Patent Description:
A thermoelectric effect is a phenomenon caused due to movements of electrons and holes in a material and means direct energy conversion between heat and electricity.

A thermoelectric element is a generic term for a device which uses a thermoelectric effect and has a structure in which a P-type thermoelectric material and an N-type thermoelectric material are disposed between metal electrodes and bonded to form a pair of PN junctions.

The thermoelectric element may be classified into an element using a temperature variation in electrical resistance, an element using the Seebeck effect in which an electromotive force is generated due to a temperature difference, an element using the Peltier effect which is a phenomenon in which heat absorption or heat radiation occurs due to a current and the like. <CIT> provides an example of a thermoelectric device.

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

Recently, there is a need to generate electricity using thermoelectric elements and waste heat generated from engines of vehicles, ships, and the like. In this case, a structure for improving power generation performance is required.

The present invention is directed to providing a heat conversion apparatus which generates power using waste heat.

The invention concerns a power generation apparatus which generates power using heat according to claim <NUM>. One aspect provides a heat conversion apparatus including a duct through which a cooling fluid passes, a first thermoelectric module disposed on a first surface of the duct, a second thermoelectric module disposed on a second surface which is disposed parallel to the first surface of the duct, and a gas guide member disposed on a third surface disposed between the first surface and the second surface of the duct to be spaced apart from the third surface, wherein the gas guide member includes one end in contact with the first thermoelectric module, the other end in contact with the second thermoelectric module, and an extension part connecting the one end to the other end, and wherein the gas guide member has a shape in which a distance from the third surface is increased toward a center between the one end and the other end.

The first thermoelectric module and the second thermoelectric module may include thermoelectric elements disposed on the first surface and the second surface, heat radiation substrates disposed on the thermoelectric elements, and heat sinks disposed on the heat radiation substrates; and each of the thermoelectric elements may include a plurality of first electrodes, a plurality of second electrodes, and a plurality of P-type thermoelectric legs and a plurality of N-type thermoelectric legs which are disposed between the plurality of first electrodes and the plurality of second electrodes.

Aluminum substrates may further be included between each of the first and second surfaces and the thermoelectric elements, and the aluminum substrates may be bonded to the first surface and the second surface using thermal interface materials (TIMs).

The one end of the gas guide member may be connected to at least one heat sink of the first thermoelectric module, and the other end of the gas guide member may be connected to at least one heat sink of the second thermoelectric module; a central portion of the extension part may have a predetermined angle; and the predetermined angle of a central portion may be smaller than an angle between the one end and the extension.

An air gap may be formed between the gas guide member and the third surface.

An insulating member may be disposed between the gas guide member and the third surface.

The first thermoelectric module and the second thermoelectric module may be engaged with the duct using a screw.

A heat dissipation fin may be disposed on an inner wall of the duct.

In accordance with embodiments of the present invention, a heat conversion apparatus with excellent power generation performance can be provided. In particular, in accordance with the embodiments of the present invention, it is possible to provide a heat conversion apparatus which is easily assembled and has excellent power generation performance by reducing the number of parts being used and an occupying volume. In addition, in accordance with the embodiments of the present invention, a heat conversion apparatus with improved heat transfer efficiency to thermoelectric elements can be provided. Further, in accordance with the embodiments of the present invention, a power generation capacity can be controlled by adjusting the number of unit thermoelectric modules and the number of ducts.

Also, terms including ordinal numbers such as first, second, and the like used herein may be used to describe various components, but the various components are not limited by these terms. The terms are used only for the purpose of distinguishing one component from another component. For example, a second component may be referred to as a first component, and similarly, the first component may also be referred to as the second component. The term "and/or" includes a combination of a plurality of related listed items and any one item of the plurality of related listed items.

When a component is referred to as being "connected," or "coupled" to another component, it may be directly connected or coupled to another component, but it should be understood that still another component may exist between the component and another component. On the contrary, when a component is referred to as being "directly connected," or "directly coupled" to another component, it should be understood that still another component may not be present between the component and another component.

The terms used herein are employed to describe only specific embodiments. Unless the context clearly dictates otherwise, the singular form includes the plural form. It should be understood that the terms "comprise," "include," and "have" specify the presence of stated herein features, numbers, steps, operations, components, elements, or combinations thereof, but do not preclude the presence or possibility of adding one or more other features, numbers, steps, operations, components, elements, or combinations thereof.

