KR102609889B1 - Thermoelectric element - Google Patents

Abstract

A thermoelectric element according to an embodiment of the present invention includes a first metal substrate, a first resin layer disposed on the first metal substrate, and a plurality of layers disposed on the first resin layer. A first electrode, 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. It includes an electrode, a second resin layer disposed on the plurality of second electrodes, and a second metal substrate disposed on the second resin layer, wherein the first metal substrate is a low temperature unit, and the second metal substrate is It is a high temperature portion, and the second resin layer includes a first layer in direct contact with the plurality of second electrodes and a second layer laminated on the first layer and in direct contact with the second metal substrate.

Description

Thermoelectric element {THERMOELECTRIC ELEMENT}

The present invention relates to thermoelectric devices, and more specifically, to the bonding structure of thermoelectric devices.

Thermoelectric phenomenon is a phenomenon caused by the movement of electrons and holes inside a material, and means direct energy conversion between heat and electricity.

Thermoelectric devices are a general term for devices that use thermoelectric phenomena, and have a structure in which a P-type thermoelectric material and an N-type thermoelectric material are joined between metal electrodes to form a PN junction pair.

Thermoelectric devices can be divided into devices that use temperature changes in electrical resistance, devices that use the Seebeck effect, a phenomenon in which electromotive force is generated due to a temperature difference, and devices that use the Peltier effect, a phenomenon in which heat absorption or heat generation occurs due to current. . Thermoelectric elements are widely applied to home appliances, electronic components, and communication components. For example, thermoelectric elements can be applied to cooling devices, heating devices, power generation devices, etc. Accordingly, the demand for thermoelectric performance of thermoelectric devices is increasing.

The thermoelectric element includes a substrate, an electrode, and a thermoelectric leg. A plurality of thermoelectric legs are arranged in an array between the upper substrate and the lower substrate, a plurality of upper electrodes are arranged between the plurality of thermoelectric legs and the upper substrate, and a plurality of thermoelectric legs are arranged in an array between the upper substrate and the upper substrate. A plurality of lower electrodes are disposed between the thermoelectric leg and the lower substrate. At this time, one of the upper and lower substrates may be a low temperature section, and the other may be a high temperature section. When a thermoelectric element is applied to a power generation device, the larger the temperature difference between the low-temperature section and the high-temperature section, the higher the power generation performance. Accordingly, the temperature of the high temperature part may rise above 200°C. When the temperature of the high temperature part exceeds 200℃, high mechanical shear stress is transmitted between the leg and the solder due to the difference in thermal expansion coefficient between the substrate and the electrode on the high temperature part. At this time, in order to relieve the shear stress applied between the leg and the solder, the bonding layer between the substrate and the electrode can be formed to a certain thickness or more. However, as the thickness of the bonding layer increases, the thermal resistance decreases, causing a problem in that the power generation performance of the thermoelectric element deteriorates.

The technical problem to be achieved by the present invention is to provide a bonding structure for a thermoelectric element.

A thermoelectric element according to an embodiment of the present invention includes a first metal substrate, a first resin layer disposed on the first metal substrate, and a plurality of layers disposed on the first resin layer. A first electrode, 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. It includes an electrode, a second resin layer disposed on the plurality of second electrodes, and a second metal substrate disposed on the second resin layer, wherein the first metal substrate is a low temperature unit, and the second metal substrate is It is a high temperature part, and the second resin layer includes a first layer in direct contact with the plurality of second electrodes and a second layer laminated on the first layer and in direct contact with the second metal substrate, and the first layer is in direct contact with the second metal substrate. The layer and the second layer may be in direct contact with each other.

The first metal substrate and the second metal substrate may be made of aluminum.

The thickness of the second resin layer may be greater than or equal to the thickness of the first resin layer.

The ratio of the thickness of the second resin layer to the thickness of the first resin layer may be 1 to 5.

The first layer may include a matrix resin and an insulating filler, and the second layer may include the matrix resin and a conductive filler.

The matrix resin may include polydimethylsiloxane (PDMS).

The insulating filler may include aluminum oxide, and the conductive filler may include Ag.

