KR20200091574A - Thermoelectric element - Google Patents

Abstract

An objective of the present invention is to provide a joining structure of a thermoelectric element. According to an embodiment of the present invention, the thermoelectric element comprises: a first metal substrate; a first resin layer arranged on the first metal substrate; a plurality of first electrodes arranged on the first resin layer; a plurality of P-type thermoelectric legs and a plurality of N-type thermoelectric legs arranged on the plurality of first electrodes; a plurality of second electrodes arranged on the plurality of P-type thermoelectric legs and the plurality of N-type thermoelectric legs; a second resin layer arranged on the plurality of second electrodes; and a second metal substrate arranged on the second resin layer. The first metal substrate is a low-temperature part, and the second metal substrate is a high-temperature part. The second resin layer includes a first adhesion layer directly coming in contact with the plurality of second electrodes, a second adhesion layer stacked and separated from the first adhesion layer to directly come in contact with the second metal substrate, and a third adhesion layer stacked between the first adhesion layer and the second adhesion layer.

Description

Thermoelectric element {THERMOELECTRIC ELEMENT}

The present invention relates to a thermoelectric element, and more particularly, to an assembly structure of a thermoelectric element.

Thermoelectric phenomenon is a phenomenon that occurs due to the movement of electrons and holes inside a material, which means direct energy conversion between heat and electricity.

The thermoelectric element is a device that uses 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.

The thermoelectric device can be divided into a device that uses a temperature change of electrical resistance, a device that uses the Seebeck effect, which is a phenomenon in which electromotive force is generated by a temperature difference, and a device that uses a Peltier effect, which is a phenomenon in which heat absorption or heat is generated by a current. . Thermoelectric devices are widely applied to household appliances, electronic parts, and communication parts. For example, the thermoelectric element may be applied to a cooling device, a heating device, a power generation device, and the like. Accordingly, the demand for thermoelectric performance of thermoelectric elements is increasing.

The thermoelectric element includes a substrate, an electrode, and a thermoelectric leg, and a plurality of thermoelectric legs are disposed in an array form between the upper substrate and the lower substrate, a plurality of upper electrodes are disposed between the plurality of thermoelectric legs and the upper substrate, and a plurality of A plurality of lower electrodes are disposed between the thermoelectric leg and the lower substrate. At this time, one of the upper substrate and the lower substrate may be a low temperature portion, and the other may be a high temperature portion. When a thermoelectric element is applied to a device for power generation, the larger the temperature difference between the low temperature and high temperature parts, the higher the power generation performance. Accordingly, the temperature of the high-temperature portion may increase to 200°C or higher. When the temperature of the high temperature portion is 200°C or higher, mechanically high shear stress is transmitted to the soldering portion of the leg due to the difference in thermal expansion coefficient between the substrate and the electrode on the high temperature portion. At this time, a bonding layer having stretchability is disposed between the substrate on the high temperature side and the solder, and serves to relieve shear stress transmitted to the soldering site. However, such a bonding layer has a limitation in relaxation of shear stress when the substrate overheats, and cracks are generated in the soldering portion.

Technical problem to be achieved by the present invention is to provide a junction structure of a thermoelectric element.

The thermoelectric device according to an embodiment of the present invention includes a first metal substrate, a first resin layer disposed on the first metal substrate, a plurality of first electrodes disposed on the first resin layer, and the plurality of first electrodes. On a plurality of P-type thermoelectric legs and on a plurality of N-type thermoelectric legs, on the plurality of P-type thermoelectric legs and on a plurality of N-type thermoelectric legs, on a plurality of second electrodes, on the plurality of second electrodes A second resin layer disposed on the second resin layer, and a second metal substrate disposed on the second resin layer, wherein the first metal substrate is a low temperature portion, the second metal substrate is a high temperature portion, and the second resin layer is A first adhesive layer directly contacting the plurality of second electrodes, a second adhesive layer stacked apart from the first adhesive layer and directly contacting the second metal substrate, and the first adhesive layer and the second adhesive layer It may include an insulating layer laminated between the layers.

The first metal substrate and the second metal substrate may include aluminum.

The first adhesive layer and the second adhesive layer may be polysiloxane (Polysiloxan)-based adhesive.

The first adhesive layer and the second adhesive layer may have a bonding strength of 1 kgf/mm ² or less at a temperature of 150 to 200°C.

The insulating layer may be made of polyimide.

A third adhesive layer may be further included between the first adhesive layer and the insulating layer.

A fourth adhesive layer may be further included between the second adhesive layer and the insulating layer.

According to an embodiment of the present invention, by bonding the substrate and the electrode with an adhesive material, it is possible to effectively prevent the mechanical shear stress from being transferred to the soldering portion of the leg by thermal expansion of the substrate.

