KR102441699B1 - Thermoelectric element - Google Patents

Abstract

An embodiment includes a first substrate; an adhesive layer disposed on the first substrate; a plurality of thermoelectric legs disposed on the first substrate; and a plurality of first electrodes disposed between the first substrate and the plurality of thermoelectric legs, wherein the first electrode includes at least one protrusion protruding toward the first substrate.

Description

Thermoelectric element {THERMOELECTRIC ELEMENT}

The present invention relates to a thermoelectric device, and more particularly, to a substrate and electrode structure of the thermoelectric device.

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

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

Thermoelectric devices can be classified into devices using a temperature change in electrical resistance, devices using the Seebeck effect, which is a phenomenon in which electromotive force is generated by a temperature difference, and devices using the Peltier effect, which is a phenomenon in which heat absorption or heat is generated by current.

Thermoelectric elements are widely applied to home appliances, electronic parts, communication parts, and the like. For example, the thermoelectric element may be applied to an apparatus for cooling, an apparatus for heating, an apparatus for power generation, and the like. Accordingly, the demand for the thermoelectric performance of the thermoelectric element is increasing.

An object of the present invention is to provide a substrate and an electrode structure of a thermoelectric element.

A thermoelectric device according to an embodiment of the present invention includes a first substrate; an adhesive layer disposed on the first substrate; a plurality of thermoelectric legs disposed on the first substrate; and a plurality of first electrodes disposed between the first substrate and the plurality of thermoelectric legs, wherein the first electrode includes at least one protrusion protruding toward the first substrate.

At least one protrusion of the first electrode may penetrate the adhesive layer.

At least one protrusion of the first electrode may contact the first substrate.

A thickness of the at least one protrusion of the first electrode may be the same as a thickness of the adhesive layer.

The first substrate may include at least one groove formed on an upper surface, and an end of the at least one protrusion of the first electrode may be inserted into the at least one groove of the first substrate, respectively.

At least one protrusion of the first electrode may include a central protrusion disposed in a central region of a lower surface of the first electrode.

The maximum width of the central protrusion may be 30% to 50% of the maximum width of the first electrode.

The at least one protrusion of the first electrode may include a plurality of protrusions disposed to be spaced apart from each other in the first direction from the lower surface of the first electrode.

At least one protrusion of the first electrode includes a plurality of protrusions spaced apart from each other in a first direction and a second direction from a lower surface of the first electrode and arranged in a grid shape, wherein the first direction is in the second direction can be perpendicular to

The width of the at least one protrusion of the first electrode may gradually decrease in a downward direction.

The adhesive layer includes a thermal interface material (TIM), a thermal grease, a thermal bond, a thermally conductive silicone pad, a thermally conductive adhesive tape, and a graphite sheet. Sheet) may include one selected from the group consisting of.

According to an embodiment of the present invention, a thermoelectric device having excellent thermal conductivity and high reliability can be obtained.

1 is a perspective view of a thermoelectric element according to a first embodiment of the present invention;
2 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in the thermoelectric device according to the first embodiment of the present invention;
3 is a perspective view of a lower electrode in the thermoelectric element according to the first embodiment of the present invention;
4 is a perspective view of a lower electrode in a thermoelectric element according to a second embodiment of the present invention;
5 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in a thermoelectric device according to a third embodiment of the present invention;
6 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in a thermoelectric device according to a fourth embodiment of the present invention;
7 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in a thermoelectric device according to a fifth embodiment of the present invention.

Since the present invention may have various changes and may have various embodiments, specific embodiments will be illustrated and described in the drawings. However, this is not intended to limit the present invention to a specific embodiment, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

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

When a component is referred to as being “connected” or “connected” to another component, it may be directly connected or connected to the other component, but it is understood that other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that the other element does not exist in the middle.

The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or excessively formal meaning unless explicitly defined in the present application. does not

Hereinafter, the embodiment will be described in detail with reference to the accompanying drawings, but the same or corresponding components are assigned the same reference numerals regardless of reference numerals, and overlapping descriptions thereof will be omitted.

1 is a perspective view of a thermoelectric element according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in the thermoelectric element according to the first embodiment of the present invention, and FIG. 3 is a perspective view of a lower electrode in the thermoelectric element according to the first embodiment of the present invention.