The thermal conductivity of the first layer may be 1.5 to 2 W/mK, and the thermal conductivity of the second layer may be 6.5 to 7 W/mK.

The ratio of the thickness of the second layer to the thickness of the first layer may be 0.2 to 2.5.

According to an embodiment of the present invention, the thickness of the bonding layer between the substrate and the electrode can be secured, the shear stress applied to the soldering area of the leg can be alleviated, and the durability of the thermoelectric element can be increased at high temperatures. At the same time, the part of the bonding layer that joins the substrate is made of a material with excellent conductivity, thereby preventing a decrease in thermal conductivity as the thickness of the bonding layer increases and maintaining the power generation performance of the thermoelectric element.

1 is a cross-sectional view of a thermoelectric element according to an embodiment of the present invention.
Figure 2 is a top view of a first metal substrate included in a thermoelectric device according to an embodiment of the present invention.
Figure 3 is a side view of a first metal substrate included in a thermoelectric device according to an embodiment of the present invention.
Figure 4 is a partial enlarged view of Figure 3.
Figure 5 is a perspective view of a thermoelectric element according to an embodiment of the present invention.
Figure 6 is an exploded perspective view of a thermoelectric element according to an embodiment of the present invention.
Figure 7 is a partially enlarged view of a thermoelectric element according to an embodiment of the present invention.
Figure 8 is a diagram showing a state in which a thermoelectric element according to an embodiment of the present invention is generating power.
Figure 9 is a cross-sectional view of a thermoelectric element according to another embodiment of the present invention.
Figure 10 is a partial enlarged view of Figure 9.
Figure 11 is a diagram showing a state in which power is applied to a thermoelectric element according to another embodiment of the present invention.

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

However, the technical idea of the present invention is not limited to some of the described embodiments, but may be implemented in various different forms, and as long as it is within the scope of the technical idea of the present invention, one or more of the components may be optionally used between the embodiments. It can be used by combining and replacing.

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

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

Additionally, when describing the components of an embodiment of the present invention, terms such as first, second, A, B, (a), and (b) may be used.

These terms are only used to distinguish the component from other components, and are not limited to the essence, sequence, 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 that other component, but also is connected to that component. It can also include cases where other components are 'connected', 'combined', or 'connected' due to another component between them.

Additionally, when described as being formed or disposed "above" or "below" each component, "above" or "below" refers not only to cases where two components are in direct contact with each other, but also to one This also includes cases where another component described above is formed or placed between two components. In addition, when expressed as "top (above) or bottom (bottom)", it may include not only the upward direction but also the downward direction based on one component.

Figure 1 is a cross-sectional view of a thermoelectric element according to an embodiment of the present invention, Figure 2 is a top view of a first metal substrate included in a thermoelectric element according to an embodiment of the present invention, and Figure 3 is an embodiment of the present invention. It is a side view of a first metal substrate included in a thermoelectric element according to an example, FIG. 4 is a partial enlarged view of FIG. 3, FIG. 5 is a perspective view of a thermoelectric element according to an embodiment of the present invention, and FIG. 6 is a This is an exploded perspective view of a thermoelectric element according to one 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 It includes a type thermoelectric leg 150, a plurality of second electrodes 160, a second resin layer 170, a second metal substrate 180, and a 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 to face the second metal substrate 180 . The first metal substrate 110 may be made of aluminum, aluminum alloy, copper, or copper alloy. In particular, the first metal substrate 110 may be made of aluminum. At this time, when voltage is applied to the thermoelectric element, the first metal substrate 110 absorbs heat according to the Peltier effect and acts as a low temperature section, and the second metal substrate 180 emits heat and acts as a high temperature section. do.

Meanwhile, when different temperatures are applied to the first metal substrate 110, electrons in the high-temperature region move to the low-temperature region due to the temperature difference, thereby generating thermoelectromotive force. This is called the Seebeck effect, and electricity is generated within the circuit of the thermoelectric element due to the resulting thermoelectric power.

