Thermoelectric element

Abstract

To provide a thermoelectric element in which a thermal conduction performance, a withstand voltage performance, and insulation resistance are all improved.SOLUTION: A thermoelectric element 200 includes a first substrate 210 including a first through-hole 700 formed therein, a first insulating layer 220 being disposed on the first substrate and including a second through-hole 800, a first electrode 230 on the first insulating layer, semiconductor structures 240, 250 on the first electrode, a second electrode 260 on the semiconductor structure, a second insulating layer 270 disposed on the second electrode part, and a second substrate 280 on the second insulating layer. The first substrate includes first to fourth outer peripheries which define a shape thereof, the first outer periphery and the fourth outer periphery are opposite to each other, and the second outer periphery and the third outer periphery are opposite to each other between the first outer periphery and the fourth outer periphery. The first electrode includes a first region vertically overlapping a plurality of the second electrodes, and a plurality of the first electrodes includes an extension portion extending toward the first outer periphery from the first region. The first through-hole is formed at an inside of the first region. A shortest distance between the second through hole and the first electrode among the plurality of the first electrodes is within ±10% of a shortest distance between the second outer periphery and the extension portion.SELECTED DRAWING: Figure 9

Description

Technical Field

[0001] The present invention relates to a thermoelectric element, and more particularly to a substrate and an electrode structure of a thermoelectric element.

Background Art

[0002] The thermoelectric phenomenon is a phenomenon generated by the movement of electrons and holes inside a material, and means a direct energy conversion between heat and electricity.

[0003] A thermoelectric element is a general term for elements that utilize the thermoelectric phenomenon, and has 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.

[0004] Thermoelectric elements can be classified into elements that utilize the temperature change of electrical resistance, elements that utilize the Seebeck effect, which is a phenomenon in which an electromotive force is generated due to a temperature difference, elements that utilize the Peltier effect, which is a phenomenon in which heat absorption or heat generation occurs due to an electric current, and the like.

[0005] Thermoelectric elements are widely applied to home appliances, electronic components, communication components, etc. For example, thermoelectric elements can be applied to cooling devices, heating devices, power generation devices, etc. Along with this, the requirements for the thermoelectric performance of thermoelectric elements are gradually increasing.

[0006] A thermoelectric element includes a substrate, electrodes, and thermoelectric legs. A plurality of thermoelectric legs are arranged between an upper substrate and a lower substrate, a plurality of upper electrodes are arranged between the plurality of thermoelectric legs and the upper substrate, and a plurality of lower electrodes are arranged between the plurality of thermoelectric legs and the lower substrate.

[0007] In order to improve the heat transfer performance of thermoelectric elements, attempts to use metal substrates are increasing.

[0008] Generally, a thermoelectric element can be manufactured by a process of sequentially laminating electrodes and thermoelectric legs on a pre-prepared metal substrate. When a metal substrate is used, an advantageous effect can be obtained from the perspective of heat conduction. However, in the application fields under a high-voltage environment, there is a problem that the withstand voltage characteristics must be additionally ensured.

Summary of the Invention

Problems to be Solved by the Invention

[0009] The technical problem to be achieved by the present invention is to provide a thermoelectric element in which the heat conduction performance, withstand voltage performance, and insulation resistance are all improved.

Means for Solving the Problems

[0010] A thermoelectric element according to an embodiment of the present invention includes a first metal substrate in which a first through hole is formed, a first insulating layer disposed on the first metal substrate and including a second through hole formed at a position corresponding to the first through hole, a first electrode portion disposed on the first insulating layer and including a plurality of first electrodes, a semiconductor structure disposed on the first electrode portion, a second electrode portion disposed on the semiconductor structure and including a plurality of second electrodes, a second insulating layer disposed on the second electrode portion, and a second metal substrate disposed on the second insulating layer. The first metal substrate includes a first outer contour, a second outer contour, a third outer contour, and a fourth outer contour that define the shape of the first metal substrate. The first outer contour and the fourth outer contour face each other, and the second outer contour and the third outer contour face each other between the first outer contour and the fourth outer contour. The first electrode portion includes a first region that vertically overlaps with the plurality of second electrodes. At least one of the plurality of first electrodes includes an extension portion that extends from the first region toward the first outer contour. The first through hole is formed inside the first region. The shortest distance from the second outer contour to the first electrode closest to the second through hole among the plurality of first electrodes is within ±10% of the shortest distance from the second outer contour to the extension portion.

[0011] A first hole arrangement region is formed inside the first region. The first hole arrangement region is a virtual space formed by a virtual line connecting the surfaces of a plurality of first electrodes that surround the periphery of the second through hole and are adjacent to the second through hole. The extension portion can be arranged so as to at least partially overlap with a virtual space formed by an extension line extending from the virtual line defining the first hole arrangement region.

[0012] The shortest distance between the first region and the first outer contour can be 1.2 to 2.5 times the shortest distance between the extension portion and the second outer contour.

[0013] The shortest distance between the extension portion and the second outer contour can be 12 mm or more.

[0014] The shortest distance between the first electrodes that are most adjacent to each other among the plurality of first electrodes from the end of the second through hole can be 50 to 180 times the thickness of the first insulating layer.

[0015] The shortest distance between the first electrodes that are most adjacent to each other among the plurality of first electrodes from the end of the second through hole can be 8 mm or more.

[0016] The second insulating layer includes a third through hole formed at a position corresponding to the first through hole. The second metal substrate includes a fourth through hole formed at a position corresponding to the first through hole. It can further include a fastening member disposed between the first through hole and the fourth through hole.

[0017] It can further include a heat sink disposed on the second metal substrate and including a fifth through hole formed at a position corresponding to the first through hole.

[0018] The fastening member is disposed between the fourth through hole and the fifth through hole, and can further include an insulating insertion member disposed adjacent to the fifth through hole on the heat sink.

[0019] A part of the insulating insertion member can be disposed between the fourth through hole and the fastening member.

[0020] The diameter of the fourth through hole can be 1.1 to 2.0 times the diameter of the first through hole.

[0021] It can further include a third insulating layer disposed between the first insulating layer and the first electrode portion and including a sixth through hole formed at a position corresponding to the first through hole.

[0022] At least one of the first insulating layer, the second insulating layer, and the third insulating layer can include a resin and an inorganic substance.

[0023] The inorganic substance can include aluminum or aluminum oxide.

[0024] The area of the first hole arrangement region can be 4 times or more the area of one first electrode.

[0025] The extension portions include a plurality, the plurality of extension portions include a first terminal electrode and a second terminal electrode, a first connection unit is disposed on the first terminal electrode, and a second connection unit can be disposed on the second terminal electrode.

[0026] Each of the first connection unit and the second connection unit can be a connector connected to an electric wire.

[0027] The power generation device according to an embodiment of the present invention includes a first fluid flow portion through which a first fluid flows, a second fluid flow portion through which a second fluid that is at a higher temperature than the first fluid flows, and a thermoelectric element disposed between the first fluid flow portion and the second fluid flow portion. The thermoelectric element includes a first metal substrate in which a first through hole is formed, a first insulating layer disposed on the first metal substrate and including a second through hole formed at a position corresponding to the first through hole, a first electrode portion disposed on the first insulating layer and including a plurality of first electrodes, a semiconductor structure disposed on the first electrode portion, a second electrode portion disposed on the semiconductor structure and including a plurality of second electrodes, a second insulating layer disposed on the second electrode portion, and a second metal substrate disposed on the second insulating layer. The first metal substrate includes a first outer contour, a second outer contour, a third outer contour, and a fourth outer contour that define the shape of the first metal substrate. The first outer contour and the fourth outer contour face each other, and the second outer contour and the third outer contour face each other between the first outer contour and the fourth outer contour. The first electrode portion includes a first region that vertically overlaps with the plurality of second electrodes. At least one of the plurality of first electrodes includes an extension portion that extends from the first region toward the first outer contour. The first through hole is formed inside the first region. The shortest distance from the second outer contour to the first electrode that is closest to the second through hole among the plurality of first electrodes is within ±10% of the shortest distance from the second outer contour to the extension portion.

[0028] The shortest distance between the extension portion and the second outer contour can be 12 mm or more.

[0029] The shortest distance between the first electrodes that are closest to the end of the second through hole among the plurality of first electrodes can be 8 mm or more.