First, referring to FIG. 1 , the thermoelectric element 100 according to the first embodiment of the present invention includes a P-type thermoelectric leg 120 , an N-type thermoelectric leg 130 , a lower substrate 140 , and an upper substrate 150 . , a lower adhesive layer 171 , electrodes 161 and 162 , and a lead wire 180 .

The electrodes 161 and 162 include a first electrode 161 and a second electrode 162 , and the lead wire 180 is a first lead wire 181 connected from one side to the first electrode 161 by a solder (S). and a second lead wire 182 connected to the first electrode 161 from the other side by solder (S).

The lower electrode 161 is disposed between the lower substrate 140 and the lower surfaces of the P-type thermoelectric leg 120 and the N-type thermoelectric leg 130 , and the upper electrode 162 is formed between the upper substrate 150 and the P-type thermoelectric leg. It is disposed between the upper surface of the 120 and the N-type thermoelectric leg 130 . Accordingly, the plurality of P-type thermoelectric legs 120 and the plurality of N-type thermoelectric legs 130 are electrically connected by the lower electrode 161 and the upper electrode 162 . A pair of P-type thermoelectric legs 120 and N-type thermoelectric legs 130 disposed between the lower electrode 161 and the upper electrode 162 and electrically connected may form a unit cell.

For example, when a voltage is applied to the lower electrode 161 and the upper electrode 162 through the lead wires 181 and 182, a current flows from the P-type thermoelectric leg 120 to the N-type thermoelectric leg 130 due to the Peltier effect. The substrate through which flows absorbs heat and acts as a cooling unit, and the substrate through which current flows from the N-type thermoelectric leg 130 to the P-type thermoelectric leg 120 may be heated and act as a heating unit.

Here, the P-type thermoelectric leg 120 and the N-type thermoelectric leg 130 may be bismuth telluride (Bi-Te)-based thermoelectric legs including bismuth (Bi) and tellurium (Te) as main raw materials. P-type thermoelectric leg 120 is antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium with respect to 100wt% of the total weight A mixture containing 99 to 99.999 wt% of a bismuth telluride (Bi-Te)-based main raw material containing at least one of (Ga), tellurium (Te), bismuth (Bi) and indium (In) and Bi or Te 0.001 It may be a thermoelectric leg comprising 1 wt % to 1 wt %. For example, the main raw material is Bi-Se-Te, and Bi or Te may be further included in an amount of 0.001 to 1 wt% of the total weight. N-type thermoelectric leg 130 is selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium with respect to 100wt% of the total weight A mixture containing 99 to 99.999 wt% of a bismuth telluride (Bi-Te)-based main raw material containing at least one of (Ga), tellurium (Te), bismuth (Bi) and indium (In) and Bi or Te 0.001 It may be a thermoelectric leg comprising 1 wt % to 1 wt %. For example, the main raw material is Bi-Sb-Te, and may further include Bi or Te in an amount of 0.001 to 1 wt% of the total weight.

The P-type thermoelectric leg 120 and the N-type thermoelectric leg 130 may be formed in a bulk type or a stack type. In general, the bulk-type P-type thermoelectric leg 120 or the bulk-type N-type thermoelectric leg 130 heat-treats a thermoelectric material to manufacture an ingot, grinds the ingot and sieves to obtain a powder for the thermoelectric leg, and then It can be obtained through the process of sintering and cutting the sintered body. The laminated P-type thermoelectric leg 120 or the laminated N-type thermoelectric leg 130 is formed by coating a paste containing a thermoelectric material on a sheet-shaped substrate to form a unit member, and then stacking the unit member and cutting the unit through the process. can be obtained

In this case, the pair of P-type thermoelectric legs 120 and N-type thermoelectric legs 130 preferably have the same shape and the same height, and may have different shapes and volumes. For example, since the electrical conductivity characteristics of the P-type thermoelectric leg 120 and the N-type thermoelectric leg 130 are different, the cross-sectional area of the N-type thermoelectric leg 130 is different from the cross-sectional area of the P-type thermoelectric leg 120 . may be

The performance of the thermoelectric element according to the present invention may be expressed as a Seebeck index. The Seebeck index (ZT) may be expressed as in Equation (1).

