JP2896496B2 - Thermoelectric converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric conversion device, and more particularly to a thermoelectric conversion device suitable for being applied to a thermoelectric conversion device for generating electric power by using medium or high temperature thermal energy.

[0002]

2. Description of the Related Art In a thermoelectric conversion device, for example, a thermoelectric conversion module, a pair of a p-type semiconductor thermoelectric element and an n-type semiconductor thermoelectric element are arranged in parallel, and one end thereof is connected to a common first element.
A thermoelectric element pair is formed by a π-type connection configuration soldered to the metal segment of a plurality of thermoelectric element pairs, and another thermoelectric element pair adjacent to the other end of each thermoelectric element of each thermoelectric element pair is used. the other end of the thermoelectric elements having different conductivity type from each other, and soldered to the second metal segments, thermally hot side heat transfer us section first and second metal segments respectively and the low-temperature-side heat transfer unit The structure of fixing to is adopted.

As described above, in a thermoelectric conversion device having a structure in which metal segments and the like are fixed, non-uniform heat shear stress is generated in the fixing portion, particularly when medium or high temperatures are handled, and the thermoelectric element is destroyed and the characteristics are deteriorated. Such as deterioration
There are many problems such as the stability of characteristics, reliability, and life, and the high incidence of defective products during manufacturing.

On the other hand, a medium temperature range of about 200 ° C. to 600 ° C.
In particular, it is known that PbTe exhibits excellent thermoelectric conversion characteristics in a temperature region around 500 ° C. However, when the PbTe thermoelectric element is kept at about 500 ° C. or more for a long time, the thermoelectric conversion characteristics of the element deteriorate with time due to sublimation and oxidation of the components of the element, Pb and Te.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem of thermal shear stress and the above-mentioned problem of deterioration of thermoelectric conversion characteristics due to sublimation and oxidation of components in, for example, PbTe. To enable stable thermoelectric conversion.

[0006]

The thermoelectric conversion device according to the present invention is covered with a conductive block having a concave portion for press-fitting at least a high-temperature end of a thermoelectric element, that is, an end to which heat energy is applied. This thermoelectric element
The child is fixed at the cold end by a fixing screw .

The end of the thermoelectric element is pressed into the recess of the conductive block to couple the end of the thermoelectric element to the end of the thermoelectric element. At the same time, the end of the thermoelectric element is connected to the end of the thermoelectric element by the conductive block. To cover the end portion from the surrounding atmosphere.

Also, a metal plate is joined to the press-fit end of the conductive block of the thermoelectric element into the recess, and the end of the thermoelectric element is press-fitted into the recess of the conductive block via the metal plate. To

According to the configuration of the present invention described above, the conductive block is covered at least on the high-temperature side end to which the intermediate- or high-temperature thermal energy is applied, that is, on the side where the sublimation or oxidation of the element components is likely to occur. Therefore, electrical and thermal coupling with the other part at this end can be performed by the conductive block. However, the coupling between the thermoelectric element and the conductive block is performed by the thermoelectric element to the concave portion of the conductive block. Since this is performed by press-fitting the end of the element, a "displacement" can be generated between the thermoelectric element and the conductive block microscopically, so that the generation of thermal shear stress is avoided.

Further, by covering at least the high-temperature side end of the thermoelectric element with a conductive block, it is possible to effectively prevent sublimation and oxidation of the components of the thermoelectric element, thereby preventing fluctuation of the components and deterioration of characteristics. You can do it.

Further, a metal plate is previously bonded to an end of the thermoelectric element where the conductive block is pressed into the concave portion, and the conductive block is pressed into the concave portion via the metal plate. Accordingly, the press-fitting of the conductive block at the end of the thermoelectric element into the concave portion can be performed by deformation of the metal plate, so that the force due to this press-fitting can be prevented from being directly applied to the thermoelectric element, thereby making the fragile. In the thermoelectric element, it is possible to effectively avoid the disadvantage that the thermoelectric element is damaged during the press-fitting.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a thermoelectric converter according to the present invention will be described. FIG. 1 shows an example of the apparatus of the present invention.
As shown in a schematic cross-sectional view of the thermoelectric element portion of FIG.
The conductive block 3 is crowned and fitted to at least the high temperature side end 1H of the n-type or p-type semiconductor thermoelectric element 1 made of e. In the illustrated example, both the high-temperature side end 1H and the opposite low-temperature side end 1L have these ends 1H and 1H.
This is a case where a conductive block 3 having a concave portion 2 into which L is pressed is fitted with a crown.