1 is a cross-sectional view of a thermoelectric device according to an embodiment of the present invention.
2 is a top view of a first metal substrate included in a thermoelectric device according to an embodiment of the present invention.
3 is a side view of a first metal substrate included in a thermoelectric device according to an embodiment of the present invention.
4 is a partially enlarged view of FIG. 3.
5 is a perspective view of a thermoelectric device according to an embodiment of the present invention.
6 is an exploded perspective view of a thermoelectric device according to an embodiment of the present invention.
7 is a partially enlarged view of a thermoelectric device according to an embodiment of the present invention.
8 is a view showing a state in which a thermoelectric device is generating power according to an embodiment of the present invention.
9 is a cross-sectional view of a thermoelectric device according to another embodiment of the present invention.
10 is a partially enlarged view of FIG. 9.
11 is a view showing a state in which power is applied to a thermoelectric element according to another embodiment of the present invention.
12 is a graph showing a rate of change of resistance to a temperature cycle test of a thermoelectric device according to Examples and Comparative Examples.

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

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the technical spirit scope of the present invention, one or more of its components between embodiments may be selectively selected. It can be used by bonding and substitution.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless specifically defined and described, can be generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as meaning, and commonly used terms, such as predefined terms, may interpret the meaning in consideration of the contextual meaning of the related technology.

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

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

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

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

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

Further, when described as being formed or disposed in the "top (top) or bottom (bottom)" of each component, the top (top) or bottom (bottom) is one as well as when the two components are in direct contact with each other It also includes a case in which another component described above is formed or disposed between two components. In addition, when expressed as "up (up) or down (down)", it may include the meaning of the downward direction as well as the upward direction based on one component.

1 is a cross-sectional view of a thermoelectric device according to an embodiment of the present invention, Figure 2 is a top view of a first metal substrate included in the thermoelectric device according to an embodiment of the present invention, Figure 3 is an embodiment of the present invention A side view of a first metal substrate included in a thermoelectric device according to an example, FIG. 4 is a partially enlarged view of FIG. 3, FIG. 5 is a perspective view of a thermoelectric device according to an embodiment of the present invention, and FIG. 6 is a view of the present invention It is an exploded perspective view of a thermoelectric element according to an embodiment.

1 to 6, the thermoelectric element includes a first metal substrate 110, a first resin layer 120, a plurality of first electrodes 130, a plurality of P-type thermoelectric legs 140, and a plurality of N The thermoelectric leg 150 includes a plurality of second electrodes 160, a second resin layer 170, a second metal substrate 180 and sealing means 190.

The first metal substrate 110 is formed in a plate shape. The first metal substrate 110 is spaced apart from the second metal substrate 180. The first metal substrate 110 and the second metal substrate 180 may be made of aluminum, aluminum alloy, copper, copper alloy, or the like. For example, the first metal substrate 110 and the second metal substrate 180 may be made of aluminum. Here, the area of the first metal substrate 110 and the second metal substrate 180 is 40mmx40mm to 200mmx200mm, and the thickness may be 1 to 100mm. At this time, the area or thickness of the first metal substrate 110 and the second metal substrate 180 may be the same or different.

At this time, when a voltage is applied to the thermoelectric element, the first metal substrate 110 absorbs heat due to the Peltier effect and acts as a low temperature portion, and the second metal substrate 180 releases heat to act as a high temperature portion.

On the other hand, when different temperatures are applied to the first metal substrate 110, heat power is generated while electrons in the high temperature region move to the low temperature region due to a temperature difference. This is called the Seebeck effect, and electricity is generated in the circuit of the thermoelectric element due to the thermal power.

Here, the first metal substrate 110 may directly contact the first resin layer 120. To this end, the first metal substrate 110 is provided on all or part of the surface on which the first resin layer 120 is disposed, that is, the first resin layer 120 of the first metal substrate 110 facing each other. Surface roughness can be formed. According to this, the problem that the first resin layer 120 is lifted up during thermal compression between the first metal substrate 110 and the first resin layer 120 can be prevented. In the present specification, the surface roughness means unevenness, and may be mixed with surface roughness.

2 to 4, a surface on which the first resin layer 120 is disposed on both surfaces of the first metal substrate 110, that is, a surface facing the first resin layer 120 of the first metal substrate 110 Includes a first region 112 and a second region 114, and the second region 114 can be disposed inside the first region 112. That is, the first region 112 may be disposed within a predetermined distance from the edge of the first metal substrate 110 toward the center region, and the first region 112 may surround the second region 114.

