite to the thermoelectric element layer 6. In this embodiment, the support is a substrate remaining 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 the "coating layer". Also, the first high thermal conductivity layer and the second high thermal conductivity layer may be collectively referred to as the "high thermal conductivity layer".

[0015] FIG. 2 is a schematic plan view of a support provided with electrodes in a predetermined array pattern. As shown in FIG. 2, the electrode 3 provided on one main surface of the rectangular support 2 includes a plurality of first electrode portions 3a (connection electrodes) for electrically connecting each column of the plurality of thermoelectric element layers 6 provided in a plurality of columns, and two external connection second electrode portions 3b (thermoelectric power extraction electrodes) serving as terminals for extracting the thermoelectric power from the thermoelectric element layer 6 or applying a voltage to the thermoelectric element layer 6, and a large number of third electrode portions 3c for electrically connecting the P-type thermoelectric elements 5 and the N-type thermoelectric elements 4 arranged in columns adjacent to each other alternately. Each of the electrode portions 3a to 3c is divided and arranged in an island shape.

[0016] FIG. 3 is a plan view showing an arrangement pattern of P-type thermoelectric elements and N-type thermoelectric elements provided on one main surface side of a support provided with electrodes. As shown in FIG. 3, a plurality of columns of the thermoelectric element layer 6 composed of the P-type thermoelectric elements 5 and the N-type thermoelectric elements 4 are arranged side by side. In each column of the thermoelectric element layer 6, the third electrode portion 3c is arranged so as to overlap the joint portion of the adjacent thermoelectric elements 4 and 5 other than the ends. The first electrode portion 3a is arranged so as to be in contact with one end of each column of the thermoelectric element layer 6. The first electrode portion 3a electrically joins the P-type thermoelectric element 5 or the N-type thermoelectric element 4 at one end of a certain column of the thermoelectric element layer 6 and the N-type thermoelectric element 4 or the P-type thermoelectric element 5 at one end of the next column of the thermoelectric element layer 6. The other end of each column of the thermoelectric element layer 6 is similarly electrically joined to the end of the next column of the thermoelectric element layer 6 by the first electrode portion 3a. The thermoelectric elements 4 and 5 at one end in the columns of the thermoelectric element layer 6 located at both ends are respectively connected to the second electrode portion 3b. Thus, the P-type thermoelectric elements 5 and the N-type thermoelectric elements 4 two-dimensionally arranged on the support 2 are electrically connected in series by the respective electrode portions 3a to 3c, and as a result, a current path is formed so as to meander on the main surface of the support 2.

[0017] The shapes of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 are not particularly limited. However, from the perspective of facilitating the alternating arrangement of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 while electrically connecting adjacent thermoelectric element layers 6 to each other, 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. With the thermoelectric elements 4 and 5 having such a shape, while increasing the number of repetitions per unit area of the P-type thermoelectric element 5 and the N-type thermoelectric element 4, the width of the strip-shaped row of the arranged P-type thermoelectric element 5 and N-type thermoelectric element 4 can be increased, and the thermoelectric efficiency can be improved. The length of the short side of the rectangular thermoelectric elements 4 and 5 is preferably 0.3 to 3 mm, and more preferably 0.5 to 2 mm. The length of the long side is preferably 2 to 20 mm, and 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 the direction perpendicular to the direction Y of the arrangement of the thermoelectric elements 4 and 5 in a plan view according to the plan view of FIG. 3, and is usually the coating direction Z when applying a thermoelectric semiconductor composition (coating liquid) onto a support in the "step of forming the thermoelectric element layer 6" described later.

[0018] FIG. 4 is a diagram showing an arrangement pattern of a first high thermal conductivity layer provided on the main surface side of a support including a P-type thermoelectric element and an N-type thermoelectric element. In addition, in FIG. 4, for ease of understanding, the illustration of the first coating layer 81 is omitted. As shown in FIG. 4, the first high thermal conductivity layer 91 is formed in a plurality of stripe shapes arranged so as to intersect the columns of each thermoelectric element layer 6. The first high thermal conductivity layer 91 covers every other junction of the P-type thermoelectric element 5 and the N-type thermoelectric element 4. The second high thermal conductivity layer 92 is also formed in a plurality of stripe shapes intersecting the columns of each thermoelectric element layer 6. Although not shown in FIG. 4, when viewed from a direction perpendicular to the main surface of the support 2, the second high thermal conductivity layer 92 is disposed at a position corresponding to the junction of the thermoelectric elements 4 and 5 not covered by the first high thermal conductivity layer 91. As a result, in the longitudinal cross section in the arrangement direction of the stripe-shaped high thermal conductivity layers 91 and 92, the first high thermal conductivity layer 91 and the second high thermal conductivity layer 92 are arranged alternately with respect to the thermoelectric element layer 6. In the direction perpendicular to the main surface of the support 2, the end in the width direction of the first high thermal conductivity layer 91 and the end in the width direction of the second high thermal conductivity layer 92 may coincide, may overlap, or may be separated.

[0019] In FIGS. 2 and 3, the number of the third electrode portions 3c is 42 (= 7×6 columns), the number of the first electrode portions 3a is 5, and the numbers of the P-type thermoelectric elements 5 and the N-type thermoelectric elements 4 are each 24 (= 4×6 columns). In FIG. 4, the number of the first high thermal conductivity layers 91 is 4, but these numbers can be appropriately changed. The sizes and positions of the respective electrode portions 3 can also be appropriately changed. 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 thereto. The two second electrode portions 3b may be arranged so as to be in contact with different sides of the support 2 according to the application field and use environment of the thermoelectric conversion module.

[0020] In the above embodiment, no layer is provided in the region where the high thermal conductivity layer is not provided on the coating layer. However, for example, a member such as a low thermal conductivity layer may be provided. In this case, the coating layer can also function as a fixing material for members such as a low thermal conductivity layer in addition to the high thermal conductivity layer. From the viewpoint of improving the thermoelectric conversion performance of the thermoelectric conversion module, it is preferable that the thermal conductivity of the low thermal conductivity layer is lower than the thermal conductivity of the high thermal conductivity layer. In addition, when no layer is provided in the region where the high thermal conductivity layer is not provided on the coating layer and the coating layer is exposed, air exists instead of the low thermal conductivity layer. Since the thermal conductivity of air is very low, for example, about 0.02 W / (m·K), it is possible to exhibit thermoelectric conversion performance equal to or better than that in the case where the low thermal conductivity layer is provided.

[0021] FIG. 5 is a partial cross-sectional view of the thermoelectric conversion module along the line indicated by the reference sign III-III in FIG. 3. The cross-section 50 shown in FIG. 5 is a cross-section of the support 2 and the thermoelectric elements 4 and 5 along the direction perpendicular to the arrangement direction of the thermoelectric elements 4 and 5 (i.e., the moving direction of electrons in the thermoelectric element layer 6) (the coating direction Z in FIG. 3). Note that the line indicated by the reference sign III-III in FIG. 3 is a line along the center of the length of the second thermoelectric elements 4 and 5 from the right in the direction Y in FIG. 3. That is, the cross-section of the thermoelectric elements 4 and 5 in FIG. 5 is a cross-section obtained when cutting in the Z direction so as to pass through the center of the length of the thermoelectric elements 4 and 5 in the direction Y (FIG. 3).

