KR102401917B1 - Thermoelectric Material Composition for Thermoelectric Element and Thermoelectric Element including the same - Google Patents

Abstract

An embodiment of the present invention, a bulk-phase crystalline thermoelectric material matrix; and a thermoelectric material that is a mixture of a non-spherical powder and a spherical powder included in the thermoelectric material matrix.
According to the present invention, the thermoelectric material composition for a thermoelectric element with improved power factor compared to the existing nano-bulk structure material by controlling the powder shape of the thermoelectric material used as the P/N cell of the thermoelectric element, and two types of thermoelectric material having different shapes By mixing powder materials to form a thermoelectric material composition, electrical conductivity and Seebeck coefficient are increased and thermal conductivity is lowered, thereby providing a thermoelectric device maximizing the Peltier effect.

Description

Thermoelectric Material Composition for Thermoelectric Element and Thermoelectric Element including the same

An embodiment of the present invention relates to a thermoelectric material composition for a thermoelectric element and a thermoelectric element including the same, and more particularly, a thermoelectric material composition for a thermoelectric element in which the performance of a thermoelectric material such as a power factor is improved by controlling the configuration of the thermoelectric material, and It relates to a thermoelectric element including the same.

A thermoelectric material is a material that generates a voltage when a temperature difference is applied between both ends of the material, and is cooled or heated when a direct current is passed through it. It is also called thermoelectric conversion material in the sense that it converts heat into electricity and generates or removes heat with electricity. Thermoelectric cooling devices provide a powerful and effective temperature control solution to industrial technology fields including semiconductors and electronic communication fields that use a thermoelectric semiconductor, an energy conversion material, as a basic material. Using the principle of thermoelectric elements, thermoelectric elements n and p type thermoelectric semiconductors are used by joining them in the form of a connection electrically in series and thermally in parallel. When a direct current is passed, if a temperature difference is applied to both sides of the element due to the thermoelectric effect, electricity is generated and the power generation function can be obtained. A thermoelectric cooling device refers to a solid state heat pump that uses the cooling effect caused by the Peltier phenomenon. The thermoelectric device is a highly reliable product that can be used for over 250000 hours without unreasonable cooling speed and Heat absorption and heat generation can be changed according to the direction, so accurate temperature control is possible. Currently, materials such as Bi ₂ Te ₃ , PbTe, and SiGe are used for thermoelectric devices. It is expected that the application fields based on thermoelectric devices will be greatly expanded in the future.

In order to improve the power factor of the thermoelectric material, the prior art has improved the figure of merit of the thermoelectric element by controlling the non-spherical nanostructure to be miniaturized to induce a phonon scattering effect in the manufacturing method.

The embodiment of the present invention has been devised to solve the above problems, and the power factor is improved compared to the existing nano-bulk structure material by controlling the powder shape of the thermoelectric material used as the P/N cell of the thermoelectric element. to provide a thermoelectric material composition for a thermoelectric device.

In addition, by mixing the other two powder materials to form a thermoelectric material composition, electrical conductivity and Seebeck coefficient are increased and thermal conductivity is lowered to provide a thermoelectric device maximizing the Peltier effect.

An embodiment of the present invention is to achieve the above object, a bulk-phase crystalline thermoelectric material matrix; and a thermoelectric material that is a mixture of a non-spherical powder and a spherical powder included in the thermoelectric material matrix.

In addition, the particle diameter of the non-spherical powder and the spherical powder is characterized in that 1 to 100㎛.

In addition, the P-type material of the thermoelectric material is a mixture of Bi _{2 -x} Sb _x Te ₃ (0<x<1.6) and Ag.

In addition, the content of the components Bi _{2 -x} Sb _x Te ₃ (0<x<1.6) 99.9 to 99.99% by weight and Ag 0.01 to 0.1% by weight, characterized in that.

In addition, the N-type material of the thermoelectric material is a mixture of Bi ₂ Te _{3 -y} Se _y (0.1<y<0.2) and Cu.

In addition, the content of the components is Bi ₂ Te _{3 -y} Se _y (0.1<y<0.2) 99.9 to 99.99% by weight and Cu, it is characterized in that the mixture of 0.01 to 0.1% by weight.

In addition, the content of the non-spherical powder and the spherical powder is characterized in that 25 to 75% by weight and 25 to 75% by weight, respectively.

