KR20200114779A - Thermo electric leg and thermo electric element comprising the same - Google Patents

Abstract

According to an embodiment of the present invention, provided is a thermoelectric leg which provides stable thermoelectric performance. The thermoelectric leg comprises: a first metal layer; a first plating layer disposed on the first metal layer; a first reaction layer disposed on the first plating layer and including Te; a thermoelectric material layer disposed on the first reaction layer and including Bi and Te; a second reaction layer disposed on the thermoelectric material layer and including Te; a second plating layer disposed on the second reaction layer; and a second metal layer disposed on the second plating layer. The thermoelectric material layer includes: a first region in which a ratio of a content of Te to a content of Bi is greater than or equal to 1.05 and less than 1.2; a second region which is disposed between the first region and the first reaction layer, wherein the ratio of the content of Te to the content of Bi is greater than 1.2 and less than 1.35; and a third region which is disposed between the first region and the second reaction layer, wherein the ratio of the content of Te to the content of Bi is greater than 1.2 and less than 1.35.

Description

Thermoelectric leg and thermoelectric element including the same {THERMO ELECTRIC LEG AND THERMO ELECTRIC ELEMENT COMPRISING THE SAME}

The present invention relates to a thermoelectric element, and more particularly, to a thermoelectric leg included in the thermoelectric element.

The thermoelectric phenomenon is a phenomenon that occurs by the movement of electrons and holes in a material, and means direct energy conversion between heat and electricity.

The thermoelectric element is a generic term for a device using a thermoelectric phenomenon, and has a structure in which a P-type thermoelectric leg and an N-type thermoelectric leg are bonded between metal electrodes to form a PN junction pair.

Thermoelectric devices can be divided into devices that use the temperature change of electrical resistance, devices that use the Seebeck effect, which is a phenomenon in which electromotive force is generated due to the temperature difference, and devices that use the Peltier effect, which is a phenomenon in which heat absorption or heat generation by current occurs. .

Thermoelectric elements are applied in various ways to home appliances, electronic parts, and communication parts. For example, the thermoelectric element may be applied to a cooling device, a heating device, a power generation device, or the like. Accordingly, the demand for thermoelectric performance of a thermoelectric element is increasing more and more.

Meanwhile, in order to stably bond the thermoelectric leg to the electrode, a metal layer may be formed between the thermoelectric leg and the electrode. In this case, a plating layer may be formed between the thermoelectric leg and the metal layer to prevent the thermoelectric performance from deteriorating due to a reaction between the semiconductor material and the metal layer in the thermoelectric leg and to prevent oxidation of the metal layer.

However, in the process of simultaneously sintering the plating layer and the thermoelectric leg, part of the semiconductor material in the thermoelectric leg may diffuse into the plating layer, and thus, the semiconductor material may be unevenly distributed at the boundary between the plating layer and the thermoelectric leg. For example, when the thermoelectric leg includes Bi and Te, when Te diffuses into the plating layer, a Bi-rich layer containing a relatively large amount of Bi may be formed. Resistance increases in the Bi-rich layer, which may result in degradation of the thermoelectric element performance.

The technical problem to be achieved by the present invention is to provide a thermoelectric element having excellent thermoelectric performance and a thermoelectric leg included therein.

The thermoelectric leg according to an embodiment of the present invention includes a first metal layer, a first plating layer disposed on the first metal layer, a first reaction layer disposed on the first plating layer and including Te, and on the first reaction layer. A thermoelectric material layer disposed on and including Bi and Te, a second reaction layer disposed on the thermoelectric material layer and including Te, a second plating layer disposed on the second reaction layer, and on the second plating layer And a second metal layer disposed in the thermoelectric material layer, wherein the thermoelectric material layer comprises a first region in which a ratio of the content of Te to the content of Bi is 1.05 or more and less than 1.2, and is disposed between the first region and the first reaction layer, A second region in which the ratio of the content of Te to the content exceeds 1.2 and is less than 1.35, and the third region disposed between the first region and the second reaction layer, wherein the ratio of the content of Te to the content of Bi exceeds 1.2 and is less than 1.35 Include area.

The first plating layer may include at least one metal of Ni, Sn, Ti, Fe, Sb, Cr, and Mo, and the first reaction layer may further include the at least one metal included in the first plating layer. have.

The boundary region between the thermoelectric material layer and the first reaction layer may include the at least one metal and Bi included in the first plating layer, and a ratio of the content of Te to the content of Bi may exceed 1.35.

The content of Te in the first reaction layer is higher than the content of the at least one metal included in the first plating layer, the content of Te decreases from the thermoelectric material layer toward the first plating layer, and the first The content of the at least one metal included in the plating layer may be increased.

The boundary area between the first reaction layer and the first plating layer may include a point where the content of the at least one metal included in the first plating layer is higher than the content of Te.

The content of Te in the second area relative to the content of Te in the first area may be 1.01 to 1.2.

The content of Te in the second area relative to the content of Te in the first area may be 1.05 to 1.15.

The thermoelectric material layer is antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tellurium (Te) , At least one of bismuth (Bi) and indium (In) may be further included.

At least one of the first metal layer and the second metal layer may be selected from copper, a copper alloy, aluminum, and an aluminum alloy.

At least one of the first metal layer and the second metal layer may include aluminum, and at least one of the first plating layer and the second plating layer may include Ni.

The thermoelectric device according to an embodiment of the present invention includes a first substrate, a plurality of P-type thermoelectric legs and a plurality of N-type thermoelectric legs alternately disposed on the first substrate, the plurality of P-type thermoelectric legs, and the plurality of A second substrate disposed on the N-type thermoelectric leg, a plurality of first electrodes connecting the first substrate and the plurality of P-type thermoelectric legs and the plurality of N-type thermoelectric legs in series, and the second substrate and the plurality of A P-type thermoelectric leg and a plurality of second electrodes connecting the plurality of N-type thermoelectric legs in series, wherein any one of the plurality of P-type thermoelectric legs and the plurality of N-type thermoelectric legs is a first metal layer, the A first plating layer disposed on the first metal layer, a first reaction layer disposed on the first plating layer and including Te, a thermoelectric material layer disposed on the first reaction layer and including Bi and Te, the thermoelectric A second reaction layer disposed on the material layer and including Te, a second plating layer disposed on the second reaction layer, and a second metal layer disposed on the second plating layer, wherein the thermoelectric material layer is Bi A first region in which the ratio of the content of Te to the content of is 1.05 or more and less than 1.2, and a second region disposed between the first region and the first reaction layer, wherein the ratio of the content of Te to the content of Bi exceeds 1.2 and is less than 1.35 A region and a third region disposed between the first region and the second reaction layer, wherein the ratio of the content of Te to the content of Bi is greater than 1.2 and less than 1.35.