[0022] The gauge element thickness t of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 ga When they are different, since heat from the outside of the thermoelectric conversion module 1B preferentially transfers to the thicker thermoelectric element, reducing the thickness difference t dif in the thicker thermoelectric element is preferable in that it can further improve the electromotive force of the thermoelectric element layer 6. On the other hand, when the gauge element thicknesses t ga of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 are equal, since there is no preferential heat transfer as described above, it is preferable to reduce the thickness difference t dif of either the P-type thermoelectric element 5 or the N-type thermoelectric element 4 as well. Here, the gauge element thickness t ga is the thickness of the thermoelectric element obtained by measuring the thickness at one point with a thickness gauge for the thermoelectric element and subtracting the thickness of the support from the measured thickness. Here, the gauge element thickness t gaThe calculation is performed as follows, for example, as shown in the embodiments described later. First, for five thermoelectric elements randomly selected from a plurality of thermoelectric elements in a single support with a thermoelectric element layer, the gauge element thickness t ga is measured, and the first average value, which is the average of the measured values of the five thermoelectric elements, is calculated. Such thickness measurement is performed for three supports with thermoelectric element layers, and the average of the three first average values for the three supports with thermoelectric element layers is calculated as the second average value, and this second average value is taken as the gauge element thickness t ga . Note that there is no particular limitation on the thickness gauge used for measuring the gauge element thickness t ga , and for example, commercially available products such as the digital indicator PC-465J manufactured by Techlock Co., Ltd. can be mentioned.

[0023] The values of the gauge element thickness t ga of the P-type thermoelectric element and the N-type thermoelectric element are not particularly limited, and as described above, the two may have the same thickness or different thicknesses. From the viewpoints of flexibility and material cost, the gauge element thickness t ga of the P-type thermoelectric element and the N-type thermoelectric element is preferably 0.1 to 300 μm, and more preferably 1 to 200 μm.

[0024] Note that when forming the thermoelectric element layer by the screen printing method as follows, the thermoelectric element formed later (the N-type thermoelectric element 4 in FIGS. 6A and 6B) is usually larger in gauge element thickness t ga than the thermoelectric element formed earlier (the P-type thermoelectric element 5 in FIGS. 6A and 6B). 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 disposed above the support 2, and a thermoelectric semiconductor composition (coating liquid) is applied onto the support 2 through the opening (hole portion) 61 of the printing plate 60 and dried, thereby forming one of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 (the P-type thermoelectric element 5 in FIG. 6A) on the support 2. Next, as shown in FIG. 6B, the printing plate 60 is disposed above the support 2 so as not to crush the thermoelectric element (the P-type thermoelectric element 5 in FIG. 6B) already formed on the support 2, and a thermoelectric semiconductor composition (coating liquid) is applied onto the support 2 through the opening (hole portion) 61 of the printing plate 60 and dried, thereby forming the other thermoelectric element of the P-type thermoelectric element 5 and the N-type thermoelectric element 4 (the N-type thermoelectric element 4 in FIG. 6B) on the support 2. Thereafter, annealing treatment is performed. Here, the application direction (application direction Z) of the thermoelectric semiconductor composition is preferably the vertical direction Z with respect to the arrangement direction Y 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 vertical direction Z with respect to the arrangement direction Y of the thermoelectric elements 4 and 5. In this case, when the thermoelectric semiconductor composition is applied in the arrangement direction Y of the thermoelectric elements 4 and 5, the squeegee is likely to catch on the long side of the rectangular pattern of the printing plate, and there may be an obstacle to the application. By setting the application direction Z to the long side direction of the thermoelectric elements 4 and 5, that is, the vertical direction Z with respect to the arrangement direction Y of the thermoelectric elements 4 and 5, such a problem can be avoided and the application can be facilitated.

[0025] Hereinafter, the thickness difference t dif will be described with reference to FIG. 5 for the language necessary to define it. 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. Also, a line segment 52 from one end P of the boundary line 51 to the inside by 1 / 6L and a line segment 53 from the other end Q of the boundary line 51 to the inside by 1 / 6L are removed from the boundary line 51 having a length L, and the line segment having a length of 2 / 3L is defined as the central 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 main surface 2a of the support is defined as the central portion 57. Furthermore, 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.

[0026] Hereinafter, the calculation of the thickness difference t defined in the present invention will be described with reference to FIG. 5. dif (1) First, the thickness profiles of the thermoelectric elements 4 and 5 in the cross section of FIG. 5 are measured with a stylus surface profilometer. Here, the thickness profile is measured for the entire area of the cross section (i.e., the central portion 57 and both end portions 58 and 59). Note that the stylus surface profilometer used for measuring the thickness profile is not particularly limited, and examples thereof include commercially available products such as Dectak150 manufactured by ULVAC, Inc. The measurement frequency of the thickness in the thickness profile is not particularly limited, but it is preferably greater than the frequency per 1 μm (the frequency is less than 1 μm) in terms of obtaining a more accurate thickness profile. Note that the thickness profile is measured as shown in, for example, the examples described later. First, thickness profile measurements are 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 measurements are performed on three substrates with thermoelectric element layers. That is, 15 thickness profiles are obtained. In the present specification, the "substrate with a thermoelectric element layer" is a unit including a substrate as a support and a thermoelectric element layer, and corresponds to the "thermoelectric conversion module" of the present invention. (2) Next, from the measured thickness profiles, the average thickness in the central portion 57 excluding both end portions 58 and 59 of the thermoelectric elements 4 and 5 is calculated for each thickness profile, and the calculated average thickness is defined as the element average thickness t av . (3) Further, from the measured thickness profiles, the maximum value of the thickness of the thermoelectric elements 4 and 5 is detected for each thickness profile, and the detected maximum value of the 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 ​) is calculated for each thickness profile. First, for the five randomly selected thermoelectric elements, the average of the differences between the maximum thickness t max and the average element thickness t av is calculated (i.e., the average of the five differences obtained from the five thickness profiles), and this is taken as the first average value. Further, the average of the three first average values for three substrates with thermoelectric element layers (i.e., the average of the 15 differences obtained from 15 thickness profiles) is calculated, and this is taken as the second average value. This second average value is defined as the thickness difference t dif . Here, the thickness profiles of three substrates with thermoelectric element layers were measured. However, if only two substrates with thermoelectric element layers can be obtained, the thickness profiles of the two substrates with thermoelectric element layers are measured, and the second average value is calculated in the same manner as above. Also, if only one substrate with a thermoelectric element layer can be obtained, the first average value is taken as the second average value.

[0027] In the thermoelectric element layer in the thermoelectric conversion module of the present invention, that is, in the in-plane type thermoelectric element layer formed by alternately forming P-type thermoelectric elements and N-type thermoelectric elements by coating such as screen printing, the thickness difference t dif in at least one of the P-type thermoelectric element and the N-type thermoelectric element is 50 μm or less, so that the heat applied from the outside is efficiently transmitted by the thermoelectric element layer, the heat transfer efficiency between the thermoelectric element layer and the outside of the thermoelectric module can be improved, and the electromotive force can be improved.

[0028] The thickness difference t dif is not particularly limited as long as it is 50 μm or less, but is preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 20 μm 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 during formation may be corrected by pressing, polishing, etc. (i.e., the maximum thickness t max may be reduced), or the viscosity of the thermoelectric semiconductor composition (coating liquid) may be adjusted to reduce the maximum thickness t max . Also, from the viewpoint of further improving the electromotive force, generally, the gauge element thickness t of the thermoelectric elements 4 and 5 ga and the absolute value of the element average thickness t av are preferably increased.

[0029] Although the thermoelectric element layer in the thermoelectric conversion module of the present invention is formed by coating, when coating is performed by a screen printing method using a printing plate having a rectangular opening (hole portion) as in the examples described later, the cross section of the thermoelectric element is usually, as shown in FIG. 5, the maximum thickness t at the end portion 59 on the end side of the coating max exists. Such a tendency is remarkable when the length of the rectangular opening in the coating direction is, for example, 2 mm or more.

[0030] 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 temporary fixing support 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 electrodes and the like in addition to the thermoelectric element layer, and the substrate may further support a coating layer, a high thermal conductivity layer, and the like. As the support, it is preferable to use a plastic film that does not affect the decrease in the electrical 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. When the support is used as a substrate, even when a thin film made of the thermoelectric semiconductor composition described later is annealed, the substrate does not undergo thermal deformation and can maintain the performance of the thermoelectric element layer. From the viewpoint of high heat resistance and dimensional stability, a polyimide film, a polyamide film, a polyetherimide film, a polyaramide film, and a polyamideimide film are preferable, and further, a polyimide film is particularly preferable from the viewpoint of high versatility. The substrate may have an adhesive layer for bonding to the thermoelectric element layer on the surface facing the thermoelectric element layer.

