KR20170003100A - Thermo electric device and method of fabricating the same - Google Patents

Abstract

The present invention relates to a thermoelectric device with an improved thermoelectric property and a method of fabricating the same. The thermoelectric device according to an embodiment of the present invention comprises: a first substrate; a second substrate facing the first substrate; and a thermoelectric material and silicon which are arranged in between the first substrate and the second substrate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a thermoelectric device,

The present invention relates to a thermoelectric device and a method of manufacturing the same.

Thermoelectric phenomenon is a phenomenon in which heat is generated and cooled at both ends of a material joint by applying current between two materials (Peltier effect), and conversely, electromotive force is generated due to temperature difference between two materials (Seebeck effect). A thermoelectric element refers to a metal or ceramic element having a function of directly converting heat into an electric furnace or electricity into heat using the above-mentioned thermoelectric phenomenon.

The thermoelectric element can convert heat generated from a computer or an automobile engine into electric energy by using the Seebeck effect. And, by using the Peltier effect, various cooling systems that do not need refrigerant can be implemented.

In the thermoelectric element, N-type and P-type semiconductor cells are disposed between the upper substrate and the lower substrate, and the N-type thermoelectric cells and the P-type thermoelectric cells are connected to each other. The above-described thermoelectric elements can be formed in a laminated manner. The laminated type method can be formed by using a paste containing a thermoelectric material and curing and sintering the same.

Specifically, a paste can be formed by mixing a thermoelectric material, a binder, a plasticizer, a dispersant, and a solvent. Binders, plasticizers, dispersants and solvents are for the synthesis of the paste. The above paste is applied on a film and cured to form a thermoelectric sheet. After peeling the thermoelectric sheet from the film, a plurality of thermoelectric sheets are laminated and sintered to form N-type and P-type cells.

However, the strength and performance of the N-type and P-type cells may be deteriorated by the binder contained in the paste.

Specifically, when the amount of the binder contained in the paste is small, the thermoelectric sheet may be broken when the thermoelectric sheet is peeled from the film. On the contrary, when the paste contains too much binder, when the paste is cured, voids are generated in the thermoelectric sheet or the binder is not evaporated completely, and the thermally conductive property of the cell is deteriorated due to the remaining binder.

Embodiments of the present invention provide a thermoelectric element with improved strength and thermoelectric properties and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a thermoelectric device including: a first substrate; A second substrate facing the first substrate; And a thermoelectric material and silicon disposed between the first substrate and the second substrate. At this time, the coupling agent may be selected from among silane, acrylate, titanate, and chromium coupling agents.

According to another aspect of the present invention, there is provided a method of manufacturing a thermoelectric device, including: forming a paste by mixing a thermoelectric material and a coupling agent in a solvent; Curing the paste to form a thermoelectric sheet; Stacking a plurality of thermoelectric sheets; And sintering the laminated thermoelectric conversion sheets to form thermoelectric cells. At this time, the coupling agent may be selected from among silane, acrylate, titanate, and chromium coupling agents.

The thermoelectric element and its manufacturing method of the embodiment have the following effects.

First, the paste for forming the thermoelectric sheet further comprises a coupling agent, so that the coupling agent binds simultaneously with the binder and the thermoelectric material. Therefore, an intermolecular force acts between the binder molecules and the thermoelectric material molecules, so that the physical strength of the thermoelectric sheet is improved. This makes it possible to prevent the thermoelectric sheet from being broken when the thermoelectric sheet is peeled from the film.

Second, the weight percentage (wt%) of the binder contained in the paste is reduced, and the weight percentage of the thermoelectric material is increased by the decrease of the binder, so that the thermoelectric material characteristics can be improved. Accordingly, the thermoelectric characteristics of the thermoelectric element including the N-type thermoelectric cell and the P-type thermoelectric cell made of the thermoelectric sheet as described above are improved.

Third, when the coupling agent is a silane coupling agent, the N-type thermoelectric cell and the P-type thermoelectric cell include a thermoelectric material and silicon (Si). At this time, silicon (Si) functions as a dopant and the thermoelectric characteristics of the N-type thermoelectric cell and the P-type thermoelectric cell can be further improved.

1 is a flow chart for manufacturing a thermoelectric sheet of an embodiment of the present invention.
2 is a schematic diagram showing the structure of a general thermoelectric sheet.
3 is a model diagram showing the structure of the thermoelectric sheet of the embodiment of the present invention.
4 is a cross-sectional view of a thermoelectric element in an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the embodiments of the present invention are not intended to be limited to the specific embodiments but include all modifications, equivalents, and alternatives falling within the spirit and scope of the embodiments.