At this time, the surface roughness of the second region 114 is greater than the surface roughness of the first region 112, and the first resin layer 120 may be disposed on the second region 114. Here, the first resin layer 120 may be disposed to be spaced a predetermined distance from the boundary between the first region 112 and the second region 114. That is, the first resin layer 120 is disposed on the second region 114, and the edge of the first resin layer 120 may be located inside the second region 114. Accordingly, at least a portion of the groove 400 formed by the surface roughness of the second region 114 is a part of the first resin layer 120, that is, the epoxy resin 600 included in the first resin layer 120 and A portion 604 of the inorganic filler may permeate, and adhesion between the first resin layer 120 and the first metal substrate 110 may be increased.

However, the surface roughness of the second region 114 may be formed to be larger than the particle size D50 of some of the inorganic fillers included in the first resin layer 120 and smaller than the particle size D50 of the other portions. Here, the particle size D50 means a particle diameter corresponding to 50% of the weight percentage in the particle size distribution curve, that is, a particle diameter in which the passing mass percentage is 50%, and may be mixed with the average particle diameter. For example, when the first resin layer 120 includes aluminum oxide and boron nitride as an inorganic filler, aluminum oxide does not affect the adhesion performance between the first resin layer 120 and the first metal substrate 110. , Since boron nitride has a smooth surface, it may adversely affect the adhesion performance between the first resin layer 120 and the first metal substrate 110. Accordingly, when the surface roughness of the second region 114 is larger than the particle size D50 of aluminum oxide included in the first resin layer 120, but smaller than the particle size D50 of boron nitride, the second region 114 of the second region 114 Since only aluminum oxide is disposed in the groove formed by the surface roughness, and boron nitride is difficult to be disposed, the first resin layer 120 and the first metal substrate 110 can maintain high bonding strength.

The surface roughness can be measured using a surface roughness meter. The surface roughness measuring instrument measures the cross-sectional curve using a probe, and can calculate the surface roughness using the peak, valley, average and reference lengths of the cross-section curve. In this specification, the surface roughness may mean arithmetic mean roughness (Ra) by the center line average calculation method. The arithmetic mean roughness Ra can be obtained through Equation 2 below.

That is, when the cross-section curve obtained by the probe of the surface roughness measuring instrument is extracted by the reference length L, and the average line direction is the x-axis, and the height direction is the y-axis, it is expressed by the function (f(x)). The obtained value can be expressed in μm.

At this time, although not shown in the drawings, the first metal substrate 110 may be formed with a surface roughness corresponding to the second region 114 on the front surface. In addition, the surface roughness formed on the first metal substrate 110 may be equally applied to the second metal substrate 180 to be described later.

The first resin layer 120 is disposed on the first metal substrate 110. The first resin layer 120 is formed with a smaller area than the first metal substrate 110. Accordingly, the first resin layer 120 may be disposed in a region spaced a predetermined distance from the edge of the first metal substrate 110.

The first resin layer 120 may be made of an epoxy resin composition including an epoxy resin and an inorganic filler, or may be made of a silicone resin composition containing polydimethylsiloxane (PDMS).

Here, the inorganic filler may be included as 68 to 88 vol% of the epoxy resin composition. If the inorganic filler is included below 68 vol%, the thermal conductivity effect may be low, and when the inorganic filler is included in excess of 88 vol%, the adhesion between the resin layer and the metal substrate may be lowered, and the resin layer may be easily broken.

The epoxy resin may include an epoxy compound and a curing agent. In this case, the curing agent may be included in a volume ratio of 1 to 10 based on 10 volume ratio of the epoxy compound. Here, the epoxy compound may include at least one of a crystalline epoxy compound, an amorphous epoxy compound and a silicone epoxy compound. The crystalline epoxy compound may include a mesogen structure. Mesogen is a basic unit of a liquid crystal and includes a rigid structure. In addition, the amorphous epoxy compound may be a conventional amorphous epoxy compound having two or more epoxy groups in the molecule, for example, bisphenol A or glycidyl ether derivative derived from bisphenol F. Here, the curing agent may include at least one of an amine-based curing agent, a phenol-based curing agent, an acid anhydride-based curing agent, a polymercaptan-based curing agent, a polyaminoamide-based curing agent, an isocyanate-based curing agent and a block isocyanate-based curing agent, and two or more kinds of curing agents It can also be used by mixing.