[0031] 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 viewpoints of flexibility, heat resistance, and dimensional stability. Also, the above film preferably has a decomposition temperature of 300 °C or higher.

[0032] 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-like form.

[0033] <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 this arrangement. Here, adjacent P-type thermoelectric elements and N-type thermoelectric elements are preferably electrically connected on the side surface of the element, for example, as shown in FIG. 1. Furthermore, the thermoelectric element layer satisfies at least one of (1) being composed of a coating film and (2) being composed 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.

[0034] (Thermoelectric semiconductor particles) The thermoelectric semiconductor particles used in the thermoelectric element layer are preferably obtained by pulverizing a thermoelectric semiconductor material to a predetermined size using a fine pulverizer or the like.

[0035] The materials constituting the P-type thermoelectric element and the N-type thermoelectric element are not particularly limited as long as they are materials that can generate thermoelectromotive force by applying a temperature difference, and examples of such materials include bismuth-tellurium-based thermoelectric semiconductor materials such as P-type bismuth telluride and N-type bismuth telluride; telluride-based thermoelectric semiconductor materials such as GeTe and PbTe; antimony-tellurium-based thermoelectric semiconductor materials; zinc-antimony-based thermoelectric semiconductor materials such as ZnSb, Zn3Sb2, and Zn4Sb3; silicon-germanium-based thermoelectric semiconductor materials such as SiGe; bismuth selenide-based thermoelectric semiconductor materials such as Bi2Se3; β-FeSi2, CrSi2, MnSi 1.73 Silicide-based thermoelectric semiconductor materials such as Mg2Si; oxide-based thermoelectric semiconductor materials; Heusler materials such as FeVAl, FeVAlSi, and FeVTiAl; sulfide-based thermoelectric semiconductor materials such as TiS2; and skutterudite materials are used. These may be used alone or in combination of two or more. Among these, silicide-based thermoelectric semiconductor materials are preferred from the viewpoint of not containing rare metals whose supply is unstable due to geopolitical issues, and skutterudite materials are preferred from the viewpoint of making it easier to make the thermoelectric conversion module function in a high-temperature environment.

[0036] 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 bismuth telluride or N-type bismuth telluride. P-type bismuth telluride has positive holes as carriers and a positive Seebeck coefficient. For example, Bi X Te3Sb 2-X In this case, X is preferably 0. <X≦0.8であり、より好ましくは0.4≦X≦0.6である。Xが0より大きく0.8以下であるとゼーベック係数と電気伝導率が大きくなり、P型熱電変換材料としての特性が維持されるので好ましい。 In addition, N-type bismuth telluride has electrons as carriers and a negative Seebeck coefficient, for example, Bi2Te 3-Y Se YThose represented by [formula] are preferably used. In this case, Y is preferably 0 ≦ Y ≦ 3 (when Y = 0: Bi2Te3). When Y is 0 or more and 3 or less, the Seebeck coefficient and the electrical conductivity increase, and the characteristics as an N-type thermoelectric conversion material are maintained, which is preferable.

[0037] The blending amount of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass. More preferably, it is 50 to 98% by mass, and still more preferably, it is 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 Peltier coefficient) is large, the decrease in electrical conductivity is suppressed, and only the thermal conductivity decreases, so that high thermoelectric performance is exhibited, and a film having sufficient film strength and flexibility can be obtained, which is preferable.

[0038] 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. If it is within the above range, uniform dispersion becomes easy and the electrical conductivity can be increased. The method for obtaining thermoelectric semiconductor particles by pulverizing the thermoelectric semiconductor material is not particularly limited, and it may be pulverized to a predetermined size by a known fine pulverization device such as a jet mill, a ball mill, a bead mill, a colloid mill, a conical mill, a disk mill, an edge mill, a powder mill, a hammer mill, a pellet mill, a Wiley mill, a roller mill, etc. The average particle size of the thermoelectric semiconductor particles was obtained by measuring with a laser diffraction particle size analyzer (Master Sizer 3000, manufactured by Malvern) and used as the median of the particle size distribution.

[0039] Also, the thermoelectric semiconductor particles are preferably those subjected to annealing treatment (hereinafter sometimes referred to as "annealing treatment A"). By performing annealing treatment A, the crystallinity of the thermoelectric semiconductor particles is improved, and further, the surface oxide film of the thermoelectric semiconductor particles is removed. Therefore, the Seebeck coefficient (absolute value of the Peltier coefficient) of the thermoelectric conversion material increases, and the thermoelectric performance index can be further improved. Annealing treatment A is not particularly limited, but before preparing the thermoelectric semiconductor composition, it is preferably carried out in an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere such as hydrogen, or under vacuum conditions, with the gas flow rate controlled so as not to adversely affect the thermoelectric semiconductor particles. It is more preferably carried out in a mixed gas atmosphere of an inert gas and a reducing gas. The specific temperature conditions depend on the thermoelectric semiconductor particles used, but usually, it is preferably carried out at a temperature below the melting point of the particles and at 100 to 1500 °C for several minutes to several tens of hours.

[0040] (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 film strength of the thermoelectric conversion material. The resin is not particularly limited, but when crystallizing the thermoelectric semiconductor particles by annealing treatment or the like on a thin film composed of the thermoelectric semiconductor composition, it is preferable to use a resin whose various physical properties such as mechanical strength and thermal conductivity as a resin are maintained without being impaired. Examples of the resin include polyamide resin, polyamideimide resin, polyimide resin, polyetherimide resin, polybenzoxazole resin, polybenzimidazole resin, epoxy resin, and copolymers having the chemical structures of these resins. The resin may be used alone or in combination of two or more. Among these, polyamide resin, polyamideimide resin, polyimide resin, and epoxy resin are preferable from the viewpoints of high heat resistance and no adverse effect on the crystal growth of thermoelectric semiconductor particles in the thin film. Polyamide resin, polyamideimide resin, and polyimide resin are more preferable from the viewpoint of more excellent heat resistance. When using a polyimide film as the above-described support, polyimide resin is more preferable as the resin from the viewpoint of adhesion to the polyimide film and the like. In the present specification, the polyimide resin is a general term for polyimide and its precursors (for example, polyamic acid, etc.).

[0041] The resin preferably has a decomposition temperature of 300 °C or higher. If the decomposition temperature is within the above range, as described later, even when a thin film made of a thermoelectric semiconductor composition is annealed, the function as a binder is not lost, and the film strength of the thermoelectric conversion material can be maintained.

[0042] Also, the resin preferably has a mass reduction rate at 300 °C by thermogravimetric measurement (TG) of 10% or less, more preferably 5% or less, and even more preferably 1% or less. If the mass reduction rate is within the above range, as described later, even when a thin film made of a thermoelectric semiconductor composition is annealed, the function as a binder is not lost, and the film strength of the thermoelectric conversion material can be maintained.

[0043] 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 even more preferably 0.7 to 20% by mass. If the blending amount of the resin is within the above range, a film with both high thermoelectric performance, printability, and film strength can be easily obtained.

[0044] (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 in a liquid state in a wide temperature range of -50 or higher and less than 400 °C. The ionic liquid has characteristics such as an extremely low vapor pressure and being non-volatile, excellent thermal stability and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive auxiliary agent, it can effectively suppress the reduction of the electrical conductivity between thermoelectric semiconductor particles. In addition, the ionic liquid exhibits high polarity based on its aprotic ionic structure and has excellent compatibility with resins, so it can make the electrical conductivity of the thermoelectric conversion material uniform.

[0045] As the ionic liquid, those known or commercially available can be used. For example, nitrogen-containing cyclic cation compounds such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, imidazolium and their derivatives; tetraalkylammonium-based amine cations and their derivatives; phosphine-based cations such as phosphonium, trialkylsulfonium, tetraalkylphosphonium and their derivatives; lithium cation and its derivatives, etc. as the cation component, and Cl - , Br - , I - , AlCl4 - , Al2Cl7 - , BF4 - , PF6 - , ClO4 - , NO3 - , CH3COO - , CF3COO - , CH3SO3 - , CF3SO3 - , (FSO2)2N - , (CF3SO2)2N - , (CF3SO2)3C - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , F(HF) n - , (CN)2N - , C4F9SO3 - , (C2F5SO2)2N -, C3F7COO - , (CF3SO2)(CF3CO)N - Examples include those composed of anionic components such as these.