는 제벡계수[V/K]이고,

는 전기 전도도[S/m]이며,

는 파워 인자(Power Factor, [W/mK²])이다. 그리고 T는 온도이고, k는 열전도도[W/mK]이다. k는

로 나타낼 수 있으며, a는 열확산도[cm²/S]이고, cp 는 비열[J/gK]이며,

는 밀도[g/cm³]이다.here,

is the Seebeck coefficient [V/K],

is the electrical conductivity [S/m],

is the Power Factor ([W/mK ² ]). And T is the temperature, k is the thermal conductivity [W/mK]. k is

It can be expressed as, a is the thermal diffusivity [cm ² /S], cp is the specific heat [J / gK],

is the density [g/cm ³ ].

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

Here, the lower electrode 120 is disposed between the lower substrate 140 and the P-type thermoelectric leg 120 and the N-type thermoelectric leg 130 , and the upper substrate 150 and the P-type thermoelectric leg 120 and the N-type thermoelectric leg 120 . The upper electrode 162 disposed between the thermoelectric legs 130 may include at least one of copper (Cu), silver (Ag), and nickel (Ni).

In addition, the lower substrate 140 and the upper substrate 150 facing each other may be insulating substrates. The insulating substrate may be an alumina substrate or a flexible polymer resin substrate. The flexible polymer resin substrate has high permeability such as polyimide (PI), polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copoly (COC), polyethylene terephthalate (PET), and resin. Various insulating resin materials such as plastic may be included. Alternatively, the insulating substrate may be a fabric. The metal substrate may include Cu, a Cu alloy, or a Cu-Al alloy. In addition, when the lower substrate 140 and the upper substrate 150 are metal substrates, a dielectric layer is further formed between the lower substrate 140 and the lower electrode 161 and between the upper substrate 150 and the upper electrode 162 , respectively. can be The dielectric layer may include a material having a thermal conductivity of 5 to 10 W/K.

In this case, the sizes of the lower substrate 140 and the upper substrate 150 may be different. For example, the volume, thickness, or area of one of the lower substrate 140 and the upper substrate 150 may be larger than the volume, thickness, or area of the other. Accordingly, heat absorbing performance or heat dissipation performance of the thermoelectric element may be improved.

The lower adhesive layer 171 is disposed between the lower electrode 161 and the lower substrate 140 to suppress contraction and expansion due to a temperature difference between the lower substrate 140 and the upper substrate 150 . ) and the lower substrate 140 may be adhered.

Of course, although not shown, an upper adhesive layer (not shown) may be further included, and the upper adhesive layer (not shown) is disposed between the upper electrode 162 and the upper substrate 150 , and the lower substrate 140 and the upper substrate The upper electrode 162 and the upper substrate 150 may be bonded to each other in order to suppress contraction and expansion due to the temperature difference therebetween.

The lower adhesive layer 171 may include a non-conductive adhesive.

The lower adhesive layer 171 includes a thermal interface material (TIM), a thermal grease, a thermal bond, a thermally conductive silicone pad, a thermally conductive adhesive tape, and graphite. It may include one selected from the group consisting of a sheet (Graphite Sheet).

The lower adhesive layer 171 may be cured through thermal compression, and may be cured to bond the lower electrode 161 and the lower substrate 140 .

Meanwhile, referring to FIGS. 2 and 3 , the lower electrode 161 includes a plurality of protrusions 165 protruding from the lower surface of the lower electrode 161 toward the lower substrate 140 .

The plurality of protrusions 165 of the lower electrode 161 may be formed of bar-shaped protrusions 165a disposed to be spaced apart from each other in the first direction, which is the width direction.

Here, the thickness T1 of the lower adhesive layer 171 is the same as the thickness T2 of the plurality of protrusions 165 of the lower electrode 161 , and each of the plurality of protrusions 165 of the lower electrode 161 has a lower adhesive layer. Through 171 , it may be in contact with the lower substrate 140 .

Through this, a heat transfer path between the lower electrode 161 and the lower substrate 140 can be directly formed without going through the lower adhesive layer 171 having relatively low thermal conductivity, thereby improving heat transfer efficiency.

Accordingly, a through hole 175 through which the plurality of protrusions 165 of the lower electrode 161 pass may be formed in the lower adhesive layer 171 .

Here, the lower adhesive layer 171 is preferably cured after the plurality of protrusions 165 of the lower electrode 161 are inserted before being cured.

4 is a perspective view of a lower electrode in the thermoelectric element according to the second embodiment of the present invention.

