KR20180082044A - Thermoelectric materials, and thermoelectric element and thermoelectric module comprising the same - Google Patents

Abstract

The present invention relates to a thermoelectric material, and a thermoelectric device and a thermoelectric module including the same. According to an embodiment of the present invention, the thermoelectric material comprises: thermoelectric powder in accordance with chemical formula 1, Bi_xSb_(2-x)Te_3, wherein x is 0.4 <= x <= 0.5; and 0.01 to 0.1 wt % of a glass frit. According to an embodiment of the present invention, the thermoelectric module comprises: a lower substrate; a first electrode disposed on the lower substrate; a thermoelectric device disposed on the first electrode; a second electrode disposed on the thermoelectric device; and an upper electrode disposed on the second electrode. The thermoelectric device includes the thermoelectric material comprising thermoelectric powder in accordance with chemical formula 1, Bi_xSb_(2-x)Te_3, wherein x is 0.4 <= x <= 0.5, and 0.01 to 0.1 wt % of a glass frit.

Description

TECHNICAL FIELD The present invention relates to a thermoelectric material and a thermoelectric module including the thermoelectric material and a thermoelectric module,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric element, and more particularly, to a thermoelectric material with high efficiency and a thermoelectric element and a thermoelectric module including the same.

Thermoelectric phenomenon is a phenomenon caused by the movement of electrons and holes inside a material, which means direct energy conversion between heat and electricity.

Thermoelectric elements are collectively referred to as elements using thermoelectric phenomenon, and have a structure in which a PN junction pair is formed by bonding a P-type thermoelectric element and an N-type thermoelectric element between metal electrodes.

The thermoelectric element can be classified into a device using a temperature change of electrical resistance, a device using a Seebeck effect that generates electromotive force by a temperature difference, a device using a Peltier effect that is a phenomenon in which heat is generated by heat or a heat is generated .

Thermoelectric devices are widely applied to household appliances, electronic components, and communication components. For example, a thermoelectric element can be applied to a cooling device, a heating device, a power generation device, and the like. As a result, there is a growing demand for thermoelectric performance of thermoelectric elements.

Bi-Sb-Te thermoelectric materials have a high thermal conductivity and thus have difficulty in improving the figure of merit.

The present invention is directed to a thermoelectric material having a high Seebeck coefficient and a low thermal conductivity.

The present invention also provides a thermoelectric device including the thermoelectric material with high efficiency.

The present invention also provides a high-efficiency thermoelectric module including the thermoelectric element.

A thermoelectric material and a thermoelectric device according to an embodiment of the present invention include thermoelectric powders according to Formula 1; And 0.01 to 0.1% by weight of glass frit.

&Lt; Formula 1 >

Bi _x Sb _{2 - x} Te ₃

X is 0.4? X? 0.5.

A thermoelectric module according to an embodiment of the present invention includes a lower substrate; A first electrode disposed on the lower substrate; A thermoelectric element disposed on the first electrode; A second electrode disposed on the thermoelectric element; And an upper substrate disposed on the second electrode, wherein the thermoelectric element comprises a thermoelectric powder according to Formula 1; And 0.01% to 0.1% by weight of glass frit.

&Lt; Formula 1 >

Bi _x Sb _{2 - x} Te ₃

X is 0.4? X? 0.5.

According to the embodiment of the present invention, a Bi-Sb-Te thermoelectric material having a high Seebeck coefficient and a low thermal conductivity can be provided. Accordingly, the embodiment can provide a thermoelectric element and a thermoelectric module having excellent thermoelectric performance.

1 is an electron micrograph of a thermoelectric powder according to an embodiment.
2 is an electron micrograph of a glass frit according to an embodiment.
3 is an electron micrograph of a thermoelectric material according to an embodiment.
4 is an electron micrograph of a thermoelectric material according to a comparative example.
5 is a graph showing the results of evaluation of thermal conductivity, Seebeck coefficient, electric conductivity and performance index according to Comparative Examples and Examples.
6 is a cross-sectional view of a thermoelectric device according to an embodiment.
7 is a perspective view of a thermoelectric device according to an embodiment.
8 is a cross-sectional view of a thermoelectric leg and an electrode according to another embodiment.
9 to 11 are views showing thermoelectric legs of a laminated structure.
12 to 14 are views showing a heat transfer member disposed on the thermoelectric module according to the embodiment.

The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated and described in the drawings. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terms including ordinal, such as second, first, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the second component may be referred to as a first component, and similarly, the first component may also be referred to as a second component. And / or &lt; / RTI &gt; includes any combination of a plurality of related listed items or any of a plurality of related listed items.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings, wherein like or corresponding elements are denoted by the same reference numerals, and redundant description thereof will be omitted.

The present invention relates to a high-efficiency thermoelectric material with enhanced thermoelectric performance, a thermoelectric device including the same, and a thermoelectric module.

The performance index (ZT) defined by the following equation (1) is used as an index for measuring the performance of the thermoelectric material.

&Quot; (1) &quot;

In Equation (1), ZT represents a dimensionless figure of merit, S represents a Seebeck coefficient,? Represents electrical conductivity, T represents absolute temperature, and k represents thermal conductivity.

In order to increase the figure of merit (ZT), a material having high Seebeck coefficient and electrical conductivity, that is, a high power factor (S ² σ) and low thermal conductivity is required.

However, since the Bi-Sb-Te thermoelectric material has a high thermal conductivity, there is a limitation in improving the figure of merit.

The present invention relates to a high-efficiency thermoelectric material having a high Seebeck coefficient and a low thermal conductivity, a thermoelectric element including the same, and a thermoelectric module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3, the thermoelectric material according to the embodiment includes thermoelectric powder; And glass frit.

1 is a photograph of a thermoelectric powder.

The thermoelectric powder included in the thermoelectric material according to the embodiment may include a compound represented by the following formula (1).

&Lt; Formula 1 >

Bi _x Sb _{2 - x} Te ₃

In Formula 1, x is 0.4? X? 0.5.

