JP2001230457A - Thermoelectric conversion module and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric conversion module in which voids are much smaller than in conventional cases so as to be dense, which has an electrode structure maintaining superior electric conductivity, in which a stress to be generated in a thermionic element is small, in which the thermionic element is not broken down, whose production yiled, reliability and conversion efficiency are high, and which has the electrode structure capable of being made easily large-sized. SOLUTION: In the thermoelectric conversion module 10, in a form 11 in which a plurality of through holes 12 are formed and in which a plurality of grooves 13 for electrodes used to connect the through holes 12 are formed, p-type thermionic elements 14 and n-type thermionic elements 15 are arranged alternately in the through holes 12, and aluminum thermal spraying electrodes 16 which electrically connect the thermionic elements 14, 15 alternately in series are buried in the grooves 13 for the electrodes. A thermal spraying layer which has a thickness of 30 to 80 μm and which is composed of molybdenum or a thermal spraying layer whose covering rate on the thermionic elements is at 50 to 95% and which is composed of molybdenum is formed as a substrate layer 17 in the interface between the thermionic elements 14, 15 and the thermal spraying electrode 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric conversion module for directly converting heat into electricity and a method for manufacturing the same, and more particularly to a thermoelectric module using large-scale exhaust heat as a heat source, such as a power plant or a waste incineration facility. It is useful in power generators.

[0002]

2. Description of the Related Art A thermoelectric conversion module usually has a plurality of p-types.
It is manufactured by alternately arranging type thermoelectric elements and n-type thermoelectric elements, and electrically connecting these thermoelectric elements in series via a conductive material such as metal. This thermoelectric conversion module can generate a thermoelectromotive force by the Seebeck effect by giving a temperature difference to a thermoelectric element, and can convert a part of heat into electric power by connecting an electric load to take out the electric power. A power generator using this thermoelectric conversion module has features such as a simple structure, no moving parts that generate vibration, noise, wear, etc., and the scale of the heat source is not limited. It is attracting attention as a means of recovering heat as electric power and using it effectively.

[0003] Generally, such a thermoelectric conversion module is manufactured by, for example, the following method. First, the p-type and n-type thermoelectric materials are sintered, and the obtained sintered body is subjected to a surface treatment such as nickel plating for soldering to a surface to be joined to the electrode, and then to a desired size. Cutting is performed to produce p-type and n-type thermoelectric elements. Next, p-type and n-type thermoelectric elements are alternately arranged and soldered to metal electrodes so as to have a predetermined electrical connection to obtain a thermoelectric conversion module. In addition, to ensure that the thermoelectric conversion module needs to be electrically insulated and to improve the mechanical strength, the electrode surface is usually soldered to an electrically insulating plate such as alumina ceramic with good heat conductivity. Has been done. In addition, a skeleton type in which an electrode surface is not fixed to an insulating plate is generally known. The general technology related to such a thermoelectric conversion module is, for example, “thermoelectric semiconductor and its application” (Isao Nishida, Kinichi Uemura,
Published by Nikkan Kogyo Shimbun) or "Thermoelectric Conversion System Technology Overview"
(Takenobu Kajikawa et al., Published by Realize).

Further, as a thermoelectric conversion module with improved reliability, each thermoelectric element is sandwiched between metal segments via a metal paste and screwed in order to solve the damage caused by the difference in the coefficient of thermal expansion at each joint. (See, for example, JP-A-8-255935 and JP-A-8-306965) and to improve the mechanical strength of a thermoelectric conversion module using a small element, the thermoelectric element is made of resin. Thermoelectric conversion module having a structure embedded in an insulating material such as ceramics or glass (for example, Japanese Patent Application Laid-Open Nos.
153899) has also been proposed.
Further, a thermoelectric conversion module (see US Pat. No. 5,856,210) in which a thermoelectric element is embedded in a resin mold and a sprayed layer of aluminum is used as an electrode has been invented.