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

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

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

In the description of the embodiments, when an element is described as being formed "on or under" another element, the upper or lower (lower) (on or under) all include that the two components are in direct contact with each other or that one or more other components are indirectly formed between the two components. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one component.

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

Hereinafter, a thermoelectric device and a method of manufacturing the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a flow chart for manufacturing a thermoelectric sheet of an embodiment of the present invention.

As shown in Fig. 1, a thermoelectric sheet of the present invention is prepared by mixing a thermoelectric material, a binder, a plasticizer, a dispersant, a coupling agent and a solvent (S5).

The thermoelectric material is an N-type thermoelectric material or a P-type thermoelectric material including bismuth-tellurium (Bi ₂ Te ₃ ). The n-type thermoelectric material may be Bi ₂ Te _{3 -xy} Se _x Cu _y (0.1 <x <0.5, 0 <y <0.1) or Bi ₂ Te _{3 -x} Se _x But is not limited thereto. The p-type thermoelectric material is preferably Bi _{2 -x- y} Sb _{x -y} Te ₃ Cu _y (0.1 <x <0.5, 0 <y <0.1) or Bi _{2 -x} Sb _x Te ₃ 0 < y < 0.1). At this time, the weight percentage (wt%) of the thermoelectric material may be 60 to 90. [

The binder is a long chain polymer, which binds a thermoelectric material dispersed in an organic solvent. In particular, the binder improves the strength of the thermoelectric sheet by imparting moldability to the thermoelectric sheet. The binder may be selected from polyvinyl butyrate (PVB), polyvinyl alcohol (PVA), acrylic, polyvinyl butyral, and the like. At this time, the weight percentage (wt%) of the binder may be 0.1 to 3.

The plasticizer is included in the paste to lower the glass transition temperature of the binder to impart the flow properties, flexibility, elasticity, adhesiveness and processability of the paste. Generally, the binder has a large molecular weight, and the binder molecules have a very strong pulling force with each other. Therefore, the plasticizer can prevent the binder molecules from becoming entangled with each other between the molecules of the binder, thereby imparting plasticity to the paste. The plasticizer is selected from the group consisting of dioctyl phthalate, di-n-butyl phthalate (DBP), diisodecyl phthalate, diethyl phthalate, Di-n-hexyl phthalate (DNHP), diisobutyl phthalate, oleoyl sarcosine, and the like. At this time, the weight percentage (wt%) of the plasticizer may be 0.1 to 3.

The dispersant improves the dispersibility of the thermoelectric material, the binder and the plasticizer in the paste. The dispersant may be selected from phthalate, fatty acids, menhaden fish oil, and the like, but is not limited thereto. At this time, the weight percentage (wt%) of the dispersing agent may be 0.1 to 3.

The thermoelectric materials, binders, plasticizers, dispersants and coupling agents described above are mixed in a solvent such as toluene. The solvent is not limited thereto, and the weight percentage (wt%) of the solvent may be 0.1 to 30.

However, in a general thermoelectric sheet, the strength and performance of the thermoelectric sheet may be deteriorated by the binder contained in the paste. Specifically, when the amount of the binder contained in the paste is small, the thermoelectric sheet may be broken when the thermoelectric sheet is peeled from the film. On the contrary, when the paste contains too much binder, voids are generated in the thermoelectric sheet when the paste is cured, or the binder is not completely evaporated, and the remaining thermally conductive property of the cell is deteriorated by the binder.

Therefore, in the thermoelectric sheet of the embodiment of the present invention, the paste further comprises a coupling agent in order to minimize the amount of the binder and at the same time to improve the strength of the sheet. The coupling agent may be selected from silane, acrylate, titanate, chromium, and the like. At this time, the weight percentage (wt%) of the coupling agent may be 0.01 to 3.

The paste for forming a general thermoelectric sheet can be formed from a composition having a weight percentage as shown in Table 1 below.

division matter Weight Percentage (wt%) Thermoelectric material Bismuth-Telenium (Bi ₂ Te ₃ ) 73.3 bookbinder Polyvinyl butyral 5 Plasticizer Oleoyl sarcosine One Dispersant Phthalate 1.8 menstruum Toluene 18.9 Total (Total) Paste 100

However, the paste for producing the thermoelectric sheet of the embodiment of the present invention may be formed from a composition having a weight percentage as shown in Table 2 below.

division matter Weight Percentage (wt%) Thermoelectric material Bismuth-Telenium (Bi ₂ Te ₃ ) 75.3 bookbinder Polyvinyl butyral 2 Plasticizer Oleoyl sarcosine One Dispersant Phthalate 1.8 Coupling agent Silane coupling agent 0.01 to 1 menstruum Toluene 18.9 Total (Total) Paste 100

Comparing Table 1 and Table 2, the paste for forming the thermoelectric element of the embodiment of the present invention has a lower weight percentage of the binder than a general paste. Specifically, the weight percentage of the binder is reduced to 2 and comprises 0.01 to 1 coupling agent. Therefore, the weight percentage of the thermoelectric material can be increased as much as the binder is reduced.