Here, the first metal substrate 110 may be in direct contact with the first resin layer 120. For this purpose, the first metal substrate 110 is disposed on all or part of the side on which the first resin layer 120 is disposed, that is, the side facing the first resin layer 120 of the first metal substrate 110. Surface roughness may be formed. According to this, it is possible to prevent the problem of the first resin layer 120 being lifted during thermal compression between the first metal substrate 110 and the first resin layer 120. In this specification, surface roughness means irregularities and may be used interchangeably with surface roughness.

Referring to FIGS. 2 to 4, among both sides of the first metal substrate 110, the side on which the first resin layer 120 is disposed, that is, the side facing the first resin layer 120 of the first metal substrate 110 includes a first area 112 and a second area 114, and the second area 114 may be disposed inside the first area 112. That is, the first area 112 may be disposed within a predetermined distance from the edge of the first metal substrate 110 toward the center area, and the first area 112 may surround the second area 114.

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

However, the surface roughness of the second region 114 may be greater 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 other parts. Here, the particle size D50 refers to the particle size corresponding to 50% of the weight percentage in the particle size distribution curve, that is, the particle size at which the passing mass percentage is 50%, and can be used interchangeably with the average particle size. For example, if the first resin layer 120 contains aluminum oxide and boron nitride as inorganic fillers, 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 have a negative effect on the adhesion performance between the first resin layer 120 and the first metal substrate 110. Accordingly, if the surface roughness of the second region 114 is greater than the particle size D50 of the aluminum oxide contained in the first resin layer 120, but smaller than the particle size D50 of the boron nitride, the surface roughness of the second region 114 Since only aluminum oxide is placed in the groove formed by the surface roughness, and boron nitride is difficult to be placed, the first resin layer 120 and the first metal substrate 110 can maintain high bonding strength.

This surface roughness can be measured using a surface roughness measuring device. The surface roughness measuring device measures the cross-section curve using a probe, and can calculate the surface roughness using the peak line, trough line, average line, and reference length of the cross-section curve. In this specification, surface roughness may mean arithmetic average roughness (Ra) based on the center line average calculation method. Arithmetic average roughness (Ra) can be obtained through Equation 2 below.

In other words, when the cross-sectional curve obtained from the probe of the surface roughness measuring device is extracted by the standard length L and expressed as a function (f(x)) with the average line direction as the x-axis and the height direction as the y-axis, according to Equation 2 The obtained value can be expressed in ㎛ meters.

At this time, although not shown in the drawing, it is possible that a surface roughness corresponding to the second area 114 is formed on the entire surface of the first metal substrate 110. Additionally, the surface roughness formed on the first metal substrate 110 can be equally applied to the second metal substrate 180, which will 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 an area 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 containing an epoxy resin and an inorganic filler, or may be made of a silicone resin composition containing PDMS (polydimethylsiloxane).

In this way, 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 are formed without a separate ceramic substrate. Heat transfer between the layers 130 is possible, and no separate adhesive or physical fastening means is required due to the adhesive performance of the first resin layer 120 itself. In particular, the first resin layer 120 can be implemented with a significantly thinner thickness compared to the existing ceramic substrate, so heat transfer performance between the plurality of first electrodes 130 and the first metal substrate 110 can be improved, and thermoelectric energy can be improved. The overall size of the device can also be reduced.

A plurality of first electrodes 130 are disposed on the first resin layer 120. And 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).

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 P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 may be joined to the first electrode 130 by soldering.

At this time, the P-type thermoelectric leg 140 and N-type thermoelectric leg 150 may be bismuth telluride (Bi-Te)-based thermoelectric legs containing bismuth (Bi) and tellurium (Te) as main materials. The P-type thermoelectric leg 140 contains antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), and gallium for 100 wt% 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 0.001 wt% of Bi or Te. It may be a thermoelectric leg containing from 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. The N-type thermoelectric leg 150 contains selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), and gallium for 100 wt% 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 0.001 wt% of Bi or Te. It may be a thermoelectric leg containing from 1 wt%. For example, the main raw material is Bi-Sb-Te, and Bi or Te may be further included in an amount of 0.001 to 1 wt% of the total weight.

