KR102248813B1 - Method for manufacturing porous thermoelectric material and thermoelectric device comprising porous thermoelectric material - Google Patents

Abstract

The present invention relates to a porous thermoelectric material including micro-pores, a manufacturing method thereof, and a thermoelectric element having increased thermoelectric performance by including the porous thermoelectric material. In the present invention, it is easy to adjust a pore size and porosity included in a thermoelectric material and due to regular pores included in a manufactured thermoelectric material, thermoelectric performance can be increased by greatly reducing thermal conductivity without significantly lowering electrical conductivity and a Seebeck coefficient.

Description

Method of manufacturing a porous thermoelectric material and a thermoelectric device including the porous thermoelectric material {METHOD FOR MANUFACTURING POROUS THERMOELECTRIC MATERIAL AND THERMOELECTRIC DEVICE COMPRISING POROUS THERMOELECTRIC MATERIAL}

The present invention relates to a porous thermoelectric material including micropores and a method for manufacturing the same, and to a thermoelectric device including the porous thermoelectric material with improved thermoelectric performance.

Thermoelectric technology is a technology that directly converts thermal energy into electrical energy and electrical energy into thermal energy in a solid state, and is applied in the field of thermoelectric power generation that converts thermal energy into electrical energy and thermoelectric cooling that converts electrical energy into thermal energy. The thermoelectric material used for such thermoelectric power generation and thermoelectric cooling improves the performance of the thermoelectric element as the thermoelectric property increases. The thermoelectric performance is determined by thermoelectric power (V), Seebeck coefficient (α), Peltier coefficient (π), Thompson coefficient (τ), Nernst coefficient (Q), Ettingshausen coefficient (P), and electrical conductivity (σ). ), output factor (PF), figure of merit (Z), dimensionless performance index (ZT=α2σT/κ (where T is the absolute temperature)), thermal conductivity (κ), Lorentz number (L), electrical resistivity ( ρ), etc. In particular, the dimensionless figure of merit (ZT) is an important factor in determining the energy efficiency of thermoelectric conversion, and the efficiency of cooling and power generation by manufacturing a thermoelectric element using a thermoelectric material having a high value of the figure of merit (Z=α2σ/κ) Will be able to increase. That is, the thermoelectric material has excellent thermoelectric performance as the Seebeck coefficient and electrical conductivity are higher and the thermal conductivity is lower.

Meanwhile, the thermoelectric material is generally manufactured by melting and solidifying raw materials constituting the thermoelectric material to produce a master alloy, followed by pressing and sintering it. These thermoelectric materials have some differences in manufacturing methods and conditions, and it has been difficult to secure desired levels of Seebeck coefficient, electrical conductivity, and thermal conductivity.

The present invention has been devised to solve the above-described problems, and the method and method for manufacturing a thermoelectric material that can simultaneously improve performance and reduce the amount of use by reducing thermal conductivity while maintaining electrical conductivity by securing porosity in the thermoelectric material. It is a technical problem to provide a porous thermoelectric material manufactured by

In addition, the present invention is another technical problem to provide a thermoelectric device including the above-described porous thermoelectric material.

Other objects and advantages of the present invention can be more clearly explained by the following detailed description and claims.

In order to achieve the above technical problem, the present invention comprises the steps of: (i) dissolving and solidifying a raw material for a thermoelectric material to form a master alloy; (ii) rapidly cooling the master alloy to form a metal ribbon; (iii) mixing the metal ribbon and a polymer that is pyrolyzed at a predetermined temperature or higher, and pulverizing it in an inert atmosphere; And (iv) sintering the pulverized product of step (iii) at a temperature higher than the thermal decomposition temperature of the polymer.

According to one embodiment of the present invention, the pyrolytic polymer may be pyrolyzed by sintering to form and remove a plurality of pores.

According to one embodiment of the present invention, the pyrolytic polymer may be selected from the group consisting of a thermoplastic polymer having a pyrolysis temperature of 200 to 500°C, a natural polymer, and a water-soluble polymer.

According to an embodiment of the present invention, the thermally decomposable polymer may have a residual carbon content of 5.0% or less after thermal decomposition.

According to an embodiment of the present invention, the thermally decomposable polymer is polymethyl methacrylate (PMMA), polybutyl methacrylate (PBMA), polybromoniated biphenyl (PBB), polyvinyl alcohol (PVA), And it may be one or more selected from the group consisting of ethyl cellulose (EC).

According to one embodiment of the present invention, the thermally decomposable polymer may be spherical particles having _{an average particle diameter (D 50) of 5 to 50 μm.}

According to one embodiment of the present invention, the thermally decomposable polymer may be added in an amount of 0.1 to 2 parts by weight based on the total weight of the metal ribbon.

According to an embodiment of the present invention, step (iv) may be sintered by putting the pulverized product of step (iii) into a molding mold and hot pressing.

According to one embodiment of the present invention, the thermoelectric material may be at least one of a Bi-Te thermoelectric material and a Skuttrudite thermoelectric material.

According to an embodiment of the present invention, the porous thermoelectric material may have a porosity of 0.1 to 10%, a pore size of 5 to 50 μm, and a density of 90 to 99.9%.

In addition, the present invention provides a porous thermoelectric material manufactured by the above-described method.

In addition, the present invention is a first substrate; A second substrate disposed opposite to the first substrate; A first electrode and a second electrode respectively disposed between the first and second substrates; A plurality of thermoelectric legs interposed between the first electrode and the second electrode; A thermoelectric element comprising a bonding material disposed between at least one of the first electrode and the thermoelectric leg, and between the thermoelectric leg and the second electrode, wherein at least one of the plurality of thermoelectric legs includes the aforementioned porous thermoelectric material Provides.

According to one embodiment of the present invention, the bonding material is Sn-based solder; Alternatively, it may have a composition including the Sn-based solder and metal dendrite having an average branch length of 5 to 50 μm.

According to one embodiment of the present invention, the thermoelectric element may be applied to at least one of cooling, power generation, and thin-film sensor.

According to an embodiment of the present invention, when a thermoelectric material is manufactured, a porous thermoelectric material uniformly containing a micropore size and workability can be easily manufactured by using a polymer that can be pyrolyzed by a sintering process as a pore former.