The inorganic filler may include aluminum oxide and nitride, and the nitride may be included as 55 to 95 wt% of the inorganic filler, more preferably 60 to 80 wt%. When the nitride is included in this numerical range, it is possible to increase the thermal conductivity and bonding strength. Here, the nitride may include at least one of boron nitride and aluminum nitride. Here, the boron nitride may be a plate-like boron nitride or a boron nitride agglomerate in which the plate-like boron nitride is agglomerated, and the surface of the boron nitride may be coated with a polymer resin. Here, any polymer resin may be used as long as it can be combined with boron nitride or coated on the surface of boron nitride. The polymer resin includes, for example, acrylic polymer resin, epoxy polymer resin, urethane polymer resin, polyamide polymer resin, polyethylene polymer resin, EVA (ethylene vinyl acetate copolymer) polymer resin, polyester polymer resin and PVC ( polyvinyl chloride) polymer resin. Further, the polymer resin may be a polymer resin having the following unit 1.

Unit 1 is as follows.

[Unit 1]

Here, one of R ¹ , R ² , R ³ and R ⁴ is H, and the other is selected from the group consisting of C ₁ to C ₃ alkyl, C ₂ to C ₃ alkene and C ₂ to C ₃ alkyne, and R ⁵ May be a linear, branched or cyclic divalent organic linker having 1 to 12 carbon atoms.

In one embodiment, one of R ¹ , R ² , R ³ and R ⁴ other than H is selected from C ₂ to C ₃ alkene, the other of the other and the other from C ₁ to C ₃ alkyl Can be selected. For example, the polymer resin according to the embodiment of the present invention may include the following unit 2.

[Unit 2]

Alternatively, the rest of R ¹ , R ² , R ³ and R ⁴ other than H may be selected to be different from each other in a group consisting of C ₁ to C ₃ alkyl, C ₂ to C ₃ alkene, and C ₂ to C ₃ alkyne. have.

As described above, when the polymer resin according to unit 1 or unit 2 is coated on boron nitride, functional groups are easily formed, and when functional groups are formed on boron nitride, affinity with the resin may be increased.

As described above, when the first resin layer 120 is disposed between the first metal substrate 110 and the plurality of first electrodes 130, the first metal substrate 110 and the plurality of first electrodes may be used without a separate ceramic substrate. Heat transfer between 130 is possible, and a separate adhesive or physical fastening means is not required due to the adhesive performance of the first resin layer 120 itself. In particular, since the first resin layer 120 can be implemented with a significantly thinner thickness than the conventional ceramic substrate, it is possible to improve the heat transfer performance between the plurality of first electrodes 130 and the first metal substrate 110, and You can also reduce the overall size of the device.

The plurality of first electrodes 130 are disposed on the first resin layer 120. In addition, a plurality of P-type thermoelectric legs 140 and a plurality of N-type thermoelectric legs 150 are disposed on the first electrode 130. At this time, the first electrode 130 is electrically connected to the P-type thermoelectric leg 140 and the N-type thermoelectric leg 150. Here, the first electrode 130 may include at least one of copper (Cu), aluminum (Al), silver (Ag), and nickel (Ni).

The plurality of P-type thermoelectric legs 140 and the plurality of N-type thermoelectric legs 150 are disposed on the first electrode 130. At this time, the P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 may be joined to the first electrode 130 by soldering.

In this case, the P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 may be bismuthelluride (Bi-Te)-based thermoelectric legs including bismuth (Bi) and tellurium (Te) as main raw materials. P type thermoelectric leg 140 is antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium, with respect to 100 wt% of the total weight (Ga), bismutelluride (Bi-Te)-based main raw material material containing at least one of tellurium (Te), bismuth (Bi), and indium (In) 99 to 99.999 wt% and a mixture containing Bi or Te 0.001 It may be a thermoelectric leg containing to 1wt%. For example, the main raw material is Bi-Se-Te, and may further include Bi or Te at 0.001 to 1 wt% of the total weight. The N-type thermoelectric leg 150 is selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium with respect to 100 wt% of the total weight (Ga), bismutelluride (Bi-Te)-based main raw material material containing at least one of tellurium (Te), bismuth (Bi), and indium (In) 99 to 99.999 wt% and a mixture containing Bi or Te 0.001 It may be a thermoelectric leg containing to 1wt%. For example, the main raw material is Bi-Sb-Te, and may further include Bi or Te at 0.001 to 1 wt% of the total weight.

The P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 may be formed in a bulk type or a stacked type. In general, the bulk P-type thermoelectric leg 140 or the bulk-type N-type thermoelectric leg 150 is produced by heat-treating a thermoelectric material to produce an ingot, and crushing and sieving the ingot to obtain powder for the thermoelectric leg, and then It can be obtained through the process of sintering and cutting the sintered body. The stacked P-type thermoelectric leg 140 or the stacked N-type thermoelectric leg 150 is coated with a paste containing a thermoelectric material on a sheet-shaped substrate to form a unit member, and then stacked and cut the unit member. Can be obtained.