Unless otherwise defined, all terms including technical or scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. General terms that are defined in a dictionary should be construed as having meanings that are consistent in the context of the relevant art and are not to be interpreted as having an idealistic or excessively formalistic meaning unless clearly defined in the present application.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, the same reference numerals are given to the same or corresponding components regardless of drawing symbols, and a duplicate description thereof will be omitted.

<FIG> is a perspective view illustrating a heat conversion apparatus according to one embodiment of the present invention, <FIG> is a partially enlarged view illustrating the heat conversion apparatus according to one embodiment of the present invention, <FIG> is a cross-sectional view taken along line X-X' of <FIG>, and <FIG> is an exploded view illustrating a unit module of <FIG>. <FIG> is a diagram for describing a structure in which a thermoelectric module is engaged with a duct, <FIG> is a cross-sectional view illustrating a thermoelectric element included in the thermoelectric module according to one embodiment of the present invention, and <FIG> is a perspective view illustrating the thermoelectric element included in the thermoelectric module according to one embodiment of the present invention.

Referring to <FIG>, a heat conversion apparatus <NUM> includes a plurality of ducts <NUM>, a plurality of first thermoelectric modules <NUM>, a plurality of second thermoelectric modules <NUM>, and a plurality of gas guide members <NUM>. The heat conversion apparatus <NUM> according to the embodiment of the present invention may produce power using a difference in temperature between a cooling fluid flowing through the plurality of ducts <NUM> and a high-temperature gas passing through separation spaces between the plurality of ducts <NUM>, that is, a difference in temperature between heat absorption surfaces and heat radiation surfaces of the plurality of first thermoelectric modules <NUM> and the plurality of second thermoelectric modules <NUM>.

The plurality of ducts <NUM> allow a cooling fluid to pass therethrough and are disposed to be spaced apart from each other at predetermined intervals. For example, the cooling fluid introduced into the plurality of ducts <NUM> may be water, and the cooling fluid may be one of various types of fluids having cooling performance. A temperature of the cooling fluid introduced into the plurality of ducts <NUM> may be less than <NUM>, preferably less than <NUM>, and more preferably less than <NUM>, A temperature of a cooling fluid, which passes through the plurality of ducts <NUM> and then is discharged, may be higher than that of the cooling fluid introduced into the plurality of ducts <NUM>. Each of the ducts <NUM> includes a first surface <NUM>, a second surface <NUM> opposite to the first surface <NUM> and disposed parallel to the first surface <NUM>, a third surface <NUM> disposed between the first surface <NUM> and the second surface <NUM>, and a fourth surface <NUM> disposed opposite to the third surface <NUM> between the first surface <NUM> and the second surface <NUM>. The cooling fluid passes through an interior of each duct formed of the first surface <NUM>, a second surface <NUM>, a third surface <NUM>, and a fourth surface <NUM>. The cooling fluid is introduced into cooling fluid inlets of the plurality of ducts <NUM> and discharged through cooling fluid outlets thereof. In order to support the plurality of ducts <NUM> and allow the cooling fluid to be easily introduced and discharged, an inlet support member <NUM> and an outlet support member <NUM> may be further disposed at the cooling fluid inlets and the cooling fluid outlets of the plurality of ducts <NUM>. Each of the inlet support member <NUM> and the outlet support member <NUM> has a plate shape in which a plurality of openings are formed. A plurality of openings <NUM> formed in the inlet support member <NUM> are formed to correspond to sizes, shapes, and positions of the cooling fluid inlets of the plurality of ducts <NUM>. The plurality of openings formed in the outlet support member <NUM> are formed to correspond to sizes, shapes, and positions of the cooling fluid outlets of the plurality of ducts <NUM>.

Heat dissipation fins <NUM> may be disposed on an inner wall of each duct <NUM>. Shapes and the number of the heat dissipation fins <NUM> and an area of the heat dissipation fins <NUM> occupying the inner wall of each duct <NUM> may be variously changed according to a temperature of the cooling fluid, a temperature of waste heat, and a required power generation capacity. For example, an area of the heat dissipation fins <NUM> occupying the inner wall of each duct <NUM> may range from <NUM>% to <NUM>% of a cross-sectional area of each duct <NUM>. Thus, it is possible to obtain high thermoelectric conversion efficiency without hindering a flow of the cooling fluid.