For example, x may be 0.5. That is, the thermoelectric powder included in the thermoelectric material according to the embodiment is Bi _{0 . 5} Sb _{1 . 5} Te ₃ .

For example, x may be 0.4. That is, the thermoelectric powder included in the thermoelectric material according to the embodiment is Bi _{0 . 4} Sb _{1 . 6} Te ₃ . However, the embodiment is not limited thereto, and it goes without saying that the content of the composition of Bi and Sb may vary within the range of x.

2 is a photograph of a glass frit. The glass frit included in the thermoelectric material according to the embodiment may be glass powder.

The glass frit may be silicon oxide (SiO ₂ ) - aluminum oxide (Al ₂ O ₃ ) - sodium oxide (Na ₂ O) - potassium oxide (K ₂ O) series. The glass frit according to an embodiment may be a lead-free glass powder not containing lead oxide (PbO). Accordingly, it can be a glass frit that meets international environmental regulations.

The glass frit may be soda glass containing 60 wt% or more of silicon oxide and 15 wt% to 25 wt% of an alkali oxide. Here, the alkali oxide may mean sodium oxide (Na ₂ O) and potassium oxide (K ₂ O). As the glass frit according to the embodiment contains the alkali oxide, the melting point of the glass may be lowered.

The glass frit may be a silicon oxide (SiO ₂₎ as main component, said silicon oxide (SiO ₂₎ may comprise more than 70% by weight.

In addition, the glass frit may contain 10 wt% or more of sodium oxide (Na ₂ O).

The glass frit may contain 5 wt% or more of aluminum oxide (Al ₂ O ₃ ) and potassium oxide (K ₂ O), respectively. For example, the glass frit may contain the same weight percent of aluminum oxide (Al ₂ O ₃ ) and potassium oxide (K ₂ O), respectively.

The ratio of the weight% of sodium oxide (Na ₂ O) to the sum of the weight% of aluminum oxide (Al ₂ O ₃ ) and potassium oxide (K ₂ O) contained in the glass frit may be 1 or more (Na ₂ O wt% / (Al ₂ O ₃ wt% + K ₂ O wt%) ≥ 1). For example, the ratio of the weight percent of sodium oxide (Na ₂ O) to the sum of the weight percentages of aluminum oxide (Al ₂ O ₃ ) and potassium oxide (K ₂ O) contained in the glass frit may be greater than 1 (Na ₂ O wt% / (Al ₂ O ₃ wt% + K ₂ O wt%)> 1).

For example, the glass frit may comprise from 65 to 80% by weight of silicon oxide (SiO ₂ ), from 5 to 10% by weight of aluminum oxide (Al ₂ O ₃ ), from 10 to 15% by weight of sodium oxide (Na ₂ O) By weight and potassium oxide (K ₂ O) 5% by weight to 10% by weight. Further, the glass frit according to the embodiment can have a small thermal expansion coefficient, and the workability can be improved.

The glass frit may include ceramics. The glass frit may comprise an oxide. Accordingly, the weight% composition of each element included in the glass frit may be 30% by weight or more of oxygen (O). For example, oxygen (O) contained in the glass frit may be 40 wt% or more.

Besides oxygen, the glass frit may contain various elements.

For example, sodium (Na) contained in the glass frit may be 20 wt% or more. The amount of sodium (Na) contained in the glass frit may be 20 wt% to 25 wt%.

For example, silicon (Si) contained in the glass frit may be 20 wt% or more. The silicon (Si) contained in the glass frit may be 20 wt% to 25 wt%.

For example, the ratio of the weight percent of sodium (Na) to the weight percent of silicon (Si) contained in the glass frit may be from about 0.95 to about 1.05.

For example, potassium (K) contained in the glass frit may be 7 wt% or more. The potassium (K) contained in the glass frit may be 10 wt% to 15 wt%.

For example, aluminum (Al) contained in the glass frit may be 1 wt% or more. The amount of aluminum (Al) contained in the glass frit may be 1 wt% to 3 wt%.

The glass frit may contain different kinds of elements. The glass frit may include different elements of oxygen (O), sodium (Na), silicon (Si), potassium (K), and aluminum (Al).

The oxygen (O) contained in the glass frit may be 50 atomic% or more. The oxygen (O) contained in the glass frit may be 50 atom% to 60 atom%.

Sodium (Na) contained in the glass frit may be at least 15 atomic%. The oxygen (O) contained in the glass frit may be 15 atom% to 25 atom%.

The silicon (Si) contained in the glass frit may be 10 atomic% or more. The silicon (Si) contained in the glass frit may be 10 atom% to 20 atom%.

The potassium (K) contained in the glass frit may be 10 atomic% or more. The silicon (Si) contained in the glass frit may be 10 atom% to 20 atom%.

The aluminum (Al) contained in the glass frit may be 1 atomic% or more. The aluminum (Al) contained in the glass frit may be 1 atom% to 2 atom%.

The glass frit may be amorphous. That is, the glass frit may include an irregular crystal structure. The glass frit may comprise irregular grain structure.

Referring to FIG. 2, the glass frit may include glass powders of various shapes. The glass frit may have a polygonal shape. That is, one glass powder of the glass frit may include at least two portions having different sizes depending on the measurement position. The one glass powder of the glass frit may include at least five portions different in size depending on the measurement position and the measurement angle. The one glass powder of the glass frit may include at least 10 portions having different sizes depending on the measurement position or the measurement angle.

The glass frit may include a rupture part. The glass frit may have a fractured shape. Accordingly, one glass powder of the glass frit may include portions having different thicknesses.

The plurality of glass frit may have various thicknesses. For example, the glass frit may include one glass frit having a first thickness, and another glass frit having a thickness different from the first thickness.

Alternatively, one glass frit can have various thicknesses. For example, one glass powder of the glass frit may include at least two portions having different thicknesses depending on the measurement position. For example, one glass powder of the glass frit may include at least three portions having different thicknesses depending on the measurement position.

The glass frit may include at least two portions having different surface roughness.