In addition, in the present invention, compared to non-porous thermoelectric materials, it is economical by reducing the amount of use of thermoelectric materials, and due to the regular pores contained in the thermoelectric material, the thermal conductivity is reduced without significantly lowering the electrical conductivity and the Seebeck coefficient. It can improve performance.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a process flow chart of a manufacturing method according to an embodiment of the present invention.
2 is a schematic diagram of a thermoelectric material according to the manufacturing method of the present invention.
3 is an electron micrograph of a pyrolytic polymer.
4 is a perspective view showing a thermoelectric device according to an embodiment of the present invention.
5 is a cross-sectional view of a thermoelectric device according to an embodiment of the present invention.
6 is a graph of a thermal decomposition rate according to temperature of a thermally decomposable polymer.
7 is a power factor graph using the thermoelectric elements of Examples 1 to 12 and Comparative Example 1.
8 is a graph of a thermoelectric performance index using the thermoelectric elements of Examples 1 to 12 and Comparative Example 1. FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments of the present invention are provided to more completely describe the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, and the scope of the present invention is described below. It is not limited to examples. In this case, the same reference numerals refer to the same structure throughout the present specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used with meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, so the present invention is not necessarily limited to the illustrated bar. In the drawings, the thicknesses are enlarged in order to clearly express various layers and regions. In addition, in the drawings, for convenience of description, the thicknesses of some layers and regions are exaggerated.

In addition, throughout the specification, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated. In addition, throughout the specification, the term "above" or "on" means not only the case that is located above or below the target part, but also includes the case where there is another part in the middle, and must always refer to the direction of gravity. It does not mean that it is located above the standard. In addition, in the present specification, terms such as "first" and "second" do not represent any order or importance, but are used to distinguish components from each other.

In addition, throughout the specification, the term "on a plane" means when the target part is viewed from above, and when "cross-sectional" refers to when the target part is viewed from the side when a vertically cut section is viewed from the side.

In the present invention, by mixing a pore former with a thermoelectric material having a high thermal decomposition rate and easy particle size control when manufacturing a thermoelectric device, it is intended to improve thermoelectric properties by using a thermoelectric material that is porous with a predetermined pore size and porosity. do.

When some pores are contained in the thermoelectric material as described above, the electrical conductivity is not significantly affected, but the thermal conductivity may be reduced, so that the thermoelectric performance index (ZT) value may be improved. Accordingly, it is possible to manufacture a more excellent thermoelectric device, as well as to reduce the cost by reducing the amount of use of thermoelectric materials.

In particular, in the present invention, instead of the conventional composite pore former containing inorganic and organic ingredients, a thermally decomposable polymer of an organic ingredient that is thermally decomposed in the application temperature range of the sintering process is adopted and used as the pore former. The thermally decomposable polymer is mixed with a powder of a thermoelectric material (eg, a metal ribbon), pulverized with a ball mill, and then sintered through a hot press (HP). At this time, since the pyrolytic polymer is an organic component having a high thermal decomposition rate, the diameter and porosity of the pores after sintering can be easily controlled by adjusting the particle diameter, content, and shape of the pyrolytic polymer to be used. In addition, since there is almost no residual carbon during pyrolysis, when it is removed by pyrolysis and/or carbonization by the sintering process, the thermal conductivity is reduced through the formation of micropores without deteriorating the general characteristics of the thermoelectric element due to the residue. And it is possible to secure an improvement in thermoelectric performance.

<Method of manufacturing porous thermoelectric material>

Hereinafter, a method of manufacturing a porous thermoelectric material according to an embodiment of the present invention will be described. However, it is not limited only by the following manufacturing method, and the steps of each process may be modified or selectively mixed and performed as necessary.

In the present invention, a conventional thermoelectric material used as a thermoelectric material for thermoelectric power generation and cooling is made porous, and specifically, a raw material for thermoelectric material is pulverized after forming a metal ribbon through a rapid solidification method (RSP) (e.g., ball mill method). And sintering (eg, hot pressing), but a porous thermoelectric material is manufactured by using a polymer that can be pyrolyzed within the application temperature range of the sintering process as a pore former.

In a preferred embodiment of the manufacturing method, (i) dissolving and solidifying a raw material for a thermoelectric material to form a master alloy ('S10 step'); (ii) rapidly cooling the master alloy to form a metal ribbon ('S20 step'); (iii) mixing the metal ribbon and the thermally decomposable polymer and pulverizing it in an inert atmosphere ('S30 step'); And (iv) sintering the pulverized product of step (iii) at a temperature higher than the thermal decomposition temperature of the polymer ('S40 step').

Meanwhile, FIG. 1 is a conceptual diagram illustrating a method of manufacturing a porous thermoelectric material according to the present invention in each step. Hereinafter, the manufacturing method will be described by dividing each process step with reference to FIG. 1 as follows.

(i) master alloy formation step ('S10 step')

In this step, the raw material of the thermoelectric material is mixed in accordance with the stoichiometric ratio constituting the porous thermoelectric material, dissolved and solidified to form a master alloy.

The thermoelectric material according to the present invention may be a conventional thermoelectric material known in the art, and is not particularly limited. Non-limiting examples of usable thermoelectric materials include Bi-Te-based, Co-Sb-based, Pb-Te-based, Ge-Tb-based, Si-Ge-based, Sb-Te-based, Sm-Co-based, transition metal silicide-based , Skuttrudite-based, silicide-based, half-whisler, or a combination thereof. Preferably, it may be a Bi-Te-based or Skuttrudite-based thermoelectric material.

For example, in the case of manufacturing a Bi-Te-based thermoelectric material, Bi, Te, Sb, and Se may be used as raw materials for the thermoelectric material in step S10, which may differ depending on the composition for cooling/power generation.

As a usable raw material for a thermoelectric material, Bi and Te may be used as main materials, and the composition may further include Se or Sb components, respectively, depending on n-type and p-type. For example, the Bi raw material and the Te raw material may be mixed in a ratio according to the stoichiometric composition of _{Bi 2} Te _{3ㅁ0.2 , preferably Bi 2} Te _3ㅁ0.15 .

In one embodiment of the present invention, the raw material for the thermoelectric material includes: (i) at least one first element selected from the group consisting of Bi and Sb; And it may be a composition comprising a raw material of a composition comprising at least one second element selected from the group consisting of Te and Se. More specifically, when the raw material for the n-type thermoelectric material is a Bi-Te-Se-based alloy composition, 50 to 55% by weight of Bi, 40 to 45% by weight of Te, and 3 to 4% by weight of Se based on 100% by weight of the total It may be a composition containing. In addition, when the raw material for the p-type thermoelectric material is a Bi-Sb-Te alloy composition, the composition may include 10 to 15% by weight of Bi, 25 to 30% by weight of Sb, and 55 to 60% by weight of Te based on 100% by weight of the total. have.

In the present invention, a doping element powder may be added to the composition of the thermoelectric material to be manufactured.

