Thermoelectric leg and method for manufacturing the same, and thermoelectric element containing the same

Abstract

A thermoelectric leg, a method for manufacturing the same, and a thermoelectric element including the same are disclosed. The method for manufacturing the thermoelectric leg may include a sintered solid forming step, which includes a basic sintering step of sintering a powder of a soluble substance or a powder of a semiconductor substance in a hot-press step in a mold; an additional sintering step of performing one or more additional sintering steps in another mold with the sintered solid and the powder of the soluble substance or the powder of the semiconductor substance to form a sintered solid for dissolution that includes all of the soluble substance and the semiconductor substance; and a hollow forming step of exposing the soluble substance in the sintered solid for dissolution to a solvent and selectively removing it to form a hollow.

Description

Technical Field

[0001] The present invention relates to a thermoelectric leg, a method for manufacturing the same, and a thermoelectric element including the same.

Background Art

[0002] A thermoelectric device is a device that generates electric power by utilizing the thermoelectric effect and makes use of the principle that a temperature difference causes an intermetallic potential difference. This device is composed of expensive p-type and n-type LEGs, and for commercialization, it is important to reduce the power generation cost. The present invention proposes a thermoelectric element with a new structure that can greatly reduce the amount of thermoelectric material used and thus reduce the power generation cost. In particular, by using a sintering-dissolving method using a soluble substance such as NaCl to form a structure with a perforated center, it is possible to provide the possibility of increasing the power production efficiency and saving costs.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The problem to be solved by the present invention is to maintain or improve the performance while reducing the power generation cost of the thermoelectric element. For this purpose, a method of reducing the amount of material used is proposed by developing a thermoelectric leg with a new structure including a hollow (space or hole). Such an approach can help reduce the material cost and the energy consumption in the manufacturing process. Also, such a structural change can have a positive impact on the thermal and electrical characteristics of the thermoelectric element and provide the possibility of improving the performance.

Means for Solving the Problems

[0004] On one aspect, the present invention provides a thermoelectric leg including a semiconductor and at least one hollow formed in the semiconductor.

[0005] In one embodiment, the hollow can penetrate the side surface of the thermoelectric leg.

[0006] In one embodiment, the hollow can be formed inside the thermoelectric leg and closed off.

[0007] In one embodiment, the hollow can penetrate the thermoelectric leg vertically.

[0008] In one embodiment, the thermoelectric leg may further include an insertion spacer located within the hollow space.

[0009] In one embodiment, the insertion spacer can be formed in a tubular shape including a sub-hollow that penetrates the insertion spacer vertically.

[0010] In one embodiment, the insertion spacer can be formed in an I-beam shape, where the cross-section is I-shaped.

[0011] In one embodiment, the insertion spacer may have the same height as the hollow space.

[0012] In one embodiment, the semiconductor may include one or more semiconductor materials selected from the group including BiTeSe, BiSbTe, Bi2Te3, PbTe, SiGe, GeTe, Sb2Te3, AgSbTe2, Cu2Se, InSb, MgSi, and Zn2Sb.

[0013] In other aspects, the present invention provides a thermoelectric element comprising: a plurality of p-type and n-type thermoelectric legs; a plurality of conductors in contact with at least a portion of the p-type and n-type thermoelectric legs; a first electrode in contact with at least a portion of the conductors; and a second electrode in contact with at least a portion of the conductors and separated from the first electrode.

[0014] In one embodiment, at least a portion of the thermoelectric leg may be a thermoelectric leg according to the embodiment of the present invention described above.

[0015] In other respects, the present invention provides a method for manufacturing thermoelectric legs, comprising: a basic sintering step of sintering a powder of a soluble substance or a powder of a semiconductor substance in a hot-pressing step in a mold; an additional sintering step of performing one or more additional sintering steps in another mold with the sintered solid and the powder of the soluble substance or the powder of the semiconductor substance in a hot-pressing step in another mold to form a sintered solid for dissolution containing all of the soluble substance and the semiconductor substance; and a hollow forming step of exposing the soluble substance in the sintered solid for dissolution to a solvent and selectively removing it to form a hollow.