In addition, the interior of each duct <NUM> may be divided into a plurality of regions. When the interior of each duct <NUM> is divided into a plurality of regions, even though a flow rate of the cooling fluid is not sufficient to fill the interior of each duct <NUM>, the cooling fluid may be uniformly distributed in each duct <NUM> so that it is possible to obtain uniform thermoelectric conversion efficiency with respect to the entire surface of each duct <NUM>.

Meanwhile, the plurality of first thermoelectric modules <NUM> are disposed on a first surface <NUM> which is included in the first surface <NUM> of each duct <NUM> and disposed toward the outside of each duct <NUM>, and the plurality of second thermoelectric modules <NUM> are disposed to be symmetrical to the plurality of first thermoelectric modules <NUM> on a second surface <NUM> which is included in the second surface <NUM> of each duct <NUM> and disposed toward the outside of each duct <NUM>.

In this case, the first thermoelectric module <NUM> and the second thermoelectric module <NUM> disposed to be symmetrical to the first thermoelectric module <NUM> may be referred to as a pair of thermoelectric modules or a unit thermoelectric module.

A plurality of pairs of thermoelectric modules, that is, a plurality of unit thermoelectric modules, may be disposed on each duct <NUM>. For example, when m pairs of thermoelectric modules are disposed on each duct <NUM> and the heat conversion apparatus <NUM> includes n ducts <NUM>, the heat conversion apparatus <NUM> may include m*n pairs of thermoelectric modules, that is, <NUM>*m*n thermoelectric modules. In this case, the number of unit thermoelectric modules and the number of ducts may be adjusted according to a required amount of power generation.

In this case, at least some of the plurality of first thermoelectric modules <NUM> connected to each duct <NUM> may be electrically connected to each other using a bus bar <NUM>, and at least some of the plurality of second thermoelectric modules <NUM> connected to each duct <NUM> may be electrically connected to each other using another bus bar (not shown). For example, the bus bar <NUM> may be disposed at an outlet through which a high-temperature gas passing through the separation spaces between the plurality of ducts <NUM> is discharged, that is, disposed on the fourth surface <NUM> of each duct <NUM>, and may be connected to an external terminal. Thus, without arranging a printed circuit board (PCB) for the plurality of first thermoelectric modules <NUM> and the plurality of second thermoelectric modules <NUM>, power may be supplied to the plurality of first thermoelectric modules <NUM> and the plurality of second thermoelectric modules <NUM> so that it is easy to design and assemble the heat conversion apparatus.

Referring to <FIG>, the first thermoelectric module <NUM> and the second thermoelectric module <NUM> may be engaged with the duct <NUM> using screws S. Thus, the plurality of first thermoelectric modules <NUM> and the plurality of second thermoelectric modules <NUM> may be stably coupled to surfaces of the ducts <NUM>.

Referring to <FIG> again, the first thermoelectric module <NUM> and the second thermoelectric module <NUM> include thermoelectric elements <NUM> and <NUM> disposed on the first surface <NUM> and the second surface <NUM>, heat radiation substrates <NUM> and <NUM> disposed on the thermoelectric elements <NUM> and <NUM>, and heat sinks <NUM> and <NUM> disposed on the heat radiation substrates <NUM> and <NUM>. As described above, the duct <NUM> in which a cooling fluid flows is disposed on one of two surfaces of each of the thermoelectric elements <NUM> and <NUM>, and the heat radiation substrates <NUM> and <NUM> and the heat sinks <NUM> and <NUM> are disposed on the other surface, and, when a high-temperature gas passes through the heat radiation substrates <NUM> and <NUM> and the heat sinks <NUM> and <NUM>, a difference in temperature between the heat absorption surface and the heat radiation surface of each of the thermoelectric elements <NUM> and <NUM> may be increased so that thermoelectric conversion efficiency may be increased.