[0005]

However, it is known that the power generation performance of a thermoelectric conversion module is improved as a large temperature difference is applied. However, a brazing material such as solder is used for joining the thermoelectric element and the electrodes. When used, the upper limit temperature is governed by the brazing material, and there is a concern that the power generation performance may be reduced due to the diffusion of the components of the brazing material into the thermoelectric element.
Further, in the thermoelectric conversion module in which the electrode surface is soldered to the insulating plate in order to improve the mechanical strength, there is a problem that the element is easily broken due to the difference in the coefficient of thermal expansion of each member and the reliability is poor. Was. In order to solve this problem, a skeleton type thermoelectric conversion module has been proposed, but it has been pointed out that the mechanical strength is low and the handling is inconvenient. In addition, since the cross-sectional area of the conventional thermoelectric element is at most about 1 to 5 mm square, the output current of one module is limited. In order to obtain a large current output, there is a method of connecting small cross-sectional area elements in parallel.However, not only variations in module characteristics but also variations in the state of thermal contact with the modules and variations in the temperature of the contacting heat source cause variations between modules. There is a technical problem in that the output voltages of the above-mentioned devices vary, and that they are connected in parallel as they are.

When large-scale exhaust heat is used as a heat source, a large-sized thermoelectric conversion module is desired from the viewpoint of design and construction and maintenance. However, the conventional thermoelectric conversion module has a complicated structure. It was not suitable for upsizing. Further, all of the thermoelectric conversion modules currently on the market are thermoelectric elements having a small cross-sectional area of about 1 to 5 mm square, and have not yet been widely used for large power generation.
The reason that the thermoelectric conversion module using the large cross-sectional area element is not manufactured is that, in the thermoelectric conversion module in which an aluminum layer is formed as an electrode, an aluminum electrode and a molybdenum layer that is a base layer between the electrode and the thermoelectric element are It is presumed that the stress concentration is large enough to break the thermoelectric element (see the experimental example described later), so that the cross-sectional area of the element is reduced without stopping to reduce the concentration. Conventionally, as a countermeasure against this stress generation, as described above, in addition to reducing the element cross-sectional area, a large amount of voids are introduced into the aluminum electrode to adjust the coefficient of thermal expansion and Young's modulus, The generated stress was further reduced. However, the introduction of voids in the aluminum electrode clearly contradicts the low resistance characteristics originally required of the electrode.

In view of the above situation, the applicant of the present application has
A thermoelectric conversion module which has high reliability and conversion efficiency and is easy to increase in size, and a method of manufacturing the same have been proposed (Japanese Patent Laid-Open No. 11-3).
No. 40526). This thermoelectric conversion module uses a thermoelectric element having a large cross-sectional area of about 113 m ² , generates a large power of about 59 W per unit, and has higher reliability than a conventional thermoelectric conversion module. However, a long-term durability test of three months caused a problem that a power generation amount was reduced by about 15%, and a crack was generated in the element due to thermal stress at the time of forming the sprayed electrode.

[0008] Accordingly, an object of the present invention is to provide a thermoelectric element with a small stress, while having a dense and excellent electrical conductivity while having a much smaller gap than conventional ones.
An object of the present invention is to provide a thermoelectric conversion module having an electrode structure that has a high production yield, high reliability and high conversion efficiency, and can be easily increased in size, because the thermoelectric element is not destroyed, and a method for manufacturing the same.

[0009]

SUMMARY OF THE INVENTION The present invention provides the above object,
This has been achieved by providing the following thermoelectric conversion module and a method for manufacturing the same. "In an electrically and thermally insulating form provided with a plurality of through-holes and a plurality of electrode grooves connecting the through-holes, a p-type thermoelectric element and an n-type thermoelectric element are alternately provided in the through-hole. Arranged, a thermoelectric conversion module in which these p-type thermoelectric elements and n-type thermoelectric elements are electrically connected alternately and electrically in series and embedded in the electrode groove, wherein the sprayed electrodes are aluminum sprayed electrodes. A thermoelectric conversion module comprising a sprayed layer made of molybdenum having a thickness of 30 to 80 μm as an underlayer at an interface between the p-type and n-type thermoelectric elements and the sprayed electrode (hereinafter referred to as “first”). In the case of the thermoelectric conversion module, the thermoelectric conversion module is referred to.) "" An electrically and thermally insulating formwork provided with a plurality of through holes and a plurality of electrode grooves connecting the through holes, p-type thermoelectric element and n-type A thermoelectric conversion module in which electric elements are alternately arranged in the through holes, and thermal spray electrodes for electrically connecting the p-type thermoelectric elements and the n-type thermoelectric elements alternately in series are embedded in the electrode grooves. The sprayed electrode is an aluminum sprayed electrode, and the interface between the p-type and n-type thermoelectric elements and the sprayed electrode has a coverage of 50 to 95% on the p-type and n-type thermoelectric elements as a base layer. (The thermoelectric conversion module is characterized by having a thermal spray layer made of molybdenum.) (Hereinafter, the second thermoelectric conversion module refers to this thermoelectric conversion module.) " Forming an electrically and thermally insulating mold having a plurality of through-holes and a plurality of electrode grooves connecting the through-holes, and forming a p-type thermoelectric in the through-hole of the mold. Element and n-type thermoelectric element A step of one another arrangement, as an underlying layer on the both surfaces of the thermoelectric device having an array formwork, sprayed layer of molybdenum having a thickness of 30~80μm or coverage onto the above thermoelectric elements 5
A step of forming a thermal spray layer of molybdenum of 0 to 95%, a step of forming an aluminum spray electrode on the underlayer, and an unnecessary aluminum spray electrode formed other than the electrode grooves of the mold. And a step of removing the thermoelectric conversion module. "