[0046] Among the above ionic liquids, from the viewpoints of high-temperature stability, compatibility with thermoelectric semiconductor particles and resin, suppression of the decrease in electrical conductivity in the thermoelectric semiconductor particle gaps, etc., it is preferable that the cationic component of the ionic liquid contains at least one selected from pyridinium cations and their derivatives, imidazolium cations and their derivatives.

[0047] Specific examples of ionic liquids in which the cationic component contains a pyridinium cation and its derivatives include 4-methyl-butylpyridinium chloride, 3-methyl-butylpyridinium chloride, 4-methyl-hexylpyridinium chloride, 3-methyl-hexylpyridinium chloride, 4-methyl-octylpyridinium chloride, 3-methyl-octylpyridinium chloride, 3,4-dimethyl-butylpyridinium chloride, 3,5-dimethyl-butylpyridinium chloride, 4-methyl-butylpyridinium tetrafluoroborate, 4-methyl-butylpyridinium hexafluorophosphate, 1-butylpyridinium bromide (N-butylpyridinium bromide), 1-butyl-4-methylpyridinium bromide, 1-butyl-4-methylpyridinium hexafluorophosphate, etc. 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.

[0048] In addition, specific examples of the ionic liquid in which the cation component includes an imidazolium cation and its derivatives are [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-methylimidazolium chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium bromide, 1-dodecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-methyl-3-butylimidazolium methyl sulfate, 1,3-dibutylimidazolium methyl sulfate, and the like. 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 preferred.

[0049] The above ionic liquid preferably has an electric conductivity of 10 -7 S / cm or more. If the ionic conductivity is within the above range, as a conductive auxiliary agent, it is possible to effectively suppress the reduction of the electric conductivity between the thermoelectric semiconductor particles.

[0050] In addition, the above ionic liquid preferably has a decomposition temperature of 300 °C or higher. If the decomposition temperature is within the above range, as will be described later, even when a thin film made of a thermoelectric semiconductor composition is annealed, the effect as a conductive auxiliary agent can be maintained.

[0051] Further, the ionic liquid preferably has a mass reduction rate of 10% or less, more preferably 5% or less, and even more preferably 1% or less at 300 °C as measured by thermogravimetry (TG). If the mass reduction rate is within the above range, as described later, even when a thin film made of a thermoelectric semiconductor composition is annealed, the effect as a conductive auxiliary agent can be maintained.

[0052] 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 even more preferably 1.0 to 20% by mass. If the blending amount of the ionic liquid is within the above range, a decrease in electrical conductivity can be effectively suppressed, and a film having high thermoelectric performance can be obtained.

[0053] (Inorganic ionic compound) The inorganic ionic compound contained in the thermoelectric element layer is a compound composed of at least a cation and an anion. 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 suppress a decrease in electrical conductivity between thermoelectric semiconductor particles as a conductive auxiliary agent.

[0054] As the cation constituting the inorganic ionic compound, a metal cation is used. Examples of the metal cation include an alkali metal cation, an alkaline earth metal cation, a typical metal cation, and a transition metal cation, and an alkali metal cation or an alkaline earth metal cation is more preferable. Examples of the alkali metal cation include Li + , Na + , K + , Rb + , Cs + and Fr + and the like. Examples of the alkaline earth metal cation include Mg 2+ , Ca 2+ , Sr 2+ and Ba 2+ and the like.

[0055] Examples of the anion constituting the inorganic ionic compound include F - , Cl - , Br - , I - , OH - , CN - , NO3 - , NO2 - , ClO - , ClO2 - , ClO3 - , ClO4 - , CrO4 2- , HSO4 - , SCN - , BF4 - , PF6 - and the like.

[0056] As the inorganic ionic compound contained in the thermoelectric element layer, known or commercially available ones can be used. For example, a cation component such as a potassium cation, a sodium cation, or a lithium cation, and Cl - , AlCl4 - , Al2Cl7 - , ClO4 - and other chloride ions, Br - and other bromide ions, I - and other iodide ions, BF4 - , PF6 - and other fluoride ions, F(HF) n - and other halide anions, NO3 - , OH - , CN - and the like.

[0057] Among the above inorganic ionic compounds, from the viewpoints of high-temperature stability, compatibility between the thermoelectric semiconductor particles and the resin, suppression of the decrease in the electrical conductivity of the gaps between the thermoelectric semiconductor particles, etc., it is preferable that the cation component of the inorganic ionic compound contains at least one selected from potassium, sodium, and lithium. Further, it is preferable that the anion component of the inorganic ionic compound contains a halide anion, and Cl - , Br - , and I- It is more preferable to further contain at least one selected from

[0058] Specific examples of the inorganic ionic compound in which the cation component contains potassium cations include KBr, KI, KCl, KF, KOH, K2CO3, etc. 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 in which the cation component contains sodium cations include NaBr, NaI, NaOH, NaF, Na2CO3, etc. 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 in which the cation component contains lithium cations include LiF, LiOH, LiNO3, etc. These may be used alone or in combination of two or more. Among these, LiF and LiOH are preferable.

[0059] The above inorganic ionic compound preferably has an electrical conductivity of 10 -7 S / cm or more, and more preferably 10 -6 S / cm or more. If the electrical conductivity is within the above range, as a conductive auxiliary agent, the reduction of the electrical conductivity between the thermoelectric semiconductor particles can be effectively suppressed.

[0060] Also, the above inorganic ionic compound preferably has a decomposition temperature of 400 °C or higher. If the decomposition temperature is within the above range, as described later, even when a thin film made of a thermoelectric semiconductor composition is annealed, the effect as a conductive auxiliary agent can be maintained.

[0061] Also, the above inorganic ionic compound preferably has a mass reduction rate at 400 °C by thermogravimetric measurement (TG) of 10% or less, more preferably 5% or less, and even more preferably 1% or less. If the mass reduction rate is within the above range, as described later, even when a thin film made of a thermoelectric semiconductor composition is annealed, the effect as a conductive auxiliary agent can be maintained.

[0062] The compounding 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 still more preferably 1.0 to 10% by mass. If the compounding amount of the inorganic ionic compound is within the above range, a decrease in electrical conductivity can be effectively suppressed, and as a result, a film with improved thermoelectric performance can be obtained. In addition, 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 0.5 to 30% by mass, and still more preferably 1.0 to 10% by mass.

[0063] <Electrode> The electrode is 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 to the outside. Various electrode materials can be used for the electrode. From the viewpoints 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 those obtained by laminating these metals or alloys. The thickness of the electrode is preferably 1 μm to 50 μm, more preferably 2.5 μm to 30 μm, and still more preferably 3 μm to 20 μm. If the thickness of the electrode is within the above range, the electrical conductivity is high and the resistance is low, and the total electrical resistance value of the thermoelectric element layer can be suppressed low. In addition, sufficient strength can be obtained as an electrode. Furthermore, the volume of the electrode can be increased, and even if diffusion of the metal element constituting the electrode into the thermoelectric element occurs during use, a decrease in the performance of the electrode can be suppressed. Moreover, the electrode is 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 likely to be stable.