In this case, aluminum substrates <NUM> and <NUM> may be further disposed between the first surface <NUM>, the second surface <NUM>, and thermoelectric elements <NUM> and <NUM> and may be bonded to the first surface <NUM> and the second surface <NUM> using thermal interface materials (TIMs) <NUM> and <NUM>. Since the aluminum substrates <NUM> and <NUM> have excellent heat transfer performance, heat transfer between one of two surfaces of each of the thermoelectric elements <NUM> and <NUM> and the duct <NUM> in which the cooling fluid flows is easy. In addition, when the aluminum substrates <NUM> and <NUM> and the duct <NUM> through which the cooling fluid flows are bonded using the TIMs <NUM> and <NUM>, heat transfer between the aluminum substrates <NUM> and <NUM> and the duct <NUM> through which the cooling fluid flows may not be hindered.

In this case, a structure of each of the thermoelectric elements <NUM> and <NUM> may have a structure of a thermoelectric element <NUM> illustrated in <FIG> and <FIG>. Referring to <FIG> and <FIG>, the thermoelectric element <NUM> includes a lower substrate <NUM>, a lower electrode <NUM>, a P-type thermoelectric leg <NUM>, an N-type thermoelectric leg <NUM>, an upper electrode <NUM>, and an upper substrate <NUM>.

The lower electrode <NUM> is disposed between the lower substrate <NUM> and lower bottom surfaces of the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM>, and the upper electrode <NUM> is disposed between the upper substrate <NUM> and upper bottom surfaces of the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM>. Accordingly, a plurality of P-type thermoelectric legs <NUM> and a plurality of N-type thermoelectric legs <NUM> are electrically connected by the lower electrode <NUM> and the upper electrode <NUM>. A pair of the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM>, which are disposed between the lower electrode <NUM> and the upper electrode <NUM> and electrically connected to each other, may form a unit cell.

For example, when voltages are applied to the lower electrode <NUM> and the upper electrode <NUM> through lead lines <NUM> and <NUM>, a substrate in which a current flows from the P-type thermoelectric leg <NUM> to the N-type thermoelectric leg <NUM> may serve as a heat absorption surface, and a substrate in which a current flows from the N-type thermoelectric leg <NUM> to the P-type thermoelectric leg <NUM> may serve as a heat radiation surface.

Here, each of the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM> may be a bismuth telluride (Bi-Te)-based thermoelectric leg containing Bi and Ti as main raw materials. The P-type thermoelectric leg <NUM> at <NUM> wt% may be a thermoelectric leg which includes <NUM> to <NUM> wt% Bi-Te-based main low material containing at least one among antimony (Sb), nickel (Ni), aluminum (Al), copper (Cu), silver (Ag), lead (Pb), boron (B), gallium (Ga), Te, Bi, and indium (In) and includes <NUM> to <NUM> wt% mixture containing Bi or Te. For example, the P-type thermoelectric leg <NUM> at <NUM> wt% may include Bi-Se-Te as the main raw material and may further include <NUM> to <NUM> wt% Bi or Te. The N-type thermoelectric leg <NUM> at <NUM> wt% may be a thermoelectric leg which includes <NUM> to <NUM> wt% Bi-Te-based low material containing at least one among selenium (Se), Ni, Al, Cu, Ag, Pb, B, Ga, Te, Bi, and In and includes <NUM> to <NUM> wt% mixture containing Bi or Te. For example, the N-type thermoelectric leg <NUM> at <NUM> wt% may include Bi-Sb-Te as the main raw material and may further include <NUM> to <NUM> wt% Bi or Te.

Each of the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM> may be formed in a bulk shape or a stacked shape. Generally, a bulk-shaped P-type thermoelectric leg <NUM> or a bulk-shaped N-type thermoelectric leg <NUM> may be obtained by heat-treating a thermoelectric material to produce an ingot, crushing and sieving the ingot to obtain a thermoelectric leg powder, sintering the thermoelectric leg powder, and cutting the sintered body. A stack-shaped P-type thermoelectric leg <NUM> or a stack-shaped N-type thermoelectric leg <NUM> may be obtained by applying a paste containing a thermoelectric material on sheet-shaped substrates to form unit members, stacking the unit members, and cutting the stacked unit members.