Since the doping element (dopant) is introduced to make the Bi-Te-based thermoelectric material have n-type or p-type properties, conventional components in the art that can be used for n-type or p-type thermoelectric materials can be used without limitation. . For example, it may be one or more metals selected from the group consisting of Al, Sn, Mn, Ag, Cu, and Ga. By doping the above-described metal component, it is possible to improve thermoelectric performance. At this time, the content of the one or more metals to be doped is not particularly limited, and for example, may be in the range of 0.001 to 1% by weight based on the total weight.

In the present invention, the size and shape of the thermoelectric material are not particularly limited, but may be in the form of a mass having a size of about 2 to 5 mm. In addition, it is preferable that the purity of the thermoelectric material is 5N or higher.

As a specific example of the step S10, after charging the above-described raw material for thermoelectric material into a quartz tube, a quartz tube in a vacuum state is charged into the furnace, and the temperature is 600 to 1000°C for 1-10 hours. Stir and dissolve at a rate of ~15 times/min to form a master alloy.

In order to manufacture a ribbon using the rapid solidification method (RSP), _{a master alloy of a uniform thermoelectric material (eg, Bi 2} -Te ₃ system) must be manufactured. Accordingly, the master alloy may be manufactured in a size of Φ30 * 100㎜ or approximately Φ 20 ~ 30 * 100 ~ 150㎜. It may be a Bi-Te-based or a Skuttrudite-based alloy having a high purity of 5N or more prepared through the step S10.

(ii) Metal ribbon formation step ('S20 step')

In this step, a metal ribbon (eg, Bi-Te-based) having a complex microstructure is manufactured through a rapid solidification method (R.S.P) of the master alloy of the thermoelectric material obtained in the previous step.

As an example of the step S20, after charging the master alloy ingot into a nozzle installed in a melt spinning equipment, heat is supplied and completely dissolved using a heating element that can be continuously maintained to form a melt, and then in the melt. By pressurizing and spraying an inert gas, the melt is brought into contact with the surface of a rotating high-speed rotating wheel for rapid cooling. Through this, a metal ribbon made of a thermoelectric material (eg, Bi-Te-based) is formed.

Here, the heating element is not particularly limited as long as it can continuously supply and maintain heat, and a conventional resistance heating element known in the art may be used. For example, a resistance heating element that generates heat by receiving current may be used. As a non-limiting example of the usable resistance heating element, it is possible to control the temperature with an electric furnace type heater, for example, a graphite heater.

At this time, the temperature range at which the resistance heating element generates heat is not particularly limited as long as it is a range capable of completely dissolving the master alloy of the thermoelectric material (Bi-Te type), and for example, it is maintained in the range of 500 to 800°C, preferably 600 to 700°C. It becomes.

In addition, the type or the pressurization range of the inert gas is not particularly limited, and it is preferable to pressurize injection in the range of 0.1 to 0.5 MPa using argon gas or the like as an example.

In the step S20, the high-speed rotating wheel in contact with the melt may be a conventional wheel known in the art, for example a copper wheel (Cu wheel). Here, the rotation speed of the high-speed rotation wheel is not particularly limited, and for example, the linear speed of the wheel may be in the range of 5 to 50 m/s. When the above-described conditions are satisfied, the melt in contact with the surface of the wheel is rapidly cooled, and an alloy ribbon made of a thermoelectric material having a thin thickness and a microstructure may be formed.

In the present invention, by controlling the cooling rate of the dissolved master alloy, uniform particle size control is possible, and in general, when the cooling rate is slow, nano-sized amorphous powder can be prepared, or fine particle powder can be prepared. . In addition, it can be manufactured by varying the manufacturing conditions according to the concentration and type of raw materials.

The master alloy that has undergone the above-described process does not become crystalline through a rapid cooling (RSP) process, but is solidified in a state in which an amorphous structure and a crystalline structure are mixed. At this time, if the rapid cooling rate is very fast, it is manufactured in the form of a ribbon, but when the cooling rate is adjusted, powder having a size of several hundred nanometers may be manufactured as a simple connected half-ribbon.

The thermoelectric material (eg, Bi-Te-based) ribbon having a thin thickness may be formed through the rapid cooling in step S20 described above. For example, the length of the manufactured metal ribbon may be 5 to 15 mm, the width may be 0.5 to 5 mm, and the thickness may be 10 μm or less.

(iii) Metal ribbon crushing/crushing step ('S30 step')

In this step, when crushing ribbon-like raw materials with high brittleness due to rapid solidification by direct spraying of the molten mother alloy, a predetermined thermally decomposable polymer is added to the nano-sized amorphous fine powder having a fine particle size and shape and thermal decomposition. A pulverized product in which polymers are uniformly mixed is prepared.

At this time, in the present invention, in order to manufacture a porous thermoelectric material, pulverization is performed by adding a thermally decomposable polymer that is pyrolyzed at a predetermined temperature together with the metal ribbon as a pore former.

In the conventional pore former, a composite component including both an organic component and an inorganic component was used. The pore-forming agent removes the organic component after heat treatment to form a pore structure, whereas the inorganic component remains in the final thermoelectric material, and thus the performance of the thermoelectric material may be deteriorated due to unwanted metal residues. In addition, since the conventional pore formers contain inorganic components, it has been difficult to control the desired pore size or pore size.

In contrast, the thermally decomposable polymer employed in the present invention is an organic component that is thermally decomposed by a molding and sintering process to be described later to form a plurality of pores and removed at the same time without performing a separate heat treatment process. These pyrolytic polymers are pore formers that form a predetermined pore size and pore size in the thermoelectric material, and since the content of residual carbon is minimized after sintering, deterioration of the performance of the thermoelectric material due to residues can be fundamentally prevented. have. In addition, since the pyrolytic polymer is an organic component that is 100% pyrolyzed during pyrolysis, the size, shape, and porosity of pores after sintering can be easily controlled by adjusting the average particle diameter, content, and shape of the polymer used.

The pyrolytic polymer is not particularly limited in its components, content, shape, etc., as long as it is pyrolyzed and carbonized by the application temperature of the sintering process described later, and is removed, and conventional polymers, copolymers, resins, etc. Can be used. In addition, the use of monomolecular compounds is also within the scope of the present invention.

For example, the thermally decomposable polymer may be selected from the group consisting of a thermoplastic polymer having a thermal decomposition temperature of 200 to 500°C, a natural polymer, and a water-soluble polymer. In addition, the thermally decomposable polymer may have a residual carbon content of 5.0% or less after thermal decomposition by sintering, specifically 0 to 1.0% or less, more specifically 0 to 0.5% or less based on the total 100% of the pyrolytic polymer. .