Effects of the Invention

[0030] According to an embodiment of the present invention, a thermoelectric element with excellent performance and high reliability can be obtained. In particular, according to an embodiment of the present invention, a thermoelectric element with improved not only in thermal conductivity performance but also in withstand voltage performance and insulation resistance can be obtained. Accordingly, it is possible to satisfy the withstand voltage characteristics additionally required in applications under a high voltage environment.

[0031] The thermoelectric element according to an embodiment of the present invention can be applied not only to applications embodied in a small size but also to applications embodied in a large size such as vehicles, ships, steel mills, incinerators, and the like.

Brief Description of the Drawings

[0032]

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Best Mode for Carrying Out the Invention

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0034] However, the technical idea of the present invention is not limited to some of the described embodiments, and can be embodied in various different forms. Within the scope of the technical idea of the present invention, one or more of the components can be selectively combined and replaced between the embodiments for use.

[0035] Also, the terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having a meaning generally understood by those having ordinary knowledge in the technical field to which the present invention pertains, unless specifically defined and described otherwise. Terms that are generally used like those defined in a dictionary can have their meaning interpreted in consideration of the meaning in the context of the related art.

[0036] Also, the terms used in the embodiments of the present invention are for explaining the embodiments and are not intended to limit the present invention.

[0037] In this specification, the singular form can include the plural form unless otherwise particularly mentioned in the text. When described as "at least one (or one or more) of A and (or) B, C", it can include one or more of all combinations that can be combined with A, B, and C.

[0038] Also, when explaining the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. can be used.

[0039] Such terms are only for distinguishing their components from other components, and are not limited to the essence, order or sequence of such components by such terms.

[0040] And when any component is described as being "connected", "coupled" or "joined" to a certain component, that component can include not only the case where it is directly connected, coupled or joined to other components, but also the case where it is "connected", "coupled" or "joined" by still other components between that component and the other components.

[0041] Also, when it is described as being formed or disposed "above (upper) or below (lower)" each component, "above (upper) or below (lower)" includes not only the case where two components are in direct contact with each other, but also the case where one or more still other components are formed or disposed between the two components. Also, when expressed as "above (upper) or below (lower)", it can include the meaning not only in the upward direction but also in the downward direction with respect to one component.

[0042] FIG. 1 is a cross-sectional view of a thermoelectric element, and FIG. 2 is a perspective view of the thermoelectric element. FIG. 3 is a perspective view of a thermoelectric element including a sealing member, and FIG. 4 is an exploded perspective view of the thermoelectric element including the sealing member.

[0043] Referring to FIGS. 1 and 2, the thermoelectric element 100 includes a lower substrate 110, a lower electrode 120, a P-type thermoelectric leg 130, an N-type thermoelectric leg 140, an upper electrode 150, and an upper substrate 160.

[0044] The lower electrode 120 is disposed between the lower substrate 110 and the lower bottom surfaces of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140, and the upper electrode 150 is disposed between the upper substrate 160 and the upper bottom surfaces of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140. Accordingly, the plurality of P-type thermoelectric legs 130 and the plurality of N-type thermoelectric legs 140 are electrically connected by the lower electrode 120 and the upper electrode 150. A pair of P-type thermoelectric leg 130 and N-type thermoelectric leg 140 disposed between and electrically connected to the lower electrode 120 and the upper electrode 150 can form a unit cell.

[0045] For example, when a voltage is applied to the lower electrode 120 and the upper electrode 150 via the lead wires 181 and 182, the substrate through which current flows from the P-type thermoelectric leg 130 to the N-type thermoelectric leg 140 due to the Peltier effect absorbs heat and acts as a cooling part, and the substrate through which current flows from the N-type thermoelectric leg 140 to the P-type thermoelectric leg 130 can be heated and act as a heat generating part. Or, when a temperature difference is applied between the lower electrode 120 and the upper electrode 150, charges can move within the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 due to the Seebeck effect, generating electricity.

[0046] Here, the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 can be bismuth telluride (Bi-Te)-based thermoelectric legs containing bismuth (Bi) and tellurium (Te) as main raw materials. The P-type thermoelectric leg 130 can be a bismuth telluride (Bi-Te)-based thermoelectric leg containing at least one of antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tellurium (Te), bismuth (Bi), and indium (In). For example, the P-type thermoelectric leg 130 can contain 99 - 99.999 wt% of Bi-Sb-Te, which is the main raw material substance, with respect to the total weight of 100 wt%, and can contain at least one of nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), and indium (In) at 0.001 - 1 wt%. The N-type thermoelectric leg 140 can be a bismuth telluride (Bi-Te)-based thermoelectric leg containing at least one of selenium (Se), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), tellurium (Te), bismuth (Bi), and indium (In). For example, the N-type thermoelectric leg 140 can contain 99 - 99.999 wt% of Bi-Se-Te, which is the main raw material substance, with respect to the total weight of 100 wt%, and can contain at least one of nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), and indium (In) at 0.001 - 1 wt%.

[0047] The P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 can be formed in a bulk type or a laminated type. Generally, the bulk type P-type thermoelectric leg 130 or the bulk type N-type thermoelectric leg 140 is obtained through a process of heat-treating a thermoelectric material to produce an ingot, crushing the ingot, sieving it to obtain powder for the thermoelectric leg, sintering the powder, and cutting the sintered body. At this time, the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 can be polycrystalline thermoelectric legs. For the polycrystalline thermoelectric legs, when sintering the powder for the thermoelectric leg, it can be compressed at 100 MPa to 200 MPa. For example, when sintering the P-type thermoelectric leg 130, the powder for the thermoelectric leg can be sintered at 100 to 150 MPa, preferably 110 to 140 MPa, more preferably 120 to 130 MPa. And when sintering the N-type thermoelectric leg 130, the powder for the thermoelectric leg can be sintered at 150 to 200 MPa, preferably 160 to 195 MPa, more preferably 170 to 190 MPa. In this way, when the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 are polycrystalline thermoelectric legs, the strength of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 can be increased. The laminated type P-type thermoelectric leg 130 or the laminated type N-type thermoelectric leg 140 is obtained through a process of applying a paste containing a thermoelectric material on a sheet-like substrate to form a unit member, laminating the unit members, and cutting them.

[0048] At this time, the pair of P-type thermoelectric leg 130 and N-type thermoelectric leg 140 can have the same shape and volume, or can have different shapes and volumes from each other. For example, since the electrical conduction characteristics of the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 are different, the height or cross-sectional area of the N-type thermoelectric leg 140 can be formed to be different from the height or cross-sectional area of the P-type thermoelectric leg 130.

[0049] At this time, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 can have a cylindrical shape, a polygonal prism shape, an elliptical prism shape, etc.

[0050] Alternatively, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 can also have a laminated structure. For example, the P-type thermoelectric leg or the N-type thermoelectric leg can be formed by a method of laminating a plurality of structures in which a semiconductor material is applied to a sheet-like base material and then cutting this. Along with this, it is possible to prevent material loss and improve electrical conduction characteristics. Each structure can further include a conductive layer having an opening pattern, and along with this, it is possible to increase the adhesive force between the structures, reduce the thermal conductivity, and increase the electrical conductivity.

[0051] Alternatively, the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140 can also be formed such that the cross-sectional area is different within one thermoelectric leg. For example, the cross-sectional areas of both end portions arranged so as to face the electrodes within one thermoelectric leg can also be formed larger than the cross-sectional area between both end portions. According to this, since it is possible to form a large temperature difference between both end portions, the thermoelectric efficiency can be increased.

[0052] The performance of the thermoelectric element according to one embodiment of the present invention can be represented by the thermoelectric figure of merit (ZT). The thermoelectric figure of merit (ZT) can be represented as in Equation 1.

[0053]

Equation

[0054] Here, α is the Seebeck coefficient [V / K], σ is the electrical conductivity [S / m], and α 2 σ is the power factor ([W / mK 2 ). And, T is the temperature, and k is the thermal conductivity [W / mK]. k can be represented 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 .

[0055] In order to obtain the thermoelectric performance index of the thermoelectric element, the Z value (V / K) can be measured using a Z meter, and the thermoelectric performance index (ZT) can be calculated using the measured Z value.

[0056] Here, the lower electrode 120 disposed between the lower substrate 110 and the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140, and the upper electrode 150 disposed between the upper substrate 160 and the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 include at least one of copper (Cu), silver (Ag), aluminum (Al), and nickel (Ni), and may have a thickness of 0.01 mm to 0.3 mm. When the thickness of the lower electrode 120 or the upper electrode 150 is less than 0.01 mm, its function as an electrode will fail, and the electrical conductivity may be low. When it exceeds 0.3 mm, the conduction efficiency may be low due to the increase in resistance.