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first thermoelectric conversion module according to the present invention will be described with reference to an embodiment shown in FIG.
As shown in FIG. 1, the thermoelectric conversion module 1 of the present embodiment
0 denotes an electrically and thermally insulating mold 11 provided with a plurality of through holes 12 and a plurality of electrode grooves 13, and p-type thermoelectric elements alternately arranged in the through holes 12 of the mold 11. 14, the n-type thermoelectric element 15, and the electrode groove 13 of the mold 11.
And a molybdenum base layer 17 formed between the sprayed electrode 16 and the p-type and n-type thermoelectric elements 14 and 15. The p-type thermoelectric elements 14 and the n-type thermoelectric elements 15 are electrically connected in series alternately via the aluminum sprayed electrodes 16. The p-type and n-type thermoelectric elements 14 and 15 and the molybdenum base layer 17
In addition, the aluminum sprayed electrode 16 is connected to the mold 11
It is integrally fixed to.

The molybdenum underlayer 17 has a thickness of 3
It is a sprayed layer of molybdenum having a thickness of 0 to 80 μm, preferably 30 to 50 μm. Examples of the method for forming the molybdenum base layer 17 include general methods such as plasma spraying, gas spraying, arc spraying, and high-speed flame spraying, and plasma spraying is particularly preferable. At this time, in order to obtain a thin sprayed layer of molybdenum having a thickness of 30 to 80 μm, the amount of powder supplied during spraying may be reduced, or the number of spray passes may be appropriately adjusted.

The aluminum spray electrode 16 is
Although it can be formed by a general method such as plasma spraying, gas spraying, arc spraying, and flame spraying, it is preferable to form the electrode by plasma spraying and gas spraying in order to obtain a dense and uniform electrode. The aluminum sprayed layer constituting the aluminum sprayed electrode 16 preferably has a porosity of 10% or less, particularly preferably 8% or less (see FIG. 2).

The above-mentioned electrically and thermally insulating form 11
For example, a mold formed of a molded body of calcium silicate can be used. Calcium silicate has crystalline phases called zonotolite and tobermorite, and those formed by mixing an organic binder with them are called artificial wood.
This artificial wood has characteristics such as non-combustibility, low thermal conductivity, light weight, and good workability, and thus is suitable as an insulating mold for a thermoelectric conversion module. For example, the thermal conductivity is 1.2 W / mK for general lead glass, whereas the molded product of calcium silicate is 0.08 W / mK, which is as small as about 1/15. 1/5 compared to 0.4 W / mK of polyimide which is heat resistant resin
About small. In addition, in terms of specific gravity, lead glass and polyimide have a specific gravity of 3.0 and 1.4, respectively.
As small as about 0.5, it is desirable as an insulating mold material for a thermoelectric conversion module.

The thermoelectric materials used as the p-type thermoelectric element 14 and the n-type thermoelectric element 15 are known Bi ₂ Te ₃ , BiSb, FeSi ₂ , PbTe.
It is possible to use a single crystal or a sintered body of a thermoelectric semiconductor such as a SiGe-based thermoelectric semiconductor, but when using a mold made of the above-described calcium silicate molded body as the insulating mold 11, The Bi ₂ Te ₃ system is preferable from the temperature range where the mold can be used. Further, when the p-type and n-type thermoelectric elements 14 and 15 have a cross-sectional area of 0.36 cm ² or more, the effect becomes particularly clear. Practically, the cross-sectional area is 0.3
Those having a size of 6 to 10 cm ² are preferably used.