At least one of the first substrate and the second substrate may include a metal.

At least one of between the first substrate and the plurality of first electrodes and between the second substrate and the plurality of second electrodes may further include a dielectric layer.

At least one of the volume, thickness, and area of the first substrate and the second substrate may be different from each other.

According to an embodiment of the present invention, it is possible to obtain a thermoelectric element having excellent thermoelectric performance and a thin and small size. In particular, it is possible to obtain a thermoelectric leg that stably bonds to an electrode and provides a stable thermoelectric performance due to a uniform distribution of the semiconductor material.

1 is a cross-sectional view of a thermoelectric device, and FIG. 2 is a perspective view of a thermoelectric device.
3 is a cross-sectional view of a thermoelectric leg according to an embodiment of the present invention.
4(a) is a schematic diagram of the thermoelectric leg of FIG. 3, and FIG. 4(b) is a cross-sectional view of a thermoelectric element including the thermoelectric leg of FIG. 4(a).
5 is a graph showing a rate of change in resistance according to the thickness of a reaction layer.
6 is a cross-sectional view of a thermoelectric leg and a distribution of Te content in the thermoelectric leg according to an embodiment of the present invention.
7 to 8 illustrate a method of manufacturing a thermoelectric leg according to an embodiment of the present invention.
9 is a graph showing a normalized composition distribution for each region of a thermoelectric leg.
10 shows a method of manufacturing a thermoelectric leg according to a comparative example.
11 shows the Te content of each region of a thermoelectric leg according to a comparative example.
12 shows a composition distribution for each region of a thermoelectric leg according to a comparative example.

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

However, the technical idea of the present invention is not limited to some embodiments to be described, but may be implemented in various different forms, and within the scope of the technical idea of the present invention, one or more of the constituent elements may be selectively selected between the embodiments. It can be combined with and substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention are generally understood by those of ordinary skill in the art, unless explicitly defined and described. It can be interpreted as a meaning, and terms generally used, such as terms defined in a dictionary, may be interpreted in consideration of the meaning in the context of the related technology.

In addition, terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, the singular form may include the plural form unless specifically stated in the phrase, and when described as "at least one (or more than one) of A and (and) B and C", it is combined with A, B, and C. It may contain one or more of all possible combinations.

In addition, terms such as first, second, A, B, (a), and (b) may be used in describing the constituent elements of the embodiment of the present invention.

These terms are only for distinguishing the component from other components, and are not limited to the nature, order, or order of the component by the term.

And, when a component is described as being'connected','coupled' or'connected' to another component, the component is not only directly connected, coupled or connected to the other component, but also the component and It may also include the case of being'connected','coupled' or'connected' due to another component between the other components.

In addition, when it is described as being formed or disposed in the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) is one as well as when the two components are in direct contact with each other. It also includes a case in which the above other component is formed or disposed between the two components. In addition, when expressed as "upper (upper) or lower (lower)", the meaning of not only an upward direction but also a downward direction based on one component may be included.

1 is a cross-sectional view of a thermoelectric device, and FIG. 2 is a perspective view of a thermoelectric device.

1 to 2, the thermoelectric device 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 an upper substrate. Includes 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, and the upper electrode 150 is the upper substrate 160 and the P-type It is disposed between the thermoelectric leg 130 and the upper bottom surface of the N-type thermoelectric leg 140. 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 disposed between the lower electrode 120 and the upper electrode 150 and electrically connected to each other may form a unit cell.

For example, when voltage is applied to the lower electrode 120 and the upper electrode 150 through the lead wires 181 and 182, current from the P-type thermoelectric leg 130 to the N-type thermoelectric leg 140 due to the Peltier effect The substrate that flows through absorbs heat and acts as a cooling unit, and the substrate through which current flows from the N-type thermoelectric leg 140 to the P-type thermoelectric leg 130 may be heated to function as a heat generating unit. Alternatively, when a temperature difference between the lower electrode 120 and the upper electrode 150 is applied, charges in the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 move due to the Seebeck effect, and electricity may be generated. .

Here, the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 may be bismuth steluride (Bi-Te) based thermoelectric legs including bismuth (Bi) and tellurium (Te) as main raw materials. P-type thermoelectric leg 130 is antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tellurium It may be a bismuth steluride (Bi-Te)-based thermoelectric leg containing at least one of (Te), bismuth (Bi), and indium (In). For example, the P-type thermoelectric leg 130 contains 99 to 99.999 wt% of Bi-Sb-Te, which is a main raw material, based on 100 wt% of the total weight, and nickel (Ni), aluminum (Al), and copper (Cu) , Silver (Ag), lead (Pb), boron (B), gallium (Ga), and at least one of indium (In) may contain 0.001 to 1 wt%. The N-type thermoelectric leg 140 includes selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), and tellurium. It may be a bismuth steluride (Bi-Te)-based thermoelectric leg containing at least one of (Te), bismuth (Bi), and indium (In). For example, the N-type thermoelectric leg 140 contains 99 to 99.999 wt% of Bi-Se-Te, which is a main raw material, based on 100 wt% of the total weight, and nickel (Ni), aluminum (Al), and copper (Cu) , Silver (Ag), lead (Pb), boron (B), gallium (Ga), and at least one of indium (In) may contain 0.001 to 1 wt%.

The P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 may be formed in a bulk type or a stacked type. In general, the bulk-type P-type thermoelectric leg 130 or the bulk-type N-type thermoelectric leg 140 heats a thermoelectric material to produce an ingot, pulverizes the ingot and sifts it to obtain powder for thermoelectric legs, It can be obtained through the process of sintering and cutting the sintered body. In this case, the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 may be polycrystalline thermoelectric legs. For polycrystalline thermoelectric legs, when the powder for thermoelectric legs is sintered, it can be compressed to 100 MPa to 200 MPa. For example, when the P-type thermoelectric leg 130 is sintered, the powder for the thermoelectric leg may be sintered to 100 to 150 MPa, preferably 110 to 140 MPa, and more preferably 120 to 130 MPa. In addition, when the N-type thermoelectric leg 130 is sintered, the powder for the thermoelectric leg may be sintered to 150 to 200 MPa, preferably 160 to 195 MPa, and more preferably 170 to 190 MPa. As described above, when the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 are polycrystalline thermoelectric legs, the strength of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 may be increased. The stacked P-type thermoelectric leg 130 or the stacked N-type thermoelectric leg 140 forms a unit member by applying a paste containing a thermoelectric material on a sheet-shaped substrate, and then laminating and cutting the unit member. Can be obtained.