[0057] And the mutually opposing lower substrate 110 and upper substrate 160 may be metal substrates, and their thickness may be 0.1 mm to 1.5 mm. If the thickness of the metal substrate is less than 0.1 mm or exceeds 1.5 mm, the heat dissipation characteristics or thermal conductivity may become excessively high, so the reliability of the thermoelectric element may decrease. Also, when the lower substrate 110 and the upper substrate 160 are metal substrates, insulating layers 170 may be further formed between the lower substrate 110 and the lower electrode 120 and between the upper substrate 160 and the upper electrode 150, respectively. The insulating layer 170 can include a material having a thermal conductivity of 1 to 20 W / mK and can correspond to the first insulating layer 220 and the second insulating layer 270 described later. Also, each insulating layer can be formed of a plurality of layers.

[0058] At this time, the sizes of the lower substrate 110 and the upper substrate 160 can also be formed differently. For example, the volume, thickness, or area of one of the lower substrate 110 and the upper substrate 160 can be formed larger than the volume, thickness, or area of the other one. Accordingly, the heat absorption performance or heat dissipation performance of the thermoelectric element can be enhanced. Preferably, the volume, thickness, or area of the lower substrate 110 can be formed larger than at least one of the volume, thickness, or area of the upper substrate 160. At this time, when the lower substrate 110 is disposed in a high-temperature region due to the Seebeck effect, applied to a heat generation region due to the Peltier effect, or when a sealing member for protecting from the external environment of the thermoelectric module described later is disposed on the lower substrate 110, at least one of the volume, thickness, or area can be made even larger than that of the upper substrate 160. At this time, the area of the lower substrate 110 can be formed in the range of 1.2 to 5 times the area of the upper substrate 160. When the area of the lower substrate 110 is formed less than 1.2 times that of the upper substrate 160, the influence on the improvement of the heat transfer efficiency is not high. When it exceeds 5 times, on the contrary, the heat transfer efficiency is significantly inferior, and it may be difficult to maintain the basic shape of the thermoelectric module.

[0059] Also, a heat dissipation pattern, for example, a concavo-convex pattern, can be formed on at least one surface of the lower substrate 110 and the upper substrate 160. Accordingly, the heat dissipation performance of the thermoelectric element can be enhanced. When the concavo-convex pattern is formed on the surface in contact with the P-type thermoelectric leg 130 or the N-type thermoelectric leg 140, the bonding characteristics between the thermoelectric leg and the substrate can also be improved. The thermoelectric element 100 includes a lower substrate 110, a lower electrode 120, a P-type thermoelectric leg 130, an N-type thermoelectric leg 140, an upper electrode 150, and an upper substrate 160.

[0060] As shown in FIGS. 3 and 4, a sealing member 190 can be further disposed between the lower substrate 110 and the upper substrate 160. The sealing member can be disposed on the sides of the lower electrode 120, the P-type thermoelectric leg 130, the N-type thermoelectric leg 140, and the upper electrode 150 between the lower substrate 110 and the upper substrate 160. Accordingly, the lower electrode 120, the P-type thermoelectric leg 130, the N-type thermoelectric leg 140, and the upper electrode 150 can be sealed from external moisture, heat, contamination, etc. Here, the sealing member 190 includes a sealing case 192 disposed at a predetermined distance from the outermost contours of the plurality of lower electrodes 120, the outermost contours of the plurality of P-type thermoelectric legs 130 and the plurality of N-type thermoelectric legs 140, and the outermost contours of the plurality of upper electrodes 150, a sealing material 194 disposed between the sealing case 192 and the lower substrate 110, and a sealing material 196 disposed between the sealing case 192 and the upper substrate 160. In this way, the sealing case 192 can contact the lower substrate 110 and the upper substrate 160 through the sealing materials 194 and 196. Accordingly, when the sealing case 192 is in direct contact with the lower substrate 110 and the upper substrate 160, heat conduction will occur through the sealing case 192, and as a result, the problem of a reduced temperature difference between the lower substrate 110 and the upper substrate 160 can be prevented. Here, the sealing materials 194 and 196 can include at least one of an epoxy resin and a silicone resin, or a tape with at least one of an epoxy resin and a silicone resin coated on both sides. The sealing materials 194 and 194 serve to airtight the space between the sealing case 192 and the lower substrate 110 and between the sealing case 192 and the upper substrate 160, and can enhance the sealing effect of the lower electrode 120, the P-type thermoelectric leg 130, the N-type thermoelectric leg 140, and the upper electrode 150, and can be mixed with wall materials, finishing layers, waterproof materials, waterproof layers, etc. Here, the sealing material 194 for sealing between the sealing case 192 and the lower substrate 110 is disposed on the upper surface of the lower substrate 110, and the sealing material 196 for sealing between the sealing case 192 and the upper substrate 160 can be disposed on the side surface of the upper substrate 160. For this purpose, the area of the lower substrate 110 may be larger than the area of the upper substrate 160.On the one hand, the sealing case 192 may be formed with guide grooves G for drawing out lead wires 181 and 182 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 in combination with the sealing cover. However, the above description of the sealing member is merely illustrative, and the sealing member can be deformed in various forms. Although not shown, a heat insulating material may further be included so as to surround the sealing member. Alternatively, the sealing member may include a heat insulating component.

[0061] On the one hand, the P-type thermoelectric leg 130 and the N-type thermoelectric leg 140 may have the structures shown in FIG. 1(a) or FIG. 1(b). Referring to FIG. 1(a), the thermoelectric legs 130 and 140 may include thermoelectric material layers 132 and 142, first plating layers 134-1 and 144-1 laminated on one surface of the thermoelectric material layers 132 and 142, and second plating layers 134-2 and 144-2 laminated on the other surface disposed opposite to one surface of the thermoelectric material layers 132 and 142. Alternatively, referring to FIG. 1(b), the thermoelectric legs 130 and 140 may include thermoelectric material layers 132 and 142, first plating layers 134-1 and 144-1 laminated on one surface of the thermoelectric material layers 132 and 142, second plating layers 134-2 and 144-2 laminated on the other surface disposed opposite to one surface of the thermoelectric material layers 132 and 142, first buffer layers 136-1 and 146-1 and second buffer layers 136-2 and 146-2 respectively disposed between the thermoelectric material layers 132 and 142 and the first plating layers 134-1 and 144-1 and between the thermoelectric material layers 132 and 142 and the second plating layers 134-2 and 144-2. Alternatively, the thermoelectric legs 130 and 140 may further include metal layers laminated between the first plating layers 134-1 and 144-1 and the second plating layers 134-2 and 144-2 and the lower substrate 110 and the upper substrate 160 respectively.

[0062] Here, the thermoelectric material layers 132 and 142 can include bismuth (Bi) and tellurium (Te) which are semiconductor materials. The thermoelectric material layers 132 and 142 can have the same material or shape as the aforementioned P-type thermoelectric leg 130 or N-type thermoelectric leg 140. When the thermoelectric material layers 132 and 142 are polycrystalline, the bonding force between the thermoelectric material layers 132 and 142, the first buffer layers 136-1 and 146-1, and the first plating layers 134-1 and 144-1, and the bonding force between the thermoelectric material layers 132 and 142, the second buffer layers 136-2 and 146-2, and the second plating layers 134-2 and 144-2 can be increased. Accordingly, even when the thermoelectric element 100 is applied to an application where vibration occurs, such as a vehicle, etc., the problem that the first plating layers 134-1 and 144-1 and the second plating layers 134-2 and 144-2 are detached from the P-type thermoelectric leg 130 or N-type thermoelectric leg 140 and carbonize can be prevented, and the durability and reliability of the thermoelectric element 100 can be enhanced.

[0063] And the metal layer can be selected from copper (Cu), copper alloy, aluminum (Al), and aluminum alloy, and can have a thickness of 0.1 to 0.5 mm, preferably 0.2 to 0.3 mm.

[0064] Next, the first plating layers 134-1 and 144-1 and the second plating layers 134-2 and 144-2 can each include at least one of Ni, Sn, Ti, Fe, Sb, Cr, and Mo, and can have a thickness of 1 to 20 μm, preferably 1 to 10 μm. The first plating layers 134-1 and 144-1 and the second plating layers 134-2 and 144-2 can prevent the reaction between the Bi or Te which is a semiconductor material in the thermoelectric material layers 132 and 142 and the metal layer, so that the performance degradation of the thermoelectric element can be prevented and the oxidation of the metal layer can be prevented.