In this case, the pair of the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM> may have the same shape and volume or may have different shapes and volumes. For example, since electrical conductivity characteristics of the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM> are different, a height or a cross-sectional area of the N-type thermoelectric leg <NUM> may be formed differently from that of the P-type thermoelectric leg <NUM>.

Performance of a thermoelectric element according to one embodiment of the present invention may be expressed by a Seebeck index. A Seebeck index ZT may be expressed by Equation <NUM>.

Here, α is a Seebeck coefficient (V/K), σ is electrical conductivity (S/m), and α<NUM>σ is a power factor (W/mK<NUM>). Further, T is a temperature, and k is thermal conductivity (W/mK). k may be expressed as a·cp·ρ, a is thermal diffusivity (cm<NUM>/S), cp is a specific heat (J/gK), and ρ is a density (g/cm<NUM>).

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

According to an embodiment of the present invention, the P-type thermoelectric leg <NUM> and the N-type thermoelectric leg <NUM> may have a structure shown in <FIG>. Referring to <FIG>, the thermoelectric legs <NUM> and <NUM> include thermoelectric material layers <NUM> and <NUM>, first plating layers <NUM> and <NUM> deposited on one surfaces of the thermoelectric material layers <NUM> and <NUM>, second plating layers <NUM> and <NUM> stacked on the other surfaces which are disposed opposite to the one surfaces of the thermoelectric material layers <NUM> and <NUM>, first bonding layers <NUM> and <NUM> disposed between the thermoelectric material layers <NUM> and <NUM> and the first plating layers <NUM> and <NUM> and between the thermoelectric material layers <NUM> and <NUM> and the second plating layers <NUM> and <NUM>, and the first bonding layers <NUM> and <NUM> and the second metal layers <NUM> and <NUM> which are disposed on the second bonding layers <NUM> and <NUM>, the first plating layers <NUM> and <NUM>, and the second plating layers <NUM> and <NUM>.

Here, the thermoelectric material layers <NUM> and <NUM> may include Bi and Te which are semiconductor materials. The thermoelectric material layers <NUM> and <NUM> may have the same material or shape as the P-type thermoelectric leg <NUM> or the N-type thermoelectric leg <NUM> which is described with reference to <FIG>.

In addition, each of the first metal layers <NUM> and <NUM> and the second metal layers <NUM> and <NUM> may be formed of a material selected from Cu, a Cu alloy, Al, and an Al alloy and may have a thickness ranging from <NUM> to <NUM>, and preferably ranging from <NUM> to <NUM>. A thermal expansion coefficient of each of the first metal layers <NUM> and <NUM> and the second metal layers <NUM> and <NUM> is similar to or greater than that of each of the thermoelectric material layers <NUM> and <NUM>, and thus, during sintering, since compressive stress is applied to interfaces between the first metal layers <NUM> and <NUM>, the second metal layers <NUM> and <NUM>, and the thermoelectric material layers <NUM> and <NUM>, cracks or delamination may be prevented. In addition, since bonding forces between the first metal layers <NUM> and <NUM>, the second metal layers <NUM> and <NUM>, and the electrodes <NUM> and <NUM> are large, the thermoelectric legs <NUM> and <NUM> may be stably coupled to the electrodes <NUM> and <NUM>.

Next, each of the first plating layers <NUM> and <NUM> and the second plating layers <NUM> and <NUM> may include at least one among Ni, Sn, Ti, Fe, Sb, Cr, and Mo and have a thickness ranging from <NUM> to <NUM>, and preferably ranging from <NUM> to <NUM>. The first plating layers <NUM> and <NUM> and the second plating layers <NUM> and <NUM> prevent reaction between the semiconductor material Bi or Te in the thermoelectric material layers <NUM> and <NUM> and the first and second metal layers <NUM> and <NUM> so that degradation in performance may be prevented and oxidation of the first metal layers <NUM> and <NUM> and the second metal layers <NUM> and <NUM> may be prevented.