If the amount of the coupling agent is too small, the coupling agent can not be bonded to the thermoelectric material and the binder, and the thermoelectric sheet can not be prevented from breaking. Therefore, the weight percentage of the coupling agent may be 0.1 or more. In addition, when the weight percentage of the coupling agent is too high, the strength of the thermoelectric sheet is improved, but the content of the coupling agent relative to the thermoelectric material is increased, and the characteristics of the thermoelectric sheet can be reduced. Thus, the coupling agent may be lower than the weight percentage of the binder, and the coupling agent may have a weight percentage of from 0.01 to 1.

In particular, silane-based coupling agents have two functional groups capable of interacting with organic and inorganic materials. Therefore, when the silane coupling agent is included in the paste, the silane coupling agent strengthens the bonding force between the thermoelectric material and the binder, and the strength of the thermoelectric sheet can be improved. In this case, the silane-based coupling agent may be selected from the group consisting of 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane represented by the following Chemical Formula 1, 3-Glycidoxypropyl methyldimethoxysilane represented by the Chemical Formula 2, 3-Glycidoxypropyl trimethoxysilane represented by the Chemical Formula 3, 3-Glycidoxypropyl methyldimethoxysilane represented by the Chemical Formula 4, -Glycidoxypropyl triethoxysilane, but is not limited thereto.

Referring again to FIG. 1, the paste prepared as described above is applied on a film (S10), and then the paste is cured to form a thermoelectric sheet from which solvent has been removed (S15). At this time, the thermoelectric sheet refers to a paste cured on a film, and the thermoelectric sheet includes a thermoelectric material, a binder, a plasticizer, a dispersant, and a coupling agent. Next, the thermoelectric sheet is peeled from the film (S20).

In the thermoelectric sheet of the present invention as described above, the coupling agent bonds with the binder and the thermoelectric material at the same time, so that an intermolecular force acts between the binder molecule and the thermoelectric material molecule. Therefore, when the thermoelectric sheet is peeled from the film, it is possible to prevent the thermoelectric sheet from being broken. Moreover, the weight percentage of the binder contained in the paste is reduced, and the weight percentage of the thermoelectric material is increased as the binder is reduced. Therefore, the ratio of the thermoelectric material can be improved and the thermoelectric properties of the thermoelectric sheet can be improved.

FIG. 2 is a schematic diagram showing the structure of a general thermoelectric sheet, showing only a thermoelectric material and a binder. 3 is a schematic diagram showing the structure of the thermoelectric conversion sheet of the embodiment of the present invention, showing a thermoelectric material, a binder and a coupling agent.

As shown in Fig. 2, a general thermoelectric sheet connects the thermoelectric materials 5 to each other with the binder 6 interposed therebetween. However, as shown in Fig. 3, in the thermoelectric sheet of the present invention including the coupling agent 7, the coupling agent 7 is bonded to the binder 6 and the thermoelectric material 5 at the same time. Therefore, the bonding force of the thermoelectric materials 5 is improved and the density is increased, so that the thermoelectric properties of the thermoelectric sheet can be improved and the physical strength can be increased.

Hereinafter, a method of manufacturing a thermoelectric device according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

4 is a cross-sectional view of a thermoelectric element in an embodiment of the present invention.

4, the thermoelectric device of the embodiment of the present invention includes a second substrate 10b including a first substrate 10a including a first electrode 15a and a second electrode 15b, a first substrate 10a including a first electrode 15a, The N-type thermoelectric cell 40, the P-type thermoelectric cell 50, and the N-type thermoelectric cell (not shown) which are disposed between the first substrate 10a and the second substrate 10b and are electrically connected through the first electrode 15a and the second electrode 15b The first solder 20 disposed between one side of the P-type thermoelectric cell 50 and the first electrode 15a and the second solder 20 disposed between the other side of the N-type thermoelectric cell 40 and the P- And a second solder 30 disposed between the two electrodes 15b.