[0065] At this time, first buffer layers 136-1 and 146-1 and second buffer layers 136-2 and 146-2 may be disposed between the thermoelectric material layers 132 and 142 and the first plating layers 134-1 and 144-1, and between the thermoelectric material layers 132 and 142 and the second plating layers 134-2 and 144-2. At this time, the first buffer layers 136-1 and 146-1 and the second buffer layers 136-2 and 146-2 can contain Te. For example, the first buffer layers 136-1 and 146-1 and the second buffer layers 136-2 and 146-2 can contain at least one of Ni-Te, Sn-Te, Ti-Te, Fe-Te, Sb-Te, Cr-Te, and Mo-Te. According to an embodiment of the present invention, when the first buffer layers 136-1 and 146-1 and the second buffer layers 136-2 and 146-2 containing Te are disposed between the thermoelectric material layers 132 and 142 and the first plating layers 134-1 and 144-1 and the second plating layers 134-2 and 144-2, diffusion of Te in the thermoelectric material layers 132 and 142 into the first plating layers 134-1 and 144-1 and the second plating layers 134-2 and 144-2 can be prevented. Along with this, it is possible to prevent the problem that the electrical resistance in the thermoelectric material layer increases due to the Bi reach region.

[0066] Although the terms lower substrate 110, lower electrode 120, upper electrode 150, and upper substrate 160 have been used above, this is merely an arbitrary designation of upper and lower for ease of understanding and convenience of explanation, and the positions can also be reversed such that the lower substrate 110 and the lower electrode 120 are disposed above, and the upper electrode 150 and the upper substrate 160 are disposed below.

[0067] FIG. 5 is a top view of a substrate, an insulating layer, and electrodes included in a thermoelectric element according to an embodiment of the present invention. FIG. 6(a) is an exploded perspective view of a thermoelectric module in which a heat sink is disposed on a thermoelectric element according to an embodiment of the present invention. FIG. 6(b) is a perspective view of a thermoelectric module in which a heat sink is disposed on a thermoelectric element according to an embodiment of the present invention. FIGS. 7 and 8 are partial cross-sectional views of a substrate, an insulating layer, and electrodes included in a thermoelectric element according to an embodiment of the present invention. FIGS. 9 and 10 are cross-sectional views of a thermoelectric module according to an embodiment of the present invention. FIG. 11 is an arrangement diagram in which a plurality of thermoelectric elements according to an embodiment of the present invention are connected. For the same content as described in FIGS. 1 to 4, duplicate descriptions are omitted.

[0068] Referring to FIGS. 5 to 10, a thermoelectric module 1000 according to an embodiment of the present invention includes a thermoelectric element 200 and a heat sink 300 disposed on the thermoelectric element 200.

[0069] The thermoelectric element 200 includes a first substrate 210, a first insulating layer 220 disposed on the first substrate 210, a plurality of first electrodes 230 disposed on the first insulating layer 220, a plurality of P-type thermoelectric legs 240 and a plurality of N-type thermoelectric legs 250 disposed on the plurality of first electrodes 230, a plurality of second electrodes 260 disposed on the plurality of P-type thermoelectric legs 240 and the plurality of N-type thermoelectric legs 250, a second insulating layer 270 disposed on the plurality of second electrodes 260, and a second substrate 280 disposed on the second insulating layer 270. Although not shown, a sealing member may be further disposed between the first substrate 210 and the second substrate 280 so as to surround the first insulating layer 220, the plurality of first electrodes 230, the plurality of P-type thermoelectric legs 240 and the plurality of N-type thermoelectric legs 250, the plurality of second electrodes 260, and the second insulating layer 270.

[0070] Here, the first electrode 230, the P-type thermoelectric leg 240, the N-type thermoelectric leg 250, and the second electrode 260 can respectively correspond to the lower electrode 120, the P-type thermoelectric leg 130, the N-type thermoelectric leg 140, and the upper electrode 150 described in FIGS. 1 and 2, and the content described in FIGS. 1 and 2 may be applied identically or similarly.

[0071] Here, at least one of the first substrate 210 and the second substrate 280 can be a metal substrate. For example, at least one of the first substrate 210 and the second substrate 280 can be made of at least one of aluminum, aluminum alloy, copper, and copper alloy. The first substrate 210 and the second substrate 280 can be made of different materials. For example, the substrate that requires more voltage resistance performance among the first substrate 210 and the second substrate 280 can be made of an aluminum substrate, and the substrate that requires more heat conduction performance can be made of a copper substrate.

[0072] Although not shown in the figure, a solder layer is disposed between the plurality of first electrodes 230, the plurality of P-type thermoelectric legs 240, and the plurality of N-type thermoelectric legs 250, so that the plurality of first electrodes 230, the plurality of P-type thermoelectric legs 240, and the plurality of N-type thermoelectric legs 250 can be joined. Then, a solder layer is disposed between the plurality of P-type thermoelectric legs 240, the plurality of N-type thermoelectric legs 250, and the plurality of second electrodes 260, so that the plurality of P-type thermoelectric legs 240, the plurality of N-type thermoelectric legs 250, and the plurality of second electrodes 260 can be joined. And a solder layer is disposed between the second substrate 280 and the heat sink 300, so that the second substrate 280 and the heat sink 300 can be joined.

[0073] In this specification, the voltage resistance performance may mean a characteristic that is maintained without dielectric breakdown for a predetermined period under a predetermined voltage and a predetermined current. For example, when it is maintained without dielectric breakdown for 10 seconds under a voltage of AC 2.5 kV and a current of 1 mA, the voltage resistance can be said to be 2.5 kV.

[0074] On one hand, since a power source is connected to an electrode generally disposed on the low-temperature side of the thermoelectric element 200, higher withstand voltage performance may be required on the low-temperature side than on the high-temperature side. On the other hand, when the thermoelectric element 200 is driven, the high-temperature side of the thermoelectric element 200 may be exposed to a high temperature, for example, about 180° C. or higher, and peeling between the electrode, the insulating layer, and the substrate may become a problem due to the different coefficients of thermal expansion of the electrode, the insulating layer, and the substrate. Along with this, the high-temperature side of the thermoelectric element 200 may be required to have higher thermal shock relaxation performance than the low-temperature side. Along with this, the structure on the high-temperature side and the structure on the low-temperature side can also be made different.

[0075] Hereinafter, the description will focus on the connection of the terminal electrode 400 to the first electrode 230 disposed on the first substrate 210.

[0076] As described above, the first insulating layer 220 is disposed on the first substrate 210, and a plurality of first electrodes 230 are disposed on the first insulating layer 220.

[0077] At this time, the plurality of first electrodes 230 may be arranged to form a plurality of electrode outlines, and the first substrate 210 may have a plurality of substrate outlines corresponding to the plurality of electrode outlines. Here, the electrode outline may mean the end portions of the plurality of first electrodes 230, and the substrate outline may mean the end portions of the first substrate 210. For example, when the plurality of first electrodes 230 are arranged in a square shape, the plurality of first electrodes 230 may have first to fourth electrode outlines E1 to E4, and the first substrate 210 may have first to fourth substrate outlines S1 to S4 corresponding to the first to fourth electrode outlines E1 to E4, respectively.

[0078] According to an embodiment of the present invention, the terminal electrode is an electrode for connecting an electric wire and may be disposed on the same plane as the plurality of first electrodes 230 on the first insulating layer 220. Along with this, the terminal electrode can also be expressed as a configuration included in the plurality of first electrodes 230, that is, one of the plurality of first electrodes 230. Alternatively, the terminal electrode can also be expressed as being arranged to be directly or indirectly connected to at least one of the plurality of first electrodes 230 among the plurality of first electrodes 230.