In this case, the first bonding layers <NUM> and <NUM> and the second bonding layers <NUM> and <NUM> may be disposed between the thermoelectric material layers <NUM> and <NUM> and the first plating layers <NUM> and <NUM> and between the thermoelectric material layers <NUM> and <NUM> and the second plating layers <NUM> and <NUM>. In this case, each of the first bonding layers <NUM> and <NUM> and the second bonding layers <NUM> and <NUM> may include Te. For example, each of the first bonding layers <NUM> and <NUM> and the second bonding layers <NUM> and <NUM> may include at least one among Ni-Te, Sn-Te, Ti-Te, Fe-Te, Sb-Te, Cr-Te, and Mo-Te. According to an embodiment of the present invention, a thickness of each of the first bonding layers <NUM> and <NUM> and the second bonding layers <NUM> and <NUM> may range from <NUM> to <NUM>, and preferably from <NUM> to <NUM>. According to an embodiment of the present invention, the first bonding layers <NUM> and <NUM> and the second bonding layers <NUM> and <NUM>, which include Te, are disposed in advance between the thermoelectric material layers <NUM> and <NUM>, the first plating layers <NUM> and <NUM>, and the second plating layers <NUM> and <NUM> so that it is possible to prevent Te in the thermoelectric material layers <NUM> and <NUM> from diffusing to the first plating layers <NUM> and <NUM> and the second plating layers <NUM> and <NUM>. Consequently, occurrence of a Bi-rich region may be prevented.

Meanwhile, the lower electrode <NUM> disposed between the lower substrate <NUM>, the P-type thermoelectric leg <NUM>, and the N-type thermoelectric leg <NUM>, and the upper electrode <NUM> disposed between the upper substrate <NUM>, the P-type thermoelectric leg <NUM>, and the N-type thermoelectric leg <NUM> may each include at least one among Cu, Ag, and Ni and may each have a thickness ranging from <NUM> to <NUM>. When the thickness of the lower electrode <NUM> or the upper electrode <NUM> is less than <NUM>, a function as an electrode is lowered and thus electrical conduction performance may be degraded, and, when the thickness thereof exceeds <NUM>, conduction efficiency may be degraded due to an increase in resistance.

In addition, the lower substrate <NUM> and the upper substrate <NUM> opposite to each other may be insulating substrates or metal substrates. The insulating substrate may be an alumina substrate or a polymer resin substrate having flexibility. The polymer resin substrate having flexibility may include one of various insulating resin materials such as high permeability plastic and the like including polyimide (PI), polystyrene (PS), polymethyl methacrylate (PMMA), cyclic olefin copoly (COC), polyethylene terephthalate (PET), and a resin. The metal substrate may include Cu, a Cu alloy, or a Cu-Al alloy, and a thickness of the metal substrate may range from <NUM> to <NUM>. When the thickness of the metal substrate is less than <NUM> or exceeds <NUM>, a heat radiation characteristic or thermal conductivity may be excessively high so that reliability of the thermoelectric element may be degraded. In addition, when the lower substrate <NUM> and the upper substrate <NUM> are metal substrates, a dielectric layer <NUM> may be further formed between the lower substrate <NUM> and the lower electrode <NUM> and between the upper substrate <NUM> and the upper electrode <NUM>. The dielectric layer <NUM> may include a material having thermal conductivity ranging from <NUM> W/K to <NUM> W/K and may be formed to have a thickness ranging from <NUM> to <NUM>. When the thickness of the dielectric layer <NUM> is less than <NUM>, insulation efficiency or a withstanding voltage characteristic may be degraded, and, when the thickness thereof exceeds <NUM>, thermal conductivity may be lowered and thus heat radiation efficiency may be degraded.

In this case, sizes of the lower substrate <NUM> and the upper substrate <NUM> may be formed to be different from each other. For example, a volume, a thickness, or an area of one among the lower substrate <NUM> and the upper substrate <NUM> may be formed to be larger than that of the other one thereamong. Consequently, heat absorbing performance or heat radiation performance of the thermoelectric element may be improved.

In addition, a heat radiation pattern, e.g., an irregular pattern, may be formed on at least one surface of either the lower substrate <NUM> or the upper substrate <NUM>. Consequently, the heat radiation performance of the thermoelectric element may be improved. When the irregular pattern is formed on a surface in contact with the P-type thermoelectric leg <NUM> or the N-type thermoelectric leg <NUM>, a bonding characteristic between the thermoelectric leg and the substrate may also be improved.