[0064] <High thermal conductivity layer> As the high thermal conductivity layer, one having excellent thermal conductivity and a thermal conductivity greater than that of the coating layer is used. It is preferable to use a high thermal conductivity layer having a thermal conductivity of 5 to 500 W / (m·K), more preferably 15 to 420 W / (m·K), and even more preferably 300 to 420 W / (m·K). 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, more preferably any one of copper, aluminum, silver, and nickel, even more preferably any one of copper, aluminum, and silver, and still more preferably any one of copper and aluminum. The high thermal conductivity layer is arranged in patterns such as stripe shape, lattice shape, honeycomb shape, comb shape, matrix shape, etc. This makes it easier to generate a temperature difference in the plane direction of the thermoelectric conversion module, and by exposing the boundary portion 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 heat absorption performance of the thermoelectric conversion module can be improved. As also described in FIG. 4, the first high thermal conductivity layer is arranged on one surface side of the thermoelectric element layer so as to cover every other joint between the P-type thermoelectric element and the N-type thermoelectric element, and the second high thermal conductivity layer is arranged at a position corresponding to the joint of the thermoelectric element not covered by the first high thermal conductivity layer when viewed from a direction perpendicular to the main surface of the support (substrate). In the longitudinal section in the arrangement direction of the high thermal conductivity layer, it is preferable that the first high thermal conductivity layer and the second high thermal conductivity layer are arranged alternately with respect to the thermoelectric element layer. From the viewpoints of flexibility, heat dissipation, and dimensional stability, the thickness of the high thermal conductivity layer is preferably 40 to 550 μm, more preferably 60 to 530 μm, and even more preferably 80 to 510 μm. When providing two high thermal conductivity layers, namely the first high thermal conductivity layer 91 and the second high thermal conductivity layer 92, these may be of the same material or different materials, and these may have the same thickness or different thicknesses.

[0065] <Coating layer> The coating layer is arranged to cover the thermoelectric element layer. By arranging the coating layer in this way, it is not necessary to pattern and form the coating layer, so the productivity is excellent. Further, when a member such as a low thermal conductivity layer is not provided in a region where the high thermal conductivity layer of the thermoelectric element layer is not provided, if the coating layer does not cover the thermoelectric element layer, the thermoelectric element layer will be exposed. However, since the coating layer covers the thermoelectric element layer, in a region where the high thermal conductivity layer does not exist, the coating layer can protect the thermoelectric element layer.

[0066] When providing two coating layers such as the first coating layer 81 and the second coating layer 82 described above, these may be of the same material or different materials.

[0067] The second coating layer 82 laminated on the surface of the support 2 (substrate) opposite to the surface on the thermoelectric element layer 6 side may be a single layer or a multi-layer structure. Further, the second coating layer 82 may be eliminated from the thermoelectric conversion module, and a second high thermal conductivity layer may be directly provided on the back surface of the support 2.

[0068] When using a single-layer coating layer, it preferably has adhesiveness itself and can adhere and fix the high thermal conductivity layer to the thermoelectric element layer. Further, when this single-layer coating layer itself is a sealing layer, and as described later, is a layer having a water vapor transmission rate within a predetermined range or a layer made of a composition containing a polyolefin-based resin, it is more preferable because the coating layer covers the thermoelectric element layer and functions as a member for sealing the thermoelectric element layer. When using a single-layer coating layer, since the number of layers in the thermoelectric conversion module is small, the configuration of the thermoelectric conversion module can be simplified, and the manufacturing process of the thermoelectric conversion module can also be simplified. Further, since the overall thickness of the coating layer can be reduced, the efficiency of heat exchange between the high thermal conductivity layer and the thermoelectric element layer can be increased.

[0069] When the thermoelectric conversion module has a coating layer including a plurality of layers, there is an advantage that it becomes easy to distribute a plurality of functions, such as a function of adhering the high thermal conductivity layer and the thermoelectric element layer and a function of sealing, to each layer. For example, by imparting gas barrier properties to the auxiliary substrate layer, which will be 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, respectively, it is possible to easily achieve both the gas barrier function and the adhesion function. In this case, if at least one of the inner layer and the outer layer also serves as a sealing layer, the durability of the thermoelectric conversion module can be expected to be improved by the gas barrier property of the auxiliary substrate layer and the sealing property of the inner layer and / or the outer layer that is the sealing layer. When the thermoelectric conversion module has the first coating layer 81, the thickness difference t of the thermoelectric elements dif is considered to cause a more significant decrease in thermoelectric efficiency due to its large size. The reason is presumably that the large thickness difference t dif reduces the adhesiveness between the coating layer and the thermoelectric element layer and inhibits the heat conduction between the thermoelectric element layer and the outside air.

[0070] From the viewpoint of enabling efficient heat conduction between the high thermal conductivity layer and the thermoelectric element layer, the total thickness of the coating layer is preferably 1 to 200 μm, and more preferably 5 to 175 μm.

[0071] 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 conductivity layers, i.e., the first high thermal conductivity layer 91 and the second high thermal conductivity layer 92, it is possible to efficiently generate a temperature difference in the plane of the thermoelectric conversion module, which is a preferable configuration. However, for example, when it is required to increase the area of the thermoelectric conversion module or to simplify the configuration of the thermoelectric conversion module as much as possible, it is also possible to omit the second high thermal conductivity layer 92.

[0072] [Method for manufacturing a thermoelectric conversion module] As an example of the method for manufacturing a thermoelectric conversion module according to the present embodiment, a coating layer is formed on a thermoelectric element layer, and a high thermal conductivity 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 on which electrodes 3 are arranged in a pattern, as shown in FIG. 3, a step of forming a thermoelectric element layer 6 composed of a P-type thermoelectric element 5 and an N-type thermoelectric element 4 on one surface of the support 2, a step of forming a first coating layer 81 on the surface of the thermoelectric element layer 6, as shown in FIG. 4, a step of forming a first high thermal conductivity layer 91 on at least a part of the surface of the first coating layer 81, and a step of forming a second high thermal conductivity layer 92 on the other surface of the support 2 are included. Hereinafter, each step will be sequentially described with reference to the drawings.

[0073] <Step of preparing a support on which electrodes are formed> In the method for manufacturing a thermoelectric conversion module, for example, as shown in FIG. 2, first, a support 2 having electrodes 3 of a predetermined pattern formed on one main surface is prepared. In order to prepare a support on which electrodes are formed, electrodes may be formed on the support 2 using the above-described electrode material or the like. As a method for forming electrodes on a support, after providing electrodes on which no pattern is formed on the support, a known physical treatment or chemical treatment (for example, wet etching) mainly using a photolithography method, 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 can be mentioned. As a method for forming electrodes on which no pattern is formed, PVD (physical vapor deposition method) such as vacuum evaporation method, sputtering method, ion plating method, or CVD (chemical vapor deposition method) such as thermal CVD, atomic layer deposition (ALD), etc., which are dry processes, or various coating methods such as dip coating method, spin coating method, spray coating method, gravure coating method, die coating method, doctor blade method, and wet processes such as electrodeposition method, silver salt method, electrolytic plating method, electroless plating method, lamination of metal foil, etc. can be mentioned, and they are appropriately selected according to the material of the electrodes.

[0074] <Step of forming a thermoelectric element layer> Next, as shown in FIG. 3, on one main surface of the support 2 on which the electrodes 3 are pattern-arranged, a thermoelectric element layer 6 composed of a P-type thermoelectric element 5 and an N-type thermoelectric element 4 is formed using a thermoelectric semiconductor composition. The thermoelectric element layer 6 is formed, for example, by applying a varnish, ink, etc. in which each material of the above-described thermoelectric semiconductor composition is dissolved or dispersed in a solvent onto the support. As a method for applying the thermoelectric semiconductor composition onto the support, known methods such as screen printing, flexographic printing, gravure printing, spin coating, dip coating, die coating, spray coating, bar coating, doctor blade, etc. can be used, and there is no particular limitation. When forming the coating film in a pattern, screen printing, which enables easy pattern formation using a screen plate (printing plate) having a desired pattern, is preferably used. The specific embodiment of forming the thermoelectric element layer by the screen printing method is as described above. Next, a thin film is formed by drying the obtained coating film. As a drying method for the coating film, conventionally known drying methods such as hot air drying, hot roll drying, infrared irradiation, etc. 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. Also, when preparing the thermoelectric semiconductor composition using a solvent, the heating temperature for drying the coating film of this composition is not particularly limited as long as it is within the temperature range capable of drying the used solvent. Furthermore, annealing treatment may be performed on the obtained coating film. The annealing treatment can be performed under the same conditions as the above-described annealing treatment A. Note that after forming the thermoelectric element layer, the thermoelectric element layer may be peeled off from the support 2 and replaced, for example, with another support (substrate) having low heat resistance.