[0079] The terminal electrodes can be divided into a first terminal electrode 400 and a second terminal electrode 401. Each of the terminal electrodes 400 and 401 can include an extension portion extending from the active region toward any one of the first to fourth substrate outlines S1 to S4 so as to be electrically connected to the first connection unit 410 and the second connection unit 420. Here, the extension portion can be included in the terminal electrodes 400 and 401 and can mean the region where the first connection unit 410 and the second connection unit 420 are arranged. Or, the extension portion can also mean the terminal electrodes 400 and 401 themselves. Accordingly, the extension portion and the terminal electrodes 400 and 401 can be used interchangeably. At this time, depending on the connection form such as series, parallel, or series-parallel between adjacent elements, the extension portions of the first terminal electrode 400 and the second terminal electrode 401 can branch and extend respectively in single or plural numbers. In this specification, the active region can be defined as the region where a plurality of first electrodes and a plurality of second electrodes overlap vertically, that is, the region where a plurality of P-type thermoelectric legs 240 and N-type thermoelectric legs 250 are arranged so as to substantially embody the Peltier effect or the Seebeck effect. The first connection unit 410 and the second connection unit 420 can be arranged on the extension portions of the first terminal electrode 400 and the second terminal electrode 401 respectively. Each connection unit 410 and 420 can be a connector device for electrically connecting the terminal electrodes 400 and 401 to an external terminal. For example, at least one (-) terminal can be connected to the first connection unit 410 on the extension portion of the first terminal electrode 400, and at least one (+) terminal can be connected to the second connection unit 420 on the extension portion of the second terminal electrode 401. However, the number, arrangement form of the extension portions of each terminal electrode 400 and 401 and each connection unit 410 and 420, and the polarity of the external terminal are not limited thereto.

[0080] Each of the first terminal electrode 400 and the second terminal electrode 401 can be electrically connected directly or indirectly to one of the plurality of first electrodes 230 or second electrodes 260. When each of the first terminal electrode 400 and the second terminal electrode 401 is indirectly connected to one of the plurality of first electrodes 230 or second electrodes 260, at least one of the plurality of P-type thermoelectric legs 240 and the plurality of N-type thermoelectric legs 250 can be disposed on each of the first terminal electrode 400 and the second terminal electrode 401. Accordingly, the position of the terminal electrode 400 can affect the insulation resistance of the thermoelectric element 200. The insulation resistance means the electrical resistance exhibited by an insulator when a predetermined voltage is applied. When the thermoelectric element 200 is exposed to a high voltage environment, or when a plurality of thermoelectric elements 200 are connected and driven, etc., a predetermined insulation resistance must be satisfied. For example, the thermoelectric element 200 must satisfy the requirement of having an insulation resistance of 500 MΩ or more when a 500 V dc voltage is applied.

[0081] According to an embodiment of the present invention, an attempt is made to improve the insulation resistance by using the position of the terminal electrode 400.

[0082] According to an embodiment of the present invention, when the terminal electrode 400 is connected to a part of the plurality of first electrodes 230 disposed on the first electrode outer contour E1 or is disposed between the plurality of first electrodes 230 disposed on the first electrode outer contour E1, the distance d1 between the first electrode outer contour E1 and the first substrate outer contour S1 may be longer than the distances d2 to d4 between the second to fourth electrode outer contours E2 to E4 and the second to fourth substrate outer contours S2 to S4. At this time, the terminal electrode 400 can be drawn out to the outside of a sealing member (not shown) disposed so as to surround the first insulating layer 220, the plurality of first electrodes 230, the plurality of P-type thermoelectric legs 240 and the plurality of N-type thermoelectric legs 250, the plurality of second electrodes 260, and the second insulating layer 270 between the first substrate 210 and the second substrate 280.

[0083] Here, the shortest distance A1 between the terminal electrode 400 and the first substrate outer contour S1 can be 12 mm or more, preferably 14 mm or more, more preferably 16 mm or more.

[0084] And the shortest distance B1 between the second substrate outline S2 connected to the first substrate outline S1 and the terminal electrode 400 and the shortest distance B2 between the third substrate outline S3 connected to the first substrate outline S1 and the terminal electrode 401 can each be 12 mm or more, preferably 14 mm or more, more preferably 16 mm or more.

[0085] Or, the shortest distance F1 from the point where the first substrate outline S1 and the second substrate outline S2 are in contact, that is, the vertex between the first substrate outline S1 and the second substrate outline S2 to the terminal electrode 400 and the shortest distance F2 from the point where the first substrate outline S1 and the third substrate outline S3 are in contact, that is, the vertex between the first substrate outline S1 and the third substrate outline S3 to the terminal electrode 401 can each be 12 mm or more, preferably 14 mm or more, more preferably 16 mm or more.

[0086] Thus, by adjusting the distance between the substrate outline and the terminal electrode 400, a thermoelectric element with an insulation resistance of 500 MΩ or more under a DC voltage of 500 V can be obtained.

[0087] More specifically, the ratio of the distance d1 between the first electrode outline E1 and the first substrate outline S1 to the distances A1, B1, F1, A2, B2, F2 between the substrate outline and the terminal electrodes 400, 401 can be 1.2 to 2.5. That is, the shortest distance d1 between the effective region and the first substrate outline S1 can be 1.2 to 2.5 times the shortest distances A1, A2 between the end portions of the terminal electrodes 400, 401 and the first substrate outline S1. Here, the effective region can mean a region where a plurality of first electrodes 230 and a plurality of second electrodes 260 overlap vertically. For example, when the shortest distance A1 between the terminal electrodes 400, 401 and the first substrate outline S1 is 12 mm, the distance d1 between the first electrode outline E1 and the first substrate outline S1 can be 14.5 to 30 mm. If the ratio of the distance d1 between the first electrode outline E1 and the first substrate outline S1 to the distances A1, B1, F1, A2, B2, F2 between the substrate outline and the terminal electrodes 400, 401 is less than 1.2, a spark may occur due to a short circuit between the first connection unit 410 or the second connection unit 420 arranged on the terminal electrodes 400, 401 and the plurality of first electrodes 230 arranged along the first electrode outline E1. On the contrary, when the ratio of the distance d1 between the first electrode outline E1 and the first substrate outline S1 to the distances A1, B1, F1, A2, B2, F2 between the substrate outline and the terminal electrodes 400, 401 exceeds 2.5, the area of the effective region, that is, the region where the thermoelectric legs can be arranged, may be substantially narrowed. Therefore, when the thermoelectric module is a power generation module using the Seebeck effect, the power generation amount can be reduced.

[0088] At this time, each of the first connection unit 410 and the second connection unit 420 can be a connector to which an electric wire is detachably fitted. As described above, a part of the terminal electrode 400, each of the first connection unit 410 and the second connection unit 420 can be arranged outside the sealing member. According to this, wire connection is easy, and the possibility of disconnection between the electrode and the wire can be minimized.

[0089] In addition, each of the first connection unit 410 and the second connection unit 420 can be sealed with a resin containing silicon. According to this, the insulation resistance and breakdown voltage performance of the thermoelectric element can be further enhanced.

[0090] On the other hand, referring to FIGS. 5 and 7, at least one first through hole 700 can be formed to penetrate the first substrate 210 and the first insulating layer 220. At this time, the first through hole 700 can be a fastening hole for the fastening member 900 to penetrate as shown in FIGS. 9 and 10. The fastening member 900 can be connected from the heat sink 300 to the first substrate 210. Although not shown, when the thermoelectric element is a power generation device using the Seebeck effect, the fastening member 900 can be connected from the heat sink 300 to a first fluid flow portion (not shown) disposed below the first substrate 210. As another example, the first substrate 210 and the first fluid flow portion (not shown) can be connected via another fastening member outside the effective region on the first substrate 210. The first fluid flow portion can have a flow path formed so that the first fluid flows, and in some cases, the first fluid flow portion can be omitted so that the first fluid directly flows to the first substrate 210. Specifically, the first fluid can flow adjacent to the first substrate 210, and the second fluid can flow adjacent to the second substrate 280 and the heat sink 300. At this time, the heat sink 300 can be a second fluid flow portion having a flow path formed so that the second fluid flows. At this time, the temperature of the second fluid may be even higher than the temperature of the first fluid. As another example, the temperature of the first fluid may be even higher than the temperature of the second fluid, and in this case, the heat sink 300 can be omitted or connected to the first substrate 210. The absolute value of the temperature difference between the second fluid and the first fluid can be 40 ° C or more, preferably 70 ° C or more, and more preferably 95 ° C to 185 ° C.