At this time, the pair of P-type thermoelectric legs 140 and N-type thermoelectric legs 150 may have the same shape and volume, or may have different shapes and volumes. For example, since the electrical conduction characteristics of the P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 are different, the height or cross-sectional area of the N-type thermoelectric leg 150 is the height or cross-sectional area of the P-type thermoelectric leg 140. It may be formed differently.

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

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

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

The P-type thermoelectric leg 140 or the N-type thermoelectric leg 150 may have a cylindrical shape, a polygonal column shape, an elliptical column shape, or the like. Alternatively, the P-type thermoelectric leg 140 or the N-type thermoelectric leg 150 may have a stacked structure. For example, the P-type thermoelectric leg or the N-type thermoelectric leg may be formed by stacking a plurality of structures coated with a semiconductor material on a sheet-shaped substrate and then cutting it. Accordingly, it is possible to prevent the loss of material and improve the electrical conduction properties. Alternatively, the P-type thermoelectric leg 140 or the N-type thermoelectric leg 150 may be manufactured according to a zone melting method or a powder sintering method. According to the zone melting method, after manufacturing an ingot using a thermoelectric material, the heat is slowly applied to the ingot to refinish the particles to be rearranged in a single direction, and a thermoelectric leg is obtained by cooling slowly. According to the powder sintering method, after manufacturing an ingot using a thermoelectric material, the ingot is pulverized and sieved to obtain a powder for a thermoelectric leg, and a thermoelectric leg is obtained through a process of sintering it.

The plurality of second electrodes 160 are disposed on the plurality of P-type thermoelectric legs 140 and the plurality of N-type thermoelectric legs 150. At this time, the P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 may be joined to the second electrode 160 by soldering. At this time, when the stress is applied to the soldered portion by shear, cracks may be formed in the solder. Here, the second electrode 160 may include at least one of copper (Cu), aluminum (Al), silver (Ag), and nickel (Ni).

The second resin layer 170 is disposed on the plurality of second electrodes 160. In addition, the second metal substrate 180 is disposed on the second resin layer 170. The second resin layer 170 may be formed with a smaller area than the second metal substrate 180. Accordingly, the second resin layer 170 may be disposed in a region spaced a predetermined distance from the edge of the second metal substrate 180.

At this time, the sizes of the first resin layer 120 and the second resin layer 170 may be formed differently. For example, the volume, thickness, or area of one of the first resin layer 120 and the second resin layer 170 may be larger than the other volume, thickness, or area. At this time, the thickness T2 of the second resin layer may be greater than or equal to the thickness T1 of the first resin layer. In addition, the bonding strength of the plurality of second electrodes 160 or the second metal substrate 180 directly contacting the second resin layer 170 is a plurality of first electrodes directly contacting the first resin layer 120. It may be lower than the bonding strength of the 130 or the first metal substrate 110.

The bonding strength between the first resin layer 120 and the plurality of first electrodes 130 or the first metal substrate 110 may be 5 kgf/mm ^{2 or} more, preferably 10 kgf/mm ² or more, more preferably May be 15 kgf/mm ^{2 or} more.

7 is a partially enlarged view of a thermoelectric device according to an embodiment of the present invention.

Referring to FIG. 7, the second resin layer 170 includes a first adhesive layer 171, a second adhesive layer 172 and an insulating layer. For example, the second resin layer may be provided with adhesive layers on both sides of a polyimide film.

The first adhesive layer 171 directly contacts the second electrode 160. The first adhesive layer 171 may have adhesive properties. More preferably, the first adhesive layer 171 may be a polysiloxane (Polysiloxan)-based adhesive. At this time, the bonding strength of the first adhesive layer 171 decreases as the exposure temperature increases. That is, as the exposure temperature increases, the fluidity increases, and the portion joined to the second electrode 160 may be fluidly deformed. Accordingly, the first adhesive layer 171 may block the shear stress from being transmitted to the second electrode 160 while fluidly pushing the bonded portion of the second electrode 160 even when shear stress is applied. At this time, the first adhesive layer 171 may have a bonding strength of 1 kgf/mm ² or less at a temperature of 150 to 200°C. Preferably, the first adhesive layer 171 may have a bonding strength of 0.5 kgf/mm ² or less at a temperature of 150 to 200° C., and more preferably, the first adhesive layer 171 may be 150 to 200° C. It can have a bonding strength of 0.1kgf / mm ² or less at the temperature of.