[0075] <Step of forming the first coating layer> Next, a 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 a coating layer formed in advance on a release sheet may be bonded to the thermoelectric element layer to transfer the coating layer to the thermoelectric element layer for formation.

[0076] When the coating layer is composed of a plurality of layers, a coating layer including a 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 laminated on the thermoelectric element layer to form a coating layer composed of a plurality of layers on the thermoelectric element layer.

[0077] <Step of forming the first high thermal conductivity layer> The first high thermal conductivity layer 91 is formed on at least a part of the surface of the first coating layer 81. The first high thermal conductivity layer 91 may be provided on the coating layer 81 formed on the thermoelectric element layer 6, or after providing the first high thermal conductivity layer 91 on the coating layer 81, the coating layer 81 with the first high thermal conductivity layer 91 may be provided on the support 2.

[0078] <Step of forming the second high thermal conductivity layer> The second high thermal conductivity 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 conductivity layer 92 may be provided, or the second coating layer 82 with the second high thermal conductivity layer 92 may be provided on the other surface of the support 2. By using a support on which the second high thermal conductivity layer 92 is directly formed by vapor deposition, sputtering, printing, etc., a thermoelectric conversion module in which the high thermal conductivity layer is provided in direct contact with the support can be obtained.

Example

[0079] Next, specific examples of the present invention will be described, but the present invention is not limited by these examples. The thickness difference evaluation and the electromotive force evaluation in the examples and comparative examples described later were performed according to the following procedures.

[0080] [Thickness difference evaluation] After arranging the P-type thermoelectric element and the N-type thermoelectric element and before performing the annealing treatment, for the thermoelectric element formed on the substrate with the thermoelectric element, the thickness was measured at one point using a thickness gauge (manufactured by Techlock Co., Ltd., digital indicator PC-465J), and the thickness of the thermoelectric element was obtained by subtracting the thickness of the substrate (50 μm) from the measured thickness. In obtaining the thickness of the thermoelectric element, first, the thickness was measured for 5 thermoelectric elements randomly selected from a plurality of thermoelectric elements in one substrate with a thermoelectric element layer, and the first average value, which is the average of the measured values of the 5 thermoelectric elements, was calculated. Such thickness measurement was performed for 3 substrates with thermoelectric element layers, and the average of the 3 first average values for the 3 substrates with thermoelectric element layers was calculated as the second average value, and this second average value was taken as the gauge element thickness t ga and used as such.

[0081] Next, a substrate with a thermoelectric element similar to the above substrate with a thermoelectric element layer was bonded 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, the element with a larger gauge element thickness t ga (hereinafter, the element with a larger gauge element thickness t ga is also referred to as the "thicker element".) (Examples 1 to 5 and Comparative Examples 1 to 4: N-type thermoelectric element, Example 6: P-type thermoelectric element), the thickness profile of the cross-section along the direction perpendicular to the arrangement direction of the thermoelectric element (the coating directions of the coating liquid (P) and the coating liquid (N) described later) was measured using a stylus-type surface shape measuring instrument (manufactured by Ulvac, Dectak150). The measurement frequency was set to every 0.4 μm. The measurement site was the part where no electrode was provided. The average of the thicknesses at the central part excluding both ends of the thermoelectric element was calculated, and this calculated average of the thicknesses was taken as the element average thickness t av and used as such. The central part is the region defined as described above. The measurement of the thickness profile was first performed for 5 thermoelectric elements randomly selected from a plurality of thermoelectric elements in one substrate with a thermoelectric element layer. As a result, 5 element average thicknesses t av were obtained. Such measurement of the thickness profile was performed for 3 substrates with thermoelectric element layers. As a result, 15 element average thicknesses t avwas obtained. Further, from the 15 measured thickness profiles, the maximum value of the thickness of the thermoelectric element (the thickness at the thickest part) was detected for each thickness profile, and the detected maximum value of the thickness was defined as the maximum thickness t max Thereafter, 15 maximum thicknesses t max were obtained. Further, the average of the difference between the maximum thickness t max and the average element thickness t av was calculated for the above-mentioned five randomly selected thermoelectric elements, and defined as the first average value (i.e., the average of the five differences obtained from the five thickness profiles). Such calculation was performed for the above-mentioned three substrates with thermoelectric element layers, and the average of the three first average values for the three substrates with thermoelectric element layers was calculated and defined as the second average value (i.e., the average of the 15 differences obtained from the 15 thickness profiles), and this second average value was defined as the thickness difference t dif . The results are shown in Table 1.

[0082] [Thermoelectric Power Evaluation] For the thermoelectric conversion modules fabricated in the examples and comparative examples, with a temperature difference of 20 °C applied by a hot plate and a water-cooled chiller (the set temperatures of the hot plate and the water-cooled chiller were adjusted so that the temperature difference was 20 °C), the thermoelectric power between the extraction electrodes was measured using a digital high tester (manufactured by Hioki E.E. Corporation, model name: 3801-50). When the thermoelectric power between the extraction electrodes was 0.4 V or more, it was regarded as (○: acceptable), and when it was less than 0.4 V, it was regarded as (×: defective). Note that the measurement of the thermoelectric power was performed while installing thermocouples on both sides of the fabricated thermoelectric conversion module and measuring the actual measured value of the temperature difference between the high-temperature side and the low-temperature side. Note that when the actual measured value of the temperature difference did not match 20 °C and a difference within ±5 °C occurred, based on the proportional relationship between the thermoelectric power and the temperature difference, the thermoelectric power measured as described above was corrected and calculated to be equivalent to 20 °C. The results are shown in Table 1.

[0083] [Fabrication of Thermoelectric Conversion Module] [Example 1] (Fabrication of Thermoelectric Semiconductor Particles) P-type bismuth telluride Bi, which is a bismuth-tellurium-based thermoelectric semiconductor material 0.4 Te3Sb 1.6(Manufactured by High-Purity Chemical Research Institute, particle size: 90 μm) was pulverized using a planetary ball mill (manufactured by Fritsch Japan, Premium line P-7) under a nitrogen gas atmosphere to produce thermoelectric semiconductor fine particles T1 with an average particle size of 2.5 μm as thermoelectric semiconductor particles. Also, N-type bismuth telluride Bi2Te3, which is a bismuth-tellurium-based thermoelectric semiconductor material (manufactured by High-Purity Chemical Research Institute, particle size: 90 μm), was pulverized in the same manner as above to produce thermoelectric semiconductor fine particles T2 with an average particle size of 2.5 μm as thermoelectric semiconductor particles. The average particle sizes of T1 and T2 were obtained by measuring the particle size distribution of the thermoelectric semiconductor particles obtained by pulverization using a laser diffraction particle size analyzer (manufactured by Malvern, Mastersizer 3000).

[0084] (Preparation of thermoelectric semiconductor composition) 94.6 parts by mass of the obtained fine particles T1 of the P-type bismuth-tellurium-based thermoelectric semiconductor material, 2.9 parts by mass (in terms of solid content) of a polyamideimide solution as a resin (manufactured by Arakawa Chemical Industries, Ltd., product name: Compolasen AI301, solvent: N-methylpyrrolidone, solid content concentration: 18% by mass), and 2.5 parts by mass of N-butylpyridinium bromide as an ionic liquid were mixed and dispersed to prepare a coating liquid (P) composed of a thermoelectric semiconductor composition. Also, 95.0 parts by mass of the obtained fine particles T2 of the N-type bismuth-tellurium-based thermoelectric semiconductor material, 2.7 parts by mass (in terms of solid content) of a polyamideimide solution as a resin (manufactured by Arakawa Chemical Industries, Ltd., product name: Compolasen AI301, solvent: N-methylpyrrolidone, solid content concentration: 18% by mass), and 2.3 parts by mass of N-butylpyridinium bromide as an ionic liquid were mixed and dispersed to prepare a coating liquid (N) composed of a thermoelectric semiconductor composition.