In addition, the content of the non-spherical powder and the spherical powder is characterized in that 75% by weight and 25% by weight, respectively.

In addition, the thermoelectric material matrix is characterized in that it includes at least one mixture selected from the group consisting of bismuth (Bi), antimony (Sb), tellute (Te), and selenium (Se).

In addition, an embodiment of the present invention provides a thermoelectric device including the thermoelectric material composition in order to achieve the above object.

In addition, the thermoelectric element is characterized in that it includes a pellet in which a thin plate-shaped water tank of 5 to 30 μm and a random structure of 0.1 to 5 μm are mixed.

According to an embodiment of the present invention, the thermoelectric material composition and shape for a thermoelectric element with improved Power Factor compared to the existing nano-bulk structure material by controlling the powder shape of the thermoelectric material used as the P/N cell of the thermoelectric element. By mixing the other two powder materials to form a thermoelectric material composition, electrical conductivity and Seebeck coefficient are increased and thermal conductivity is lowered to provide a thermoelectric device maximizing the Peltier effect.

1 to 5 are particle images of the powder of Comparative Example 1 (FIG. 1), Comparative Example 2 (FIG. 2), Example 1 (FIG. 3), Example 2 (FIG. 4) and Example 3 (FIG. 5), respectively. Photo.
6 to 10 are particle images of the powder of Comparative Example 1 (FIG. 6), Comparative Example 2 (FIG. 7), Example 1 (FIG. 8), Example 2 (FIG. 9), and Example 3 (FIG. 10), respectively. Photo.
11 and 12 are photographs of microstructures after etching in Comparative Example 1 and Example 1, respectively.

Hereinafter, the configuration and operation according to the present invention will be described in detail with reference to the accompanying drawings. In the description with reference to the accompanying drawings, the same components are given the same reference, regardless of the reference numerals, and redundant description thereof will be omitted.

An embodiment of the present invention, a bulk-phase crystalline thermoelectric material matrix; and a thermoelectric material that is a mixture of a non-spherical powder and a spherical powder included in the thermoelectric material matrix.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

An embodiment of the present invention mixes non-spherical (irregular shape) and spherical (spherical shape) powder with a thermoelectric material used as a P/N cell of a thermoelectric element, compared to conventional nano-bulk structure materials, "Power Factor (electrical conductivity * Seebeck) It is characterized in that the coefficient ² )" is improved.

That is, the embodiment of the present invention is a device that can maximize the Peltier effect by applying powders of different shapes (non-spherical vs. spherical powders 1 or 2 or more) to increase electrical conductivity and Seebeck coefficient and lower thermal conductivity ) to improve the performance as a material, and as a result of mixing powders having different shapes in the embodiment of the present invention, the electrical properties can be improved by the difference in the microstructure of the pellets for thermoelectric materials.

In an embodiment of the present invention, it is preferable to use a particle diameter of 1 to 100 μm of the non-spherical powder and the spherical powder. Even if nano-ization is not performed to improve the performance of the thermoelectric material as in the prior art, the practice of the present invention As in the example, by mixing different types of powder, the effect of improving the performance can be obtained. If the particle diameter of the powder is less than 1㎛, it is not preferable because the electrical properties are lowered, and if it is larger than 100㎛, it is not preferable because the thermal conductivity increases.

As an embodiment of the present invention, the P-type material of the thermoelectric material may be used without limitation in the technical field of the present invention as long as it does not impair the effects of the present invention, for example, Bi _{2 -x} Sb _x Te It is preferably a mixture of ₃ (0<x<1.6) and Ag.

The Ag is an additive, and the content of the constituents is preferably Bi _{2 -x} Sb _x Te ₃ (0<x<1.6) 99.9 to 99.99% by weight (?) and 0.01 to 0.1% by weight of Ag. The electrical properties can be improved by adding Ag additives.

In addition, the P-type semiconductor material is antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tell A main raw material consisting of bismuth telluride (BiTe) including rurium (Te), bismuth (Bi), and indium (In), and Bi or Te corresponding to 0.001 to 1.0 wt% of the total weight of the main raw material are mixed It is preferable to form using a mixture. For example, the main raw material may be a Bi-Sb-Te material, and Bi or Te may be formed by further adding a weight corresponding to 0.001 to 1.0 wt% of the total weight of Bi-Sb-Te. That is, when 100 g of the weight of Bi-Sb-Te is added, the additionally mixed Bi or Te may be added in the range of 0.001 g to 1 g. The weight range of the material added to the above-described main raw material is significant in that, outside the range of 0.001 wt% to 0.1 wt%, the thermal conductivity does not decrease and the electrical conductivity decreases, so that the improvement of the ZT value cannot be expected.