Next, a second thermoelectric conversion module of the present invention will be described. In the second thermoelectric conversion module of the present invention, the molybdenum base layer composed of the molybdenum sprayed layer is p-type.
The same as the above-described first thermoelectric conversion module of the present invention, except that the thermoelectric conversion module is formed in a patch shape so that the coverage on the mold and the n-type thermoelectric element is 50 to 95%, preferably 70 to 90%. It is configured. Examples of the method of obtaining the mottled molybdenum sprayed layer include a method of vibrating the spraying device during spraying, a method of intermittently supplying powder, a method of using a mesh filter between the spraying device and the object to be sprayed, and the like. However, a method using a mesh filter is preferable from the viewpoint of reproducibility. Further, the thickness of the molybdenum sprayed layer is preferably such that the thickness of the sprayed layer excluding voids is 200 μm or less.

The first and second embodiments of the present invention having the above-described structure.
The thermoelectric conversion module can be applied to a thermoelectric power generation system using exhaust heat of a power plant, exhaust heat of a garbage incineration facility, exhaust heat of an automobile, sunlight, and the like.

Next, a method of manufacturing a thermoelectric conversion module according to the present invention will be described with reference to FIG. 3, taking the case of manufacturing the thermoelectric conversion module of the embodiment shown in FIG. 1 described above as an example. First, as shown in FIG. 3A, an electric and thermal insulating material is used to form an electrical and thermal insulating material in which a plurality of through holes 12 and a plurality of electrode grooves 13 communicating between the through holes 12 are provided. In addition, a thermally insulating mold 11 is manufactured. When calcium silicate is used as the insulating material, first, a molded body of calcium silicate is produced by a production method described in, for example, JP-A-62-213053 or JP-A-3-3635, and is obtained. It is preferable to fabricate the insulating mold 11 by machining the molded body.

Next, as shown in FIG. 3B, a p-type thermoelectric element 14 and an n-type
The thermoelectric elements 15 are alternately arranged using element spacers 18 and 19.

Next, the element spacers 18 and 19 are removed, and as shown in FIG.
7 are formed on both surfaces of the p-type thermoelectric element 14 and the n-type thermoelectric element 15 by plasma spraying or the like. At this time, the molybdenum base layer 17 has a thin sprayed layer having a thickness of 30 to 80 μm (or a coverage of 50 to 95 on the p-type and n-type thermoelectric elements).
% Of the sprayed layer). After the molybdenum base layer 17 is formed, aluminum sprayed electrodes 16 are formed using aluminum so as to cover both surfaces of the insulating mold 11.

Next, as shown in FIG. 3D, unnecessary sprayed electrodes formed on the insulating mold 11 other than the electrode grooves 13 are ground and removed using a surface grinder or the like. The thermoelectric conversion module of the embodiment shown in FIG. When the unnecessary thermal spray electrode is removed by grinding, the surface of the insulating mold 11 is slightly ground to ensure the flatness of the electrode surface.

[0021]

In the thermoelectric conversion module according to the first and second aspects of the present invention, the electrode is an aluminum sprayed electrode and the underlying layer is a thin molybdenum sprayed layer or a molybdenum sprayed layer. Low stress concentration and no element cracking. Therefore, it can be manufactured stably,
The yield is improved.

The thermoelectric conversion module of the present invention according to claim 3 has a dense electrode structure having excellent electrical conductivity because the aluminum sprayed electrode is made of an aluminum sprayed layer having a porosity of 10% or less. Power generation performance is improved. Further, the thermoelectric conversion module of the present invention according to claim 4 has a large element cross-sectional area, so that it can be easily used for electric power.

According to the method for manufacturing a thermoelectric conversion module of the present invention according to claim 5, a large-area thermoelectric conversion module can be manufactured with a relatively simple process and a good yield, and a thermoelectric module adapted to a large-scale heat source can be manufactured. A conversion module can be obtained.

[0024]

EXAMPLES The effects of the present invention will be specifically described below with reference to experimental examples and examples.