[0016] In one embodiment, the soluble substance can be arranged such that the hollow formed in the hollow formation step penetrates the side surface of the thermoelectric leg.

[0017] In one embodiment, the soluble substance can be arranged such that the hollow formed in the hollow formation step is closed off inside the thermoelectric leg.

[0018] In one embodiment, the portion of the semiconductor material powder that has been sintered can have one or more pores formed so that the soluble substance is exposed to the solvent.

[0019] In one embodiment, the sintered solid formation step can be performed two or more times such that the additional sintering step is inserted into the portion in which the soluble substance has been sintered.

[0020] In one embodiment, the solid obtained by sintering the semiconductor material can be formed in a tubular or I-beam shape.

[0021] In one embodiment, the semiconductor material may include one or more semiconductor materials selected from the group including BiTeSe, BiSbTe, Bi2Te3, PbTe, SiGe, GeTe, Sb2Te3, AgSbTe2, Cu2Se, InSb, MgSi, and Zn2Sb.

[0022] In one embodiment, the soluble substance can include sodium chloride (NaCl).

Advantages of the Invention

[0023] The advantages of the present invention provide the possibility of simultaneously improving the efficiency and economy of thermoelectric devices. In particular, by adopting a thermoelectric leg with a new structure, the material cost can be reduced and the complexity of the manufacturing process can be decreased, thereby increasing the energy efficiency and cost efficiency in the overall production process. Also, the present invention can achieve weight reduction and miniaturization without inhibiting the performance of thermoelectric devices, and can expand the scope of application in various applications. For example, it can be effectively used in waste heat recovery systems of mobile means such as automobiles and airplanes, thereby providing an opportunity to improve energy efficiency and provide an environmentally friendly energy solution.

Brief Description of the Drawings

[0024] [Figure 1] It is a drawing that illustrates an example of a method for manufacturing a thermoelectric leg according to an embodiment of the present invention in cross section. [Figure 2] It is a drawing that illustrates another example of a method for manufacturing a thermoelectric leg according to an embodiment of the present invention in cross section. [Figure 3] It is a drawing that illustrates still another example of a method for manufacturing a thermoelectric leg according to an embodiment of the present invention in cross section. [Figure 4] It is a drawing that shows an example of manufacturing a thermoelectric leg according to an embodiment of the present invention. [Figure 5] It is a drawing that compares the manufacturing costs of a conventional thermoelectric leg and a thermoelectric leg according to an embodiment of the present invention. [Figure 6] It is a drawing that compares the power output and power production costs of a conventional thermoelectric leg and a thermoelectric leg according to an embodiment of the present invention. [Figure 7] It is a drawing that shows a thermoelectric leg according to an embodiment of the present invention that closes the hollow or further includes an insertion spacer. [Figure 8]This graph shows the manufacturing cost, power generation cost, and power generation amount of the conventional thermoelectric leg and the thermoelectric leg according to the embodiment of the present invention. [Figure 9] This graph shows the manufacturing cost, power generation cost, and power generation amount of the conventional thermoelectric leg and the thermoelectric leg according to the embodiment of the present invention. [Figure 10] This document describes how to calculate the β value, a parameter related to the power generation cost of a thermoelectric leg. [Figure 11] This shows the power generation cost based on β. [Figure 12] This diagram illustrates the diverse shapes of thermoelectric legs and the resulting effects on the β value. [Figure 13] This diagram includes graphs showing the electrical resistance of different thermoelectric unit couple devices. [Figure 14] This diagram shows the results of measuring the temperature difference between a high-temperature and a low-temperature section of various thermoelectric unit couple devices based on the input heat quantity (Q_in). [Figure 15] This diagram shows the results of measuring the power output (P_out) based on the input heat quantity (Q_in) for various thermoelectric unit couple devices. [Figure 16] This diagram shows the relative weights of other thermoelectric unit couple devices normalized based on the "FF(β=1.0)" type. [Figure 17] This diagram shows the power output per unit weight of each thermoelectric unit couple device, normalized to the unit weight, based on the "FF(β=1.0)" type. [Figure 18] This diagram shows the cost per unit volume ($ / cm^3) of the thermoelectric materials p-type (Bi_0.5Sb_1.5Te_3) and n-type (Bi_2Te_2.7Se_0.3) legs, compared to the costs of the supporting materials, glass fabric and NaCl. [Figure 19] This diagram shows the normalized power generation cost ($ / W) of a thermoelectric unit couple device based on the "FF(β=1.0)" type. [Modes for carrying out the invention]