A method of manufacturing a thermoelectric device in accordance with an embodiment of the present invention includes printing a first solder 20 on a first substrate 10a including a first electrode 15a and printing a second solder 20 on a second substrate 15b including a second electrode 15b 10b), the second solder 30 is printed on the second substrate 10b. The first solder 20 is printed on the first electrode 15a and the second solder 30 is printed on the second electrode 15b. At this time, the first and second solders 20 and 30 are made of a conductive material so that the first solder 20 is electrically connected to the first electrode 15a and the second solder 30 is electrically connected to the second And may be electrically connected to the electrode 15b.

The first substrate 10a and the second substrate 10b may include at least one of Al ₂ O ₃ (Alumina), BN (Boron Nitride), and carbon material. Carbon materials include, for example, aluminum silicon carbide composite materials (AlSiC), graphite, carbon black, graphene, fullerene, carbon nanotube (CNT) And mixtures thereof.

Then, the N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 are placed on the first substrate 10a. The N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 are disposed on the first solder 20, respectively. Then, the second substrate 10b is positioned so that the N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 are in contact with the second solder 30.

The N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 can be formed using the thermoelectric element of the embodiment of the present invention described above, and the N-type thermoelectric cell 40 and the P- The steps are as follows.

The N-type thermoelectric cells 40 are formed by stacking two or more N-type thermoelectric sheets 40a. That is, the paste formed by mixing the N-type thermoelectric material, the binder, the dispersant, the plasticizer, the coupling agent, and the solvent is cured to form the N-type thermoelectric sheet from which the solvent has been removed, and one or a plurality of N- do. At this time, the thickness of the N-type thermoelectric cell 40 can be adjusted by adjusting the number of the N-type thermoelectric sheets 40a to be laminated.

Then, when the laminated N-type thermoelectric sheet 40a is sintered at 400 ° C to 500 ° C, the binder, dispersant, plasticizer and coupling agent are removed, leaving only the N-type thermoelectric material. Next, the sintered N-type thermoelectric sheet 40a is cut to form the N-type thermoelectric cell 40. [ In this case, the N-type thermoelectric material is preferably Bi ₂ Te _3-xy Se _x Cu _y (0.1 <x <0.5, 0 <y <0.1) or Bi ₂ Te _{3 -x} Se _x &Lt; 0.1), but is not limited thereto.

The P-type thermoelectric cell 50 has a structure in which two or more P-type heat transfer sheets 50a are laminated. Specifically, the paste formed by mixing the P-type thermoelectric material binder, the plasticizer, the dispersant, the coupling agent, and the solvent is cured to form the P-type thermoelectric sheet 50a from which the solvent has been removed. When the laminated P-type thermoelectric sheet 50a is sintered at 400 ° C to 500 ° C after one or more P-type thermoelectric sheets 50a are laminated, the binder, plasticizer, dispersant, plasticizer and coupling agent are volatilized Only the P-type thermoelectric material remains. Then, the sintered P-type thermoelectric sheet 50a is cut to form the P-type thermoelectric cell 50. [ At this time, the P-type thermoelectric material is Bi _{2 -x- y} Sb _{x -y} Te ₃ Cu _y (0.1 <x <0.5, 0 <y <0.1) or Bi _{2 -x} Sb _x Te ₃ , 0 < y < 0.1).

In particular, the coupling agent may be selected from silane, acrylate, titanate, chromium, and the like as described above. If the amount of the coupling agent is too small, the coupling agent can not be bonded to the thermoelectric material and the binder, and the thermoelectric sheet can not be prevented from breaking. Therefore, the weight percentage of the coupling agent is 0.1 wt% or more. In addition, when the weight percentage of the coupling agent is too high, the strength of the thermoelectric sheet is improved, but the content of the coupling agent relative to the thermoelectric material is increased, and the characteristics of the thermoelectric sheet can be reduced. Thus, the coupling agent is lower than the weight percentage of the binder, and the coupling agent has a weight percentage of from 0.01 wt% to 1 wt%.

In particular, when a silane coupling agent is used, sintering the thermoelectric sheets 40a and 50a volatilizes the binder, the plasticizer, and the dispersing agent, but the silicon (Si) of the silane coupling agent remains. The content of silicon (Si) remaining in the thermoelectric sheets 40a and 50a is as follows.

Table 3 shows the content of silicon (Si) according to the molecular weights of the silane coupling agents represented by the above-mentioned Chemical Formulas 1 to 5 and the atomic mass of silicon (Si).