In this case, the pair of P-type thermoelectric legs 130 and N-type thermoelectric legs 140 may have the same shape and volume, or may have different shapes and volumes. For example, since the electrical conduction characteristics of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 are different, the height or cross-sectional area of the N-type thermoelectric leg 140 is the height or cross-sectional area of the P-type thermoelectric leg 130 It can also be formed differently.

At this time, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 may have a cylindrical shape, a polygonal column shape, an elliptical column shape, or the like.

Alternatively, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 may have a stacked structure. For example, the P-type thermoelectric leg or the N-type thermoelectric leg may be formed by laminating a plurality of structures coated with a semiconductor material on a sheet-shaped substrate and then cutting them. Accordingly, it is possible to prevent material loss and improve electrical conduction properties. Each structure may further include a conductive layer having an opening pattern, thereby increasing adhesion between structures, lowering thermal conductivity, and increasing electrical conductivity.

Alternatively, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 may be formed to have different cross-sectional areas within one thermoelectric leg. For example, a cross-sectional area of both ends disposed to face the electrode in one thermoelectric leg may be formed larger than a cross-sectional area between both ends. Accordingly, since the temperature difference between both ends can be formed large, thermoelectric efficiency can be increased.

The performance of the thermoelectric device according to an embodiment of the present invention may be expressed as a figure of merit (ZT). The thermoelectric performance index (ZT) can be expressed as in Equation 1.

Here, α is the Seebeck coefficient [V/K], σ is the electrical conductivity [S/m], and α ² σ is the power factor (W/mK ² ]). And, T is the temperature, and k is the thermal conductivity [W/mK]. k can be expressed as a·c _p ·ρ, a is the thermal diffusivity [cm ² /S], c _p is the specific heat [J/gK], and ρ is the density [g/cm ³ ].

In order to obtain the thermoelectric performance index of the thermoelectric element, the Z value (V/K) is measured using a Z meter, and the thermoelectric performance index (ZT) can be calculated using the measured Z value.

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, and the upper substrate 160 and the P-type thermoelectric leg 130 and N-type The upper electrode 150 disposed between the thermoelectric legs 140 includes at least one of copper (Cu), silver (Ag), aluminum (Al), and nickel (Ni), and has a thickness of 0.01mm to 0.3mm. I can. If the thickness of the lower electrode 120 or the upper electrode 150 is less than 0.01 mm, the function as an electrode may be degraded, resulting in a decrease in electrical conduction performance, and if it exceeds 0.3 mm, the conduction efficiency may decrease due to an increase in resistance. .

In addition, the lower substrate 110 and the upper substrate 160 facing each other may be an insulating substrate or a metal substrate. When the lower substrate 110 and the upper substrate 160 are metal substrates, they may include Cu, Cu alloy, Al, Al alloy, or Cu-Al alloy, and the thickness may be 0.1mm to 0.5mm. When the thickness of the metal substrate is less than 0.1 mm or exceeds 0.5 mm, heat dissipation characteristics or thermal conductivity may be excessively high, and thus reliability of the thermoelectric element may be deteriorated. In addition, when the lower substrate 110 and the upper substrate 160 are metal substrates, a resin 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, respectively. ) Can be further formed. The resin layer 170 includes a material having a thermal conductivity of 5 to 20 W/mK, and may be formed to a thickness of 0.01 mm to 0.15 mm. When the thickness of the resin layer 170 is less than 0.01 mm, insulation efficiency or withstand voltage characteristics may be deteriorated, and when the thickness of the resin layer 170 is greater than 0.15 mm, thermal conductivity may be lowered and heat dissipation efficiency may decrease.

When the lower substrate 110 and the upper substrate 160 are insulating substrates, they may be an alumina substrate or a polymer resin substrate. Polymeric resin substrates include polyimide (PI), polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copoly (COC), polyethylene terephthalate (PET), and highly permeable plastics such as resin. It may contain various insulating resin materials, and may be flexible.

The resin layer 170 is made of an epoxy resin composition including an epoxy resin and an inorganic filler, or a silicone resin composition including a silicone resin such as PDMS (polydimethylsiloxane) and an inorganic filler, and the lower substrate 110 or the upper substrate 160 When) is a metal substrate, bonding strength with the thermoelectric element 100 may be increased.

Here, the inorganic filler may be included in 68 to 88 vol% of the polymer resin substrate. If the inorganic filler is contained in less than 68 vol%, the heat conduction effect may be low, and if the inorganic filler is included in excess of 88 vol%, the polymer resin substrate may be easily broken.

The thickness of the resin layer 170 may be 0.02 to 0.6mm, preferably 0.1 to 0.6mm, more preferably 0.2 to 0.6mm, and the thermal conductivity is 1W/mK or more, preferably 10W/mK or more, and more Preferably, it may be 20W/mK or more. When the thickness of the polymer resin substrate satisfies this numerical range, even if the polymer resin substrate repeatedly contracts and expands according to temperature changes, bonding to the metal substrate may not be affected.

To this end, the epoxy resin may include an epoxy compound and a curing agent. In this case, the curing agent may be included in a volume ratio of 1 to 10 with respect to 10 volume ratio of the epoxy compound. Here, the epoxy compound may include at least one of a crystalline epoxy compound, an amorphous epoxy compound, and a silicone epoxy compound. The inorganic filler may include aluminum oxide and nitride, and the nitride may be included as 55 to 95 wt% of the inorganic filler, and more preferably 60 to 80 wt%. When the nitride is included in this numerical range, thermal conductivity and bonding strength can be increased. Here, the nitride may include at least one of boron nitride and aluminum nitride.

In this case, the nitride may be a boron nitride agglomerate, the particle size D50 of the boron nitride agglomerate may be 250 to 350 μm, and the particle size D50 of the aluminum oxide may be 10 to 30 μm. When the particle size D50 of the boron nitride agglomerates and the particle size D50 of the aluminum oxide satisfy these numerical ranges, the boron nitride agglomerates and aluminum oxide can be evenly dispersed in the polymer resin substrate, and thus even heat conduction effect and adhesion throughout the polymer resin substrate You can have performance.

In this case, the size of the lower substrate 110 and the upper substrate 160 may be formed differently. For example, the volume, thickness, or area of one of the lower substrate 110 and the upper substrate 160 may be formed larger than the other volume, thickness, or area. Accordingly, heat absorption performance or heat dissipation performance of the thermoelectric element can be improved. In addition, one of the lower substrate 110 and the upper substrate 160 may be a metal substrate, and the other may be an insulating substrate.