The glass frit may have various sizes. The glass frit may include glass powders of different sizes. The glass frit may include a plurality of first glass frit having a particle size of less than 10 mu m and a plurality of second glass frit having a particle size of more than 10 mu m.

2 shows the measurement of the maximum size of the glass frit particles. The glass frit has a plurality of first glass frit having particle sizes of 4.14 탆, 5.63 탆, 8.08 탆 and 8.37 탆, and a plurality of first glass frit having a size of 11.88 탆, 14.76 탆, Mu m, 32.92 mu m, and the like. The size measured in Fig. 2 is an example, and the size of the glass frit is not limited thereto.

The particle size of the glass frit can be measured by a particle size analyzer. The particle size of the glass frit may be in the range of 3 탆 to 7 탆 at a 10% relative particle content and in the range of 30 탆 to 35 탆 at a 90% relative particle content.

The particle size of the glass frit may be a particle size (D50) at a 50% relative particle content of 7 mu m to 10 mu m. That is, the average particle size (D50) of the glass frit may be 7 탆 to 10 탆.

The maximum particle size (Dmax) of the glass frit may be from 35 탆 to 45 탆. For example, the maximum particle size (Dmax) of the glass frit may be between 38 μm and 42 μm.

3 is a photograph of a thermoelectric material according to an embodiment.

The thermoelectric material according to the embodiment can be formed by mixing the thermoelectric powder and the glass frit and then sintering.

The thermoelectric material may be a sintered body obtained by mixing the thermoelectric powder with the glass frit in an amount of 0.01 to 0.1 wt% and then spark plasma sintering, that is, Spark Plasma Sintering (SPS).

The glass frit included in the thermoelectric material can be identified through the portion where the shading in FIG. 3 appears. In other words, you can see the glass frit through the shaded area inside the dotted line.

4 is a photograph of the thermoelectric material according to the comparative example.

The thermoelectric material according to the comparative example is a photograph of the thermoelectric material in which the thermoelectric powder is sintered. Unlike the thermoelectric material of the embodiment, it can be confirmed that the glass frit is not included. That is, since the shadows do not include other particles, it can be confirmed that there is no glass frit.

Hereinafter, a method of manufacturing thermoelectric materials and thermoelectric elements will be described.

First, a method of manufacturing the thermoelectric powder will be described.

Bi, Sb and Te are prepared to form the thermoelectric powder. Next, the thermoelectric powder is prepared so as to have a composition of Bi _x Sb _{2 - x} Te ₃ (0.4 _{? X?} 0.5) of the formula 1, and then an ingot is produced. The prepared ingot may have a single crystal structure. Next, the ingot may be pulverized to form a thermoelectric powder. At this time, the ingot may be pulverized according to a melt spinning technique. Thus, a thermoelectric material of the flaky flakes can be obtained.

Second, a manufacturing method of glass frit is described.

The glass frit is charged into a crucible by charging silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), sodium oxide (Na ₂ O) and potassium oxide (K ₂ O), heating and melting, . &Lt; / RTI &gt;

Accordingly, the glass frit may contain 65 to 80% by weight of silicon oxide (SiO ₂ ), 5 to 10% by weight of aluminum oxide (Al ₂ O ₃ ), 10 to 15% by weight of sodium oxide (Na ₂ O) ₂ O) 5 to 10% by weight. At this time, the average particle size (D50) of the glass frit may be 7 to 10 mu m and the maximum particle size (Dmax) may be 35 to 45 mu m.

Third, a method of manufacturing a thermoelectric material will be described.

The thermoelectric powder of the single crystal having a composition of Bi _x Sb _{2 - x} Te ₃ (0.4 _{? X?} 0.5) of the formula 1 is mixed with 65 to 80 wt% of silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ) The amorphous glass frit having a composition of 10 to 15 wt%, sodium oxide (Na ₂ O) 10 to 15 wt%, and potassium oxide (K ₂ O) 5 to 10 wt% is mixed.

At this time, the thermoelectric powder and the glass frit may be mixed at different weight percentages. The thermoelectric powder may have a larger weight percentage than the glass frit. For example, the thermoelectric powder may be 99.9 wt% to 99.99 wt%. The glass frit may be 0.01 wt% to 0.1 wt%.

When the glass frit is contained in the thermoelectric material in an amount of 0.01 to 0.1% by weight, the Seebeck coefficient is high, the thermal conductivity is low, and the figure of merit can be improved.

For example, when the thermoelectric material contains glass frit in an amount of 0.01 to 0.1 wt%, the figure of merit (ZT) of the thermoelectric element calculated by Equation (1) at 25 DEG C may be more than 1.0. In detail, when the thermoelectric material contains glass frit in an amount of 0.01 wt% to 0.1 wt%, the figure of merit (ZT) of the thermoelectric element calculated by Equation (1) at 25 캜 can be 1.05 or more. In detail, when the thermoelectric material contains glass frit in an amount of 0.01 wt% to 0.1 wt%, the figure of merit (ZT) of the thermoelectric element calculated by Equation (1) at 25 캜 can be 1.1 or more.

Accordingly, the embodiment can provide a thermoelectric material with high efficiency. However, the figure of merit may have a variable value depending on the temperature. For example, the figure of merit of the thermoelectric device according to the embodiment measured at 100 ° C may be 1.3 or higher. In detail, the performance index of the thermoelectric device according to the embodiment measured at 100 ° C may be 1.3 to 1.4.

If the thermoelectric material does not contain glass frit, or if the glass frit is contained in an amount of less than 0.01% by weight, the thermoelectric element performance index (ZT) may be less than 1.05 at 25 ° C.

If the thermoelectric material contains glass frit in an amount exceeding 0.1 wt%, the figure of merit (ZT) of the thermoelectric element at 25 캜 may be less than 1.05.

The thermoelectric material of the flaky flakes can be milled together with the glass frit. For this purpose, for example, a super mixer, a ball mill, an attrition mill, a 3 roll mill, or the like can be used.