The P-type thermoelectric leg 140 and N-type thermoelectric leg 150 may be formed in a bulk or stacked form. In general, the bulk P-type thermoelectric leg 140 or the bulk N-type thermoelectric leg 150 is manufactured by heat-treating a thermoelectric material to produce an ingot, crushing and sieving the ingot to obtain powder for the thermoelectric leg, and then manufacturing the ingot. 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 formed by applying a paste containing a thermoelectric material on a sheet-shaped substrate to form a unit member, and then through the process of stacking and cutting the unit members. 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 changed to the height or cross-sectional area of the P-type thermoelectric leg 140. It may be formed differently.

The performance of a thermoelectric element according to an embodiment of the present invention can be expressed as a thermoelectric performance index. The thermoelectric performance index (ZT) can be expressed as Equation 1.

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

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

The P-type thermoelectric leg 140 or N-type thermoelectric leg 150 may have a cylindrical shape, a polygonal pillar shape, an elliptical pillar shape, etc. Alternatively, the P-type thermoelectric leg 140 or N-type thermoelectric leg 150 may have a stacked structure. For example, a P-type thermoelectric leg or an 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 them. Accordingly, material loss can be prevented and electrical conduction characteristics can be improved. Alternatively, the P-type thermoelectric leg 140 or 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, heat is slowly applied to the ingot to refine the particles to rearrange in a single direction, and then slowly cooled to obtain a thermoelectric leg. According to the powder sintering method, after manufacturing an ingot using a thermoelectric material, the ingot is crushed and sieved to obtain powder for the thermoelectric leg, and the thermoelectric leg is obtained through the process of sintering the powder.

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 N-type thermoelectric leg 150 may be joined to the second electrode 160 by soldering. At this time, if stress is applied to the soldered portion due to shear, cracks may be formed in the soldered portion. 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. And, a 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 an area spaced a predetermined distance from the edge of the second metal substrate 180.

At this time, the first resin layer 120 and the second resin layer 170 may have different sizes. For example, the volume, thickness, or area of one of the first resin layer 120 and the second resin layer 170 may be formed to be larger than the volume, thickness, or area of the other one. In addition, the bonding strength between the plurality of second electrodes 160 or the second metal substrate 180 in direct contact with the second resin layer 170 is determined by the strength of the bonding strength between the plurality of first electrodes 160 in direct contact with the first resin layer 120. (130) or the bonding strength with the first metal substrate 110 may be lower. 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 It may be more than 15kgf/mm ² . On the other hand, the bonding strength between the second resin layer 170 and the plurality of second electrodes 160 or the second metal substrate 180 may be 1 kgf/mm ² or less.

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. Preferably, the thickness T1 of the first resin layer 120 may be about 40 ㎛, and the thickness T2 of the second resin layer 170 may be 40 to 200 ㎛. That is, the ratio of the thickness T2 of the second resin layer 170 to the thickness T1 of the first resin layer 120 may be 1 to 5.

The second resin layer 170 transfers the heat generated by the P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 to the second metal substrate 180, and simultaneously connects the second metal substrate 180 and the second Current can be prevented from passing between the electrodes 160. To this end, the portion of the second resin layer 170 adjacent to the second electrode 160 may have insulating properties, and the portion adjacent to the second metal substrate 180 may have thermal conductivity.

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

Referring to FIG. 7, the second resin layer 170 includes a first layer 171 and a second layer 172.

The first layer 171 is in direct contact with the second electrode 160. The first layer 171 has insulating properties and serves to block the current flowing through the second electrode 160 from being transmitted to the second metal substrate 180. To this end, the first layer 171 may include a matrix resin and an insulating filler. Here, the matrix resin may include polydimethylsiloxane (PDMS). Additionally, the insulating filler may include ceramic powder such as aluminum oxide, aluminum nitride, or boron nitride. Preferably, the ceramic powder may be included in an amount of 50 to 99 wt%. More preferably, aluminum oxide powder may be included in an amount of 50 to 99 wt%. At this time, the thermal conductivity of the first layer 171 may be 1.5 to 3.5 W/mK.

The second layer 172 is disposed on the first layer 171 and is in direct contact with the second metal substrate 180. The second layer 172 is in direct contact with the first layer 171. At this time, the second layer 172 is conductive and transfers heat generated from the P-type thermoelectric leg 140 and the N-type thermoelectric leg 150 to the second metal substrate 180.