The conductive block 3 is made of, for example, pure iron, and the recess 2 is selected to have an inner shape and size corresponding to the cross-sectional shape and size of the ends 1H and 1L of the thermoelectric element 1 to be press-fitted. , The depth of which is, for example, 1 mm.

As shown in FIG. 2, the ends 1H and 1L of the thermoelectric element 1 press-fitted into the recesses 2 of the conductive block 3 are made of, for example, pure iron and have a thickness of 0.1 mm.
For example, a metal plate 4 of 1 mm to 0.5 mm is integrally joined together with, for example, molding of a thermoelectric element, and a recess 2 at an end of the thermoelectric element 1 is formed.
When the metal plate 4 is press-fitted, the metal plate 4 is deformed, and the gap between the end portions 1H and 1L of the thermoelectric element 1 and the concave portion 2, mainly the peripheral surfaces of the end portions 1H and 1L and the inner peripheral surface of the concave portion 2 is formed. The intermediate portions 1H and 1L and the conductive block 3 are preferably mechanically, electrically, and thermally coupled to each other.

Each thermoelectric element 1 can be formed in a quadrangular prism shape as shown in the figure, or can be formed in another polygonal column shape or a cylindrical shape.

The n-type semiconductor thermoelectric element can be constituted by, for example, a PbTe-based element to which PbI ₂ is added as a dopant. C. for 20 minutes to 30 minutes under pressure to heat the n-type thermoelectric element 1 of the metal plate 4.
Can be joined to the end of the wire.

The p-type semiconductor thermoelectric element can be constituted by, for example, a PbTe-based element to which Na is added as a dopant. In this case, a pure iron metal plate 4 coated with ZnTe powder is prepared,
Is heated and melted for 1 hour, so that the surface of the metal plate has an FePb thickness of about 0.05 mm to 0.01 mm.
A compound film of Te is formed, and then the surface on which the compound film is formed is brought into contact with the end of the p-type thermoelectric element so that the metal plate 4
By pressing and heating at 808 ° C. for 2 minutes to 4 minutes in this state, the metal plate 4 can be joined to the end of the p-type thermoelectric element 1.

As described above, the bonding of the metal plate 4 to each of the n-type and p-type thermoelectric elements 1 can be performed independently. Therefore, the composition of each thermoelectric element 1 and the composition suitable for the thermoelectric element 1 can be achieved. The material selection of the metal plate and the joining method can be applied.

The recess 2 of the conductive block 3 is
In the press-fit state of the ends 1H and 1L, the ends 1H and 1L
L has a bottomed shape which covers these ends 1H and 1L in a gas-tight manner from outside air.

The conductive block 3 includes, as shown in FIG.
The thermoelectric element 1 may be individually fitted to both ends 1H and 1L, or may be fitted to only one end 1H on the high temperature side of the thermoelectric element (not shown). As in the conventional case, the metal segments or the conductive blocks may be fixed by soldering or the like.

In the case where a plurality of n-type and p-type thermoelectric elements are connected in a so-called π-type, for example, FIG.
As shown in FIG. 1, for example, a pair of concave portions 2 are formed in the conductive block 3, and one end portion of each of a plurality of n-type and p-type thermoelectric elements 1 in each of which a metal plate 4 is fixed at an end portion,
As shown in the sectional view of FIG. 4, the metal plate 4 is press-fitted so as to be deformed, and a common conductive block 3 is attached to these ends.
And electrically connecting each end of the pair of n-type and p-type thermoelectric elements 1 by the conductive block 3.

In this case, the other low-temperature side end 1L of each thermoelectric element 1 is, as shown in a sectional view of FIG.
Each of the conductive blocks 3 each having one recess 2 can be similarly covered with a metal plate 4.
As shown in FIG. 6, a conductive block 3 having a pair of concave portions 2 as in the high temperature side end 1H is connected to each low temperature side end 1L of the p-type and n-type thermoelectric elements 1 of another conductivity type. A plurality of thermocouples of n-type and p-type of each pair by π-type connection constitute a thermoelectric conversion device by a large number of thermoelectric elements sequentially connected in series by π-type connection by each conductive block. You can also.

As described above, the ends 1H and 1L of the thermoelectric element 1 are covered with the conductive block 3 so as to cover the ends 1H and 1L of the thermoelectric element 1 and shut off these ends from the surrounding atmosphere. To do.