Non-limiting examples of the pyrolytic polymer that can be used include polymethyl methacrylate (PMMA), polybutyl methacrylate (PBMA), polybromoniated biphenyl (PBB), polyvinyl alcohol (PVA), ethyl cellulose (EC), or mixtures thereof. In addition, polyethylene, polypropylene, glucose, fructose, sucrose, xylose, starch, cellulose, and the like can also be used. PMMA, PBMA or mixtures thereof having a relatively low decomposition temperature and no residual carbon are preferred. In particular, PMMA, PBMA, etc. undergoes 100% thermal decomposition at approximately 400°C, so that almost no residue is generated.

In the present invention, it is possible to easily adjust the pore diameter, porosity, pore shape, etc. formed after sintering according to the particle diameter, shape, and content of the pyrolytic polymer used.

Accordingly, the size of the thermally decomposable polymer is not particularly limited, and may be appropriately adjusted in consideration of the porosity and the pore size to be formed. For example, the average particle diameter (D ₅₀ ) of the thermally decomposable polymer may be 5 to 50 μm, and specifically 5 to 30 μm. In addition, the shape of the thermally decomposable polymer is not particularly limited, and may be, for example, a spherical, triangular or more polygonal shape, acicular, plate, or amorphous. It is preferably spherical (spherical) particles, more preferably may be a spherical shape with excellent sphericity.

In addition, the addition amount of the thermally decomposable polymer is not particularly limited, and as an example, it may be added in an amount of 0.1 to 2 parts by weight based on the total weight of the pulverized metal ribbon.

The pulverization process of step S30 may be performed without limitation in a conventional crushing/crushing process known in the art, and for example, pulverization may be performed using a ball mill method. At this time, the particle size of the powder to be pulverized is not particularly limited, and may be appropriately adjusted within a range known in the art. For example, the average particle diameter of a pulverized product obtained by mixing a thermoelectric material (eg, Bi-Te-based) and a thermally decomposable polymer may be 100 μm or less, preferably 10 to 100 μm.

In order to control the degree of oxidation of the metal ribbon, the crushing/crushing process described above is performed in an inert atmosphere. At this time, the type or pressure range of the inert gas is not particularly limited, and may be, for example, nitrogen gas, argon gas, or an atmosphere in which they are mixed.

As the pulverization is carried out under the condition that oxygen is not included as described above, the oxidation degree can be controlled to be low by reducing the oxygen content in the crushed powder. As an example, the pulverized product according to the present invention can reduce the oxygen content in the range of about 30% or more, specifically 30 to 45%, compared to the pulverized product carried out under atmospheric conditions containing oxygen, and preferably the The oxygen content in the pulverized product can be controlled to be 0.03% or less, preferably in the range of 0.02 to 0.03%.

(iv) forming and sintering step ('S40 step')

In this step, the mixture of the pulverized metal ribbon and the thermally decomposable polymer obtained in the above step is extruded to produce a preform, and then a high-density thermoelectric material is manufactured through pressure sintering.

In this step S40, a molded article having a predetermined shape is manufactured to ensure high density in the pressure sintering process.

The compression process may use a conventional method known in the art, and as an example, it is preferable to use a cold press or a compressor. In addition, the compression conditions are not particularly limited, and may be appropriately adjusted under conventional compression conditions known in the art.

Subsequently, the preform is sintered to prepare a thermoelectric material having high density and porosity.

The pressurized sintering method usable in the present invention includes a hot press (HP) and the like.

Here, the pressure sintering conditions are not particularly limited, and for example, sintering can be performed using a hot press device under a pressure of 20 to 80 MPa, specifically 40 to 70 MPa for 40 to 80 minutes at a temperature of 200 to 500°C. have. If it is smaller than the above condition, it is impossible to have the desired pore size and porosity, and if the above condition is exceeded, the vapor pressure of Te is high and volatilization becomes unsuitable for the target composition. high.

Meanwhile, FIG. 2 is a schematic diagram showing a change in the structure of a thermoelectric material containing a pyrolytic polymer according to the molding and sintering steps.

Referring to FIG. 2, step S40 is described, FIG. 2 (a) is a preform manufactured to a predetermined standard through an extrusion process, wherein the preform has a predetermined particle diameter and shape in a matrix made of a thermoelectric material. It shows a structure in which polymers are randomly distributed.

Subsequently, when the preform is sintered using a hot press (HP) device, the volume of the polymer decreases as the heat decomposable polymer is gradually pyrolyzed and/or carbonized as the temperature increases (see FIG. 2(b)), As a result, when the thermal decomposition of the polymer is completed, a porous structure is formed in which a plurality of pores exist at the site from which the polymer is removed (see FIG. 2(c)). Such a plurality of pores may be regularly distributed or irregularly formed, and may be a closed type that is not connected to each other, or may have an open pore structure that is connected to each other in three dimensions.

The porous thermoelectric material of the present invention manufactured through the above-described manufacturing method may have a fine pore size and a uniform porosity.

For example, the porosity of the porous thermoelectric material may be 0.1 to 10%, specifically 0.5 to 5%. In addition, the pore size included in the porous thermoelectric material can be easily adjusted according to the average particle diameter of the pyrolytic polymer to be used. For example, the pore size may be 5 to 50 μm.

For another embodiment, the porous thermoelectric material may have a relative density of 90 to 99.9%, and specifically 92% to 99.9%. In addition, since the pulverization process is performed in an inert gas atmosphere, the degree of oxidation is adjusted so that the oxygen content in the thermoelectric material can be controlled within a predetermined range.

<Thermoelectric element>

The thermoelectric device of the present invention includes the aforementioned porous thermoelectric material, and includes all thermoelectric power generation and/or cooling devices.

A thermoelectric element according to an embodiment of the present invention includes two substrates facing each other; A conductive electrode and a plurality of thermoelectric materials (thermoelectric legs) respectively disposed above and below the two substrates; And a bonding layer disposed between the thermoelectric material and the conductive electrode, wherein at least one of the plurality of thermoelectric legs includes the aforementioned porous thermoelectric material.

Hereinafter, preferred embodiments of the thermoelectric device according to the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

4 is a perspective view schematically showing the structure of the thermoelectric device 100 according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view of the thermoelectric device 100.

4 and 5, the thermoelectric element 100 may include a first substrate 11; A second substrate 11 disposed opposite to the first substrate 11; A first electrode 20a and a second electrode 20b disposed between the first and second substrates 11 and 11, respectively; A plurality of thermoelectric legs 30 interposed between the first electrode 20a and the second electrode 20b; And a bonding material 40 disposed between at least one of between the first electrode 20a and the thermoelectric leg 30 and between the thermoelectric leg 30 and the second electrode 20b.

Hereinafter, each configuration of the thermoelectric element will be described in detail.