Experimental Example An analysis was performed using the finite element method in order to know the thermal stress distribution when a thermal cycle or a rapid temperature change was applied to the electrode junction of the thermoelectric conversion module. FIG. 6 shows an analysis model used in the finite element method. Considering the symmetry of the shape (cylinder) of this model, the constraint condition and the thermal load condition, an axially symmetric model was used. The physical properties of the electrode layer, the underlayer, and the thermoelectric element used in this analysis are shown in Table 1 below. For analysis, a general-purpose stress analysis solver MSC / NASTRAN (Ver. 70.5) was used.

[0026]

[Table 1]

FIG. 7 shows a stress distribution diagram when the temperature change amount is -200 ° C. From this stress distribution diagram, it can be seen that the molybdenum underlayer is distorted near the underlayer because the thermal shrinkage is small. Further, for this reason, it can be seen that stress concentration occurs at the edge of the molybdenum base layer, which affects the inside of the thermoelectric element. A strong tensile stress is generated at the edge of the molybdenum underlayer in the axial direction (element length direction). Therefore,
It is considered that cracks are likely to progress to the thermoelectric element side having low mechanical strength from the vicinity of the edge of the molybdenum base layer due to the application of a heat cycle to the module or a rapid temperature change at the time of forming the thermal spray electrode.

In order to examine the effect of the thickness of the molybdenum underlayer on the maximum principal stress, the change of the maximum principal stress when the thickness of the underlayer was changed and the thickness of the aluminum electrode layer was changed is shown in FIG. As is clear from FIG. 8, the change due to the thickness of the aluminum electrode layer is almost constant at about 1 mm or more, but the thinner the molybdenum underlayer, the smaller the maximum principal stress. FIG. 9 shows the change in the maximum principal stress when the thickness of the molybdenum underlayer was changed when the thickness of the aluminum electrode layer was 1.4 mm. In this figure,
The reason why the plot changes discontinuously when the thickness of the molybdenum underlayer is around 0.09 to 0.1 mm is that the number of meshes in the axial direction of the molybdenum underlayer is reduced and accuracy is deteriorated. The results also show that the thickness of the molybdenum underlayer sensitively affects the maximum principal stress, and that the principal principal stress in the axial direction decreases as the thickness decreases.

The molybdenum underlayer was not formed into a uniform layer, but was formed in a patchy form. The analysis was performed by the finite element method. That is, in the analysis model of FIG. 6, the mesh of the interface portion corresponding to the molybdenum underlayer was divided to obtain the stress distribution. As shown in FIGS. 10 and 11, as a result of dividing the molybdenum underlayer every 4 meshes and every 1 mesh (1 mesh = 0.1 mm), the maximum principal stresses were 59.3 kgf / mm ² and 26.3, respectively.
a kgf / mm ^2, it was revealed that smaller compared to 79.9kgf / mm ² when the Mo underlayer has a uniform layer.

From the above analysis results, it has been clarified that the maximum principal stress generated at the electrode junction due to a thermal cycle or a rapid temperature change can be reduced by making the molybdenum underlayer thin or having a mottled structure. .

Embodiment 1 In this embodiment, a mold made of a molded body of calcium silicate is used as a thermoelectric element material, using a Bi ₂ Te ₃ system as a thermoelectric element, and using an exhaust gas of about 400 ° C. from an internal combustion power plant as a heat source. To
An aluminum sprayed electrode having a porosity of 8% was used as an electrode, and a molybdenum sprayed layer having a thickness of 80 μm was used as a molybdenum base layer. First, an insulating mold 11 shown in FIGS. 4 and 5 was machined (N) by using a molded product of calcium silicate (registered trademark; Woody Serum, manufactured by Ube Industries, Ltd.).
C router). As described above, the molded body of calcium silicate has characteristics such as nonflammability, low thermal conductivity, light weight, and good workability, and thus is suitable as an insulating mold for a thermoelectric conversion module. The method for producing a molded product of calcium silicate shown here is described in, for example,
This is described in detail in JP-A-1233053 and JP-A-3-3635. FIG. 4A is a plan view of the insulating mold 11 of the thermoelectric conversion module on the low temperature side, and FIG. 5A is a plan view of the insulating mold 11 of the thermoelectric conversion module on the high temperature side. FIG.