4, since the configuration of the protrusion 165a and the protrusion 165b of the lower electrode 161 shown in FIG. 3 is different in the thermoelectric element according to the second embodiment of the present invention, the protrusion part ( Only the configuration of 165b) will be described in detail, and detailed descriptions will be omitted for reference numerals overlapping the same configuration.

The plurality of protrusions 165b of the lower electrode 161 of the thermoelectric element according to the second exemplary embodiment of the present invention have a bar shape arranged to be spaced apart from each other in a first direction that is a width direction and a second direction perpendicular to the first direction. The plurality of protrusions 165b may be configured in a grid shape.

That is, when the plurality of protrusions 165b of the lower electrode 161 penetrate the lower adhesive layer 171 , a smaller external force may be required.

In addition, when the plurality of protrusions 165b of the lower electrode 161 penetrate the lower adhesive layer 171 , it is possible to minimize the lower adhesive layer 171 that overflows and is pushed outward.

5 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in a thermoelectric device according to a third exemplary embodiment of the present invention.

Referring to FIG. 5 , in the thermoelectric element according to the third embodiment of the present invention, since the configuration of the lower electrode 261 is different from that of the thermoelectric element shown in FIG. 2 , hereinafter, only the different configuration of the lower electrode 261 will be described. It will be described in detail, and a detailed description of the reference numerals overlapping the same configuration will be omitted.

The lower electrode 261 includes one protrusion 265 protruding downward from the central region of the lower surface.

Here, the protrusion 265 of the lower electrode 261 may penetrate the lower adhesive layer 271 and contact the lower substrate 140 .

Through this, a heat transfer path can be directly formed between the lower electrode 261 and the lower substrate 140 without going through the lower adhesive layer 271 having relatively low thermal conductivity, thereby improving heat transfer efficiency.

Accordingly, a through hole 275 through which the protrusion 265 of the lower electrode 161 passes may be formed in the lower adhesive layer 271 .

Here, the central region of the lower electrode 261 may be a region in which heat is concentrated.

Through this, first, the process of forming the protrusion 265 can be simple, the area ratio of the protrusion 265 and the lower electrode 261 can be easily set, and the center where heat is concentrated in the lower electrode 261 . Heat exchange efficiency between the region and the lower substrate 140 may be increased.

Meanwhile, the width W2 of the protrusion 265 may be set to 30% to 50% of the width W1 of the lower electrode 261 .

Here, when the width W2 of the protrusion 265 is less than 30% of the width W1 of the lower electrode 261 , the heat exchange effect between the lower electrode 261 and the lower substrate 140 is insufficient, and the protrusion 265 is ), when the width W2 is greater than 50% of the width W1 of the lower electrode 261 , the adhesion effect between the lower electrode 261 and the lower substrate 140 by the lower adhesive layer 271 may be insufficient. .

Here, the lower adhesive layer 271 is preferably cured after the protrusion 265 of the lower electrode 261 is inserted before being cured.

6 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in a thermoelectric device according to a fourth embodiment of the present invention.

Referring to FIG. 6 , in the thermoelectric element according to the fourth embodiment of the present invention, since the configuration of the lower electrode 361 is different from that of the thermoelectric element shown in FIG. 2 , hereinafter, only the configuration of the lower electrode 361 is different. It will be described in detail, and a detailed description of the reference numerals overlapping the same configuration will be omitted.

The lower electrode 361 includes a plurality of protrusions 365 protruding from the lower surface of the lower electrode 361 toward the lower substrate 140 .

Here, the protrusion 365 of the lower electrode 361 may penetrate the lower adhesive layer 371 and contact the lower substrate 140 .

Through this, a heat transfer path can be directly formed between the lower electrode 361 and the lower substrate 140 without going through the lower adhesive layer 371 having relatively low thermal conductivity, thereby improving heat transfer efficiency.

Accordingly, a through hole 375 through which the protrusion 365 of the lower electrode 161 passes may be formed in the lower adhesive layer 371 .

Meanwhile, each of the plurality of protrusions 365 may gradually decrease in width toward a lower direction. That is, the side surfaces of the plurality of protrusions 365 may have a predetermined inclination with respect to the lower surface of the lower electrode 361 and meet each other at the ends to have a needle shape.

Accordingly, a through hole 375 through which the plurality of protrusions 365 of the lower electrode 361 pass may be formed in the lower adhesive layer 371 .