The second layer 172 may include a matrix resin and a conductive filler. Here, the matrix resin may include a silicone resin, for example, polydimethylsiloxane (PDMS). At this time, the mattress resin applied to the second layer 172 is preferably the same as the matrix resin applied to the first layer 171. Additionally, the conductive filler may include metal powder such as silver (Ag)-based, gold (Au)-based, or aluminum (Al)-based. Preferably, the metal powder may be included in an amount of 50 to 99 wt%. More preferably, silver (Ag)-based metal powder may be included in an amount of 50 to 99 wt%. At this time, the thermal conductivity of the second layer 172 may be 6.0 to 10.0 W/mK.

Here, the first layer 171 and the second layer 172 may have adhesiveness or adhesiveness.

The thickness t1 of the first layer 171 may be about 40 to 100 μm. At this time, if the thickness (t1) of the first layer 171 is less than 40㎛, insulation is not secured and there is a risk of electricity conduction, and if the thickness (t2) of the first layer 171 is greater than 40㎛, heat conduction A phenomenon in which the temperature decreases occurs, and the power generation performance of the thermoelectric element deteriorates. Additionally, the thickness t2 of the second layer 172 may be 40 to 200 μm. That is, the ratio of the thickness t2 of the second layer 172 to the thickness t1 of the first layer 171 may be 0.2 to 2.5.

The second metal substrate 180 is disposed on the second resin layer 170 facing the first metal substrate 110. The second metal substrate 180 may be made of aluminum, aluminum alloy, copper, or copper alloy. In particular, the second metal substrate 180 may be made of aluminum. At this time, the second metal substrate 180 can be placed in a high temperature area for power generation, or the second metal substrate 180 can be applied to the high temperature area by the Peltier effect by applying current to the thermoelectric element.

At this time, the second metal substrate 180 has a surface on all or part of the side on which the second resin layer 170 is disposed, that is, the side facing the second resin layer 170 of the first metal substrate 180. Roughness may form.

Here, the first metal substrate 110 and the second metal substrate 180 may have an area of 40mmx40mm to 200mmx200mm and a thickness of 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.

Figure 8 is a diagram showing a state in which a thermoelectric element according to an embodiment of the present invention is generating power.

Referring to FIG. 8, when the second metal substrate 180 of the thermoelectric element is placed in a high temperature area and the first metal substrate 110 is placed in a low temperature area, electrons between a plurality of thermoelectric legs connected in series due to the Seebeck effect Electricity is generated through movement. At this time, the second metal substrate 180 exposed to high temperature may expand in volume due to heat. At this time, due to the horizontal expansion of the second metal substrate 180, shear stress may be applied to the second resin layer 170. Shear stress is transmitted to the soldering portion of the second electrode 160, causing cracks in the soldering portion and reducing durability at high temperatures. At this time, the thermoelectric element according to the embodiment can secure the thickness of the second resin layer 170, relieve shear stress transmitted to the soldering joint portion, and secure durability at high temperatures. Although not shown, the same can be applied to thermal expansion that occurs when the second metal substrate 180 operates at a high temperature due to the Peltier effect when voltage is applied to the thermoelectric element.

Referring again to FIGS. 5 and 6, the sealing means 190 may be disposed on the side of the first resin layer 120 and the side of the second resin layer 170. That is, the sealing means 190 may be disposed on the side of the first resin layer 120 and the second resin layer 170. 1 disposed between the metal substrate 110 and the second metal substrate 180, the side of the first resin layer 120, the outermost edge of the plurality of first electrodes 130, and the plurality of P-type thermoelectric legs 140 And it may be arranged to surround the outermost part of the plurality of N-type thermoelectric legs 150, the outermost part of the plurality of second electrodes 150, and the side surface of the second resin layer 170. Accordingly, the first resin layer 120, a plurality of first electrodes 130, a plurality of P-type thermoelectric legs 140, a plurality of N-type thermoelectric legs 150, a plurality of second electrodes 150 and 2 The resin layer can be sealed from external moisture, heat, contamination, etc.