In addition, a heat radiation pattern, for example, an uneven pattern may be formed on at least one surface of the lower substrate 110 and the upper substrate 160. Accordingly, the heat dissipation performance of the thermoelectric element can be improved. When the uneven pattern is formed on a surface in contact with the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140, bonding characteristics between the thermoelectric leg and the substrate may also be improved.

According to an embodiment of the present invention, metal layers are formed on both sides of the thermoelectric leg for stable coupling between the thermoelectric leg and the electrode.

3 is a cross-sectional view of a thermoelectric leg according to an embodiment of the present invention, FIG. 4(a) is a schematic diagram of the thermoelectric leg of FIG. 3, and FIG. 4(b) is a thermoelectric leg including the thermoelectric leg of FIG. 4(a). It is a cross-sectional view of the device.

3, 4(a) and 4(b), the thermoelectric leg 700 according to an embodiment of the present invention is disposed on one side of the thermoelectric material layer 710 and the thermoelectric material layer 710. The first plating layer 720, the second plating layer 730 disposed on the other side disposed opposite to one side of the thermoelectric material layer 710, between the thermoelectric material layer 710 and the first plating layer 720, and thermoelectric On the first and second reaction layers 740 and 750 respectively disposed between the material layer 710 and the second plating layer 730, and on the first plating layer 720 and the second plating layer 730, respectively The first metal layer 760 and the second metal layer 770 are disposed.

That is, the thermoelectric leg 700 according to an embodiment of the present invention includes a thermoelectric material layer 710, a first metal layer 760 disposed on one side of the thermoelectric material layer 710, and on the other side opposite to the one side. ) And the second metal layer 770, the first reaction layer 740 disposed between the thermoelectric material layer 710 and the first metal layer 760, and the thermoelectric material layer 710 and the second metal layer 770 The second reaction layer 750 to be formed, and between the first plating layer 720 and the second metal layer 770 and the second reaction layer 750 disposed between the first metal layer 760 and the first reaction layer 740 And a second plating layer 730 disposed thereon.

Here, the thermoelectric material layer 710 may include bismuth (Bi) and tellurium (Te), which are semiconductor materials. The thermoelectric material layer 710 may have the same material or shape as the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 described in FIGS. 1 to 2.

And, the first metal layer 760 and the second metal layer 770 may be selected from copper (Cu), copper alloy, aluminum (Al) and aluminum alloy, 0.1 to 0.5 mm, preferably 0.2 to 0.3 mm It can have a thickness. Since the coefficient of thermal expansion of the first metal layer 760 and the second metal layer 770 is similar to or greater than the coefficient of thermal expansion of the thermoelectric material layer 710, the first metal layer 760 and the second metal layer 770 and Since compressive stress is applied at the interface between the thermoelectric material layers 710, cracking or peeling can be prevented. In addition, since the bonding force between the first metal layer 760 and the second metal layer 770 and the electrodes 120 and 150 is high, the thermoelectric leg 700 can stably couple with the electrodes 120 and 150.

Next, the first plating layer 720 and the second plating layer 730 may each include at least one of Ni, Sn, Ti, Fe, Sb, Cr, and Mo, and 1 to 20 μm, preferably 1 to It may have a thickness of 10 μm. The first plating layer 720 and the second plating layer 730 prevent a reaction between Bi or Te, which is a semiconductor material in the thermoelectric material layer 710, and the first metal layer 760 and the second metal layer 770. In addition to preventing performance degradation, oxidation of the first metal layer 760 and the second metal layer 770 may be prevented.

At this time, the first reaction layer 740 and the second reaction layer 750 are disposed between the thermoelectric material layer 710 and the first plating layer 720 and between the thermoelectric material layer 710 and the second plating layer 730. I can. In this case, the first reaction layer 740 and the second reaction layer 750 may include Te, and may further include a metal included in the first plating layer 720 and the second plating layer 730. For example, the first reaction layer 740 and the second reaction layer 750 are at least one of Ni-Te, Sn-Te, Ti-Te, Fe-Te, Sb-Te, Cr-Te and Mo-Te It may include. According to an embodiment of the present invention, the thickness of each of the first reaction layer 740 and the second reaction layer 750 is 1 to 100㎛, preferably 1 to 40㎛, more preferably 1 to 30㎛, further Preferably it may be 1 to 20㎛. Referring to FIG. 5, which is a graph showing the rate of change in resistance according to the thickness of the reactive layer, it can be seen that the rate of change in resistance increases as the thickness of the reactive layer increases. In particular, when the thickness of the reaction layer exceeds 100 μm, the rate of change in resistance increases rapidly, and as a result, the thermoelectric performance of the thermoelectric element may be adversely affected.

In general, among the semiconductor materials included in the thermoelectric material layer 710, Te is a first plating layer 720 and a second plating layer 730 including at least one of Ni, Sn, Ti, Fe, Sb, Cr, and Mo. Easy to spread When Te in the thermoelectric material layer 710 is diffused into the first plating layer 720 and the second plating layer 730, near the boundary between the thermoelectric material layer 710 and the first plating layer 720 and the second plating layer 730 Compared to Te, a region in which Bi is more distributed (hereinafter referred to as a Bi-rich region) may occur. The Bi-rich region may be a Te-poor region, and in the Te-poor region, the carrier concentration decreases, so that the resistance in the thermoelectric leg 700 increases, and as a result, performance of the thermoelectric element may be deteriorated.

Accordingly, in the embodiment of the present invention, it is intended to prevent the occurrence of the Bi-rich region.

According to an embodiment of the present invention, the content of Te is higher than the content of Bi in all regions of the thermoelectric material layer 710.

6 is a cross-sectional view of a thermoelectric leg and a distribution of Te content in the thermoelectric leg according to an embodiment of the present invention, and FIGS. 7 to 8 illustrate a method of manufacturing a thermoelectric leg according to an embodiment of the present invention.

6, the thermoelectric leg 700 according to an embodiment of the present invention includes a thermoelectric material layer 710, a first plating layer 720, a second plating layer 730, a first reaction layer 740, and a second The reactive layer 750, the first metal layer 760, and the second metal layer 770 are included, and in this regard, duplicate descriptions of the same contents as those described in FIGS. 1 to 4 will be omitted.