Meanwhile, the P-type thermoelectric leg <NUM> or the N-type thermoelectric leg <NUM> may have a cylindrical shape, a polygonal column shape, an elliptical column shape, or the like.

According to one embodiment of the present invention, a portion of the P-type thermoelectric leg <NUM> or the N-type thermoelectric leg <NUM> to be bonded to the electrode may be formed to have a wide width.

Alternatively, according to another embodiment of the present invention, the lower substrate <NUM> and the upper substrate <NUM> may be omitted.

Referring to <FIG> again, one gas guide member <NUM> may be disposed in each duct <NUM> or a plurality of gas guide members <NUM> may be disposed in each duct <NUM>. The gas guide member <NUM> may be disposed in a direction in which a high-temperature gas is guided. For example, when the third surface <NUM> of each duct <NUM> is directed toward the direction in which the high-temperature gas introduced and the fourth surface <NUM> thereof is disposed to face a direction in which the high-temperature gas passes through the separation spaces between the plurality of ducts <NUM> and then is discharged, the gas guide member <NUM> may be disposed on the third surface <NUM> of each duct <NUM>.

In this case, a temperature of a gas introduced into the separation spaces between the plurality of ducts <NUM> is higher than that of a gas discharged from the separation spaces therebetween. For example, the gas introduced into the separation spaces between the plurality of ducts <NUM> may be waste heat generated from an engine of a vehicle, a ship, or the like. For example, the temperature of the gas introduced into the separation spaces between the plurality of ducts <NUM> may be <NUM> or higher, preferably <NUM> or higher, and more preferably in a range of <NUM> to <NUM>. In this case, a width of each of the separation spaces between the plurality of ducts <NUM> may range from several millimeters to several tens of millimeters and may be varied according to a size of the heat conversion device, the temperature of the gas being introduced, an inflow velocity of the gas, and a required amount of power generation.

One end <NUM> of the gas guide member <NUM> is connected to the first thermoelectric module <NUM> and may extend to be spaced apart from the third surface <NUM> on the third surface <NUM> included in the third surface <NUM> of each duct <NUM> and facing the outside of each duct <NUM>, and the other end <NUM> thereof is connected to the second thermoelectric module <NUM>. Thus, a high-temperature gas, e.g., waste heat, may pass through the separation spaces between the plurality of ducts <NUM> through the gas guide member <NUM>.

In this case, the gas guide member <NUM> may be formed in a unit of a pair of the thermoelectric modules <NUM> and <NUM> or formed in a unit of a plurality of pairs of the thermoelectric modules <NUM> and <NUM> consecutively disposed on one duct <NUM>.

An extended surface <NUM> between the one end <NUM> and the other end <NUM> of the gas guide member <NUM> may have a shape in which a distance from the third surface <NUM> is increased toward a center between the one end <NUM> and the other end <NUM>. That is, the extended surface <NUM> of the gas guide member <NUM> may have an umbrella shape or a roof shape. Thus, the high-temperature gas may be guided to pass through the separation spaces between the plurality of ducts <NUM>.

In addition, when the extended surface <NUM> of the gas guide member <NUM> has an umbrella shape or a roof shape, air gaps are formed between the gas guide member <NUM> and a side surface of the first thermoelectric module <NUM> and between the third surface <NUM> and a side surface of the second thermoelectric module <NUM> so that heat insulation performance may be improved.

Here, the one end <NUM> of the gas guide member <NUM> is connected to the heat sink <NUM> of the first thermoelectric module <NUM>, and the other end <NUM> thereof is connected to the heat sink <NUM> of the second thermoelectric module <NUM> so that sealing may be achieved. Accordingly, since the high-temperature gas passing between the plurality of ducts <NUM> passes only the heat radiation substrates <NUM> and <NUM> and the heat sinks <NUM> and <NUM> of the first thermoelectric module <NUM> and the second thermoelectric module <NUM>, it is possible to prevent a problem in that the high-temperature gas comes into direct contact with the thermoelectric elements <NUM> and <NUM> included in the first thermoelectric module <NUM> and the second thermoelectric module <NUM>, and it is possible to achieve heat insulation between the gas guide member <NUM> and the side surface of the first thermoelectric module <NUM> and between the third surface <NUM> and the side surface of the second thermoelectric module <NUM> so that a problem of degradation in thermoelectric conversion performance may be prevented.