[0091] Here, the shortest distance a between the plurality of first electrodes 230 from the end of the first through hole 700 can be 8 mm or more, preferably 8 mm to 12 mm, more preferably 8 mm to 10 mm, and even more preferably 8 mm to 9 mm. At this time, the shortest distance a between the plurality of first electrodes 230 from the end of the first through hole 700 can be 50 times or more, preferably 50 times to 180 times the thickness b of the first insulating layer 220. According to this, even if a spark occurs at the electrode under a high voltage, a sufficient insulation distance can be ensured so as not to affect the substrate, and thus a thermoelectric element having high withstand voltage performance can be obtained. In particular, when the shortest distance a between the plurality of first electrodes 230 from the end of the first through hole 700 is less than 50 times the thickness b of the first insulating layer 220, the heat transfer characteristics deteriorate due to an increase in the thermal resistance of the first insulating layer 220, and accordingly, the power generation amount can decrease. On the other hand, when the shortest distance a between the plurality of first electrodes 230 from the end of the first through hole 700 exceeds 180 times the thickness b of the first insulating layer 220, the thermal resistance of the first insulating layer 220 decreases and the heat transfer characteristics improve, but the area where the thermoelectric legs can be arranged can decrease, and the possibility that the first insulating layer 220 peels off at a high temperature increases.

[0092] On one hand, the ratio between the shortest distance a between the plurality of first electrodes 230 from the end of the first through-hole 700 and the thickness b of the first insulating layer 220 can vary depending on the type of the first insulating layer 220, and the first insulating layer 220 can be formed of one or more layers. For example, the first insulating layer 220 can be a resin layer containing resin and inorganic substances, or can be a layer composed of at least one of layers of inorganic substances alone. The inorganic substances can include at least one of oxides, carbides, and nitrides containing aluminum, titanium, zirconium, boron, zinc, etc. Among these, in the case of aluminum oxide which is an oxide of aluminum, the withstand voltage characteristics can be affected by the content of aluminum oxide. For example, when the shortest distance a between the plurality of first electrodes 230 from the end of the first through-hole 700 is under the same conditions, if the first insulating layer 220 is a resin layer with a relatively high content of aluminum oxide, a withstand voltage with the same performance can be obtained with a thinner thickness compared to the case where the first insulating layer 220 is a resin layer with a relatively low content of aluminum oxide. When the shortest distance a between the plurality of first electrodes 230 from the end of the first through-hole 700 is under the same conditions, if the first insulating layer 220 is a layer of inorganic substances alone containing aluminum oxide, a withstand voltage with the same performance can be obtained with a thinner thickness compared to the case where the first insulating layer 220 is a resin layer.

[0093] At this time, a plurality of first through-holes 700 can be formed in the first substrate 210, and accordingly, a plurality of hole arrangement regions 702 can also be formed. For example, the first substrate 210 can include four first through-holes 700 and four hole arrangement regions 702. Here, the hole arrangement region 702 can be defined as the space formed by the virtual line connecting the surfaces of the electrodes adjacent to the first through-hole 700 and adjacent to each other. The hole arrangement region 702 can be formed in a polygonal shape, preferably in a quadrangular shape. A plurality of first electrodes 230 may not be arranged within the hole arrangement region 702.

[0094] At this time, among the plurality of first electrodes 230, two (230-1, 230-2) adjacent to the hole arrangement region 702 can be arranged such that the length direction is toward the second direction X, and the other two (230-3, 230-4) adjacent to the hole arrangement region 702 can also be arranged such that the length direction is toward the second direction X. Accordingly, a multiple of two among the plurality of first electrodes 230 can be arranged to face the second direction X. More specifically, at least 16 (230-1,..., 230-4) among the plurality of first electrodes 230 can be arranged to face the second direction X. Also, the remaining first electrodes 230 can be arranged such that the length direction is toward the first direction Y.

[0095] Also, among the 2n (n is an integer of 1 or more) first electrodes 230-2n adjacent to at least one of the four first electrodes 230-1,..., 230-4 arranged to face the second direction X adjacent to any one of the hole arrangement regions 702, the length direction can also be arranged to face the second direction X. Here, the positions where the 2n first electrodes 230-2n are arranged can be variously deformed according to the arrangement structure of the plurality of second electrodes 260.

[0096] Also, here, a plurality of electrodes can be arranged between the hole arrangement region 702 and the 2n first electrodes 230-2n. However, the 2n first electrodes 230-2n can be arranged to face the second direction X by overlapping at least a part with the virtual space formed by the extension lines extending from each virtual line defining the hole arrangement region 702.

[0097] At this time, the extension part of the terminal electrode can also be arranged to overlap at least a part with the virtual space formed by the extension lines extending from each virtual line defining the hole arrangement region 702.

[0098] In FIG. 5, it is illustrated that the 2n first electrodes 230-2n are arranged in the second direction X, but it is not limited thereto, and the 2n second electrodes can also be arranged in the first direction Y.

[0099] Two rows arranged in the second direction X so as to face each other in the end region may be included in the first electrode 230 disposed on the first substrate 210 or in the second electrode 260 disposed on the second substrate 280.

[0100] On the other hand, the area of the hole arrangement region 702 can be 4 times or more, preferably 6 times or more, and more preferably 8 times or more the area of one first electrode 230. When the area of the hole arrangement region 702 is less than 4 times the area of one first electrode 230, current may move to the first substrate 210 through the first through hole 700 under a high voltage of AC 1 kV or more, causing electrical breakdown of the thermoelectric module. Therefore, in application fields under high voltage, it is important to ensure a sufficient insulation distance to prevent electrical breakdown of the thermoelectric module. When the area of the hole arrangement region 702 is 8 times or more the area of one first electrode 230, electrical breakdown does not occur even under a high voltage of AC 2.5 kV or more.

[0101] Also, among the plurality of first electrodes 230, the electrodes arranged to be closest to the first end portion (not shown) of the first substrate 210 can all be arranged periodically, and the path between the start point and the end point of an imaginary line connecting the electrode surfaces arranged to be closest to the first end portion of the first substrate 210 can be arranged to be a straight line without a bent region. That is, in all the first electrodes 230 closest to the first end portion of the first substrate 210, among the four electrode surfaces of each first electrode 230, the electrode surface closest to the first end portion of the first substrate 210 can be arranged at the same interval as the first end portion of the first substrate 210 along one direction without a removed region. For example, when the path between the start point and the end point of an imaginary line connecting the electrode surfaces arranged to be closest to the first end portion of the first substrate 210 is a straight line, it can be meant that all the electrodes in the first row (not shown) among the plurality of first electrodes 230 are arranged periodically. According to this, when arranging the plurality of first electrodes 230 on the first substrate 210, the complexity of the process can be reduced, and the arrangement structure of the second electrode 260 arranged on the second substrate 280 and the thermoelectric legs arranged between the first electrode 230 and the second electrode 260 can be simplified. Also, since the shortest distance between the end portion of the first substrate 210 and the first electrode 230 arranged to be closest to the end portion of the first substrate 210 is kept constant, the first electrode 230 arranged to be closest to the end portion of the first substrate 210 can have uniform electrical characteristics.

[0102] If the path between the starting point and the ending point of an imaginary line connecting the electrode surfaces arranged so as to be most adjacent to the first end of the first substrate 210 includes a bent region, it may mean that some of the electrodes in the first column among the plurality of first electrodes 230 are removed, or a sunken region is included, and the periodicity of the arrangement is lost. The electrode surface arranged so as to be most adjacent to the first end of the first substrate 210 in the bent region may be the electrode surface arranged in the second column (not shown) which is the next column to the first column. Here, the second column is a column arranged further away from the first end of the first substrate 210 than the first column, and may not be the outermost column. Although the first electrode 230 can be arranged to include a bent region, according to this, as described above, in the application field under high voltage, a sufficient insulation distance cannot be ensured, so electrical breakdown of the thermoelectric module may occur, or the effective area of the first electrode portion may decrease, and as a result, the efficiency of the thermoelectric module can be reduced.

[0103] Similarly, among the plurality of first electrodes 230, the electrode (the Nth column) closest to the second end portion (not shown) facing the first end portion of the first substrate 210, the electrode (the first row) closest to the third end portion (not shown) between the first end portion and the second end portion of the first substrate 210, and the electrode (the Mth row) closest to the fourth end portion (not shown) facing the third end portion of the first substrate 210 can all be arranged such that the path between the starting point and the ending point of the virtual line connecting the electrode surfaces closest to each end portion of the first substrate 210 is a straight line without a bending region. However, depending on the design such as the arrangement of the terminal electrodes, only one of the outermost columns or outermost rows, for example, one of the first column, the Nth column, the first row, and the Mth row, may have an exceptional path. For example, the terminal electrode may be connected to a plurality of first electrodes 230 arranged in one of the outermost columns or outermost rows, i.e., the first column, the Nth column, the first row, and the Mth row, or may be arranged between a plurality of first electrodes 230 arranged in one of the first column, the Nth column, the first row, and the Mth row, or may extend from a first electrode 230 arranged in one of the first column, the Nth column, the first row, and the Mth row. Accordingly, except for one column or row in which the terminal electrode is arranged among the outermost columns and outermost rows, the remaining columns or rows can be arranged to have a certain interval from the corresponding end portions of the first substrate 210.