According to an embodiment of the present invention, the thermoelectric material layer 710 includes Bi and Te, and the content of Te is higher than the content of Bi in all regions of the thermoelectric material layer 710. In the present specification, the content may be mixed with weight ratio, atomic weight ratio, mole ratio, weight percentage, atomic weight percentage, mole percentage, wt%, at%, mol%, and the like.

In the thermoelectric material layer 710 according to an embodiment of the present invention, the thermoelectric material layer 710 may include a first region 712, a second region 714, and a third region 716, and the first region 712 may mean an area including the center C of the thermoelectric material layer 710, and the second area 714 is disposed between the first area 712 and the first reaction layer 740. It may mean a region, and the third region 716 may mean a region disposed between the first region 712 and the second reaction layer 750. The first region 712 may be distinguished from the second region 714 and the third region 716 by the content of Te or the ratio of the content of Te to the content of Bi. That is, the content of Te in the second area 714 and the content of Te in the third area 716 may be higher than the content of Te in the first area 712. For example, the Te content of the second region 714 or the Te content of the third region 716 relative to the Te content of the first region 712 may be 1.01 to 1.2, preferably 1.05 to 1.15.

As described above, the Te content of each of the second region 714 in direct contact with the first reaction layer 740 and the third region 716 in direct contact with the second reaction layer 750 When the content is higher than the Te content, it is possible to prevent an increase in resistance of the thermoelectric leg by increasing the carrier concentration, so that excellent thermoelectric performance can be obtained by increasing electrical conductivity.

At this time, the Te content is maintained at a level higher than the Te content in the first region 712 even in the boundary region 900 between the thermoelectric material layer 710 and the first reaction layer 740, and then the first reaction layer 740 ) Gradually decreases toward the first plating layer 720, and may decrease rapidly as it enters the first plating layer 720 from the first reaction layer 740. Accordingly, a significant amount of Te may not be detected in the first plating layer 720 and the first metal layer 760. Similarly, the Te content is maintained at a level higher than the Te content in the first region 712 in the boundary region 902 between the thermoelectric material layer 710 and the second reaction layer 750, and then the second reaction layer ( It gradually decreases from 750 to the second plating layer 730, and may decrease rapidly as it enters the second plating layer 730 from the second reaction layer 750. Accordingly, a significant amount of Te may not be detected in the second plating layer 730 and the second metal layer 770.

In order to obtain a thermoelectric leg according to an exemplary embodiment of the present invention, referring to FIGS. 7 to 8, a plating layer disposed on a metal substrate is prepared (S100 ). Here, the metal substrate may be the first metal layer 760 and the second metal layer 770 of the thermoelectric leg 700 of FIG. 6. That is, the metal substrate may be selected from copper (Cu), copper alloy, aluminum (Al), and aluminum alloy. The plating layer may be the first plating layer 720 and the second plating layer 730 of the thermoelectric leg 700 of FIG. 6. The plating layer may be a Ni plating layer, but is not limited thereto, and may be formed of at least one metal selected from Sn, Ti, Fe, Sb, Cr, and Mo. In addition, the plating layer may be formed on both sides of the metal substrate. In this specification, a layer containing at least one metal among Ni, Sn, Ti, Fe, Sb, Cr, and Mo is expressed as a plating layer, but this includes not only the layer formed by plating, but also the layer deposited by various techniques. It can mean to include.

Next, after disposing the thermoelectric material powder including an excess of Te on the plating layer (S110), disposing the thermoelectric material powder (S120), and disposing the thermoelectric material powder including an excessive amount of Te (S130). Here, the thermoelectric material powder may mean a powder having a basic composition constituting the thermoelectric material layer, and in the case of a P-type thermoelectric leg, the main raw material Bi-Sb-Te is 99 to 99.999 wt% based on 100 wt% of the total weight. , Nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga) and at least one of indium (In) in 0.001 to 1 wt% In the case of an N-type thermoelectric leg, it contains 99 to 99.999 wt% of Bi-Se-Te, the main raw material, based on 100 wt% of the total weight, and nickel (Ni), aluminum (Al), and copper (Cu ), silver (Ag), lead (Pb), boron (B), gallium (Ga), and indium (In) at least one of 0.001 to 1 wt%. Here, the powder having a basic composition constituting the thermoelectric material layer may mean Bi ₂ Te ₃ powder. That is, in the case of a P-type thermoelectric leg, it may be a Bi ₂ Te ₃ powder with Sb added as a dopant, for example, Bi _0.4 Sb _1.6 Te _3.0 to Bi _0.5 Sb _1.5 Te _3.0 , and in the case of an N-type thermoelectric leg, Se is added Bi ₂ Te ₃ powder, for example, Bi ₂ Se _0.2 Te _2.8 to Bi ₂ Se _0.3 Te _2.7 . The thermoelectric material powder including an excessive amount of Te may be a thermoelectric material powder further including 1 to 5 parts by weight of Te based on 100 parts by weight of the powder having the basic composition constituting the thermoelectric material layer described above. That is, in steps S110, S120 and S130, a first thermoelectric material powder having a high Te content, a second thermoelectric material powder having a lower Te content than the first thermoelectric material powder, and a third thermoelectric material having a higher Te content than the second thermoelectric material powder It may mean arranging the powder in the form of a sandwich.

Then, the plating layer disposed on the metal substrate is disposed so that the plating layer and the thermoelectric material powder face each other on the thermoelectric material powder disposed up to step S130 (S140), and then pressurized and sintered (S150). FIG. 8(a) shows a state in which materials constituting the thermoelectric legs are sequentially arranged as in steps S100 to S140, and FIG. 8(b) shows a state after pressing and sintering as in step S150. Through the pressing and sintering process, a part of Te in the thermoelectric material powder including an excess of Te may be diffused into the plating layer, thereby forming the reaction layers 740 and 750. In addition, among Te in the thermoelectric material powder containing an excessive amount of Te, Te remaining without diffusion in the plating layer direction may form a Te-rich region such as the second region 714 and the third region 716.

According to an embodiment of the present invention, since a reaction layer is formed through the process of diffusing a portion of Te in the thermoelectric material powder containing Te in the direction of the plating layer, the thickness of the reaction layer is 1 to 100 μm, preferably 1 to It is possible to form a 40㎛, more preferably 1 to 30㎛, more preferably 1 to 20㎛. In particular, compared to a method of forming a reaction layer by applying Te on a plating layer disposed on a metal substrate and then performing heat treatment, it is possible to form a thin reaction layer.