Next, a Bi ₂ Te ₃ -based thermoelectric element was manufactured as follows. First, the atomic ratio of Bi _0.3 Sb _1.7 Te
Each raw material was weighed so as to be ₃ (p-type) and Bi ₂ Te _2.4 Se _0.6 (n-type). To the n-type, 0.1% by weight of SbI ₃ was added to adjust the carrier density. Next, these materials were vacuum-sealed in a glass tube and melt-stirred at 650 ° C. for 1 hour to produce a Bi ₂ Te ₃ thermoelectric material. These thermoelectric materials were subjected to stamp mill and ball mill to obtain an average particle size of 1
After pulverizing to about 0 μm, a reduction treatment was performed at 390 ° C. for 12 hours. The obtained thermoelectric material powder was sintered at 490 ° C. for 15 minutes using a hot press to obtain a sintered body of the thermoelectric material. A columnar thermoelectric element (12φ × 7 mmh) was prepared from the obtained sintered body by using a slicer, an ultrasonic machine or the like.

Next, the p-type thermoelectric element 14 and the n-type thermoelectric element 1
5 after sandblasting to roughen the surface.
As shown in (b), element spacers 18 and 19 were used to alternately arrange in an insulating mold. Next, as shown in FIG. 3C, a molybdenum base layer 17 having a thickness of 80 μm is formed by plasma spraying to improve the adhesion strength between the thermoelectric element and the aluminum electrode, and an aluminum sprayed electrode 16 is formed thereon by about 2 mm. did. At this time, the aluminum sprayed layer constituting the aluminum sprayed electrode had a dense structure as shown in FIG. The formation of the backside molybdenum underlayer and the aluminum sprayed electrode was performed in the same manner. However, the element spacer is not required at the time of thermal spraying of the back surface.

Next, as shown in FIG. 3D, unnecessary portions of the aluminum sprayed electrodes 16 formed on both surfaces of the insulating mold 11 are ground using a surface grinder, and the thermoelectric conversion module 10 is mounted. Produced. At this time, the insulating mold was slightly cut to secure the flatness of the electrode surface.

The thermoelectric conversion module fabricated as described above (79 pairs of elements, module size 150 × 300 ×
10 mm) is sandwiched between an electric heater and a water-cooled plate, and the low-temperature side is set at 30 ° C. and the high-temperature side is set at 230 ° C.
A temperature difference of ° C. was applied to evaluate power generation characteristics. An electronic load was used for the measurement, and the load resistance was measured at 0.15Ω. At this time, one thermoelectric conversion module performs 62.
A maximum electric output of 1 W can be generated, and a thermoelectric conversion module corresponding to a large-scale heat source can be manufactured. In addition, a three-month continuous test was conducted under the above conditions.
No reduction in power generation performance was observed, and it was confirmed that the reliability was excellent. In addition, when five thermoelectric conversion modules were manufactured, there was no increase in internal resistance, and five thermoelectric conversion modules were successfully manufactured, and the yield was improved.

Embodiment 2 When forming a molybdenum underlayer by plasma spraying, a mesh filter is used between the spraying apparatus and the object to be sprayed.
The underlayer is formed as a patchy structure having a thickness of 50 to 150 μm (coverage 90
%), Except that the thermoelectric conversion module was manufactured in the same manner as in Example 1. The thermoelectric conversion module manufactured in this manner was able to generate a maximum electric output of 61 W by itself, and was excellent in reliability and yield as in the thermoelectric conversion module of Example 1.

[0037]

The thermoelectric conversion module of the present invention has an electrode structure with much smaller voids and a dense and excellent electrical conductivity, but the stress generated in the thermoelectric element is small and the thermoelectric element is destroyed. Therefore, the electrode structure has a high production yield, high reliability and high conversion efficiency, and can be easily enlarged.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a thermoelectric conversion module of the present invention.

FIG. 2 is an electron micrograph showing a cross-sectional structure of an electrode part of the thermoelectric conversion module of the present invention.

3 (a), 3 (b), 3 (c) and 3 (d) are process diagrams showing an example of a method for manufacturing a thermoelectric conversion module according to the present invention.

FIG. 4A is a plan view of a low-temperature side of an insulating mold used in an embodiment of the present invention, and FIG.
FIG. 4C is a cross-sectional view taken along line BB ′ of FIG.