As described above, the plurality of thermoelectric elements 1 to which the conductive blocks 3 are coupled are, for example, as shown in FIG.
The high-temperature side heat conduction plate 11H to which medium- or high-temperature heat energy is supplied, and the low-temperature side heat conduction plate 11
And L. In this case, the high temperature side ends 1H and 1L of each thermoelectric element 1 are
H and 11L, respectively, via an insulating thin film 12 such as mica.
L is clamped while the thermoelectric element 1 is clamped by, for example, a tightening screw. In this way, the high-temperature side end 1H of each thermoelectric element 1 is thermally insulated and electrically insulated from the low-temperature end 1L to the low-temperature side heat conduction plate 11L, respectively. And combine.

According to the above configuration, the end 1 of the thermoelectric element 1
Since the conductive block 3 is covered with H and 1L, electrical and thermal coupling with other portions at this end can be performed by the conductive block. And the conductive block 3 are joined by press-fitting the end of the thermoelectric element into the concave portion 1 of the conductive block 3, so that microscopically, "shift" between the thermoelectric element and the conductive block. Can be generated, even if high-temperature heating is performed at the high-temperature side end 1H, generation of thermal shear stress due to this is avoided.

In addition, since the end of the thermoelectric element, particularly at least the high-temperature end, is covered with the conductive block 3, sublimation and oxidation of the components of the thermoelectric element 1 can be effectively avoided. Variation of components and deterioration of characteristics can be avoided.

Further, a metal plate 4 is previously bonded to the end of the thermoelectric element 1 where the conductive block 3 is pressed into the recess 2, and the thermoelectric element 1 is connected to the recess of the conductive block via the metal plate 4. Since the press-fitting is performed by deformation of the metal plate 4, the force applied at the time of press-fitting can be prevented from being directly applied to the thermoelectric element, whereby the fragile thermoelectric element 1 such as PbTe can be avoided. In this case, it is possible to effectively avoid inconveniences such as breakage at the time of press-fitting, and it is possible to securely connect the thermoelectric element 1 and the conductive block 3 by the press-fitting.

In the configuration shown in FIG. 7, both ends 1 of each thermoelectric element 1 are provided.
In this case, the adjacent thermoelectric elements in H and 1L are connected in series to each other by the conductive block 3, respectively. For example, as shown in FIG. In the case where the conductive blocks 3 are individually fitted with respect to 1, FIG.
As shown in the cross-sectional view of the main part, adjacent thermoelectric elements 1 to be electrically connected to each other at a low temperature side end 1L.
Metal segments 13 over each conductive block 3
Can be arranged in abutment, and these metal segments 13 can be electrically connected to each other.

[0029] In particular the present invention, for example as shown in FIG. 8, the parts corresponding to those in FIG. 7 is a repeated explanation thereof are denoted by the same reference numerals, in the low temperature side, the heat conduction plate 11 By screwing a fixing screw 14 made of insulating ceramic, Teflon, or the like from the side through the metal segment 13 and the conductive block 3 which abuts on the metal segment 13,
It is intended to simplify the setting and assembling of the mutual positional relationship between the thermoelectric element 1, the metal segment 13, and the like, and to improve the overall mechanical strength .

In this case, the hermetic screw into which the fixing screw 14 is screwed is selected to a depth that does not penetrate the conductive block 3, thereby preventing the thermoelectric element 1 from being hermetically covered by the conductive block 3. In the case where such a problem as sublimation or oxidation does not occur on the low temperature side, a core screw into which the fixing screw 14 is screwed is formed to penetrate the conductive block 3. You can also.

The thermoelectric elements 1 can be arranged two-dimensionally, that is, with a plurality of rows and columns, between the high-temperature-side heat conductive plate 11H and the low-temperature-side heat conductive plate 11L. FIG. 9 is a plan view of an example thereof, and FIG. 10 is a side view thereof. 9 and 10, parts corresponding to those in FIG.
9 and 10, a configuration is adopted in which the high-temperature-side heat conductive plate 11H and the low-temperature-side heat conductive plate 11L are fixed with the thermoelectric element 1 sandwiched therebetween by a tightening screw 15 with a spring 15 interposed.