As an embodiment of the present invention, the N-type material of the thermoelectric material may be used without limitation in the technical field of the present invention as long as it does not impair the effects of the present invention, for example, Bi ₂ Te _{3 -y} Se It is preferably a mixture of _y (0.1<y<0.2) and Cu.

The Cu is an additive, and the content of the components is preferably Bi ₂ Te _{3 -y} Se _y (0.1<y<0.2) 99.9 to 99.99% by weight and Cu 0.01 to 0.1% by weight. The properties of the Seebeck coefficient can be improved by adding a Cu additive.

In addition, the N-type semiconductor material is selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tell A main raw material composed of bismuth telluride (BiTe) including rurium (Te), bismuth (Bi), and indium (In), and Bi or Te corresponding to 0.001 to 1.0 wt% of the total weight of the main raw material are mixed It can be formed using a mixture of For example, the main raw material may be a Bi-Se-Te material, and Bi or Te may be formed by adding a weight corresponding to 00.001 to 1.0 wt% of the total weight of Bi-Se-Te. That is, Bi When the weight of -Se-Te is 100 g, it is preferable to add Bi or Te to be added in the range of 0.001 g to 1.0 g. As described above, the weight range of the material added to the above-described main raw material is significant in that, outside the range of 0.001 wt% to 0.1 wt%, the thermal conductivity does not decrease and the electrical conductivity does not decrease, so improvement of the ZT value cannot be expected. have

One aspect of the present invention relates to a thermoelectric element including the thermoelectric material composition, wherein it can be confirmed that the thermoelectric element contains pellets in which a thin plate-shaped water tank of 5 to 30 μm and a random structure of 0.1 to 5 μm are mixed. have.

Hereinafter, the present invention will be described in more detail through examples. These examples are only for illustrating the present invention in more detail, and it will be apparent to those skilled in the art that the scope of the present invention is not limited by these examples according to the gist of the present invention. .

[Example]

1. Powder composition of Comparative Examples and Examples according to the present invention

Non-spherical powder (wt%) spherical powder (wt%) Comparative Example 1 100 0 Example 1 75 25 Example 2 50 50 Example 3 25 75 Comparative Example 2 0 100

2. Pellet manufacturing

1. Mix non-spherical powder and spherical powder by content.

2. Put the mixed powder in the graphite mold and use SPS (Spark Plasma Sintering) equipment to manufacture a sintered compact (pellet) under the process conditions (temperature 420~500℃, pressure 500~650kgf, holding time 5~10 minutes) Each physical property was measured and summarized in the table below.

3. Experimental results

Table 2 shows the experimental results of Comparative Example 1.

Temperature (℃) power factor
(W/m·K^2) electrical conductivity
(S/m) See Baek Gye-soo
(V/K) thermal conductivity
(W/K m) 25 3.59E-03 8.88E+04 2.01E-04 1.3037 50 3.39E-03 7.92E+04 2.07E-04 1.2337 100 2.97E-03 6.22E+04 2.18E-04 1.1739 150 2.41E-03 5.03E+04 2.19E-04 1.1930

Table 3 shows the experimental results of Example 1.

Temperature (℃) power factor
(W/m·K^2) electrical conductivity
(S/m) See Baek Gye-soo
(V/K) thermal conductivity
(W/K m) 25 4.04E-03 1.05E+05 1.96E-04 1.2765 50 3.91E-03 9.52E+04 2.03E-04 1.2226 100 3.35E-03 7.50E+04 2.11E-04 1.1572 150 2.72E-03 6.03E+04 2.12E-04 1.1559

Table 4 shows the experimental results of Example 2.

Temperature (℃) power factor
(W/m·K^2) electrical conductivity
(S/m) See Baek Gye-soo
(V/K) thermal conductivity
(W/K m) 25 3.73E-03 9.35E+04 2.00E-04 1.4589 50 3.55E-03 8.50E+04 2.04E-04 1.3835 100 3.06E-03 6.68E+04 2.14E-04 1.3016 150 2.43E-03 5.34E+04 2.14E-04 1.3170

Table 5 shows the experimental results of Example 3.