The second adhesive layer 172 is spaced apart from the first adhesive layer 171 to directly contact the second metal substrate 180. At this time, the first adhesive layer 171 may have adhesiveness. More preferably, the first adhesive layer 171 may be a polysiloxane (Polysiloxan)-based adhesive. At this time, the bonding strength of the second adhesive layer 172 decreases as the exposure temperature increases. That is, as the fluidity increases as the exposure temperature increases, the portion joined to the second metal substrate 180 may be deformed fluidly. Accordingly, even when the second metal substrate 180 expands at a high temperature, it is possible to prevent the shear stress from being applied from the second metal substrate 180 while the part joined to the second metal substrate 180 is pushed fluidly. At this time, the second adhesive layer 172 may have a bonding strength of 1 kgf/mm ² or less at a temperature of 150 to 200°C. Preferably, the second adhesive layer 172 may have a bonding strength of 0.5 kgf/mm ² or less at a temperature of 150 to 200° C., more preferably, the second adhesive layer 172 may be 150 to 200° C. It can have a bonding strength of 0.1kgf / mm ² or less at the temperature of.

The bonding strength of the second adhesive layer 172 may be the same or higher than the bonding strength of the first adhesive layer 171.

The insulating layer 173 is stacked between the first adhesive layer 171 and the second adhesive layer 172. At this time, one surface of the insulating layer 173 is in contact with the upper surface of the first adhesive layer 171, the other surface is in contact with the lower surface of the second adhesive layer 172. The insulating layer 173 blocks current from the second electrode 160 from being transferred to the second metal substrate 180. The insulating layer 173 may be made of polyimide.

The thickness t1 of the insulating layer 173 may be 1 to 500 μm. As the thickness t1 of the insulating layer 173 increases, the thermal conductivity and the thermal breakdown voltage decrease, and the risk of conduction decreases. On the other hand, as the thickness t1 of the insulating layer 173 increases, thermal conductivity decreases, and power generation performance tends to decrease.

Table 1 below is a table showing the dielectric breakdown voltage, thermal conductivity and thermal conductivity according to the thickness of the insulating layer.

Insulation layer thickness (um) 5 7.8 12.3 25 37.5 50 Dielectric breakdown voltage (kV) 2.1 3.1 5.1 9.5 14.3 19.0 Thermal conductivity (W/mK) 0.18 0.18 0.16 0.16 0.16 0.16 Thermal conductivity (W/Km2) 3.60 2.31 1.30 0.64 0.43 0.32

Looking at Table 1, the thickness of the insulating layer 173 may be about 5 um. At this time, it can be seen that as the thickness of the insulating layer increases, the dielectric breakdown voltage increases, and thermal conductivity and thermal conductivity decrease. At this time, the insulation breakdown voltage required for the thermoelectric element is less than 1 kV, and when the thickness of the insulating layer is formed to about 5 um, high thermal conductivity can be secured without damage due to overload. Hereinafter, the present invention will be described in more detail with reference to Table 2 and FIG. 12 through thermoelectric elements according to embodiments and comparative examples. These examples are only presented as examples to explain the present invention in more detail. Therefore, the present invention is not limited to these examples.

Table 2 below shows measurement results for the temperature cycle test of Examples and Comparative Examples, and FIG. 12 is a graph showing the rate of change of resistance to the number of cycles of the temperature cycle tests of Examples and Comparative Examples.

Both the thermoelectric element according to the comparative example and the thermoelectric element according to the embodiment have a first metal substrate, a first resin layer, a plurality of first electrodes, a plurality of P-type thermoelectric legs, a plurality of N-type thermoelectric legs, a plurality of second electrodes, It is a thermoelectric element for power generation of 40mmx40mm size including a second resin layer and a second metal substrate. In the thermoelectric element according to the comparative example, both the first resin layer and the second resin layer are formed of a resin having a bonding strength of 5 kgf/mm ² or more, while the thermoelectric element according to the embodiment has a first resin layer of 5 kgf/mm ² or more. It was formed of a resin having bonding strength, and the second resin layer was disposed as a polyimide-based film having polysiloxane-based adhesive layers on both sides.

In the temperature cycle test, a temperature increase step of changing the temperature of the second metal substrate from 50° C. to 180° C. and a temperature reduction step of changing the temperature from 180° C. to 50° C. while maintaining the temperature of the first metal substrate at 25° C. It was performed as one cycle, and a total of 5000 cycles were performed. At this time, the temperature increase rate in the temperature increase step is 30°C/min, and the temperature reduction rate in the temperature reduction step is 22°C/min.