Here, the sealing means 190 is located on the side of the first resin layer 120, the outermost edge of the plurality of first electrodes 130, the plurality of P-type thermoelectric legs 140, and the plurality of N-type thermoelectric legs 150. A sealing case 192, the sealing case 192, and the second metal substrate 180 disposed at a predetermined distance from the outermost, outermost of the plurality of second electrodes 150, and the side of the second resin layer 170. It may include a sealing material 194 disposed between the sealing case 192 and the first metal substrate 110 and a sealing material 196 disposed between the sealing case 192 and the first metal substrate 110 . In this way, 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, the problem of lowering △T is solved. It can be prevented.

Here, the sealing materials 194 and 196 may include at least one of an epoxy resin and a silicone resin, or may include a tape with at least one of an epoxy resin and a silicone resin applied to both sides. The sealing materials 194 and 196 serve to seal the space 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 150, the plurality of second electrodes 150, and the second resin layer 170. It can be used in combination with finishing materials, finishing layers, waterproofing materials, waterproofing layers, etc.

Meanwhile, a guide groove (G) may be formed in the sealing case 192 for pulling out the wires (W1, W2) connected to the electrodes. For this purpose, the sealing case 192 may be an injection molded product made of plastic or the like, and may be used interchangeably with the sealing cover.

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

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

Figure 9 is a cross-sectional view of a thermoelectric element according to another embodiment of the present invention, Figure 10 is a partial enlarged view of Figure 9, and Figure 11 shows a state in which power is applied to the thermoelectric element 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 may include a plurality of layers. At this time, the plurality of layers is at least three and may be in direct contact with each other. At this time, the number of layers included in the second resin layer 200 can be modified.

9 and 10, the second resin layer 200 includes first to fourth layers 211, 212, 213, and 214. At this time, the first to fourth layers 211, 212, 213, and 214 are made of different materials. Additionally, the first to fourth layers 211, 212, 213, and 214 may have different thermal conductivities. The first to fourth layers 211, 212, 213, and 214 are arranged in order of increasing thermal conductivity from the first metal substrate 110 to the second metal substrate 180.

The first to fourth layers 211, 212, 213, and 214 may include a matrix resin and a conductive filler or an insulating filler. Here, the matrix resin may include a silicone resin, for example, polydimethylsiloxane (PDMS). At this time, the content of the conductive filler or insulating filler included in the first to fourth layers 211, 212, 213, and 214 may be different.

Hereinafter, the present invention will be described in more detail through thermoelectric devices according to examples and comparative examples. These embodiments are merely provided as examples to explain the present invention in more detail. Therefore, the present invention is not limited to these examples.

Both the thermoelectric device according to the comparative example and the thermoelectric device according to the embodiment include 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, and a plurality of first metal substrates as in the structure of FIG. 1. Measurement in an environment in which a temperature of 35 ℃ was applied to the first metal substrate area and 200 ℃ to the second metal substrate area of a 40mm × 40mm thermoelectric element for power generation including a second electrode, a second resin layer, and a second metal substrate. It is a result. In the thermoelectric device according to the comparative example, the second resin layer was formed entirely of a resin having insulating properties, and in the thermoelectric device according to the example, the second resin layer was composed of a first layer and a second layer, and the first layer was made of an insulating resin. The second layer was made of conductive material. At this time, the thickness of the first layer was fixed at 40㎛, and the thickness of the second layer was changed to measure the power generation amount and power generation reduction rate of the thermoelectric element.

second resin layer
Thickness (㎛) Comparative example Example Power generation (W)

)power generation
Decrease rate (%,P/

) Power generation (W) power generation
Decrease rate (%,P/

) 40 7.2 - 7.2 - 80 7.0 12 7.0 3 120 5.5 24 6.8 6 160 4.9 32 6.5 10 200 3.6 50 6.2 14

Referring to Table 1, it can be seen that in the thermoelectric element according to the comparative example, as the thickness of the second resin layer increases, the power generation decreases and the power generation reduction rate increases. On the other hand, in the thermoelectric element according to the example, as the thickness of the second resin layer increases, the amount of power generation decreases somewhat, and the rate of decrease in power generation increases, but it can be seen that the amount of power generation decreases to a significantly smaller extent than that of the comparative example.