Here, pressing and sintering may be performed by a hot press process. The hot press process may be an induction heating process or a spark plasma sintering (SPS) process in which Joule heat is generated by applying a pulse current from a DC (Direct Current) power source. Since the induction heating process or the discharge plasma sintering process proceeds through a process in which high heat energy promotes thermal diffusion between particles, excellent sintering controllability, that is, control of a sintered microstructure with little grain growth is easy. At this time, the thermoelectric material may be sintered together with the amorphous ribbon. When the powder for the thermoelectric leg is sintered together with the amorphous ribbon, the electrical conductivity increases, so that high thermoelectric performance can be obtained. At this time, the amorphous ribbon may be an Fe-based amorphous ribbon. For example, an amorphous ribbon can be placed on the side of a thermoelectric leg and then sintered. Accordingly, electrical conductivity may increase along the side of the thermoelectric leg. To this end, after the amorphous ribbon is disposed to surround the wall surface of the mold, the thermoelectric material may be filled and sintered. In this case, the amorphous ribbon may be disposed on the side of the thermoelectric material layer among the thermoelectric legs.

Hereinafter, a composition distribution for each region of the thermoelectric leg according to an embodiment of the present invention will be described in more detail. Since the content of Te in the thermoelectric leg is described in detail with respect to FIG. 6, duplicate descriptions for the same content as those described in FIGS. 1 to 6 are omitted, and hereinafter, focusing on the relative distribution of components in the thermoelectric leg. Explain. 9 is a graph showing a normalized composition distribution for each region of a thermoelectric leg.

Referring to FIG. 9, the thermoelectric material layer 710 is formed between a first region 712 including a center C of the thermoelectric material layer 710, and between the first region 712 and the first reaction layer 740. It includes a second region 714 disposed and a third region 716 disposed between the first region 712 and the second reaction layer 750.

The content of Bi is maintained almost constant in the entire region of the thermoelectric material layer 710. For example, the content of Bi in the first region 712, the second region 714, and the third region 716 is almost the same, or from the first region 712 to the second region 714 and the third region (716) It can be reduced to a subtle level with each passing. For example, each of the Bi content in the second region 714 and the Bi content in the third region 716 is 0.8 to 1 times, preferably 0.9, the Bi content in the first region 712 To 1 times, more preferably 0.95 to 1 times.

On the other hand, the content of Te in the entire area of the thermoelectric material layer 710 is higher than that of Bi, but the content of Te in the second area 714 and the content of Te in the third area 716 are respectively reduced. It may be higher than the content of Te in the first region 712. Accordingly, in the present specification, each of the second region 714 and the third region 716 is a thermoelectric material layer 710 and an interface 905 of each of the first and second reaction layers 740 and 750. A region within a predetermined distance (d) in the direction of the first region 712 including the center (C) of the thermoelectric material layer 710 from 906, and the Te content starts to be higher than the content of the first region 712 It may be defined as an area from the point where the thermoelectric material layer 710, the first reaction layer 740, and the second reaction layer 750 to the interface surfaces 905 and 906, respectively. Here, the predetermined distance d may be 0.1 to 5 μm or less.

For example, the Te content of the second region 714 or the Te content of the third region 716 relative to the Te content of the first region 712 may be 1.01 to 1.2, preferably 1.05 to 1.15.

Accordingly, the ratio of the Te content to the Bi content in the first region 712 is 1.05 or more and less than 1.2, and the Te content to the Bi content in the second region 714 and the third region 716 The ratio of may be greater than 1.2 and less than 1.35. 9 is a graph obtained by obtaining the composition of each region in at% and then normalized, but is not limited thereto, and in the present specification, the content is weight ratio, atomic weight ratio, mole ratio, weight percentage, atomic weight percentage, mole percentage, wt%, at% , mol%, and the like. wt% represents the weight ratio of each element as a percentage when the weight in a predetermined region is assumed to be 100%, and at% represents the atomic weight ratio of each element as a percentage when the atomic weight in a predetermined region is assumed to be 100% And the wt% and at% may be proportionally the same or almost similar.

As described above, in the thermoelectric material layer 710, it can be seen that the content of Te appears higher than the content of Bi in the entire region, and the Bi-rich region in which the content of Bi is higher than the content of Te does not occur.

Meanwhile, as described above, each of the first reaction layer 740 and the second reaction layer 750 is subjected to a simultaneous sintering process so that an excess of Te is transferred from the thermoelectric material layer 710 to the first plating layer 720 and the second plating layer. It can be formed by diffusing to 730. Accordingly, each of the first reaction layer 740 and the second reaction layer 750 further includes a metal included in each of the first plating layer 720 and the second plating layer 730 together with Te, and the thermoelectric material layer ( Each of the boundary region 900 between the 710 and the first reaction layer 740 and the boundary region 902 between the thermoelectric material layer 710 and the second reaction layer 750 is Bi, Te, and the first plating layer 720 and All metals included in each of the second plating layers 730 may be included. Here, as it passes from the thermoelectric material layer 710 to the first reaction layer 740 or the second reaction layer 750, the content of Bi rapidly decreases, and the content of Te gradually decreases, so the content of Te relative to the content of Bi The ratio of may include an area exceeding 1.35 times.

Meanwhile, according to an embodiment of the present invention, each of the first reaction layer 740 and the second reaction layer 750 includes Te and a metal included in each of the first plating layer 720 and the second plating layer 730, , The content of Te in the first reaction layer 740 and the second reaction layer 750 is higher than the content of metal included in each of the first plating layer 720 and the second plating layer 730. However, in each of the first and second reaction layers 740 and 750, an excess of Te diffuses from the thermoelectric material layer 710 to the first plating layer 720 and the second plating layer 730 through a simultaneous sintering process. The content of Te in each of the first reaction layer 740 and the second reaction layer 750 from the thermoelectric material layer 710 toward each of the first plating layer 720 and the second plating layer 730 Is lowered, and the content of the metal included in each of the first plating layer 720 and the second plating layer 730 may increase.

In the present specification, a portion of the material included in each layer may form a boundary region that is diffused from an interface between each layer and an adjacent layer to a partial region of each layer adjacent to each other. Here, the interface is a point at which the content of the material contained in each of the adjacent layers changes at the same time, and the interfaces 905 and 906 between the thermoelectric material layer 710 and the reaction layers 740 and 750 constitute the thermoelectric material layer 710 It may be a point where the rate of change of at least one of Bi and Te increases rapidly and the rate of change of Ni, which is a constituent material of the adjacent first reaction layer 740, rapidly increases. That is, as long as the boundary surfaces 905 and 906 between the thermoelectric material layer 710 and the reaction layers 740 and 750 are included in the boundary regions 900 and 902 between the thermoelectric material layer 710 and the reaction layers 740 and 750 It may be a point, and it may mean a point where the rate of decrease of at least one of Bi and Te increases rapidly and the rate of increase of Ni rapidly increases. Here, the rate of change, the rate of decrease, and the size of the increase rate may mean the absolute value of the slope of the tangent line in the graph showing the change in the content of Bi, Te, and Ni shown in FIG. 9, and the slope of the tangent line may be a ratio of the vertical axis to the horizontal axis. have.