In detail, the thermoelectric powder and the glass frit can be uniformly mixed by a ball mill process. That is, the glass frit can be uniformly dispersed in the thermoelectric powder. Accordingly, the plurality of glass powders of the glass frit may be spaced apart from each other. The first glass frit may be spaced apart from the second glass frit. Also, the plurality of first glass frit particles may be spaced apart from each other, and the plurality of first glass frit particles may be spaced from each other.

Next, the thermoelectric leg powder can be obtained through sieving. However, the screening process is added as needed and is not an essential process in the embodiment of the present invention. At this time, the powder for thermoelectric legs may have a particle size of, for example, micrometers.

Next, the powder for the thermoelectric leg can be sintered. The thermoelectric leg can be manufactured by cutting the sintered body obtained by the sintering process. The sintering may be carried out at 400 to 550, 35 to 60 MPa for 1 to 30 minutes, for example, using SPS (Spark Plasma Sintering) equipment, or at 400 to 550 , And 180 to 250 MPa for 1 to 60 minutes.

In detail, the thermoelectric material can be prepared by mixing the thermoelectric powder with 0.01 wt% to 0.1 wt% of the glass frit and then sintering. That is, the thermoelectric material may be a sintered body by spark plasma sintering, that is, spark plasma sintering (SPS). Accordingly, the thermoelectric element of the embodiment can be formed as a thermoelectric module that is a P-type semiconductor.

Fourth, a method for manufacturing a thermoelectric element will be described.

The thermoelectric device can be manufactured by slicing, plating and cutting the thermoelectric material as the sintered body. The composition and size of the glass frit included in the thermoelectric element may be the same or similar to the composition and size of the glass frit included in the thermoelectric material.

Therefore, the thermoelectric device according to the embodiment may include thermoelectric powder having a composition of Bi _x Sb _{2 - x} Te ₃ (0.4 _{? X?} 0.5) and 0.01 to 0.1 wt% of glass frit.

When the glass frit is contained in the thermoelectric element in an amount of 0.01 wt% to 0.1 wt%, the Seebeck coefficient is high, the thermal conductivity is low, and the figure of merit can be improved. For example, when the thermoelectric element contains 0.01 to 0.1 wt% of glass frit, the figure of merit (ZT) calculated by Equation (1) at 25 DEG C may exceed 1.0. In detail, when the thermoelectric element contains 0.01 to 0.1 wt% of glass frit, the figure of merit (ZT) calculated by Equation (1) at 25 캜 can be 1.05 or more. In detail, when the thermoelectric element contains 0.01 to 0.1% by weight of glass frit, the figure of merit ZT calculated by the above formula (1) at 25 캜 can be 1.1 or more. Thus, the embodiment can provide a thermoelectric device with high efficiency.

If the thermoelectric element does not contain glass frit or contains less than 0.01% by weight, the figure of merit (ZT) at 25 캜 may be less than 1.05.

When the thermoelectric element contains more than 0.1% by weight of glass frit, the figure of merit (ZT) at 25 캜 may be less than 1.05.

The thermoelectric element may be a P-type semiconductor.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. These embodiments are merely illustrative of the present invention in order to explain the present invention in more detail. Therefore, the present invention is not limited to these embodiments.

Example  One

Example 1 shows that Bi _{0 . 4} Sb _{1 . 6} Te ₃ , and 0.01 wt% of glass frit, and sintered by spark plasma sintering (SPS).

The composition of the glass frit was 74.6875 wt% of silicon oxide (SiO ₂ ), 6.25 wt% of aluminum oxide (Al ₂ O ₃ ), 12.8125 wt% of sodium oxide (Na ₂ O), 6.25 wt% of potassium oxide (K ₂ O) Respectively.

The glass transition temperature (Tg) of the glass frit is 333.7 ° C. The dilatometric softening point Ts is 370.2 ° C. and the coefficient of thermal expansion (CTE) is 16.02 × 10 ^-6 / Respectively.

The glass frit had a particle size (D10) at a 10% relative particle content of 5.47 占 퐉, a particle size at a 50% relative particle content (D50) of 8.53 占 퐉, a particle size (D90) at a 90% relative particle content of 32.93 占 퐉 , And the maximum particle size (Dmax) was measured as 40 mu m.

The composition of the glass frit in terms of weight percent by element was 41.02% by weight of oxygen (O), 22.68% by weight of sodium (Na), 1.98% by weight of aluminum (Al), 22.50% by weight of silicon K) of 11.82% by weight. The atomic% composition of the glass frit was 54.23 atomic% of oxygen (O), 20.87 atomic% of sodium (Na), 1.55 atomic% of aluminum (Al), 16.95 atomic% of silicon (Si) and 6.92 atomic% of potassium Respectively.

Example  2

Example 2 shows that Bi _{0 . 4} Sb _{1 . 6} Te ₃ And 0.10% by weight of glass frit, and sintered by spark plasma sintering (SPS).

Example 2 was prepared under the same conditions as in Example 1, except for the weight percentage of glass frit.

Comparative Example  One

In Comparative Example 1, Bi _{0 . 5} Sb _{1 . 5} Te ₃ Is a thermoelectric material sintered by spark plasma sintering (SPS).

Comparative Example 1 was produced under the same conditions as Example 1 except that the composition of the thermoelectric material was different from that of Example 1 and that the glass frit was not included.

Comparative Example  2

Comparative Example 2 is a Bi _{0 . 4} Sb _{1 . 6} Te ₃ Is a thermoelectric material sintered by spark plasma sintering (SPS).

Comparative Example 2 was prepared under the same conditions as in Example 1, except that the glass frit was not included.

Comparative Example  3

Comparative Example 3 is a Bi _{0 . 4} Sb _{1 . 6} Te ₃ And 1.00% by weight of glass frit, and sintered by spark plasma sintering (SPS).

Comparative Example 3 was produced under the same conditions as in Example 1 except for the weight percentage of glass frit.

5 and Experimental Examples 1 to 5 show the thermal conductivity, the Seebeck coefficient, the electrical conductivity, the power factor and the performance index of the Examples and Comparative Examples measured at 25 ° C.