That is, the thermoelectric element according to the embodiment does not significantly reduce thermal conductivity even if the thickness of the second resin layer is increased to relieve thermal stress, and sufficient power generation performance can be secured.

The thermoelectric element according to an embodiment of the present invention can be used in a power generation device, a cooling device, a heating device, etc. Specifically, thermoelectric elements according to embodiments of the present invention are mainly used in optical communication modules, sensors, medical devices, measuring devices, aerospace industry, refrigerators, chillers, automobile ventilated seats, cup holders, washing machines, dryers, and wine cellars. , can be applied to water purifiers, power supplies for sensors, thermopiles, etc.

Here, an example in which the thermoelectric element according to an embodiment of the present invention is applied to a medical device is a polymerase chain reaction (PCR) device. A PCR device is a device that amplifies DNA and determines the base sequence of DNA, and requires precise temperature control and thermal cycling. For this purpose, a Peltier-based thermoelectric element can be applied.

Another example in which the thermoelectric element according to an embodiment of the present invention is applied to a medical device is a photodetector. Here, the photo detector includes an infrared/ultraviolet detector, CCD (Charge Coupled Device) sensor, X-ray detector, TTRS (Thermoelectric Thermal Reference Source), etc. A Peltier-based thermoelectric element can be applied for cooling the photodetector. Accordingly, it is possible to prevent changes in wavelength, lower output, lower resolution, etc. due to an increase in temperature inside the photo detector.

Another example of the thermoelectric element according to an embodiment of the present invention being applied to medical devices is the field of immunoassay, in vitro diagnostics, general temperature control and cooling systems, These include physical therapy fields, liquid chiller systems, and blood/plasma temperature control fields. Accordingly, precise temperature control is possible.

Another example in which the thermoelectric element 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 thermoelectric devices according to embodiments of the present invention applied to the aerospace industry include star tracking systems, thermal imaging cameras, infrared/ultraviolet detectors, CCD sensors, Hubble Space Telescope, and TTRS. Accordingly, the temperature of the image sensor can be maintained.

Other examples of thermoelectric elements according to embodiments of the present invention being applied to the aerospace industry include cooling devices, heaters, and power generation devices.

In addition, thermoelectric elements according to embodiments of the present invention can be applied to other industrial fields for power generation, cooling, and heat.

Although the present invention has been described above with reference to preferred embodiments, those skilled in the art may make various modifications and changes to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can do it.

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 layer
172, 214: second layer
180: Second metal substrate
190: Sealing means
212: third layer
213: fourth layer

Claims (9)

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
It includes a second metal substrate disposed on the second resin layer,
The first metal substrate is a low temperature section, and the second metal substrate is a high temperature section,
The second resin layer includes a first layer in direct contact with the plurality of second electrodes and a second layer disposed on the first layer and in direct contact with the second metal substrate,
the first layer and the second layer are in direct contact with each other,
The first layer includes a matrix resin and an insulating filler,
The second layer includes a matrix resin and a conductive filler,
A thermoelectric element wherein the bonding strength between the first resin layer and the plurality of first electrodes or the first metal substrate is greater than the bonding strength between the second resin layer and the plurality of second electrodes or the second metal substrate. According to paragraph 1,
A thermoelectric device wherein the first metal substrate and the second metal substrate include aluminum. According to paragraph 1,
A thermoelectric element wherein the thickness of the second resin layer is greater than or equal to the thickness of the first resin layer. According to paragraph 3,
A thermoelectric element wherein the ratio of the thickness of the second resin layer to the thickness of the first resin layer is 1 to 5. delete According to paragraph 1,
The matrix resin is a thermoelectric element containing polydimethylsiloxane (PDMS). According to clause 6,
The insulating filler includes aluminum oxide,
The conductive filler is a thermoelectric element containing Ag. According to clause 6,
The thermal conductivity of the first layer is 1.5 to 3.5 W/mK, and the thermal conductivity of the second layer is 6.0 to 10.0 W/mK. According to paragraph 1,
A thermoelectric element wherein the ratio of the thickness of the second layer to the thickness of the first layer is 0.2 to 2.5.

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