Temperature (℃) power factor
(W/m·K^2) electrical conductivity
(S/m) See Baek Gye-soo
(V/K) thermal conductivity
(W/K m) 25 3.95E-03 1.15E+05 1.85E-04 1.4262 50 3.80E-03 1.05E+05 1.90E-04 1.3532 100 3.34E-03 8.32E+04 2.00E-04 1.2635 150 2.57E-03 6.67E+04 1.96E-04 1.2391

Table 6 shows the experimental results of Comparative Example 2.

Temperature (℃) power factor
(W/m·K^2) electrical conductivity
(S/m) See Baek Gye-soo
(V/K) thermal conductivity
(W/K m) 25 3.61E-03 8.49E+04 2.06E-04 1.2430 50 3.42E-03 7.72E+04 2.10E-04 1.2040 100 2.94E-03 6.10E+04 2.20E-04 1.1375 150 2.38E-03 4.95E+04 2.19E-04 1.1814

As can be seen from the above experimental results, it can be seen that the powder obtained by mixing the non-spherical powder and the spherical powder in an amount of 25 to 75% by weight and 25 to 75% by weight, respectively, showed excellent performance.

In particular, it can be seen that the performance increase effect of Example 1 in which the content of the non-spherical powder and the spherical powder is 75 wt% and 25 wt%, respectively, is the greatest.

1 to 5 are particle images of the powder of Comparative Example 1 (FIG. 1), Comparative Example 2 (FIG. 2), Example 1 (FIG. 3), Example 2 (FIG. 4) and Example 3 (FIG. 5), respectively. This is a picture (using JEOL FIB -SEM equipment)

6 to 10 are particle images of the powder of Comparative Example 1 (FIG. 6), Comparative Example 2 (FIG. 7), Example 1 (FIG. 8), Example 2 (FIG. 9) and Example 3 (FIG. 10), respectively. This is a photograph. The fracture surface of the sample was measured with JEOL FIB-SEM equipment.

From the image photos, it was possible to discover the difference in the microstructure of pellets made only with non-spherical powder and pellets made by mixing non-spherical powder and spherical powder. In addition, the difference between the non-spherical powder pellets and the pellets produced by mixing non-spherical and spherical powders can be seen in the microstructure photograph after the pellets are etched.

11 and 12 are photographs of microstructures after etching in Comparative Examples 1 and 1, respectively. It was measured with JEOL FIB-SEM equipment, and microstructure photos were measured after etching the sample in nitric acid (65%) solution for 3 minutes. to be.

Claims (11)

a bulk crystalline thermoelectric material matrix; and a thermoelectric material included in the thermoelectric material matrix.
The P-type material of the thermoelectric material consists of a mixture of Bi _2-x Sb _x Te ₃ (0<x<1.6), and Ag,
The Bi _2-x Sb _x Te ₃ (0<x<1.6) is 99.9 to 99.99% by weight, the Ag is 0.01 to 0.1% by weight,
The thermoelectric material is a mixture of spherical powder and non-spherical powder,
The content of the non-spherical powder and the spherical powder is 25 to 75% by weight and 25 to 75% by weight of the thermoelectric material composition for a thermoelectric element, respectively.
The method of claim 1,
The thermoelectric material composition for a thermoelectric element, characterized in that the non-spherical powder and the particle diameter of the spherical powder is 1 to 100㎛.
delete delete The method of claim 1,
The thermoelectric material composition for a thermoelectric element, characterized in that the N-type material of the thermoelectric material is a mixture of Bi ₂ Te _{3 -y} Se _y (0.1<y<0.2) and Cu.
6. The method of claim 5,
The content of the N-type material is a thermoelectric material composition for a thermoelectric element, characterized in that the mixture of Bi ₂ Te _3-y Se _y (0.1<y<0.2) 99.9 to 99.99% by weight and Cu 0.01 to 0.1% by weight.
delete 3. The method of claim 2,
The thermoelectric material composition for a thermoelectric element, characterized in that the content of the non-spherical powder and the spherical powder is 75% by weight and 25% by weight, respectively.
The method of claim 1,
The thermoelectric material matrix comprises at least one mixture selected from the group consisting of bismuth (Bi), antimony (Sb), tellute (Te) and selenium (Se).
A thermoelectric element comprising the thermoelectric material composition of any one of claims 1 to 2, 5, 6, 8, and 9. delete

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