[0104] On the other hand, referring to FIG. 8, the first insulating layer 220 can also be further arranged on at least a part of the wall surface of the first through-hole 700 formed in the first substrate 210. According to this, the withstand voltage performance of the thermoelectric element can be further improved.

[0105] On the other hand, referring to FIGS. 6(a), 6(b), 9, and 10, at least one second through-hole 800 is formed to penetrate the heat sink 300, the second substrate 280, and the second insulating layer 270, and at least one fastening member 900 can pass through at least one second through-hole 800 formed in the heat sink 300, the second substrate 280, and the second insulating layer 270 and at least one first through-hole 700 formed in the first substrate 210 and the first insulating layer 220.

[0106] At this time, as shown in FIGS. 10(a) to 10(c), at least one insulating insertion member 910 is further disposed on at least a part of the upper surface of the second substrate 280 adjacent to the second through hole 800 or the outer peripheral surface of the fastening member 900, so that an insulating distance can be further ensured, and thus the withstand voltage performance of the thermoelectric element can be further improved. Preferably, it may be effective for the withstand voltage performance that the shortest distance between the second electrodes from the end of the second through hole 800 also satisfies 8 mm or more. Referring to FIGS. 10(b) and 10(c), the insulating insertion member 910 can be disposed between the second through hole 800 and the fastening member 900. Referring to FIG. 10(b), when the insulating insertion member 910 is disposed only in the second through hole 800, the diameter of the second through hole 800 may be larger than the diameter of the first through hole 700 by the width of the insulating insertion member 910. At this time, the shortest distance between the second electrodes from the end of the second through hole 800 may be relatively reduced, but due to the arrangement of the insulating insertion member 910 in the second through hole 800 by the reduced width, there is no reduction in the insulating effect, and as a result, there is no influence on the withstand voltage performance. At this time, the diameter of the second through hole can be 1.1 times to 2.0 times the diameter of the first through hole. Although not shown, a solder layer may be disposed between at least one of the plurality of first electrodes 230, the plurality of P-type thermoelectric legs 240, and the plurality of N-type thermoelectric legs 250, between the plurality of P-type thermoelectric legs 240, the plurality of N-type thermoelectric legs 250, and the plurality of second electrodes 260, and between the second substrate 280 and the heat sink 300.

[0107] On the other hand, according to an embodiment of the present invention, the first through hole 700 can be formed to correspond to the region where the terminal electrode 400 is disposed. That is, from the outer contour S2 of the second substrate Between the ends of the first through hole 700 The shortest distance C1 can be within ±10% of the shortest distance B1 between the terminal electrodes 400 from the outer contour S2 of the second substrate. That is, from the outer contour S2 of the second substrate Between the ends of the first through hole 700 The shortest distance C1 can be 0.9 times to 1.1 times the shortest distance B1 between the terminal electrodes 400 from the outer contour S2 of the second substrate. Similarly, from the outer contour S3 of the third substrate Between the ends of the first through hole 700The shortest distance C2 can be within ±10% of the shortest distance B2 between the outer contour S3 of the third substrate and the terminal electrode 400. That is, from the outer contour S3 of the third substrate Between the ends of the first through hole 700 The shortest distance C2 can be 0.9 to 1.1 times the shortest distance B2 between the outer contour S3 of the third substrate and the terminal electrode 400. As described above, in order to increase the insulation resistance, the distances between the terminal electrode 400 and the outer contours S2 and S3 of the second substrate must satisfy a predetermined distance or more. When the first through hole 700 is formed corresponding to the position of the terminal electrode 400, not only can insulation be ensured, but stable fastening between the thermoelectric element 200 and the heat sink 300 is possible, and the arrangement of the plurality of first electrodes 230 is easy.

[0108] At this time, each of the first connection unit 410 and the second connection unit 420 can be connected to two terminals having the same polarity. That is, two (-) terminals branched by being connected to one of the plurality of first electrodes 230 can be connected to the first connection unit 410, and two (+) terminals branched by being connected to another one of the plurality of first electrodes 230 can be connected to the second connection unit 420. According to this, as shown in FIG. 11, a plurality of thermoelectric elements can be connected to each other in a series-parallel manner, and high power conversion efficiency can be obtained with a minimum area.

[0109] On the other hand, as described above, according to an embodiment of the present invention, the first insulating layer 220 can be a resin layer containing resin and an inorganic substance or a layer composed of at least one of layers of inorganic substances alone. Here, the inorganic substance can contain aluminum or aluminum oxide.

[0110] For example, the first insulating layer 220 can include a composite containing silicon and aluminum. Here, the composite can be at least one of oxides, carbides, and nitrides containing silicon and aluminum. For example, the composite can include at least one of Al-Si bonds, Al-O-Si bonds, Si-O bonds, Al-Si-O bonds, and Al-O bonds. Thus, a composite containing at least one of Al-Si bonds, Al-O-Si bonds, Si-O bonds, Al-Si-O bonds, and Al-O bonds has excellent insulating performance, and accordingly, high breakdown voltage performance can be obtained. Or the composite can be an oxide, carbide, or nitride further containing titanium, zirconium, boron, zinc, etc. together with silicon and aluminum. For this purpose, the composite is obtained through a process of mixing at least one of an inorganic binder and an organic-inorganic hybrid binder with aluminum and then performing heat treatment. The inorganic binder can include, for example, silica (SiO2), metal alkoxide, boron oxide (B2O3), and zinc oxide (ZnO x ). The inorganic binder is inorganic particles and can play a binding role by sol-gelating when it comes into contact with water. At this time, at least one of silica (SiO2), metal alkoxide, and boron oxide (B2O3) plays a role in enhancing the adhesion between aluminums or the adhesion with the first substrate 210, and zinc oxide (ZnO x ) can play a role in enhancing the strength and thermal conductivity of the first insulating layer 220.

[0111] Here, the composite can be contained in an amount of 80 wt% or more, preferably 85 wt% or more, more preferably 90 wt% or more of the entire first insulating layer 220.

[0112] The first insulating layer 220 can be formed on the first substrate 210 through a wet process. Here, the wet process can be a spray coating process, a dip coating process, a screen printing process, etc. According to this, it is easy to control the thickness of the first insulating layer 220, and it is possible to apply composites with various compositions.

[0113] Alternatively, the first insulating layer 220 may be composed of a resin layer containing at least one of an epoxy resin composition containing an epoxy resin and an inorganic substance and a silicone resin composition containing PDMS (polydimethylsiloxane).

[0114] Here, the inorganic substance may be contained in the resin layer at 60 to 90 wt%. If the inorganic substance is contained less than 60 wt%, the heat conduction effect may be low. If the inorganic substance is contained exceeding 90 wt%, it is difficult for the inorganic substance to be uniformly dispersed in the resin, and the resin layer is liable to break.

[0115] And the epoxy resin can contain an epoxy compound and a curing agent. At this time, it may be contained at a volume ratio of the curing agent of 1 to 10 with respect to 10 volume ratios of the epoxy compound. Here, the epoxy compound can contain at least one of a crystalline epoxy compound, a non-crystalline epoxy compound, and a silicone epoxy compound. The inorganic substance can contain aluminum oxide, and can further contain at least one of boron nitride and aluminum nitride.

[0116] At this time, the particle size D50 of the boron nitride aggregate may be 250 to 350 μm, and the particle size D50 of the aluminum oxide may be 10 to 30 μm. When the particle size D50 of the boron nitride aggregate and the particle size D50 of the aluminum oxide satisfy such a numerical range, the boron nitride aggregate and the aluminum oxide can be uniformly dispersed in the resin layer, and accordingly, the resin layer can have a uniform heat conduction effect and adhesion performance as a whole.