[0085] (Formation and arrangement of electrodes) According to the following procedure, a substrate provided with electrodes in an arrangement pattern according to FIGS. 2 and 3 described above was fabricated. Note that FIGS. 2 and 3 conceptually show the arrangement of the electrodes and the thermoelectric elements, and the number is different from the actually fabricated electrodes and thermoelectric elements. First, a polyimide film substrate with a copper foil attached (manufactured by Ube Eximer Co., Ltd., product name: Yupisel N, polyimide substrate thickness: 50 μm, copper foil: 9 μm) was prepared. Then, the copper foil on this polyimide film substrate was wet-etched using a ferric chloride solution to form electrodes arranged in an arrangement pattern corresponding to the arrays 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 each boundary between adjacent P-type and N-type thermoelectric elements in the arrangement of the thermoelectric elements described later. On the patterned copper foil, a nickel layer (thickness: 3 μm) was selectively laminated by electroless plating, and then a gold layer (thickness: 400 nm) was selectively laminated on the nickel layer by electroless plating to form electrodes.

[0086] (Formation of thermoelectric element layer) The coating liquid (P) prepared above was applied onto the polyimide film on which the electrodes were formed by screen printing using a printing plate for forming P-type thermoelectric elements with a plate thickness of 30 μm and an opening of 1 mm × 6 mm, with the vertical direction Z in the direction Y of the arrangement of the thermoelectric elements 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. 6A and 6C (the printing plate 60 in FIG. 6C has 3 openings (holes) 61 for the sake of clarity in illustration, but the number of openings (holes) 61 is not limited to this)). Next, similarly, the coating liquid (N) prepared above was applied onto the polyimide film by screen printing using a printing plate for forming N-type thermoelectric elements with a plate thickness of 30 μm and an opening of 1 mm × 6 mm, with the vertical direction Z in the direction Y of the arrangement of the thermoelectric elements 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). Furthermore, 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 vol%:97 vol%), held at 325 °C for 30 minutes, and annealed after thin film formation to cause crystal growth of the fine particles of the thermoelectric semiconductor material, thereby fabricating P-type and N-type thermoelectric elements.

[0087] (Arrangement of thermoelectric elements) On the electrodes on the polyimide film substrate, a P-type thermoelectric element of 1 mm × 6 mm and an N-type thermoelectric element of 1 mm × 6 mm were alternately formed by coating with coating liquid (P) and coating liquid (N). 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 the side with a length of 6 mm to form one pair. In this way, 380 pairs of P-type thermoelectric elements and N-type thermoelectric elements were provided in the plane of the polyimide film substrate so as to be electrically in series, and a thermoelectric element layer was fabricated in an arrangement similar to the arrangement of the thermoelectric elements in FIG. 3. As a result, electrons move in the direction of the arrangement of the thermoelectric elements inside the thermoelectric element layer composed of P-type thermoelectric elements and N-type thermoelectric elements. The thermoelectric element layer has a folded structure. At this time, 38 pairs of P-type thermoelectric elements and N-type thermoelectric elements connected together were taken as one row, and 10 rows of this were provided. The interval between each row of the thermoelectric element layer is 1 mm, the connecting electrode for each row of the thermoelectric element layer is 0.55 mm × 13 mm, and the electrode for extracting the electromotive force is 12.775 mm × 6 mm. In addition, the gauge element thickness t of the N-type thermoelectric element ga is larger than the gauge element thickness t of the P-type thermoelectric element ga .

[0088] (Formation of the coating layer and the high thermal conductivity layer) An aluminum-evaporated PET film (manufactured by Mitsubishi Shindoh Co., Ltd., thickness: 12 μm) was used as the insulating layer, and a coating layer having a structure in which adhesive layers (manufactured by Somal Co., Ltd., product name: EP-0002EF-01MB, thickness: 25 μm) were laminated on both sides thereof was fabricated. The lamination was performed at a temperature of 50°C. On the upper surface of the fabricated substrate with a thermoelectric element layer (the surface of the thermoelectric element layer), via the above coating layer, and on the lower surface of the substrate with a thermoelectric element layer (the surface of the substrate opposite to the side where the thermoelectric element layer is provided), via a coating layer composed of a single-layer adhesive layer (manufactured by Somal Co., trade name: EP-0002EF-01MB, thickness: 25 μm), respectively, a high thermal conductivity layer (C1020, thickness: 200 μm, width: 1 mm, length: 100 mm, interval: 1 mm, thermal conductivity: 398 (W / m·K)) made of a striped high thermal conductivity material (copper foil) was arranged. At this time, the striped high thermal conductivity layers were arranged alternately on the upper part (the surface of the thermoelectric element) and the lower part (the surface of the substrate opposite to the side where the thermoelectric element layer is provided) of the part where the P-type thermoelectric element and the N-type thermoelectric element are adjacent. In addition, the coating layer provided on the surface of the substrate with a thermoelectric element layer was arranged so that the aluminum vapor deposition formation surface of the aluminum vapor deposition PET film was distal from the thermoelectric element layer. The lamination of the coating layer on the thermoelectric element layer, the lamination of the adhesive layer on the substrate, and the lamination of the high thermal conductivity layer on the coating layer and the adhesive layer were all performed at a temperature of 80 °C. Thereafter, 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.

[0089] <Example 2> In Example 1, a thermoelectric conversion module was fabricated in the same manner as in Example 1, except that a printing plate for forming an N-type thermoelectric element with a plate thickness of 50 μm was used instead of a printing plate for forming an N-type thermoelectric element with a plate thickness of 30 μm, and the same measurements and evaluations were performed. Note that 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.

[0090] <Example 3> In Example 1, a thermoelectric conversion module was fabricated in the same manner as in Example 1, except that a printing plate for forming an N-type thermoelectric element with a plate thickness of 110 μm was used instead of a printing plate for forming an N-type thermoelectric element with a plate thickness of 30 μm, and the same measurements and evaluations were performed. Note that the gauge element thickness t ga of the N-type thermoelectric element was larger than the gauge element thickness t of the P-type thermoelectric element.ga was larger than

[0091] <Example 4> In Example 1, a thermoelectric conversion module was fabricated in the same manner as in Example 1, except that a printing plate for forming a P-type thermoelectric element with a plate thickness of 80 µm was used instead of a printing plate for forming a P-type thermoelectric element with a plate thickness of 30 µm, and the same measurements and evaluations were performed. Note that the gauge element thickness t of the N-type thermoelectric element ga was larger than the gauge element thickness t of the P-type thermoelectric element ga was larger than

[0092] <Example 5> In Example 1, a thermoelectric conversion module was fabricated in the same manner as in Example 1, except that a printing plate for forming a P-type thermoelectric element with a plate thickness of 80 µm and a printing plate for forming an N-type thermoelectric element with a plate thickness of 50 µm were used instead of a printing plate for forming a P-type thermoelectric element with a plate thickness of 30 µm and a printing plate for forming an N-type thermoelectric element with a plate thickness of 30 µm, and the same measurements and evaluations were performed. Note that the gauge element thickness t of the N-type thermoelectric element ga was larger than the gauge element thickness t of the P-type thermoelectric element ga was larger than

[0093] <Example 6> In Example 1, a thermoelectric conversion module was fabricated in the same manner as in Example 1, except that the P-type thermoelectric element was printed after the N-type thermoelectric element was printed, and the same measurements and evaluations were performed. Note that the gauge element thickness t of the P-type thermoelectric element ga was larger than the gauge element thickness t of the N-type thermoelectric element ga was larger than

[0094] <Comparative Example 1> In Example 1, a thermoelectric conversion module was fabricated in the same manner as in Example 1, except that a printing plate for forming a P-type thermoelectric element with a plate thickness of 150 µm and a printing plate for forming an N-type thermoelectric element with a plate thickness of 50 µm were used instead of a printing plate for forming a P-type thermoelectric element with a plate thickness of 30 µm and a printing plate for forming an N-type thermoelectric element with a plate thickness of 30 µm, and the same measurements and evaluations were performed. Note that the gauge element thickness t of the N-type thermoelectric elementga was larger than the gauge element thickness t of the P-type thermoelectric element. ga