Each of the first substrate 11 and the second substrate 11 causes heat generation or endothermic reaction when power is applied to the thermoelectric element 100, and may be made of a conventional electrical insulating material known in the art. For example, the first substrate 11 and the second substrate 11 may be ceramic substrates composed of one or more of _{Al 2} O ₃ , AlN, SiC, and ZrO _{2, respectively.} Alternatively, it may be composed of a high heat-resistant insulating resin or engineering plastic.

In addition, the first substrate 11 and the second substrate 11 may be metal substrates made of a conventional conductive metal material known in the art. For example, the first substrate 11 and the second substrate 11 are at least one metal selected from aluminum (Al), zinc (Zn), copper (Cu), nickel (Ni), and cobalt (Co), respectively. It may include.

In this case, when the electrodes 20a and 20b are directly disposed on the first and second substrates 11 and 11, the electrodes 20a and 20b are electrically conductive, so an electrical insulating material must be interposed therebetween. Accordingly, a first insulating layer (not shown) is formed on one surface of the first substrate 11 on which the first electrode 20a is disposed, and the second substrate 11 on which the second electrode 20b is disposed. A second insulating layer (not shown) is formed on one surface, and the first insulating layer and the second insulating layer are disposed to face each other.

The first insulating layer and the second insulating layer may be the same or different from each other, and may be formed of an electrically insulating material that is easy to form a film. For example, an insulating resin may be used alone, or a mixture of the insulating resin and a ceramic filler (powder) may be included. For example, each of the first insulating layer and the second insulating layer may be an epoxy resin layer containing a ceramic filler.

Each of the first and second substrates 11 and 11 may have a flat plate shape, and are not particularly limited in size or thickness. For example, the thickness of each of the first and second substrates 11 and 11 may be 0.5 to 2 mm, preferably 0.5 to 1.5 mm, more preferably 0.6 to 0.8 mm.

At this time, the location of heat absorption and heat generation of the substrate can be changed according to the direction of the current. One of the two substrates is a cold side substrate in which an endothermic reaction occurs, and a heat dissipation pad may be applied to such a substrate. The heat dissipation pad may be formed of a silicone polymer or an acrylic polymer, and may maximize heat transfer efficiency by having a thermal conductivity in the range of 0.5 to 5.0 W/mk. It can also act as an insulator. Also, the other of the two substrates may be a hot side.

The first electrode 20a and the second electrode 20b are respectively disposed on the first and second substrates 11 and 11 that are disposed to face each other. That is, the second electrode 20b is disposed at a position facing the first electrode 20a.

Materials of the first electrode 20a and the second electrode 20b are not particularly limited, and materials used as electrodes in the art may be used without limitation. For example, the first electrode 20a and the second electrode 20b are the same or different from each other, and each independently aluminum (Al), zinc (Zn), copper (Cu), nickel (Ni), and cobalt At least one metal of (Co) can be used. In addition, nickel, gold, silver, titanium, and the like may be further included. Its size can also be adjusted in various ways. Preferably, it may be a copper (Cu) electrode.

The first electrode 20a and the second electrode 20b may be patterned in a predetermined shape, and the shape is not particularly limited. In addition, as a method of patterning the first electrode 20a and the second electrode 20b, a conventionally known patterning method may be used without limitation. For example, a lift-off semiconductor process, a vapor deposition method, a photolithography method, or the like can be used.

A plurality of thermoelectric legs 30 are interposed between the first electrode 20a and the second electrode 20b.

Referring to FIG. 1, the thermoelectric leg 30 includes a plurality of P-type thermoelectric legs 30a and N-type thermoelectric legs 30b, respectively, and they are alternately arranged in one direction. As such, the P-type thermoelectric leg 30a and the N-type thermoelectric leg 30b adjacent in one direction are electrically connected in series with the first and second electrodes 20a and 20b, respectively. Each of these thermoelectric legs 30a and 30b includes a thermoelectric semiconductor substrate.

The thermoelectric semiconductor included in the thermoelectric leg 30 may be formed of a conventional thermoelectric material in the industry that generates electricity when a temperature difference occurs at both ends when electricity is applied, or when a temperature difference occurs at both ends. As long as it is porosity having a regular pore size and porosity in the material, it is not particularly limited to its components. For example, one or more thermoelectric semiconductors including at least one element selected from the group consisting of a transition metal, a rare earth element, a group 13 element, a group 14 element, a group 15 element, and a group 16 element may be used. Here, examples of rare earth elements include Y, Ce, and La, and examples of the transition metal include Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Fe, Co, Ni, Cu, It may be one or more of Zn, Ag, and Re, examples of the group 13 element may be one or more of B, Al, Ga, and In, and examples of the group 14 element include C, Si, Ge, Sn, and Pb It may be one or more of, and examples of the group 15 element may be one or more of P, As, Sb, and Bi, and one or more of S, Se, and Te may be used as an example of the group 16 element.

Usable thermoelectric semiconductors include bismuth (Bi), telelium (Te), cobalt (Co), samarium (Sb), indium (In), and cerium (Ce). And, non-limiting examples thereof include Bi-Te-based, Co-Sb-based, Pb-Te-based, Ge-Tb-based, Si-Ge-based, Sb-Te-based, Sm-Co-based, transition metal silicide-based, scoo Terdite (Skuttrudite) type, silicide type (Silicide) type, Half heusler (Half heusler), or a combination thereof, and the like. For example, as a Bi-Te-based thermoelectric semiconductor, a (Bi,Sb) ₂ (Te, Se) ₃ -series thermoelectric semiconductor in which Sb and Se are used as dopants may be exemplified, and as a Co-Sb-based thermoelectric semiconductor, CoSb _Three- series thermoelectric semiconductors can be exemplified, AgSbTe ₂ and CuSbTe ₂ can be exemplified as Sb-Te-based thermoelectric semiconductors, and PbTe, (PbTe) mAgSbTe ₂ and the like can be exemplified as Pb-Te-based thermoelectric semiconductors. Preferably, it may be made of a Bi-Te-based or CoSb-based thermoelectric material.

Components and structures of the porous thermoelectric material constituting the thermoelectric leg may be described with the description of the porous thermoelectric material already shown in FIG. 1 as it is, and thus a separate description will be omitted. The thermoelectric leg 30 including the P-type thermoelectric leg 30a and the N-type thermoelectric leg 30b may be formed in a predetermined shape, for example, a rectangular parallelepiped shape by a method such as cutting, and applied to a thermoelectric element.

The thermoelectric element 100 according to the present invention includes: between the first electrode 20a and the thermoelectric leg 30; And a bonding material 40 disposed between at least one of the thermoelectric legs 30 and the second electrode 20b, preferably between all of them.

