JPS608437Y2 - thermoelectric element - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a highly efficient thermoelectric element in which different types of thermoelectric materials are connected by thermal spraying.

In general, different thermoelectric materials have different heat resistances and different thermoelectric conversion efficiencies (thermoelectric capacities).

For this reason, in order to construct a thermoelectric element that utilizes each thermoelectric material at maximum efficiency, a structure is conventionally known in which different types of thermoelectric materials are stacked in a cascade according to their temperature conditions.

FIG. 1 shows an example of such a conventional thermoelectric element.

In this figure, an N-type thermoelectric material N1 and a P-type thermoelectric material P
□One end is connected via conductor IA, and the other end is connected through conductor IB.
, IC are connected to form a first thermoelectric element structure.

Similarly, N-type thermoelectric material N2, P-type thermoelectric material P2, conductor 2A
, 2B, and 2C are the second thermoelectric element structures, N-type thermoelectric material N3, P-type thermoelectric material P3, and conductors 3A, 3B, and 3C are the third
These first to third thermoelectric element structures are constructed respectively.
The thermoelectric element structures are stacked in a cascade and integrated with electrically insulating layers 4 and 5 interposed therebetween.

In this case, the thermoelectric material of the first thermoelectric element structure, which is exposed to the highest temperature, is composed of ■-Bi-Te and PbTe, which have poor thermoelectric conversion efficiency but high heat resistance, as shown in FIG. The thermoelectric material of the second thermoelectric element structure is made of Zn5b and PbTe, which have medium thermoelectric conversion efficiency and heat resistance, and the thermoelectric material of the third thermoelectric element structure is made of Bi, which has low heat resistance but high thermoelectric conversion efficiency. -5b-Te and B1-Te
-3e, and the efficiency is improved by selecting the thermoelectric material according to the temperature conditions.

However, since the thermoelectric element shown in Fig. 1 has a stacked structure, there is a manufacturing disadvantage in that it cannot be processed unless the electrical insulating layer 4.5 is deposited relatively thickly between the thermoelectric element structures at each stage. However, the thermal resistance increases, resulting in the inconvenience that the efficiency does not increase as expected.

Another problem is that it is difficult to assemble.

In order to eliminate these drawbacks, the stacking method (Segme
It is being considered to use a thermoelectric element in which a plurality of thermoelectric materials with different characteristics are stacked and welded together using the ntation method).

FIG. 3 shows the structure of a thermoelectric element produced by the above stacking method.

In this figure, N-type thermoelectric material N4. N5°N6 and P type thermoelectric material P.

P5. P6 are welded and integrated with each other, and N is connected to conductor 4A.
The type thermoelectric material N4 and the P type thermoelectric material P are connected so that electromotive force is taken out from the conductors 4B and 4C.

In this case, N-type thermoelectric material N4. N3. N6 is Ge-B1-Te in order from the part exposed to high temperature at the tip.

Zn5b, B1-3b-Te, and P-type thermoelectric material P2. P5. P6 is PbTe (
For example, it is composed of a sintered body), PbTe (cast body), and B1-Te-3e.

However, in the thermoelectric element shown in FIG. 3, it is extremely difficult to weld different types of thermoelectric materials in the form of sintered bodies or cast bodies, which is not practical.

In view of the above points, the present invention aims to provide a high-performance, easy-to-manufacture, and practical thermoelectric element by connecting different types of thermoelectric materials with a sprayed film of thermoelectric material or conductive material. .

Embodiments of the thermoelectric element according to the present invention will be described below with reference to the drawings.

In Fig. 4, CoSi core material 1 as an N-type thermoelectric material
0 is connected to a FeCoSi sintered body 12 as an N-type thermoelectric material through a ceramic 11 as an insulator, and CoS
A FeCoSi sprayed film 13 is formed by thermal spraying to connect the core material 10 and the FeCoSi sintered body 12.

Then, an alumina film 14 as an insulating film is formed by thermal spraying except for the tip surface of the FeCoSi sintered body 12, and an FeMnSi2 sintered body sleeve 15 as a P-type thermoelectric material is covered, and then a P-type thermoelectric A CrSi2 sprayed film 16 as a material is applied, and the FeCoSi sintered body 12 and the FeMnSi2 sintered body sleeve 15 are connected.

The properties of the thermoelectric material used in this example are as shown in Table 1 below.

From Table 1 above, CoSi has poor flame resistance, and FeMnSi2
However, in the above example, a CrSi2 sprayed film 16 with good flame resistance and medium specific resistance is formed on the outermost side, and CoSi is used as the core material 10. Therefore, by compensating for these drawbacks, it is possible to easily create a thermoelectric element that has excellent heat resistance, flame resistance, and high efficiency as a whole.

In the above embodiment, the thermoelectric materials are connected by thermal spraying of the thermoelectric material, but the connection may be made by thermal spraying of metal.

As described above, according to the present invention, a thermoelectric element with high performance, easy to manufacture, and practical can be obtained by connecting different types of thermoelectric materials with a sprayed film of thermoelectric material or conductive material.

[Brief explanation of the drawing]

Figure 1 is a front view showing one example of a conventional thermoelectric element, Figure 2 is a graph showing the temperature characteristics of the figure of merit of thermoelectric materials, and Figure 3 is a front view showing another example of a conventional thermoelectric element. FIG. 4 is a sectional view showing an embodiment of the thermoelectric element according to the present invention. 10...-CoSi core material, 11... Ceramic, 12... FeCoSi sintered body, 13.
...FeCoSi sprayed film, 14... Alumina film, 15... FeMnSi2 sintered body sleeve, 16... CrSi2 sprayed film.

Claims (8)

[Scope of utility model registration request] (1) A first N-type or P-type thermoelectric material 10 serving as a core material and a second thermoelectric material 12 of the same conductivity type and different nature are connected via an insulator 11, and the 2 thermoelectric materials 1
A first sprayed film 13 is provided to electrically connect 0 and 12,
An insulating second thermal sprayed film 14 is provided at least around the second thermoelectric material 12 and the first thermal sprayed film 13 except for the tip surface of the second thermoelectric material 12 to form a core material connection body. Then, the first thermoelectric material 10 as the core material is covered with a sleeve-shaped P-type or N-type thermoelectric material 15 of the opposite conductivity type to the first thermoelectric material 10, and the sleeve-shaped thermoelectric material 15 and A third sprayed film 16 comprising a different flame-resistant thermoelectric material of the same conductivity type is formed around the core connecting body protruding from the sleeve-shaped thermoelectric material 15, and the tip of the sleeve-shaped thermoelectric material 15 is A thermoelectric element characterized in that it is configured by electrically connecting the tip of the second thermoelectric material 12 with the third sprayed film 16. (2) The thermoelectric element according to claim 1, wherein the insulator 11 is made of ceramic. (3) The thermoelectric element according to claim 1, wherein the first thermoelectric material 10 serving as the core material is made of CoSi having N-type conductivity. (4) The thermoelectric element according to claim 1, wherein the second thermoelectric material 12 is made of a FeCoSi sintered body having N-type conductivity. (5) The thermoelectric element according to claim 1, wherein the first sprayed film 13 is made of FeCoSi. (6) The thermoelectric element according to claim 1, wherein the second sprayed film 14 is made of alumina. (7) The thermoelectric element according to claim 1, wherein the sleeve-shaped thermoelectric material 15 is made of a FeMnSi2 sintered body having P-type conductivity. (8) The thermoelectric element according to claim 1, wherein the third sprayed film 16 is made of CrSi2.