Number of cycles 0 100 200 300 400 500 1000 2000 3000 4000 5000 Comparative example Resistance change rate 13.3 21.7 -

Power generation change rate -23.52 -46.13 Example Resistance change rate 0 0.5 0.5 0.9 0 1.6 0.3 0.6 2.4 4.1 Power generation change rate 6.84 8.49 9.47 9.84 10.25 11.76 12.13 12.17 12.27 12.07

Referring to Table 2 and FIG. 12, the thermoelectric device according to the comparative example was able to confirm that the resistance increased rapidly from 0 to 200 cycles and the power generation amount decreased, and the destruction phenomenon of the thermoelectric device occurred when 200 cycles were exceeded. On the other hand, in the thermoelectric element according to the embodiment, the rate of change of resistance was changed within 5% during 5000 cycles, and the amount of power generation increased. In addition, it was confirmed that the destruction phenomenon of the thermoelectric element did not occur while maintaining the 5000 cycles.

That is, it can be seen that the thermoelectric element according to the embodiment has stronger product durability due to thermal change and superior power generation performance at high temperatures compared to the thermoelectric element according to the comparative example.

8 is a view showing a state in which a thermoelectric device is generating power according to an embodiment of the present invention.

Referring to FIG. 8, when the second metal substrate 180 of the thermoelectric element is disposed in a high temperature region and the first metal substrate 110 is disposed in a low temperature region, electrons between a plurality of thermoelectric legs connected in series by the Seebeck effect Electricity is generated by movement. At this time, the volume of the second metal substrate 180 exposed to high temperature may expand due to heat. At this time, due to the horizontal expansion of the second metal substrate 180, the shear direction stress may be applied to the second resin layer 170. The shear stress is transmitted to the soldering portion of the second electrode 160, causing cracks in the soldering portion and deteriorating durability at high temperatures. At this time, in the thermoelectric element according to the embodiment, the second resin layer 170 is composed of an adhesive material, so that even if the second metal substrate 180 expands at a high temperature, the second resin layer 170 remains ), it can be implemented to be pushed fluidly, alleviating shear stress transmitted to the soldering portion, and securing high temperature durability of the thermoelectric element. Although not shown, when the voltage is applied to the thermoelectric element, the second metal substrate 180 may be equally applied to thermal expansion occurring when the high temperature unit is operated by the Peltier effect.

5 and 6 again, the sealing means 190 may be disposed on the side surfaces of the first resin layer 120 and the second resin layer 170, that is, the sealing means 190 is made of 1 is disposed between the metal substrate 110 and the second metal substrate 180, the side of the first resin layer 120, the outermost of the plurality of first electrodes 130, a plurality of P-type thermoelectric legs 140 And an outermost portion of the plurality of N-type thermoelectric legs 140, an outermost portion of the plurality of second electrodes 150, and side surfaces of the second resin layer 170. Accordingly, the first resin layer 120, the plurality of first electrodes 130, the plurality of P-type thermoelectric legs 140, the plurality of N-type thermoelectric legs 140, the plurality of second electrodes 150 and the first 2 The resin layer can be sealed from external moisture, heat, pollution, etc.

Here, the sealing means 190 is the side of the first resin layer 120, the outermost of the plurality of first electrodes 130, the plurality of P-type thermoelectric legs 140 and the plurality of N-type thermoelectric legs 140 The outermost, the outermost of the plurality of second electrodes 150 and the sealing case 192, which is disposed a predetermined distance from the side of the second resin layer 170, the sealing case 192 and the second metal substrate 180 It may include a sealing material 194 disposed between, the sealing case 192 and the sealing material 196 disposed between the first metal substrate 110. As such, the sealing case 192 may contact the first metal substrate 110 and the second metal substrate 180 through the sealing materials 194 and 196. Accordingly, when the sealing case 192 is in direct contact with the first metal substrate 110 and the second metal substrate 180, heat conduction occurs through the sealing case 192, and as a result, △ T is lowered. Can be prevented.

Here, the sealing material (194, 196) may include at least one of the epoxy resin and the silicone resin, or at least one of the epoxy resin and the silicone resin may include a tape coated on both sides. The sealing materials 194 and 196 serve to hermetically seal between the sealing case 192 and the first metal substrate 110 and between the sealing case 192 and the second metal substrate 180, and the first resin layer 120 , The sealing effect of the plurality of first electrodes 130, the plurality of P-type thermoelectric legs 140, the plurality of N-type thermoelectric legs 140, the plurality of second electrodes 150 and the second resin layer 170. It can be increased, and can be mixed with a finishing material, a finishing layer, a waterproofing material, a waterproofing layer and the like.

Meanwhile, a guide groove G for drawing out the wires W1 and W2 connected to the electrode may be formed in the sealing case 192. To this end, the sealing case 192 may be an injection molding made of plastic or the like, and may be mixed with a sealing cover.

Although the structure of the sealing means 190 is specifically shown, this is only an example, and the sealing means 190 may be modified in various forms.

Although not shown, a heat insulating material may be further included to surround the sealing means 190. Alternatively, the sealing means 190 may include an insulating component.