Silane coupling agent type Total molecular weight (g / mol) The atomic mass of silicon (g / mol) Silicon Content (%) Formula 1 246.4 28.1 11.4 (2) 220.3 28.1 12.7 (3) 236.3 28.1 11.9 Formula 4 248.4 28.1 11.3 Formula 5 278.4 28.1 10.1

However, since the functional groups at both ends of the silane coupling agent are removed from the silane coupling agent by the sintering process, only the silicon remains. Therefore, the content of silicon remaining in the thermoelectric sheets 40a and 50a depends on the weight percentage of the silane coupling agent Table 4 shows the results.

Weight percent (wt%) of silane coupling agent Residue content (wt%) of the silane coupling agent of the formula (1) Residue content (wt%) of the silane coupling agent of formula (2) The residue content (wt%) of the silane coupling agent of the formula (3) The residue content (wt%) of the silane coupling agent of the formula (4) The residue content (wt%) of the silane coupling agent of the formula (5) 0.01 0.0011 0.0013 0.0012 0.0011 0.0010 One 0.1140 0.1275 0.1189 0.1131 0.1009

That is, the N-type thermoelectric transducer 40 and the P-type thermoelectric transducer 50 are made of thermoelectric material and 0.001 wt% to 0.130 wt% of silicon (Si) And the P-type thermoelectric cell 50, as shown in Fig. Therefore, the thermoelectric characteristics of the N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 can be further improved.

Next, the N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 are fixed to the first substrate 10a and the second substrate 10b between the first substrate 10a and the second substrate 10b, 1, and the second solder 20, 30 are cured. The first and second solders 20 and 30 are melted by the reflow process. Accordingly, the first solder 20, the N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 are attached to each other and the second solder 30, the N-type thermoelectric cell 40 and the P- Can be adhered to each other.

That is, the thermoelectric element of the embodiment of the present invention includes the N-type thermoelectric cell 40 and the P-type thermoelectric cell 50 formed using the paste containing the coupling agent, and the N-type thermoelectric cell 40 and the P- The strength of the cell 50 is improved. Particularly, when the paste contains a silane coupling agent, silicon (Si) of a silane coupling agent remains in the N-type thermoelectric cell 40 and the P-type thermoelectric cell 50, and silicon (Si) The thermoelectric characteristics of the thermoelectric cell 40 and the P-type thermoelectric cell 50 can be further improved.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

5: thermoelectric material 6: binder
7: coupling agent 10a: first substrate
10b: second substrate 15a: first electrode
15b: second electrode 20: first solder
30: second solder 40: N-type thermoelectric cell
40a: N-type thermoelectric sheet 50: P-type thermoelectric cell
50a: P-type thermoelectric sheet

Claims (14)

A first substrate;
A second substrate facing the first substrate; And
And a thermoelectric cell disposed between the first substrate and the second substrate, the thermoelectric device including a thermoelectric material and silicon. The method according to claim 1,
Wherein the thermoelectric cell includes a plurality of thermoelectric sheets stacked. 3. The method of claim 2,
Wherein the thermoelectric sheet is sintered from a paste containing a thermoelectric material and a coupling agent. The method of claim 3,
Wherein the coupling agent comprises a silane coupling agent. The method according to claim 1,
Wherein the thermoelectric material comprises bismuth-tellurium (Bi ₂ Te ₃ ). The method according to claim 1,
Wherein the weight percentage of the silicon is from 0.001 to 0.130. Mixing a thermoelectric material and a coupling agent in a solvent to form a paste;
Curing the paste to form a thermoelectric sheet;
Stacking a plurality of thermoelectric sheets; And
And sintering the laminated thermoelectric sheet to form a thermoelectric cell. 8. The method of claim 7,
Wherein the coupling agent comprises a silane coupling agent. 8. The method of claim 7,
Wherein the thermoelectric material comprises bismuth-tellurium (Bi ₂ Te ₃ ). 8. The method of claim 7,
Wherein the step of forming the paste further comprises mixing a binder, a plasticizer and a dispersant in the solvent. 11. The method of claim 10,
Wherein the binder is selected from the group consisting of polyvinyl butyrate (PVB), polyvinyl alcohol (PVA), acrylic, and polyvinyl butyral. 11. The method of claim 10,
The plasticizer may be selected from the group consisting of dioctyl phthalate, di-n-butyl phthalate (DBP), diisodecyl phthalate, diethyl phthalate, di- hexyl phthalate (DNHP), diisobutyl phthalate, and oleoyl sarcosine. 11. The method of claim 10,
Wherein the dispersing agent is selected from phthalate, fatty acids, and menhaden fish oil. 8. The method of claim 7,
Wherein the weight percentage (wt%) of the coupling agent in the paste is 0.01 to 1. [

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