As the bonding material 40, a conventional bonding material component known in the art may be used without limitation, and Sn-based solder may be used as an example.

In one embodiment, the bonding material 40 is Sn; Sn-based first solder composition including at least one first metal of Pb, Al, and Zn; Alternatively, the first solder may be formed of a second Sn-based solder composition including at least one second metal of Ni, Co, and Ag.

For another specific example, the bonding material 40 may be a conventional Sn-based solder known in the art, including a metal powder having a dendrite shape.

Such metal dendrites are conductive metal particles having a shape in which one main axis is provided, and a plurality of branch phases branch from the main axis vertically or obliquely to grow two-dimensionally or three-dimensionally. At this time, the main axis refers to a rod-shaped portion that serves as a basis for branching a plurality of branches. The average branch length of the metal dendrites is not particularly limited, and may be, for example, 5 to 50 µm, and preferably 5 to 30 µm.

For example, in the metal dendrite, the length of the major axis of the main axis means the total length of the main axis, and may be 5 to 50 µm, and specifically 5 to 30 µm. In addition, the length of the longest branch among the plurality of branches in the metal dendrite may be 5 to 30 µm, and specifically 10 to 25 µm. In addition, the number of branches (number of branches/major diameter) with respect to the major axis of the main axis may be 0.5 to 10 pieces/µm, specifically 1 to 8 pieces/µm. The average particle diameter (D ₅₀ ) of the metal dendrites refers to a two-dimensional size including the long diameter length of the dendrites, and may be 5 to 50 μm as an example, and specifically 5 to 30 μm. In addition, the thickness of the main axis of the dendrite may be 0.3 to 5.0 μm. As the metal dendrites have the above-described structural characteristics, they have a higher specific surface area than the spherical metal particles. For another embodiment of the present invention, the metal dendrite may have a specific surface area of 0.4 to 3.0 m ² /g, measured by a BET measurement method, and specifically 0.5 to 2.0 m ² /g. In addition, the metal dendrite may have an apparent density of 0.5 to 1.5 g/cm 3, and an oxygen content of 0.35% or less is suitable.

The metal dendrite is not particularly limited to the metal material to be used as long as it satisfies the above-described structural characteristics and physical properties. For a preferred example, copper dendrite (Cu dendrite), silver (Ag) coated copper dendrite (Ag coated Cu dendrite), or a mixture thereof may be used. In particular, copper (Cu) is not only similar in electrical conductivity to silver (Ag), but is also advantageous because it is economical.

In the bonding material according to the present invention, the content of the metal dendrite is not particularly limited, and for example, may be included in 1 to 40% by weight based on the total weight of the bonding material, and preferably 5 to 30% by weight.

For example, when using a copper dendrite (Cu dendrite) having an average branch length of 5 to 20 μm as the metal dendrite, the content of this copper dendrite is 1 to 40 weight based on the total weight of the bonding material. It is preferably contained in %, preferably 5 to 30% by weight.

In another embodiment, when using silver (Ag)-coated copper dendrite having an average branch length of 5 to 20 μm, preferably 10 to 30 μm as the metal dendrite, based on the total weight of the bonding material It is preferably included in the range of 10 to 30% by weight.

In the present invention, metal dendrite may be used alone as a bonding material component, and in addition, metal powders having various materials, particle diameters, and/or shapes are further included as a bonding material component, and are also included in the scope of the present invention. For example, the aforementioned metal dendrite and one or more metal powders such as spherical, acicular, flake, and amorphous may be mixed.

As the Sn-based solder mixed with the aforementioned metal dendrite, a conventional Sn-based solder component known in the art may be used. For a preferred example, the Sn-based solder is Sn; It may have a composition including at least one metal of Pb, Al, and Zn. .

Optionally, the thermoelectric element 100 of the present invention comprises: between the first electrode 20a and the thermoelectric leg 30; And a diffusion barrier layer (not shown) disposed between the thermoelectric leg 30 and the second electrode 20b. The diffusion barrier layer may be used without limitation of conventional components known in the art, for example, including at least one selected from the group consisting of tantalum (Ta), tungsten (W), molybdenum (Mo), and titanium (Ti). can do.

In the thermoelectric element 100 according to an embodiment of the present invention, the first electrode 20a and the second electrode 20b may be electrically connected to a power supply source. When a DC voltage is applied from the outside, holes in the p-type thermoelectric leg 30a and electrons in the n-type thermoelectric leg 30b move, so that heat generation and endothermic heat may occur at both ends of the thermoelectric leg.

In the thermoelectric element 100 according to another embodiment of the present invention, at least one of the first electrode 20a and the second electrode 20b may be exposed to a heat source. When heat is supplied by an external heat source, electrons and holes move, and current flows through the thermoelectric element, which can generate electricity.

The thermoelectric device according to the above-described embodiment may be manufactured according to a method known in the art. In one embodiment of such a manufacturing method, (a) preparing two insulating substrates; (b) forming a first electrode and a second electrode on one surface of the two insulating substrates, respectively; And (c) disposing the first electrode and the second electrode to face each other, disposing a plurality of porous thermoelectric legs therebetween, and bonding them using the bonding material. In this case, the manufacturing method is not limited only by the following method or sequence, and the steps of each process may be modified or selectively mixed and performed as necessary.

As an example of a method of manufacturing a thermoelectric leg using a thermoelectric material in the above manufacturing method, a metal ribbon is manufactured after melting a Bi-Te or Skuttrudite-based thermoelectric material using RSP, and the metal The ribbon and the thermally decomposable polymer are mixed in a predetermined range and then pulverized, and the pulverized product is formed and hot press sintered to form a porous sintered body. Subsequently, slicing is performed according to the target thickness, and lapping is performed according to the final thickness to adjust the height of the material to within 1/100. After surface coating of Co, Ni, Cr, and W is performed on the surface of the thermoelectric material having a controlled step, dicing is finally performed according to the size of the material, thereby manufacturing a thermoelectric leg.

In addition, a ceramic substrate or a metal substrate is used as a substrate, and a Cu electrode pattern is formed on one surface of the substrate, followed by heat treatment to fix it. In this case, when a metal substrate is used, an insulating resin or a mixture of the insulating resin and a ceramic filler (powder) is applied on one surface of the metal substrate on which the electrode is disposed to prevent electricity.