9 is a cross-sectional view of a thermoelectric device according to another embodiment of the present invention, FIG. 10 is a partially enlarged view of FIG. 9, and FIG. 11 shows a state in which power is applied to a thermoelectric device according to another embodiment of the present invention It is a drawing.

According to another embodiment of the present invention, the second resin layer 200 includes a plurality of adhesive layers and an insulating layer 220.

The plurality of adhesive layers is at least three, and may be in direct contact with each other. At this time, the number of adhesive layers included in the second resin layer 200 may be modified.

9 and 10, the second resin layer 200 includes first to fourth adhesive layers 211, 212, 213 and 214, wherein the first to fourth adhesive layers 211, 212, 213 and 214 are made of different materials. In addition, the first to fourth adhesive layers 211, 212, 213 and 214 may have different thermal conductivity. The first to fourth adhesive layers 211, 212, 213, and 214 are arranged in order of higher thermal conductivity from the first metal substrate 110 to the second metal substrate 180. In this case, the first adhesive layer 211 and the fourth adhesive layer 214 directly contacting the second electrode 160 and the second metal substrate 180 may have adhesive properties.

The insulating layer 220 is disposed on any one of the first to fourth adhesive layers 211,212,213,214. In the drawing, the insulating layer 220 is disposed between the second adhesive layer 212 and the third adhesive layer 213, but it is also possible to be disposed at a different position among the first to fourth adhesive layers 211,212,213,214. At this time, the insulating layer 220 is made of an insulating material, and blocks current from the second electrode 160 from being transmitted to the second metal substrate 180. Although the insulating layer is disposed adjacent to the second electrode 160, it is advantageous for blocking current, but is not limited thereto. At this time, the insulating layer 220 may be a polyimide (P olyimide) material. In addition, the thickness of the insulating layer 220 may be 1 to 500㎛, for example, the thickness of the insulating layer 220 may be about 5㎛.

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

Here, as an example in which the thermoelectric element according to an embodiment of the present invention is applied to a medical device, there is a PCR (Polymerase Chain Reaction) device. The PCR device is a device for amplifying DNA to determine the base sequence of DNA, and requires precise temperature control and a thermal cycle. To this end, a Peltier-based thermoelectric element may be applied.

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

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

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

Examples of the thermoelectric element according to an embodiment of the present invention applied to the aerospace industry include a star tracking system, a thermal imaging camera, an infrared/ultraviolet detector, a CCD sensor, a Hubble Space Telescope, and TTRS. Accordingly, the temperature of the image sensor can be maintained.

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

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

Although described above with reference to preferred embodiments of the present invention, those skilled in the art variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You can understand that you can.

110: first metal substrate
120: first resin layer
130: first electrode
140: P-type thermoelectric leg
150: N-type thermoelectric leg
160: second electrode
170,200: second resin layer
171, 211: first adhesive layer
172, 214: second adhesive layer
173,220: insulating layer
180: second metal substrate
190: sealing means
212: third adhesive layer
213: fourth adhesive layer
220: insulating layer

Claims (8)

The first metal substrate,
A first resin layer disposed on the first metal substrate,
A plurality of first electrodes disposed on the first resin layer,
A plurality of P-type thermoelectric legs and a plurality of N-type thermoelectric legs disposed on the plurality of first electrodes,
A plurality of second electrodes disposed on the plurality of P-type thermoelectric legs and the plurality of N-type thermoelectric legs,
A second resin layer disposed on the plurality of second electrodes, and
A second metal substrate disposed on the second resin layer,
The first metal substrate is a low temperature portion, the second metal substrate is a high temperature portion,
The second resin layer includes a first adhesive layer directly contacting the plurality of second electrodes, a second adhesive layer stacked apart from the first adhesive layer and directly contacting the second metal substrate, and the first adhesive layer. A thermoelectric element comprising an insulating layer disposed between a layer and the second adhesive layer. According to claim 1,
The first metal substrate and the second metal substrate is a thermoelectric element comprising aluminum. According to claim 1,
A thermoelectric element having a bonding strength of the first resin layer higher than that of the second resin layer. According to claim 1,
The first adhesive layer and the second adhesive layer are polysiloxane (Polysiloxan)-based adhesive thermoelectric elements. According to claim 4,
The first adhesive layer and the second adhesive layer are thermoelectric elements having a bonding strength of 1 kgf/mm ² or less at a temperature of 150 to 200°C. According to claim 1,
The insulating layer is a thermoelectric device comprising a polyimide (Polyimide). According to claim 1,
A thermoelectric element further comprising a third adhesive layer between the first adhesive layer and the insulating layer. According to claim 1,
A thermoelectric element further comprising a fourth adhesive layer between the second adhesive layer and the insulating layer.

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