[0032]

As described above, according to the structure of the present invention, at least the high temperature side end 1H of the thermoelectric element 1 is covered with the conductive block 3, so that the end of the thermoelectric element 1 is electrically connected to other parts. The thermal coupling can be performed by the conductive block. The coupling between the thermoelectric element 1 and the conductive block 3 is performed by press-fitting the end of the thermoelectric element into the recess 1 of the conductive block 3. Therefore, microscopically, "displacement" can be generated between the thermoelectric element and the conductive block. Therefore, even if high-temperature heating is performed at the high-temperature side end 1H, the thermal shear stress caused by this is reduced. Occurrence is avoided. And, at the low temperature side end, the fixing screw 14
Therefore, since it is fixed, more stable holding is performed.
Can be.

Further, by constituting the end of the thermoelectric element, particularly at least the end on the high-temperature side, with the conductive block 3, the sublimation and oxidation of the components of the thermoelectric element 1 can be effectively avoided. Variation of components and deterioration of characteristics can be avoided.

Further, a metal plate 4 is previously bonded to the end of the thermoelectric element 1 where the conductive block 3 is pressed into the recess 2, and the thermoelectric element 1 is connected to the recess of the conductive block via the metal plate 4. Since the press-fitting is performed by deformation of the metal plate 4, it is possible to avoid that the force applied at the time of the press-fitting is directly applied to the thermoelectric element, whereby the fragile thermoelectric element 1 made of PbTe or the like can be avoided. In this case, it is possible to effectively avoid inconveniences such as breakage at the time of press-fitting, and it is possible to securely connect the thermoelectric element 1 and the conductive block 3 by the press-fitting.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a thermoelectric element section of a thermoelectric conversion device according to the present invention.

FIG. 2 is a perspective view of a thermoelectric element of the thermoelectric device shown in FIG.

FIG. 3 shows another example of a thermoelectric device according to the present invention.
It is an exploded perspective view of a child part .

FIG. 4 is a cross-sectional view showing a process of manufacturing the thermoelectric element of the thermoelectric conversion device shown in FIG.

FIG. 5 shows another example of a thermoelectric device according to the present invention.
It is sectional drawing of a child part .

FIG. 6 is a diagram showing another example of a thermoelectric device according to the present invention.
It is sectional drawing of a child part .

FIG. 7 shows another example of a thermoelectric device according to the present invention.
It is sectional drawing of a child part .

8 is a cross-sectional view of one example of a thermoelectric conversion device according to the present invention.

FIG. 9 is a plan view of another example of the thermoelectric conversion device according to the present invention.

FIG. 10 is a side view of the thermoelectric converter shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 thermoelectric element 1H high-temperature side end 1L low-temperature side end 2 recess 3 conductive block 4 metal plate 11H high-temperature side heat conduction plate 11L low-temperature side heat conduction plate 12 insulating thin film 13 metal segment

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichi Moriya 1 Koganezawa, Kuniki, Kakuta-shi, Miyagi Japan Science and Technology Agency, Aerospace Research Institute Kanagaya 1 Koganezawa 1 Science and Technology Agency Aerospace Research Laboratory Kakuda Space Propulsion Research Center (72) Inventor Masayuki Niino 1 Kungaya 1 Koganazawa Research Institute of Aerospace Technology Kakuda City, Miyagi Pref. (72) Inventor Yasuo Tada 1 Koganezawa, Kunigaya-shi, Kakuda-shi, Miyagi Pref. Japan Science and Technology Agency Aerospace Research Institute Kakuda Space Propulsion Research Center (56) References JP-A-61-156781 (JP, A) Hei 5-152615 (JP, A) Jiko 37-20025 (JP, Y1) Jiko 34-12473 (JP, Y 1) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01L 35/32 H01L 35/06 H01L 35/08 H01L 35/16

Claims (4)

(57) [Claims] An electroconductive block having a concave portion for press-fitting the end portion is covered at least on a high temperature side end of the thermoelectric element, and the thermoelectric element is fixed at a low temperature side end by a fixing screw. A thermoelectric conversion device characterized by the above-mentioned. 2. The thermoelectric element is connected to the end of the thermoelectric element by press-fitting the end of the thermoelectric element into the recess of the conductive block, and the thermoelectric element is connected to the thermoelectric element by the conductive block. 2. The thermoelectric conversion device according to claim 1, wherein said end portion is covered to shield the end portion from the surrounding atmosphere. 3. A thermoplate, wherein a metal plate is connected to at least a high temperature side end of the thermoelectric element, and the end of the thermoelectric element is press-fitted into the recess of the conductive block via the metal plate. The thermoelectric conversion device according to claim 1 or 2, wherein: 4. The thermoelectric conversion device according to claim 1, wherein the thermoelectric element is a PbTe-based thermoelectric element.