Experimental Example  One: Example  And Comparative example  Measurement results of thermal conductivity

Thermal conductivity (W / Km) Example 1 1.1677 Example 2 1.1163 Comparative Example 1 1.2166 Comparative Example 2 1.1702 Comparative Example 3 1.1026

Referring to Table 1, the thermoelectric materials of Examples 1 and 2 may have a thermal conductivity of 1.1163 W / Km to 1.1677 W / Km.

It was confirmed that the thermal conductivity value of Comparative Example 3 containing a larger amount of glass frit was lowered as compared with Example 1 and Example 2. When the thermoelectric material contained 1.0 wt% of glass frit in excess of 0.1 wt%, the thermal conductivity decreased to 1.1026 W / Km, which was less than 1.11 W / Km.

Experimental Example  2: Example  And Comparative example Of the Seebeck coefficient  Measurement result

Seebeck coefficient (V / K) Example 1 1.91E-04 Example 2 1.93E-04 Comparative Example 1 1.93E-04 Comparative Example 2 1.85E-04 Comparative Example 3 2.00E-04

The thermoelectric materials of Examples 1 and 2 may have a Seebeck coefficient of 1.91E-04 V / K to 1.93E-04 V / K.

Referring to Table 2, it is confirmed that the increase of the glass frit content increases the Seebeck coefficient. The Seebeck coefficient of Example 1 containing 0.01 wt% of glass frit was higher than that of Comparative Example 2 containing no glass frit, and in Example 1 containing 0.10 wt% of glass frit, which is a larger amount of glass frit than Example 1 2, respectively.

Since the Seebeck coefficient has a positive value, it is confirmed that the thermoelectric materials of Examples 1 and 2 can be applied to a p-type semiconductor.

Experimental Example  3: Example  And Comparative example  Measurement results of electrical conductivity

Electrical Conductivity (S / m) Example 1 1.18E + 05 Example 2 1.11E + 05 Comparative Example 1 9.78E + 04 Comparative Example 2 1.18E + 05 Comparative Example 3 9.25E + 04

Referring to Table 3, the thermoelectric materials of Examples 1 and 2 may have electric conductivities of 1.11E + 05 S / m to 1.18E + 05 S / m.

Compared with Example 1 and Example 2, Comparative Example 3, which contained a larger amount of glass frit, confirmed that the electrical conductivity decreased. When the thermoelectric material contained 1.0 wt% of glass frit in an amount exceeding 0.1 wt%, it was confirmed that the electric conductivity decreased to 92500 S / m, which is less than 100000 S / m. Further, in Comparative Example 3 in which more glass frit was contained than in the Examples, it was confirmed that a problem of a tradeoff relation in which the electric conductivity was lowered due to the increase of the Seebeck coefficient occurred.

Experimental Example  4: Example  And Comparative example Power factor  Measurement result

Power Factor (W / mK ² ) Example 1 4.30E-03 Example 2 4.15E-03 Comparative Example 1 3.64E-03 Comparative Example 2 4.02E-03 Comparative Example 3 3.70E-03

The thermoelectric materials of Examples 1 and 2 may have a power factor of 4.30E-03 W / mK ² to 4.15E-03 W / mK ² .

Referring to Table 4, it was confirmed that the power factor was high in Examples 1 and 2.

The power factor value of Example 1 containing glass frit in an amount of 0.01% by weight was significantly larger than that of Comparative Example 2 which did not include glass frit.

It was also confirmed that the power factor of Example 2 containing 0.1 wt% of glass frit was larger than that of Comparative Example 3 containing 1.0 wt% of excess of glass frit.

Experimental Example  5: Example  And Comparative example  Performance Index ( ZT )

Performance Index (ZT) Example 1 1.10 Example 2 1.11 Comparative Example 1 0.892 Comparative Example 2 1.02 Comparative Example 3 1.00

Referring to Table 5, it was confirmed that the performance indices in Examples 1 and 2 have values of 1.10 to 1.11.

It was confirmed that the thermoelectric material of Comparative Example 1 and Comparative Example 2, which did not contain glass frit, and the thermoelectric material of Comparative Example 3, which contained an excess amount of 1.0 wt% of glass frit, had a figure of merit of less than 1.10.

5, a thermoelectric element comprising a thermoelectric powder having a composition of Bi _x Sb _{2 - x} Te ₃ (0.4 _{? X?} 0.5) and 0.01 to 0.1% by weight of glass frit was mixed with 0.01 wt% % &Lt; / RTI &gt; to 0.1% by weight of the total weight of the composition.

Since the p-type thermoelectric material according to the embodiment has a figure of merit of about 1.1 or more at room temperature, a highly efficient thermoelectric module with increased thermoelectric performance can be provided.

The present invention can provide a thermoelectric element by molding the thermoelectric material according to the embodiment by cutting or the like. The thermoelectric element according to the embodiment means that the thermoelectric material is formed into a predetermined shape. For example, the thermoelectric element may have a rectangular parallelepiped shape or a cylindrical shape, but is not limited thereto. Therefore, it is of course possible to provide a thermoelectric element and a thermoelectric module with high efficiency.

Fig. 6 is a cross-sectional view of the thermoelectric element, and Fig. 7 is a perspective view of the thermoelectric element.

6 and 7, the thermoelectric element 100 includes a lower substrate 110, a lower electrode 120, a P-type thermoelectric leg 130, an N-type thermoelectric leg 140, an upper electrode 150, And a substrate 160.

The lower electrode 120 is disposed between the lower substrate 110 and the lower bottom surface of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140. The upper electrode 150 is disposed between the upper substrate 160 and the P- Thermally conductive legs 130 and the N-type thermoelectric legs 140 are disposed between the upper and lower surfaces of the thermo- Accordingly, the plurality of P-type thermoelectric legs 130 and the plurality of N-type thermoelectric legs 140 are electrically connected by the lower electrode 120 and the upper electrode 150. A pair of P-type thermoelectric legs 130 and N-type thermoelectric legs 140, which are disposed between the lower electrode 120 and the upper electrode 150 and are electrically connected to each other, may form a unit cell.