A plurality of thermoelectric legs are disposed and bonded between the first electrode and the second electrode using the thermoelectric legs and the substrate prepared as described above. As such a bonding material, Sn-based solder; Alternatively, a Sn-based solder paste containing the Sn solder and metal dendrite at a predetermined mixing ratio is applied. As a specific example of the bonding step, a bonding material paste is applied to a predetermined thickness according to the pattern of the first electrode 20a, and n-type and p-type thermoelectric legs are arranged thereon. Thereafter, in the case of the opposite electrode (second electrode), the final configuration is completed by arranging the existing n-type and p-type thermoelectric legs in a state where only the bonding material is applied. Subsequently, heat treatment is performed at 300 to 500° C., followed by final bonding, and wires are connected to complete the manufacture of the thermoelectric element.

The above-described thermoelectric leg and/or a thermoelectric element including the same is provided in a thermoelectric cooling system, a thermoelectric power generation system, and/or a thin-film sensor, and may be applied to at least one of cooling, power generation, and thin-film sensor.

For example, such a thermoelectric power generation system refers to a conventional system that generates power by using a temperature difference, and examples include a waste heat furnace, a thermoelectric power generation system for a vehicle, a solar thermoelectric power generation system, and the like. In addition, the thermoelectric cooling system may include a micro cooling system, a general-purpose cooling device, an air conditioner, and a waste heat power generation system, but is not limited thereto. In addition, the thin-film sensor includes all fields of sensors using micro power, such as thin-film thermoelectric devices.

Each configuration and manufacturing method in the field of the thermoelectric power generation system, the thermoelectric cooling system, and/or the thin-film sensor are known in the art, and detailed descriptions thereof are omitted herein. Further, in the present invention, even if they are indicated by the same reference numerals, they may have different configurations.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are merely illustrative of the present invention, and the present invention is not limited by the following examples.

[Example 1] Preparation of porous thermoelectric material

A thermoelectric material containing Bi, Te, Sb and Se having a high purity of about 2 to 5 mm and having a high purity of 4N or more was prepared. In the case of p-type, it was made to have a ternary system such as Bi, Te, and Sb. The thermoelectric material was charged into a locking furnace, and then stirred and dissolved at 650 to 750°C for 2 to 4 hours at a rate of 10 times/min to prepare a Φ 30 * 100 mm master alloy ingot. After that, the master alloy ingot is charged into a nozzle installed in the melt spinning equipment, and completely dissolved at about 700°C using a resistance heating element (a structure that surrounds the nozzle as a graphite heater), and then, 0.1 to an inert gas is added to the melt. By pressing and spraying at 0.5 MPa, a Bi-Te-based metal ribbon was formed by contacting the surface of a rotating copper wheel and cooling rapidly. At this time, the rotational speed of the copper wheel was performed at 1000 rpm. Then, the formed metal ribbon and the thermally decomposable polymer [polymethyl methacrylate (PMMA) having an average particle diameter of 5 μm] were mixed and pulverized to have an average particle diameter of 100 μm or less by using a ball mill method in an argon (Ar) atmosphere. The pulverized product was heated up to about 525° C. at a rate of 7° C./min using hot press sintering, and then maintained for 1 hour and sintered by maintaining a pressure of 20 MPa. As a result, a porous thermoelectric material having a high density of 99% or more was manufactured.

[Examples 2 to 12] Preparation of porous thermoelectric material

During hot press sintering, Examples 2 to 12 were carried out in the same manner as in Example 1, except that the pulverized product of the thermoelectric material and polymethyl methacrylate (PMMA) were mixed and used in the composition shown in Table 1 below. Each thermoelectric material was prepared.

Pyrolytic polymer Addition amount (parts by weight) Average particle diameter (㎛) Comparative Example 1 0.00 - Example 1 0.10 5.00 Example 2 20.00 Example 3 50.00 Example 4 0.50 5.00 Example 5 20.00 Example 6 50.00 Example 7 1.00 5.00 Example 8 20.00 Example 9 50.00 Example 10 2.00 5.00 Example 11 20.00 Example 12 50.00 Pyrolytic polymer: PMMA (specific gravity: 1.20 g/cm ³ )

[Comparative Example 1] Manufacture of non-porous thermoelectric material

A thermoelectric material containing Bi, Te, Sb and Se having a high purity of about 2 to 5 mm and having a high purity of 4N or more was prepared. In the case of p-type, it was made to have a ternary system such as Bi, Te, and Sb. The thermoelectric material was charged into a locking furnace, and then stirred and dissolved at 650 to 750°C for 2 to 4 hours at a rate of 10 times/min to prepare a Φ 30 * 100 mm master alloy ingot. After that, the master alloy ingot is charged into a nozzle installed in the melt spinning equipment, and completely dissolved at about 700°C using a resistance heating element (a structure that surrounds the nozzle as a graphite heater), and then, 0.1 to an inert gas is added to the melt. By spraying by pressing at 0.5 MPa, a Bi-Te-based metal ribbon was formed by contacting the surface of a rotating copper wheel and cooling rapidly. At this time, the rotational speed of the copper wheel was performed at 1000 rpm.

Then, the formed metal ribbon was pulverized to have an average particle diameter of 100 μm or less by using a ball mill method in an argon (Ar) atmosphere. Non-porous thermoelectric material having a high density of 99% or more as a result of heating the pulverized powder by hot press sintering at a temperature increase rate of 7°C/min to about 525°C at a rate of 7°C/min and sintering by maintaining a pressure of 20 MPa Was prepared.

[Experimental Example 1] Evaluation of Physical Properties of Pyrolytic Polymer

Meanwhile, FIG. 3 is an electron micrograph of the pyrolytic polymer used in Examples 3, 6, 9, and 12 of the present application. It was confirmed that the average particle diameter was approximately 50 μm class spherical particles.

In addition, the thermal decomposition properties according to temperature were evaluated for PMMA, PBMA, PVB, and EC used as the thermally decomposable polymer in the present invention, and the results are shown in FIG. 6 below.

As a result of the experiment, it was confirmed that the thermal decomposition of PMMA and PBMA was completed without residual carbon when the temperature was raised to approximately 400°C (see FIG. 6 below).

[Experimental Example 2] Density evaluation of thermoelectric material

For each thermoelectric material prepared in Examples 1 to 12 and Comparative Example 1, the densities before and after sintering were measured by the Archimedes method, respectively, and the results are shown in Table 2.

Pyrolytic polymer Density after sintering
(g/cm ³ ) Relative density
(%) Addition amount (parts by weight) Average particle diameter (㎛) Comparative Example 1 0.00 - 6.84 - Example 1 0.10 5.00 6.82 99.71 Example 2 20.00 6.81 99.56 Example 3 50.00 6.81 99.56 Example 4 0.50 5.00 6.79 99.27 Example 5 20.00 6.78 99.12 Example 6 50.00 6.76 98.83 Example 7 1.00 5.00 6.77 98.98 Example 8 20.00 6.76 98.83 Example 9 50.00 6.72 98.25 Example 10 2.00 5.00 6.50 95.03 Example 11 20.00 6.47 94.59 Example 12 50.00 6.31 92.25

As shown in Table 2, it was found that the density decrease after sintering was not significant up to 1 part by weight of the thermally decomposable polymer.