In order to further enhance the sealing and insulation effects of the first thermoelectric module <NUM>, the third surface <NUM> of each duct <NUM>, and the second thermoelectric module <NUM>, the side surfaces of the plurality of first thermoelectric modules <NUM>, the side surfaces of the plurality of second thermoelectric modules <NUM>, and the surfaces of the ducts <NUM> disposed between the side surfaces of the plurality of first thermoelectric modules <NUM> and the side surface of the plurality of second thermoelectric modules <NUM> may be integrally sealed using a sealant <NUM>.

In order to further enhance the sealing and insulation effects of the first thermoelectric module <NUM>, the third surface <NUM> of each duct <NUM>, and the second thermoelectric module <NUM>, an insulating member may be disposed between the gas guide member <NUM> and the side surface of the first thermoelectric module <NUM> and between the third surface <NUM> and the side surface of the second thermoelectric module <NUM>.

<FIG> shows a perspective view and a cross-sectional view illustrating a gas guide member according to another embodiment of the present invention.

Referring to <FIG>, an auxiliary guide part <NUM> is further disposed between the one end <NUM> and the extension part <NUM> of the gas guide member <NUM> and between the other end <NUM> and the extension part <NUM> of the gas guide member <NUM>, and a hole H may be further formed in a region in which the auxiliary guide part <NUM> is in contact with the extension part <NUM>. In this case, the auxiliary guide part <NUM> may be formed in a shape symmetrical to the extension part <NUM>. Thus, the high-temperature gas may move along the extension part <NUM> and may be efficiently guided to the separation spaces between the plurality of ducts <NUM> through the hole H.

In addition, a groove <NUM> may be further formed in a surface of the extension part <NUM> of the gas guide member <NUM>. Thus, the high-temperature gas may move along the groove <NUM> formed in a surface of the extension part <NUM> and may be efficiently guided to the separation spaces between the plurality of ducts <NUM> through the hole H.

In addition, as shown in <FIG>, the auxiliary guide part <NUM> may extend parallel to the one end <NUM> or the other end <NUM> of the gas guide member <NUM>. When the auxiliary guide part <NUM> extends, the high-temperature gas may be efficiently guided to the thermoelectric module.

In addition, although not shown in the drawings, an angle between the one end <NUM> and the extension part <NUM> may be equal to an angle between the other end <NUM> and the extension part <NUM>, and each of the angles may be larger than <NUM>° and smaller than <NUM>°, and preferably larger than <NUM>° and smaller than <NUM>°. When the angle is smaller than <NUM>° or larger than <NUM>°, a flow of waste heat is hindered so that heat transfer efficiency may be degraded.

Claim 1:
A power generation apparatus which generates power using heat comprising:
a duct (<NUM>) through which a cooling fluid passes;
a first thermoelectric module (<NUM>) disposed on a first surface of the duct (<NUM>);
a second thermoelectric module (<NUM>) disposed on a second surface (<NUM>) opposite to the first surface (<NUM>) of the duct (<NUM>); and
a guide member (<NUM>) guiding a fluid with a different temperature from the cooling fluid and disposed on a third surface (<NUM>), which is disposed between the first surface (<NUM>) and the second surface (<NUM>) of the duct (<NUM>) to face an inlet of the fluid with the different temperature from the cooling fluid, wherein the guide member(<NUM>) includes:
one end (<NUM>) connected to the first thermoelectric module (<NUM>);
the other end (<NUM>) connected to the second thermoelectric module(<NUM>); and
an extension portion (<NUM>) connecting the one end (<NUM>) to the other end (<NUM>),
the guide member (<NUM>) has a shape in which a distance from the guide member (<NUM>) to the third surface (<NUM>) is increased in a direction toward a center between the one end (<NUM>) and the other end (<NUM>),
an auxiliary guide member (<NUM>) is disposed on at least one of the one end (<NUM>) and the other end (<NUM>) of the guide member (<NUM>),
at least one hole (H) is formed between the auxiliary guide member (<NUM>) and the at least one of the one end (<NUM>) and the other end (<NUM>) of the guide member (<NUM>), and
the fluid with the different temperature from the cooling fluid passes through the at least one hole (H).