For example, when a voltage is applied to the lower electrode 120 and the upper electrode 150 through the lead wires 181 and 182, the current flows from the P-type thermoelectric leg 130 to the N-type thermoelectric leg 140 due to the Peltier effect, The substrate on which the current flows can act as a cooling part, and the substrate through which current flows from the N-type thermoelectric leg 140 to the P-type thermoelectric leg 130 can be heated and act as a heat generating part.

The thermoelectric leg A may include the thermoelectric element according to the embodiment.

The thermoelectric module according to an embodiment includes a first electrode, a second electrode, and a thermoelectric element disposed between the first electrode and the second electrode, and the thermoelectric element includes Bi _x Sb _{2 - x} Te ₃ (0.4 _x &Lt; / = 0.5); And 0.01% to 0.1% by weight of glass frit.

Here, the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 may be bismuth telluride (Bi-Te) thermoelectric legs containing bismuth (Bi) and tellurium (Te) as main raw materials.

The base material of the P-type thermoelectric leg 130 may be Bi-Sb-Te. The P-type thermoelectric leg 130 may include oxygen (O), sodium (Na), aluminum (Al), silicon (Si), and potassium (K). As described above, the P-type thermoelectric leg 130 has a thermoelectric powder having a composition of Bi _x Sb _{2 - x} Te ₃ (0.4 _{? X?} 0.5), 65 to 80% by weight of silicon oxide (SiO ₂ ) ₂ O ₃₎ is the glass frit may be a sinter having from 5 to 10% by weight, sodium oxide (Na ₂ O) 10 to 15% by weight, potassium oxide (K ₂ O) 5 to 10% by weight of the composition.

The N-type thermoelectric leg 140 is made of selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B) 99 to 99.999 wt% of a bismuth telluride (Bi-Te) based raw material containing at least one of gallium (Ga), tellurium (Te), bismuth (Bi) and indium (In) and 0.001 Lt; / RTI &gt; to 1 wt%. For example, the base material may be Bi-Se-Te, and may further contain Bi or Te in an amount of 0.001 to 1 wt% of the total weight.

The P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 may be formed in a bulk or laminated form. Generally, the bulk type P-type thermoelectric leg 130 or the bulk N-type thermoelectric leg 140 is manufactured by heat-treating the thermoelectric material to produce an ingot, crushing and sieving the ingot to obtain a thermoelectric leg powder, Sintered body, and cutting the sintered body. The laminated P-type thermoelectric leg 130 or the laminated N-type thermoelectric leg 140 is formed by applying a paste containing a thermoelectric material on a sheet-shaped substrate to form a unit member, then stacking and cutting the unit member Can be obtained.

At this time, the pair of the P-type thermoelectric legs 130 and the N-type thermoelectric legs 140 may have the same shape and volume, or may have different shapes and volumes. Since the electrical conduction characteristics of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 are different from each other, the height or the cross-sectional area of the N-type thermoelectric leg 140 may be set to a height or a cross- May be formed differently.

Here, the lower electrode 120 disposed between the lower substrate 110 and the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140, the upper substrate 160 and the P-type thermoelectric leg 130, and the N- The upper electrode 150 disposed between the thermoelectric legs 140 includes at least one of copper (Cu), silver (Ag), and nickel (Ni), and may have a thickness of 0.01 mm to 0.3 mm. When the thickness of the lower electrode 120 or the upper electrode 150 is less than 0.01 mm, the function as an electrode may deteriorate and the electric conduction performance may be lowered. When the thickness is more than 0.3 mm, the conduction efficiency may be lowered due to an increase in resistance .

The lower substrate 110 and the upper substrate 160, which are opposite to each other, may be an insulating substrate or a metal substrate. The insulating substrate may be an alumina substrate or a polymer resin substrate having flexibility. The flexible polymer resin substrate having flexibility has high permeability such as polyimide (PI), polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copoly (COC), polyethylene terephthalate (PET) Plastic, and the like. The metal substrate may include Cu, a Cu alloy, or a Cu-Al alloy, and the thickness may be 0.1 mm to 0.5 mm. If the thickness of the metal substrate is less than 0.1 mm or exceeds 0.5 mm, the heat radiation characteristic or the thermal conductivity may become excessively high, so that the reliability of the thermoelectric device may be deteriorated. When the lower substrate 110 and the upper substrate 160 are metal substrates, a dielectric layer 170 is formed between the lower substrate 110 and the lower electrode 120 and between the upper substrate 160 and the upper electrode 150, Can be formed. The dielectric layer 170 includes a material having a thermal conductivity of 5 to 10 W / K, and may be formed to a thickness of 0.01 mm to 0.15 mm. If the thickness of the dielectric layer 170 is less than 0.01 mm, the insulation efficiency or withstanding voltage characteristics may be deteriorated. If the thickness exceeds 0.15 mm, the thermal conductivity may be lowered and the thermal efficiency may be lowered.

At this time, the sizes of the lower substrate 110 and the upper substrate 160 may be different. For example, the volume, thickness, or area of one of the lower substrate 110 and the upper substrate 160 may be greater than the volume, thickness, or area of the other. Thus, the heat absorption performance or the heat radiation performance of the thermoelectric element can be enhanced.

In addition, a heat radiation pattern, for example, a concavo-convex pattern may be formed on at least one surface of the lower substrate 110 and the upper substrate 160. Thus, the heat radiation performance of the thermoelectric element can be enhanced. When the concavo-convex pattern is formed on the surface contacting the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140, the junction characteristics between the thermoelectric leg and the substrate can be improved.

On the other hand, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 may have a cylindrical shape, a polygonal columnar shape, an elliptical columnar shape, or the like.

According to an embodiment of the present invention, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 may be formed to have a wide width at the portion to be bonded to the electrode.

8 is a cross-sectional view of a thermoelectric leg and an electrode according to an embodiment of the present invention.