[Experimental Example 3] Evaluation of properties of thermoelectric materials

The physical properties of the thermoelectric materials prepared in Examples 1 to 12 and Comparative Example 1 were measured as follows, and the results are shown in Table 3 and FIGS. 7 to 8, respectively.

(1) Measurement of Seebeck coefficient and electrical conductivity: According to JISK 7194, it was measured using ZEM-3 (manufactured by Ulvac-Riko).

(2) Power factor: Power factor was calculated using the measured Seebeck coefficient (S) and electrical conductivity (σ), and the results are shown in FIG. 7.

[Equation 1] Power factor = (Seebeck coefficient)2 * Electrical conductivity

(3) Thermoelectric performance index: The thermoelectric performance index ZT values were compared, and the results are shown in FIG. 8 below. The measured value was compared to the power factor and the value of 150°C where the ZT value had the highest value.

[Equation 2] ZT = (Seebeck coefficient) 2 *Electrical conductivity/thermal conductivity * Temperature

(4) Measurement of thermal conductivity: In accordance with JIS R 1611 and JIS R 1650-3, specific heat capacity measurement and thermal conductivity by the laser flash method were calculated. More specifically, after measuring the thermal diffusivity (D), specific heat (Cp), and density (d) by laser flash method by cutting into a disk shape having a diameter of 10 mm x 1 mm, the thermal conductivity is measured using Equation 3 below. I did.

[Equation 3] κ = DCpd

Thermal conductivity
(W/mK) Electrical conductivity
(/Ωcm) Seebeck coefficient
(μV/K) Power factor
(W/mK^2) ZT Comparative Example 1 1.48 932.19 182.09 30.91 0.87 Example 1 1.47 932.26 181.92 30.85 0.89 Example 2 1.46 930.97 181.48 30.66 0.89 Example 3 1.45 929.68 181.05 30.47 0.89 Example 4 1.43 930.32 180.27 30.23 0.90 Example 5 1.40 929.60 179.23 29.86 0.90 Example 6 1.37 926.16 177.67 29.24 0.91 Example 7 1.31 927.80 176.21 28.81 0.93 Example 8 1.26 928.08 174.50 28.26 0.95 Example 9 1.20 922.94 171.79 27.24 0.96 Example 10 1.11 877.06 158.09 21.92 0.83 Example 11 1.03 829.62 144.80 17.39 0.71 Example 12 0.93 765.33 129.24 12.78 0.58

As shown in Table 3, the thermoelectric device of the present invention including a porous thermoelectric material improves thermoelectric performance by reducing thermal conductivity without significantly lowering electrical conductivity and Seebeck coefficient due to the regular pore structure contained in the thermoelectric material. It could be seen that it could be improved.

Specifically, the decrease in electrical resistance and Seebeck coefficient was not significant up to 1 part by weight of the thermally decomposable polymer, whereas the decrease in thermal conductivity was relatively large, and the thermoelectric performance index (ZT) value showed a maximum value when 1 part by weight was added. In addition, it was found that when particles having an average particle diameter of about 50 μm were used as the thermally decomposable polymer, the maximum value of the thermoelectric performance index was displayed relative to the same amount of addition.

100: thermoelectric element
11: insulating substrate
10a: first metal laminated plate
11a: first conductive substrate
12a: first insulating layer
20a: first electrode
30: porous thermoelectric leg
30a: P-type thermoelectric leg
30b: N-type thermoelectric leg
20b: second electrode
10b: second metal laminated plate
11b: second conductive substrate
12b: second insulating layer
40: bonding material

Claims (14)

(i) dissolving and solidifying a raw material for a thermoelectric material to form a master alloy;
(ii) rapidly cooling the master alloy to form a metal ribbon;
(iii) mixing the metal ribbon with a polymer that is pyrolyzed at a predetermined temperature or higher and has a residual carbon content of 5% or less after pyrolysis, and pulverized in an inert atmosphere; And
(iv) sintering the pulverized product of step (iii) at a temperature higher than the pyrolysis temperature of the pyrolytic polymer;
Including,
The thermally decomposable polymer is added in an amount of 0.1 to 2 parts by weight based on the total weight of the metal ribbon. The method of claim 1,
The pyrolytic polymer is pyrolyzed by sintering to form and remove a plurality of pores. The method of claim 1,
The pyrolytic polymer is selected from the group consisting of thermoplastic polymers, natural polymers, and water-soluble polymers having a thermal decomposition temperature of 200 to 500°C. delete The method of claim 1,
The pyrolytic polymer is a group consisting of polymethyl methacrylate (PMMA), polybutyl methacrylate (PBMA), polybromonied biphenyl (PBB), polyvinyl alcohol (PVA), and ethyl cellulose (EC). At least one selected from, a method of manufacturing a porous thermoelectric material. The method of claim 1,
The pyrolytic polymer is a spherical particle having an average particle diameter (D ₅₀ ) of 5 to 50 μm, a method of manufacturing a porous thermoelectric material. delete The method of claim 1,
In the step (iv), the pulverized product of step (iii) is put into a molding mold and then sintered by hot pressing. The method of claim 1,
The thermoelectric material is at least one of a Bi-Te-based thermoelectric material and a Skuttrudite-based thermoelectric material. The method of claim 1,
The porosity of the porous thermoelectric material is 0.1 to 10%,
The pore size is 5 to 50 μm,
A method of manufacturing a porous thermoelectric material having a density of 90 to 99.9%. As prepared by the method of any one of claims 1 to 3, 5, 6, 8 to 10,
The porosity is 0.1 to 10%, the pore size is 5 to 50 μm,
The residual carbon content is 5% or less,
Porous thermoelectric material having a density of 90 to 99.9%. A first substrate;
A second substrate disposed opposite to the first substrate;
A first electrode and a second electrode respectively disposed between the first and second substrates; And
A plurality of thermoelectric legs interposed between the first electrode and the second electrode;
Including a bonding material disposed between at least one of between the first electrode and the thermoelectric leg, and between the thermoelectric leg and the second electrode,
At least one of the plurality of thermoelectric legs includes the porous thermoelectric material according to claim 11. The method of claim 12,
The bonding material is Sn-based solder; Or a thermoelectric element having a composition comprising the Sn-based solder and metal dendrite having an average branch length of 5 to 50 µm. The method of claim 12,
A thermoelectric element applied to at least one of cooling, power generation, and thin-film sensors.

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