In addition, the interface surfaces 915 and 916 between the reaction layers 740 and 750 and the plating layers 720 and 730 decrease the content of Te in the reaction layers 740 and 750 and the metal contained in the plating layers 720 and 730 The content increases and may be a point of intersection with each other. That is, as long as the boundary surfaces 915 and 916 between the reaction layers 740 and 750 and the plating layers 720 and 730 are included in the boundary regions 915 and 916 between the reaction layers 740 and 750 and the plating layers 720 and 730, It may be a point, and the content of the metal included in the plating layers 720 and 730 may be a point at which the content of Te in the reaction layers 740 and 750 is reversed.

In this case, in the present specification, the boundary region includes an boundary surface, and may mean a region formed by diffusion of a part of materials of each layer adjacent to each other around the boundary surface. For example, some of the material included in the metal layer is diffused from the interface between the metal layer and the plating layer to be detected within the plating layer, and some of the material included in the plating layer is diffused from the interface between the plating layer and the reaction layer and detected within the reaction layer. Part of the material included in the reaction layer may be diffused from the interface between the reaction layer and the thermoelectric material layer to be detected in the thermoelectric material layer. In addition, a part of the material included in the plating layer may diffuse from the interface between the metal layer and the plating layer and be detected within the metal layer, and a part of the material included in the reaction layer may diffuse from the interface between the plating layer and the reaction layer and be detected within the plating layer. In addition, some of the material included in the thermoelectric material layer may be diffused from the interface between the reaction layer and the thermoelectric material layer to be detected in the reaction layer.

The content of Te in the boundary region 910 between the first reaction layer 740 and the first plating layer 720 rapidly decreases, and Te content in the boundary region 912 between the second reaction layer 750 and the second plating layer 730 The content of can be rapidly lowered. Each of the boundary region 910 between the first reaction layer 740 and the first plating layer 720 and the boundary region 912 between the second reaction layer 750 and the second plating layer 730 is a first plating layer 720 and A point where the content of the metal included in each of the second plating layers 730 is higher than the content of Te may be included.

10 illustrates a method of manufacturing a thermoelectric leg according to a comparative example, FIG. 11 illustrates a Te content of each region of a thermoelectric leg according to a comparative example, and FIG. 12 illustrates a composition distribution of each region of the thermoelectric leg according to the comparative example.

Referring to FIG. 10(a), the thermoelectric leg according to the comparative example forms plating layers 820 and 830 on aluminum (Al) substrates 860 and 870 having a thickness of about 0.2 to 0.3 mm, and then two aluminum substrates. / A thermoelectric material powder having a thickness of about 1.6 mm including Bi and Te was disposed between the plating layers, and pressed and sintered. Referring to FIG. 10(b), through the process of pressing and sintering, Te in the thermoelectric material powder diffused toward Ni on the surface of the plating layer and reacted with Ni, and accordingly, the reaction layers 840 and 850 including Ni-Te ) Was formed. In addition, a Bi-rich layer having a relatively high Bi content was formed at the edge of the thermoelectric material layer 810 as Te diffused toward the plating layer.

11 to 12, the content of Te in the first plating layer 820 or the second plating layer 830 is the content of Te in the thermoelectric material layer 810 and the first reactive layer 840 or the second reactive layer ( 850), it can be seen that it appears lower than the content of Te.

In addition, as the Bi-rich layer approaches the first reaction layer 840, the Te content decreases. Accordingly, compared to the Te content of the center C of the thermoelectric material layer 810, the thermoelectric material layer 810 It can be seen that the Te content of the boundary region between the first reaction layer 840 or the boundary region between the thermoelectric material layer 810 and the second reaction layer 850 is low. This is because Te, which is a semiconductor material in the thermoelectric material layer 810, naturally diffuses into the first plating layer 820 and the second plating layer 830 to react with the first plating layer 820 and the second plating layer 830. . Accordingly, the content of Te decreases as it goes from the center surface (C) of the thermoelectric material layer 810 to the edge, and the thermoelectric material is diffused to react with the first plating layer 820 and the second plating layer 830. A Bi-rich layer is formed up to the boundary between the layer 810 and the first plating layer 820 and the second plating layer 830. Such a Bi-rich layer may be formed to a thickness of 200 μm or less. That is, in the vicinity of the center C of the thermoelectric material layer 810, the content of Te appears higher than the content of Bi, but the boundary region between the thermoelectric material layer 810 and the first reaction layer 840 or the thermoelectric material layer 810 There is a section in which the Bi content reverses the Te content around the boundary region between the and the second reaction layer 850. The Bi-rich layer is a region where an appropriate stoichiometric ratio between Bi and Te, which is a basic constituent material of a thermoelectric material, is destroyed. As the Bi-rich layer becomes thicker, the resistance change rate increases, which may be a major factor in increasing the resistance inside the thermoelectric leg.

Table 1 is a table comparing electrical conductivity of P-type thermoelectric legs according to Comparative Examples and Examples.

division Electrical conductivity (S/cm) Example 1,050 to 1,150 Comparative example 850 to 950

Referring to Table 1, it can be seen that the electrical conductivity of the thermoelectric leg manufactured according to the embodiment is higher than that of the thermoelectric leg manufactured according to the comparative example. This is because the problem of increasing the resistance of the thermoelectric leg due to the Bi-rich layer or the thick reactive layer can be prevented, and the electrical conductivity is increased due to a high Te content that can serve as a carrier between the thermoelectric material layer and the reactive layer.

Table 2 is a table comparing the tensile strength of each thermoelectric leg of 4mm*4mm*5mm size according to Examples and Comparative Examples.

division Tensile strength (kgf/mm ² ) Example 1.5 to 1.8 Comparative example 0.3 to 1.0

Referring to Table 2, it can be seen that the tensile strength of the thermoelectric leg manufactured according to the example is greater than that of the thermoelectric leg manufactured according to the comparative example. Tensile strength refers to the interlayer bonding strength in the thermoelectric leg, and the metal wires are artificially bonded to the first and second metal layers on both sides of the manufactured thermoelectric leg, and the bonded metal wires are pulled in opposite directions. It represents the maximum load it can endure. Since the higher the tensile strength, the higher the interlayer bonding strength in the thermoelectric leg, so when the thermoelectric element is driven, at least some of the metal layer, the plating layer, the reaction layer, and the thermoelectric material layer in the thermoelectric leg may be prevented from falling off from the adjacent layer.