[0095] <Comparative Example 2> In Example 1, instead of using a printing plate for forming a P-type thermoelectric element with a plate thickness of 30 μm and a printing plate for forming an N-type thermoelectric element with a plate thickness of 30 μm, a printing plate for forming a P-type thermoelectric element with a plate thickness of 150 μm and, as shown in FIGS. 7A and 7B (however, the N-type thermoelectric element forming printing plate 70 in FIG. 7B has three void portions (grooves) 70A and two openings (hole portions) 70B for the sake of clarity of illustration, but the number of void portions (grooves) 70A and openings (hole portions) 70B is not limited thereto. Further, the N-type thermoelectric element forming printing plate 70 in FIG. 7B is used after being inverted 180° about the coating direction Z), an N-type thermoelectric element forming printing plate 70 having a plate thickness T of 180 μm and a void portion (groove) 70A having a height H of 130 μm formed so that the already formed P-type thermoelectric element can be fitted therein was used. A thermoelectric conversion module was produced in the same manner as in Example 1, and the same measurements and evaluations were performed. Note that the gauge element thickness t of the N-type thermoelectric element ga was larger than the gauge element thickness t of the P-type thermoelectric element. ga

[0096] <Comparative Example 3> In Example 1, instead of using a printing plate for forming a P-type thermoelectric element with a plate thickness of 30 μm and an opening of 1 mm × 6 mm and a printing plate for forming an N-type thermoelectric element with a plate thickness of 30 μm, a printing plate for forming a P-type thermoelectric element with a plate thickness of 150 μm and an opening of 0.8 mm × 6 mm and, as shown in FIGS. 7A and 7B, an N-type thermoelectric element forming printing plate 70 having a plate thickness T of 180 μm and a void portion (groove) 70A having a height H of 130 μm formed so that the already formed P-type thermoelectric element can be fitted therein was used. A thermoelectric conversion module was produced in the same manner as in Example 1, and the same measurements and evaluations were performed. Note that the gauge element thickness t of the N-type thermoelectric element ga was larger than the gauge element thickness t of the P-type thermoelectric element. ga

[0097] <Comparative Example 4> In Example 1, instead of using a printing plate for forming a P-type thermoelectric element with a plate thickness of 30 µm and an opening of 1 mm × 6 mm, and a printing plate for forming an N-type thermoelectric element with a plate thickness of 30 µm and an opening of 1 mm × 6 mm, a printing plate for forming a P-type thermoelectric element with a plate thickness of 150 µm and an opening of 0.8 mm × 6 mm, and an N-type thermoelectric element forming printing plate 70 as shown in FIGS. 7A and 7B, with a plate thickness T of 180 µm, an opening (hole portion) 70B of 0.8 mm × 6 mm, and a void portion (groove) 70A with a height H of 130 µm formed so that the already formed P-type thermoelectric element can fit therein, were used. A thermoelectric conversion module was fabricated in the same manner as in Example 1, and the same measurements and evaluations were performed. Note that the gauge element thickness t of the N-type thermoelectric element ga was greater than the gauge element thickness t of the P-type thermoelectric element ga .

[0098]

Table 1

[0099] From Table 1, in the thermoelectric conversion modules of Comparative Examples 1 to 4, in any of the comparative examples, since the thickness difference t dif exceeded 50 µm, a high electromotive force could not be obtained (less than 0.40 V: evaluation ×). On the other hand, in the thermoelectric conversion modules of Examples 1 to 6, in any of the examples, since the thickness difference t dif was 50 µm or less, a high electromotive force was obtained (0.40 V or more: evaluation 〇).

[0100] 1A, 1B: Thermoelectric conversion module 2: Support 2a: Main surface of the support 3: Electrode 3a: First electrode portion (connection electrode portion) 3b: Second electrode portion (electromotive force extraction electrode portion) 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: Opening (hole part) 70: Printing plate (screen plate) 70A: Gap part (groove) 70B: Opening (hole part) 81: First coating layer 82: Second coating layer 91: First high - heat - conduction layer 92: Second high - heat - conduction layer H: Height P: One end Q: The other end T: Plate thickness t av : Element average thickness t max : Maximum thickness Y: Direction of thermoelectric element arrangement Z: Coating direction

Claims

1. a support; a thermoelectric element layer in which 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 connected so that electrons move in the direction of the arrangement; and the thermoelectric element layer is composed of a coating film, The thickness difference t defined by the following (1) to (4) in a cross section along the direction perpendicular to the direction of the arrangement of at least one of the P-type thermoelectric element and the N-type thermoelectric element ｄｉｆ is 14 to 17 μm, The gauge element thickness t of the P-type thermoelectric element ｇａ and the gauge element thickness t of the N-type thermoelectric element ｇａ are different, Among the P-type thermoelectric element and the N-type thermoelectric element, the gauge element thickness t ｇａ of the thermoelectric element with the larger thickness ｄｉｆ is 14 to 17 μm, a thermoelectric conversion module. (1) Measure the thickness profile of the thermoelectric element in the cross section with a stylus surface profiler. From the measured thickness profile, calculate the average thickness at the central portion of the thermoelectric element excluding both ends, and define the calculated average thickness as the element average thickness t. ａｖ However, the central portion refers to a region of the thermoelectric element that is sandwiched by line segments extending in the direction perpendicular to the main surface of the support from both ends of a central line segment, where the central line segment has a length of 2 / 3L, which is obtained by excluding line segments of 1 / 6L from the inside of one end and 1 / 6L from the inside of the other end of a boundary line between the thermoelectric element and the support in the cross section, and the length of the boundary line in the cross section is defined as L. (3) Detect the maximum value of the thickness of the thermoelectric element from the measured thickness profile, and set the detected maximum value of the thickness as the maximum thickness t ｍａｘ and. (4)The thickness difference t ｄｉｆ is the difference between the maximum thickness t ｍａｘ and the average element thickness t ａｖ (t ｄｉｆ = t ｍａｘ - t ａｖ ).

2. a support; a thermoelectric element layer in which 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 connected so that electrons move in the direction of the arrangement; and the thermoelectric element layer is composed of a thermoelectric semiconductor composition containing thermoelectric semiconductor particles and a resin, The thickness difference t defined by the following (1) to (4) in a cross section along the direction perpendicular to the direction of the arrangement of at least one of the P-type thermoelectric element and the N-type thermoelectric element ｄｉｆ is 14 to 17 μm, The gauge element thickness t of the P-type thermoelectric element ｇａ and the gauge element thickness t of the N-type thermoelectric element ｇａ are different, Among the P-type thermoelectric element and the N-type thermoelectric element, the gauge element thickness t ｇａ of the thermoelectric element with the larger thickness ｄｉｆ is 14 to 17 μm, and the thermoelectric conversion module. (1) Measure the thickness profile of the thermoelectric element in the cross section with a stylus surface profiler. (2) Calculate the average thickness at the central portion of the thermoelectric element excluding both end portions from the measured thickness profile, and set the calculated average thickness as the element average thickness t. ａｖ However, the central portion means a region of the thermoelectric element sandwiched by line segments extending in the direction perpendicular to the main surface of the support from both ends of the central line segment, when the length of the boundary line between the thermoelectric element and the support in the cross section is L, and the central line segment is a line segment with a length of 2 / 3L excluding line segments from one end of the boundary line to the inside by 1 / 6L and line segments from the other end of the boundary line to the inside by 1 / 6L. (3) Detect the maximum value of the thickness of the thermoelectric element from the measured thickness profile, and set the detected maximum value of the thickness as the maximum thickness t ｍａｘ . (4) The thickness difference t ｄｉｆ is the difference between the maximum thickness t ｍａｘ and the average element thickness t ａｖ (t ｄｉｆ = t ｍａｘ - t ａｖ ).

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