Referring to FIG. 8, the thermoelectric leg 130 includes a first element portion 132 having a first cross-sectional area, a second element portion 136 having a second cross-sectional area disposed at a position opposite to the first element portion 132, And a connection part 134 connecting the first element part 132 and the second element part 136 and having a third cross-sectional area. At this time, the cross-sectional area of the connecting portion 134 in an arbitrary region in the horizontal direction may be smaller than the first cross-sectional area or the second cross-sectional area.

If the cross-sectional area of the first element portion 132 and the second element portion 136 is formed to be larger than the cross-sectional area of the connection portion 134 in this manner, the same amount of material can be used to form the first element portion 132 and the second element portion 136, The temperature difference (T) between the electrodes 136 can be increased. Accordingly, since the amount of free electrons moving between the hot side and the cold side increases, the power generation amount increases and the heat generation efficiency or the cooling efficiency becomes high.

At this time, the width B of the section having the longest width among the horizontal sections of the connecting section 134 and the width (A or or) of the larger section of the horizontal sections of the first element section 132 and the second element section 136 C) may be 1: (1.5 to 4). Thus, the power generation efficiency, heat generation efficiency or cooling efficiency can be increased.

Here, the first element portion 132, the second element portion 136, and the connecting portion 134 may be integrally formed using the same material.

The thermoelectric leg according to an embodiment of the present invention may have a laminated structure. For example, the P-type thermoelectric leg or the N-type thermoelectric leg may be formed by stacking a plurality of structures coated with a semiconductor material on a sheet-like base material and then cutting the same. Thus, it is possible to prevent the loss of the material and improve the electric conduction characteristic.

Fig. 9 shows a method of manufacturing a thermoelectric leg of a laminated structure.

Referring to FIG. 9, a material including a semiconductor material is formed into a paste and then coated on a substrate 1110 such as a sheet or a film to form a semiconductor layer 1120. Accordingly, one unit member 1100 can be formed.

A plurality of unit members 1100a, 1100b, and 1100c are laminated to form a laminated structure 1200, and the unit thermoelectric leg 1300 can be obtained by cutting the unit structure.

As described above, the unit thermoelectric leg 1300 can be formed by a structure in which a plurality of unit members 1100 in which a semiconductor layer 1120 is formed on a substrate 1110 are laminated.

Here, the step of applying the paste on the substrate 1110 can be performed in various ways. For example, by a tape casting method. The tape casting method comprises mixing a powder of a fine semiconductor material with at least one selected from the group consisting of an aqueous or non-aqueous solvent, a binder, a plasticizer, a dispersant, a defoamer and a surfactant to form a slurry (slurry), and then molding on a moving blade or moving substrate. At this time, the substrate 1110 may be a film, a sheet, or the like having a thickness of 10 to 100 μm. As the semiconductor material to be applied, the P-type thermoelectric material or the N-type thermoelectric material for manufacturing the above-described bulk-type device may be directly applied.

The step of laminating the unit member 1100 in a plurality of layers may be performed by a method of pressing at a temperature of 50 ° C to 250 ° C. The number of the unit members 110 to be laminated is, for example, 2 to 50 . Thereafter, it can be cut into a desired shape and size, and a sintering process can be added.

The unit thermoelectric legs 1300 thus manufactured can ensure uniformity in thickness, shape, and size, and are advantageous in that they are thin and can reduce loss of materials.

The unit thermoelectric leg 1300 may have a cylindrical shape, a polygonal columnar shape, an elliptical columnar shape, or the like, and may be cut into a shape as illustrated in Fig. 9D.

On the other hand, a conductive layer may be further formed on one surface of the unit member 1100 in order to manufacture the thermoelectric leg of the laminated structure.

10 illustrates a conductive layer formed between unit members in the stacked structure of FIG.

10, the conductive layer C may be formed on the opposite side of the substrate 1110 on which the semiconductor layer 1120 is formed, and may be patterned such that a part of the surface of the substrate 1110 is exposed.

Fig. 10 shows various modifications of the conductive layer (C) according to the embodiment of the present invention. As shown in Figs. 10 (a) and 10 (b), as shown in a mesh type structure including closed-type opening patterns c1 and c2 or as shown in Figs. 10 (c) and 10 A line-type structure including open-type opening patterns c3 and c4, and the like.

The conductive layer (C) can increase the adhesion between the unit members in the unit thermoelectric legs formed by the laminated structure of the unit members, lower the thermal conductivity between the unit members, and improve the electrical conductivity. The conductive layer (C) may be a metal material, for example, Cu, Ag, Ni or the like.

On the other hand, the unit thermoelectric leg 1300 may be cut in a direction as shown in Fig. According to this structure, the thermal conduction efficiency in the vertical direction can be lowered and the electric conduction characteristic can be improved, so that the cooling efficiency can be improved.

The thermoelectric element according to the embodiment described above can be disposed together with the heat transfer member.

12 to 14 are conceptual diagrams of a heat transfer member disposed on a thermoelectric material according to an embodiment of the present invention.

12 to 14, a heat transfer member 2200 according to an embodiment of the present invention is a flat plate shaped substrate having a first plane 2210 and a second plane 2220, At least one flow path pattern 2200A.

12 to 14, the flow path pattern 2200A has a structure for folding a substrate so that a curvature pattern having a constant pitch P1 or P2 and a height T1 is formed, that is, .

As described above, the air is in surface contact with the first plane 2210 and the second plane 2220 of the heat transfer member 2200, and the area of air contact with the air by the flow path pattern 2200A can be maximized.

Referring to FIG. 12, when air flows in the flow direction C1, the air moves evenly in contact with the first plane 2210 and the second plane 222 and proceeds in the flow direction C2. As a result, the contact surface with the air is wider than that of a simple plate-like base material, so that the effect of heat absorption and heat generation is increased.

According to the embodiment of the present invention, a protruding resistance pattern 2230 may be formed on the surface of the substrate to further increase the contact area of air.

Further, as shown in FIG. 13, the resistance pattern 2230 may be formed as a protruding structure inclined so as to have a constant inclination angle? In a direction in which air is introduced. Thus, friction between the resistance pattern 2230 and the air can be maximized, so that the contact area or contact efficiency can be increased. Further, a groove 2240 may be formed on the base surface of the front portion of the resistance pattern 2230. A part of the air in contact with the resistance pattern 223 passes through the groove 2240 and moves between the front surface and the rear surface of the substrate so that the contact area or contact efficiency can be further increased.