The thermoelectric element according to an embodiment of the present invention may act as a power generation device, a cooling device, a heating device, or the like. Specifically, the thermoelectric element according to the embodiment of the present invention is mainly an optical communication module, a sensor, a medical device, a measuring device, aerospace industry, a refrigerator, a chiller, a ventilation sheet for a vehicle, a cup holder, a washing machine, a dryer, a wine cellar. , Water purifier, sensor power supply, thermopile, etc.

Here, as an example in which the thermoelectric element according to an embodiment of the present invention is applied to a power generation device, there is a power generation device using an external heat source. Here, the external heat source may generate electricity by contacting a target that emits heat such as waste heat generated from heat sources such as vehicles, ships, power plants, and incinerators, or body heat of the human body. Thermoelectric elements can be applied.

Another example to which the thermoelectric element according to the embodiment of the present invention is applied is a photo detector. Here, the photodetector includes an infrared/ultraviolet ray detector, a charge coupled device (CCD) sensor, an X-ray detector, and a Thermoelectric Thermal Reference Source (TTRS). Peltier-based thermoelectric elements may be applied to cool the photo detector. Accordingly, it is possible to prevent a wavelength change, an output decrease, and a resolution decrease due to an increase in temperature inside the photodetector.

Another example in which the thermoelectric element according to an embodiment of the present invention is applied to a medical device, an immunoassay field, an in vitro diagnostics field, a general temperature control and cooling system, Physical therapy fields, liquid chiller systems, blood/plasma temperature control fields, etc. Accordingly, precise temperature control is possible.

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

Examples of the thermoelectric element according to an embodiment of the present invention applied to the aerospace industry include a star tracking system, a thermal imaging camera, an infrared/ultraviolet ray detector, a CCD sensor, a Hubble space telescope, and TTRS. Accordingly, it is possible to maintain the temperature of the image sensor.

Other examples of the thermoelectric element according to an embodiment of the present invention applied to the aerospace industry include a cooling device, a heater, and a power generation device.

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

Although the above has been described with reference to preferred embodiments of the present invention, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. You will understand that you can do it.

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

Claims (14)

A first metal layer,
A first plating layer disposed on the first metal layer,
A first reaction layer disposed on the first plating layer and including Te,
A thermoelectric material layer disposed on the first reaction layer and including Bi and Te,
A second reaction layer disposed on the thermoelectric material layer and including Te,
A second plating layer disposed on the second reaction layer, and
Including a second metal layer disposed on the second plating layer,
The thermoelectric material layer is a first region in which the ratio of the content of Te to the content of Bi is 1.05 or more and less than 1.2, and is disposed between the first region and the first reaction layer, and the ratio of the content of Te to the content of Bi is 1.2. A thermoelectric leg comprising a second region greater than and less than 1.35 and a third region disposed between the first region and the second reaction layer and having a ratio of the content of Te to the content of Bi is greater than 1.25 and less than 1.35. The method of claim 1,
The first plating layer includes at least one metal of Ni, Sn, Ti, Fe, Sb, Cr, and Mo,
The first reaction layer is a thermoelectric leg further comprising the at least one metal included in the first plating layer. The method of claim 2,
The boundary region between the thermoelectric material layer and the first reaction layer includes the at least one metal and Bi included in the first plating layer, and includes a region in which a ratio of the Te content to the Bi content exceeds 1.35. Thermoelectric leg. The method of claim 2,
The content of Te in the first reaction layer is higher than the content of the at least one metal included in the first plating layer,
A thermoelectric leg in which the content of Te decreases from the thermoelectric material layer toward the first plating layer, and the content of the at least one metal in the first plating layer increases. The method of claim 4,
The thermoelectric leg, wherein the boundary region between the first reaction layer and the first plating layer includes a point where the content of the at least one metal contained in the first plating layer is higher than the content of Te. The method of claim 1,
A thermoelectric leg in which the content of Te in the second area is 1.01 to 1.2 relative to the content of Te in the first area. The method of claim 6,
The thermoelectric leg in which the content of Te in the second area is 1.05 to 1.15 with respect to the content of Te in the first area. The method of claim 1,
The thermoelectric material layer is antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tellurium (Te) , Bismuth (Bi) and indium (In) thermoelectric legs further comprising at least one of. The method of claim 1,
At least one of the first metal layer and the second metal layer is a thermoelectric leg selected from copper, a copper alloy, aluminum, and an aluminum alloy. The method of claim 1,
At least one of the first metal layer and the second metal layer includes aluminum,
At least one of the first plating layer and the second plating layer includes Ni. A first substrate,
A plurality of P-type thermoelectric legs and a plurality of N-type thermoelectric legs alternately disposed on the first substrate,
A second substrate disposed on the plurality of P-type thermoelectric legs and the plurality of N-type thermoelectric legs,
A plurality of first electrodes connecting the first substrate, the plurality of P-type thermoelectric legs, and the plurality of N-type thermoelectric legs in series, and
And a plurality of second electrodes connecting the second substrate, the plurality of P-type thermoelectric legs, and the plurality of N-type thermoelectric legs in series,
Any one of the plurality of P-type thermoelectric legs and the plurality of N-type thermoelectric legs
A first metal layer,
A first plating layer disposed on the first metal layer,
A first reaction layer disposed on the first plating layer and including Te,
A thermoelectric material layer disposed on the first reaction layer and including Bi and Te,
A second reaction layer disposed on the thermoelectric material layer and including Te,
A second plating layer disposed on the second reaction layer, and
Including a second metal layer disposed on the second plating layer,
The thermoelectric material layer is a first region in which the ratio of the content of Te to the content of Bi is 1.05 or more and less than 1.2, and is disposed between the first region and the first reaction layer, and the ratio of the content of Te to the content of Bi is 1.2. A thermoelectric element comprising a second region that is greater than and is less than 1.35 and a third region disposed between the first region and the second reaction layer and having a ratio of the content of Te to the content of Bi is greater than 1.2 and less than 1.35. The method of claim 11,
At least one of the first substrate and the second substrate includes a metal. The method of claim 12,
At least one of between the first substrate and the plurality of first electrodes and between the second substrate and the plurality of second electrodes further includes a dielectric layer. The method of claim 13,
At least one of the volume, thickness, and area of the first substrate and the second substrate is different from each other.

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