Through this, a smaller external force may be required when the plurality of protrusions 365 penetrate the lower adhesive layer 371, and also, when the plurality of protrusions 365 of the lower electrode 361 penetrate the lower adhesive layer 371, It is possible to minimize the lower adhesive layer 371 that overflows and is pushed outward.

Here, the lower adhesive layer 371 is preferably cured after the plurality of protrusions 365 of the lower electrode 361 are inserted before being cured.

7 is a cross-sectional view schematically illustrating a connection relationship between a lower substrate and a lower electrode in a thermoelectric device according to a fifth embodiment of the present invention.

Referring to FIG. 7 , in the thermoelectric element according to the fifth embodiment of the present invention, the configuration of the lower electrode 461 is different from that of the thermoelectric element shown in FIG. 2 , and therefore only the configuration of the lower electrode 461 that is differentiated is hereinafter. It will be described in detail, and a detailed description of the reference numerals overlapping the same configuration will be omitted.

The lower electrode 461 includes a plurality of protrusions 465 protruding from the lower surface of the lower electrode 461 toward the lower substrate 140 .

Here, the protrusion 465 of the lower electrode 461 may penetrate the lower adhesive layer 471 and contact the lower substrate 140 .

Here, a plurality of grooves 465 corresponding to each of the plurality of protrusions 465 may be formed on the upper surface of the lower substrate 140 .

The lower adhesive layer 471 has a first thickness T1 , and the protrusion 465 of the lower electrode 461 has a second thickness T2 greater than the first thickness T1 , so the protrusion of the lower electrode 461 . The end of 465 may be inserted into the groove 465 formed on the upper surface of the lower substrate 140 .

Through this, a heat transfer path can be directly formed between the lower electrode 461 and the lower substrate 140 without going through the lower adhesive layer 471 having relatively low thermal conductivity, thereby improving heat transfer efficiency.

Here, since the end of the protrusion 465 of the lower electrode 461 is inserted into the groove 445 of the lower substrate 140 , the contact area between the protrusion 465 and the lower substrate 140 can be enlarged, Heat exchange can be performed efficiently.

Here, the lower adhesive layer 471 is preferably cured after the plurality of protrusions 465 of the lower electrode 461 are inserted before being cured.

In the above, the embodiment has been mainly described, but this is only an example and does not limit the present invention, and those of ordinary skill in the art to which the present invention pertains are not exemplified above in the range that does not depart from the essential characteristics of the present embodiment. It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiment can be implemented by modification. And the differences related to these modifications and applications should be construed as being included in the scope of the present invention defined in the appended claims.

120: P-type thermoelectric leg 130: N-type thermoelectric leg
140: lower substrate 150: upper substrate
161: lower electrode 162: upper electrode
165: protrusion 171: lower adhesive layer

Claims (11)

a first substrate;
an adhesive layer disposed on the first substrate;
a plurality of thermoelectric legs disposed on the first substrate; and
a plurality of first electrodes disposed between the first substrate and the plurality of thermoelectric legs;
The first electrode includes at least one protrusion protruding toward the first substrate,
At least one protrusion of the first electrode penetrates the adhesive layer and is in contact with the first substrate.
delete delete According to claim 1,
The thickness of the at least one protrusion of the first electrode is the same as the thickness of the adhesive layer.
According to claim 1,
The first substrate includes at least one groove formed in the upper surface,
Ends of the at least one protrusion of the first electrode are respectively inserted into the at least one groove of the first substrate.
According to claim 1,
At least one protrusion of the first electrode
and a central protrusion disposed in a central region of a lower surface of the first electrode.
7. The method of claim 6,
The maximum width of the central protrusion is 30% to 50% of the maximum width of the first electrode.
According to claim 1,
At least one protrusion of the first electrode
A thermoelectric element including a plurality of protrusions spaced apart from each other in a first direction from a lower surface of the first electrode.
According to claim 1,
At least one protrusion of the first electrode
and a plurality of protrusions spaced apart from each other in each of the first direction and the second direction on the lower surface of the first electrode and arranged in a lattice shape,
The first direction is perpendicular to the second direction.
According to claim 1,
At least one protrusion of the first electrode
A thermoelectric element that gradually decreases in width toward the bottom.
The method of claim 1,
The adhesive layer includes a thermal interface material (TIM), a thermal grease, a thermal bond, a thermally conductive silicone pad, a thermally conductive adhesive tape, and a graphite sheet. A thermoelectric element comprising one selected from the group consisting of sheet).

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