Although the resistance pattern 2230 is shown as being formed on the first plane 2210, it is not limited thereto and may be formed on the second plane 2220.

Referring to FIG. 14, the flow path pattern may have various modifications.

For example, it is possible to repeatedly form a pattern having a curvature at a constant pitch P1 as shown in Fig. 14 (a), repeatedly form a pattern having an attachment as shown in Fig. 14 (b) The unit pattern may have a polygonal structure as shown in Fig. 14 (d). Although not shown, it is needless to say that a resistance pattern may be formed on the surfaces B1 and B2 of the pattern.

In Fig. 14, although the flow path pattern has a constant period and height, the present invention is not limited thereto, and the period and height T1 of the flow path pattern may be unevenly deformed.

The thermoelectric device according to the embodiment of the present invention can be applied to a power generation device, a cooling device, a thermal device, and the like. Specifically, the thermoelectric device according to an embodiment of the present invention mainly includes an optical communication module, a sensor, a medical instrument, a measuring instrument, an aerospace industry, a refrigerator, a chiller, a ventilation sheet, a cup holder, a washing machine, , A water purifier, a power supply for a sensor, a thermopile, and the like.

Here, as an example in which the thermoelectric element according to the embodiment of the present invention is applied to a medical instrument, there is a PCR (Polymerase Chain Reaction) device. The PCR device is a device for amplifying DNA to determine the DNA sequence and is a device that requires precise temperature control and thermal cycling. For this purpose, a Peltier based thermoelectric element can be applied.

Another example in which a thermoelectric element according to an embodiment of the present invention is applied to a medical instrument is a photodetector. Here, the photodetector includes an infrared / ultraviolet detector, a CCD (Charge Coupled Device) sensor, an X-ray detector, and a TTRS (Thermoelectric Thermal Reference Source). A Peltier-based thermoelectric device can be applied for cooling the photodetector. Thus, it is possible to prevent a wavelength change, an output drop, and a resolution degradation due to a temperature rise inside the photodetector.

Another example in which a thermoelectric device according to an embodiment of the present invention is applied to a medical instrument includes an immunoassay field, an in vitro diagnostics field, a general temperature control and cooling system, Physiotherapy field, liquid chiller system, and blood / plasma temperature control field. Thus, precise temperature control is possible.

Another example in which a thermoelectric element according to an embodiment of the present invention is applied to a medical instrument is an artificial heart. Thus, power can be supplied to the artificial heart.

Examples of applications of the thermoelectric devices according to the embodiments of the present invention to the aerospace industry include star tracking systems, thermal imaging cameras, infrared / ultraviolet detectors, CCD sensors, Hubble Space Telescopes and TTRS. Accordingly, the temperature of the image sensor can be maintained.

Other examples in which the thermoelectric device according to the embodiment of the present invention is applied to the aerospace industry include a cooling device, a heater, a power generation device, and the like.

In addition, the thermoelectric device according to the embodiment of the present invention can be applied to power generation, cooling, and heating in other industrial fields.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention as defined by the following claims It can be understood that

100: thermoelectric element
110: Lower substrate
120: Lower electrode
130: P-type thermoelectric leg
140: N-type thermoregulation leg
150: upper electrode
160: upper substrate

Claims (10)

Thermoelectric powders according to formula (1); And
0.0 &gt; 0.1% &lt; / RTI &gt; by weight of glass frit.
&Lt; Formula 1 &gt;
Bi _x Sb _{2 - x} Te ₃ (0.4 _{? X?} 0.5) The method according to claim 1,
The glass frit is a thermoelectric material which is a silicon oxide (SiO ₂ ) - aluminum oxide (Al ₂ O ₃ ) - sodium oxide (Na ₂ O) - potassium oxide (K ₂ O) 3. The method of claim 2,
Wherein the glass frit comprises 65 to 80 wt% of silicon oxide (SiO ₂ ), 5 to 10 wt% of aluminum oxide (Al ₂ O ₃ ), 10 to 15 wt% of sodium oxide (Na ₂ O), potassium oxide (K ₂ O) 5 to 10% by weight. The method according to claim 1,
Wherein the glass frit comprises a first glass frit having a particle size of less than 10 mu m and a second glass frit having a particle size of more than 10 mu m. The method according to claim 1,
Wherein the glass frit comprises:
A particle size (D10) at 10% relative particle content of 3 mu m to 7 mu m,
And a particle size (D90) at 90% relative particle content of 30 占 퐉 to 35 占 퐉. The thermoelectric material according to claim 2, wherein the glass frit is amorphous. A lower substrate;
A first electrode disposed on the lower substrate;
A thermoelectric element disposed on the first electrode;
A second electrode disposed on the thermoelectric element; And
And an upper substrate disposed on the second electrode,
Wherein the thermoelectric element comprises a thermoelectric powder according to Formula 1; And 0.01% to 0.1% by weight of glass frit.
&Lt; Formula 1 >
Bi _x Sb _{2 - x} Te ₃ (0.4 _{? X?} 0.5) The glass frit of claim 7, wherein the glass frit comprises from 65 to 80 wt% silicon oxide (SiO ₂ ), from 5 to 10 wt% aluminum oxide (Al ₂ O ₃ ), from 10 to 15 wt% sodium oxide (Na ₂ O) And 5 to 10% by weight of potassium (K ₂ O). 8. The method of claim 7,
Wherein the thermoelectric element has a figure of merit (ZT) calculated by Equation (1) at 25 DEG C of more than 1.0.
&Quot; (1) &quot;

In Equation (1), ZT represents a figure of merit, S represents a Seebeck coefficient,? Represents electrical conductivity, T represents absolute temperature, and k represents thermal conductivity. The thermoelectric module according to claim 7, wherein the thermoelectric element is a P-type semiconductor.

Images