[0117] Alternatively, the first insulating layer 220 may also include all of a composite containing silicon and aluminum and a resin layer containing at least one of an epoxy resin composition containing an epoxy resin and an inorganic substance and a silicone resin composition containing PDMS (polydimethylsiloxane). For example, the composite containing silicon and aluminum and the resin layer may be sequentially laminated or alternately laminated.

[0118] Alternatively, the first insulating layer 220 may be an aluminum oxide layer. When the first substrate 210 is an aluminum substrate, the first insulating layer 220 can be formed by a method of surface-oxidizing the first substrate 210, but is not limited thereto.

[0119] Table 1 and FIG. 12 show the results of measuring the resistance according to the distance between the substrate outline and the wire connection part.

[0120]

Table 1

[0121] To measure the resistance, after connecting the (+) terminal and the (-) terminal of the wire connection part, this was connected to the (+) terminal of an insulation resistance meter, and after connecting the (-) terminal of the insulation resistance meter to the substrate, a 500 V dc voltage was applied. The resistance according to the distance A1 between the wire connection part and the first substrate outline was measured.

[0122] As a result, it can be seen that when the distance A1 between the wire connection part and the first substrate outline is 12 mm or more, a resistance of 500 MΩ or more can be obtained under a 500 V dc voltage.

[0123] Table 2 and FIG. 13 show the results of measuring the breakdown voltage according to the distance between the end of the hole and the electrode, and Table 3 and FIG. 14 show the results of measuring the thermal resistance according to the distance between the end of the hole and the electrode with respect to the thickness of the insulating layer.

[0124]

Table 2

[0125] Here, the breakdown voltage performance is measured for a first example that does not contain aluminum or aluminum oxide and a second example that contains aluminum or aluminum oxide. After disposing an insulating layer on the substrate, one terminal is connected to the substrate, and different terminals are connected to nine points of the insulating layer, and the voltage that can be maintained without dielectric breakdown for 10 seconds under a current of 1 mA is tested.

[0126] Referring to Table 2 and FIG. 13, it can be seen that in the case where the shortest distance a between the first electrodes from the end of the first through hole 700 is 8 mm or more, both the first embodiment and the second embodiment can obtain a withstand voltage characteristic of 1 kV or more.

[0127] On the other hand, referring to FIG. 14, the lower the shortest distance a between the plurality of first electrodes 230 from the end of the first through hole 700 with respect to the thickness b of the first insulating layer 220, the higher the thermal resistance, and accordingly, the lower the heat transfer characteristic. It can be seen that the higher the shortest distance a between the plurality of first electrodes 230 from the end of the first through hole 700 with respect to the thickness b of the first insulating layer 220, the lower the thermal resistance, and accordingly, the better the heat transfer characteristic.

[0128] Accordingly, when the shortest distance a between the plurality of first electrodes 230 from the end of the first through hole 700 is 50 times or more, preferably 50 to 180 times or more the thickness b of the first insulating layer 220, the withstand voltage characteristic and the heat transfer characteristic can be satisfied simultaneously.

[0129] The thermoelectric element according to the embodiment of the present invention can be applied to power generation devices, cooling devices, heating devices, and the like.

[0130] As described above, the preferred embodiments of the present invention have been described with reference to the preferred embodiments. However, those skilled in the art in the relevant technical field can understand that the present invention can be variously modified and changed without departing from the spirit and scope of the present invention described in the following claims.

Claims

1. a first metal substrate; a first insulating layer disposed on the first metal substrate; a first electrode portion disposed on the first insulating layer and including a plurality of first electrodes; a semiconductor structure disposed on the first electrode portion; a second electrode portion disposed on the semiconductor structure and including a plurality of second electrodes; a second insulating layer disposed on the second electrode portion; a second metal substrate disposed on the second insulating layer, and the first metal substrate includes a first outer contour, a second outer contour, a third outer contour, and a fourth outer contour that define the shape of the first metal substrate, the first outer contour and the fourth outer contour face each other, the second outer contour and the third outer contour face each other between the first outer contour and the fourth outer contour, the first electrode portion includes a first region that overlaps perpendicularly with the plurality of second electrodes, at least one of the plurality of first electrodes includes an extension portion that extends from the first region toward the first outer contour, a first through hole penetrates through the first metal substrate and the first insulating layer, the first through hole is formed between the plurality of first electrodes inside the first region, the shortest distance from the second outer contour to the end of the first through hole is 90% to 110% of the shortest distance from the second outer contour to the extension portion, a first hole arrangement region is formed inside the first region, the first hole arrangement region is a space formed by a virtual line connecting the surfaces adjacent to the first through hole among the plurality of first electrodes surrounding the periphery of the first through hole, the extension portion is arranged to at least partially overlap with a virtual space formed by a virtual extension line extending from the virtual line defining the first hole arrangement region, a thermoelectric element.

2. the shortest distance between the first region and the first outer contour is The thermoelectric element according to claim 1, wherein the shortest distance between the extension part and the second outer contour is 1.2 to 2.5 times.

3. The thermoelectric element according to claim 1, wherein the shortest distance between the first electrodes that are most adjacent to each other among the plurality of first electrodes from the end of the first through hole is 50 to 180 times the thickness of the first insulating layer.

4. The thermoelectric element according to claim 3, wherein the shortest distance between the first electrodes that are most adjacent to each other among the plurality of first electrodes from the end of the first through hole is 8 mm to 12 mm.

5. The thermoelectric element according to claim 1, wherein the second through hole formed at a position corresponding to the first through hole penetrates through the second insulating layer and the second metal substrate, and further includes a fastening member disposed between the first through hole and the second through hole.

6. The thermoelectric element according to claim 5, further including a heat sink disposed on the second metal substrate.

7. The thermoelectric element according to claim 6, further including an insulating insertion member disposed on at least a part of the upper surface of the second metal substrate adjacent to the second through hole or the outer peripheral surface of the fastening member.

8. The thermoelectric element according to claim 7, wherein a part of the insulating insertion member is disposed between the second through hole and the fastening member.

9. The thermoelectric element according to claim 8, wherein the diameter of the second through hole is 1.1 to 2.0 times the diameter of the first through hole.

10. The thermoelectric element according to claim 5, wherein at least one of the first insulating layer and the second insulating layer contains a resin and an inorganic substance.

11. The thermoelectric element according to claim 10, wherein the inorganic substance contains aluminum or aluminum oxide.

12. The extension part includes a plurality of The plurality of extension parts include a first terminal electrode and a second terminal electrode. A first connection unit is disposed on the first terminal electrode, and a second connection unit is disposed on the second terminal electrode. The thermoelectric element according to claim 1.

13. Each of the first connection unit and the second connection unit is a connector connected to an electric wire. The thermoelectric element according to claim 12.

14. A first fluid flow part through which a first fluid flows, A second fluid flow part through which a second fluid that is at a higher temperature than the first fluid flows, A thermoelectric element disposed between the first fluid flow part and the second fluid flow part, and The thermoelectric element includes A first metal substrate, A first insulating layer disposed on the first metal substrate, A first electrode part disposed on the first insulating layer and including a plurality of first electrodes, A semiconductor structure disposed on the first electrode part, A second electrode part disposed on the semiconductor structure and including a plurality of second electrodes, A second insulating layer disposed on the second electrode part, A second metal substrate disposed on the second insulating layer, and The first metal substrate includes a first outer contour, a second outer contour, a third outer contour, and a fourth outer contour that define the shape of the first metal substrate. The first outer contour and the fourth outer contour face each other. The second outer contour and the third outer contour face each other between the first outer contour and the fourth outer contour. The first electrode part includes a first region that vertically overlaps with the plurality of second electrodes. At least one of the plurality of first electrodes includes an extension part that extends from the first region toward the first outer contour. A first through hole penetrates through the first metal substrate and the first insulating layer. The first through hole is formed between the plurality of first electrodes inside the first region. The shortest distance from the second outer contour to the end of the first through hole is 90% to 110% of the shortest distance from the second outer contour to the extension part. A first hole arrangement region is formed inside the first region. The first hole arrangement region is a space formed by a virtual line connecting the surfaces adjacent to the first through hole among the plurality of first electrodes surrounding the periphery of the first through hole. The extension part is arranged so as to at least partially overlap with a virtual space formed by an extension line extending from the virtual line defining the first hole arrangement region, a power generation device.

15. The shortest distance between the first electrodes closest to the end of the first through hole among the plurality of first electrodes is 8 mm to 12 mm, the power generation device according to claim 14.

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