5 (a) is a plan view of the insulating mold shown in FIG. 4 on the high-temperature side, and FIG. 5 (b) is a cross-sectional view taken along the line AA 'of FIG. (c) is a sectional view taken along the line BB '.

FIG. 6 is an analysis model diagram used in the finite element method.

FIG. 7 is a stress distribution diagram of a thermoelectric element when a temperature change amount is −200 ° C.

FIG. 8 is a graph showing a change in maximum principal stress depending on the thickness of an aluminum sprayed electrode layer.

FIG. 9 is a graph showing a change in maximum principal stress depending on the thickness of a molybdenum base layer.

FIG. 10 is a stress distribution diagram of a thermoelectric element when a molybdenum base layer is provided with voids of one mesh for every four meshes.

FIG. 11 is a stress distribution diagram of a thermoelectric element when a molybdenum underlayer is provided with a void of one mesh per mesh.

[Explanation of symbols]

 Reference Signs List 10 thermoelectric conversion module 11 insulating mold 12 through hole 13 electrode groove 14 p-type thermoelectric element 15 n-type thermoelectric element 16 aluminum sprayed electrode 17 molybdenum base layer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Keigo Nagao 5 Ube, Ube City, Yamaguchi Prefecture, 1978 Kogushi, Ube Research Institute (72) Inventor Atsushi Nagai 5 Ube Kobe, 1978 Ogushi, Ube City, Yamaguchi Prefecture, 5 Ube Industries Inside Ube Research Institute Co., Ltd. (72) Inventor Kazuhiro Fujii 1978 Kogushi, Obe, Ube City, Yamaguchi Prefecture Ube Industries, Ltd. Inside Ube Research Laboratories Co., Ltd. No. Kyushu Electric Power Co., Inc. (72) Inventor Hiroki Kamakura 2-1-2 Watanabe-dori, Chuo-ku, Fukuoka City, Fukuoka Prefecture Inside Kyushu Electric Power Co., Ltd. No. 82 Kyushu Electric Power Co., Inc.

Claims (5)

[Claims] A p-type thermoelectric element and an n-type thermoelectric element are penetrated through an electrically and thermally insulating form provided with a plurality of through-holes and a plurality of electrode grooves connecting between the through-holes. A thermoelectric conversion module in which the sprayed electrodes that are alternately arranged in the holes and that electrically connect the p-type thermoelectric elements and the n-type thermoelectric elements alternately and electrically in series are embedded in the electrode grooves. An aluminum sprayed electrode, at the interface between the p-type and n-type thermoelectric elements and the sprayed electrode, 30 to 80
A thermoelectric conversion module comprising a sprayed layer of molybdenum having a thickness of μm. 2. An electric and thermally insulating form provided with a plurality of through holes and a plurality of electrode grooves connecting between the through holes, penetrating the p-type thermoelectric element and the n-type thermoelectric element through the through hole. A thermoelectric conversion module in which the sprayed electrodes that are alternately arranged in the holes and that electrically connect the p-type thermoelectric elements and the n-type thermoelectric elements alternately and electrically in series are embedded in the electrode grooves. A thermal spraying of an aluminum sprayed electrode comprising molybdenum having a coverage of 50 to 95% on the p-type and n-type thermoelectric elements as an underlayer at an interface between the p-type and n-type thermoelectric elements and the sprayed electrode. A thermoelectric conversion module comprising a layer. 3. An aluminum sprayed electrode having a porosity of 1
3. An aluminum sprayed layer of 0% or less.
The thermoelectric conversion module as described. 4. The thermoelectric conversion module according to claim 1, wherein the p-type and n-type thermoelectric elements have a cross-sectional area of 0.36 cm ² or more. 5. An electrically and thermally insulating formwork having a plurality of through-holes and a plurality of electrode grooves connecting between the through-holes, using an electrically and thermally insulating material. A step of alternately arranging p-type thermoelectric elements and n-type thermoelectric elements in the through-holes of the mold, and a thickness of 30 to 80 μm as a base layer on both surfaces of the mold in which the thermoelectric elements are arranged. A step of forming a sprayed layer of molybdenum or a sprayed layer of molybdenum having a coverage of 50 to 95% on the thermoelectric element, and a step of forming an aluminum sprayed electrode on the underlayer. Removing unnecessary aluminum sprayed electrodes formed in portions other than the electrode grooves of the formwork.