[0025] Embodiments of the present invention will be described in detail below with reference to the attached drawings. The present invention can be modified in various ways and may take many forms, with specific embodiments illustrated in the drawings and described in detail in the text. However, this should be understood not as an attempt to limit the present invention to any particular disclosure, but rather as including all modifications, equivalents, or substitutes that fall within the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used for similar components. In the attached drawings, the dimensions of structures are shown enlarged for clarity of the present invention.

[0026] The terms used in this application are used solely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless they are clearly meant differently in context. In this application, terms such as “includes” or “has” are intended to specify the existence of features, figures, stages, actions, components, or combinations thereof described in the specification, and should be understood not to preemptively exclude the existence or possibility of adding one or more other features, figures, stages, actions, components, or combinations thereof. In the context of this specification, terms such as “about” may mean about ±1%, about ±2%, about ±3%, about ±4%, about ±5%, about ±6%, about ±7%, about ±8%, about ±9%, or about ±10% of the numerical values ​​described in the specification.

[0027] Furthermore, the description relating to one aspect of the present invention may be applied in the same or similar manner to the same or similar configurations or terms in the description relating to other aspects.

[0028] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the art to which this invention pertains. Terms as defined in commonly used dictionaries should be interpreted to have the meaning consistent with their meaning in the context of the relevant art, and not to be interpreted in an ideal or overly formal sense unless expressly defined herein.

[0029] A thermoelectric leg according to an embodiment of the present invention may include a semiconductor and include at least one hollow formed in the semiconductor. By being configured as described above, the thermoelectric leg can be made lighter and more efficient. Including a hollow reduces the amount of material used and the energy required in the manufacturing process, which has the potential to reduce overall manufacturing costs. Furthermore, such a structure can help optimize the thermal and electrical conductivity of the thermoelectric element to improve its performance.

[0030] In the context of this specification, a thermoelectric element refers to a device that generates electrical energy by utilizing a temperature difference. Such devices can be useful in converting waste heat into useful electrical energy in a variety of environments. For example, heat generated in industrial facilities and vehicles can be converted into electricity to improve energy efficiency and reduce environmental impact. Furthermore, improvements to such thermoelectric elements can contribute to improving the efficiency of energy harvesting and management systems in consumer electronic products. In particular, the novel structures and manufacturing methods proposed herein offer the possibility of maintaining or improving performance while reducing the size and weight of the element. This can offer advantages not only in applications in portable electronic devices and wearable technologies, but also in use in energy-limited remote areas and space exploration equipment.

[0031] In the context of this specification, "hollow" refers to a space or hole formed within a thermoelectric leg. This hollow structure can help reduce the amount of material used in the element, lower its weight, and optimize its thermal and electrical properties. Such structural modifications can improve the performance of the element and increase energy efficiency in the manufacturing process, contributing to overall cost savings. Furthermore, elements containing hollows can provide better thermal management and electrical conductivity, which is particularly advantageous for devices operating in high-temperature or extreme environments.

[0032] As long as the above-described functions are performed, the form in which the hollow is formed is not particularly limited. In one embodiment, the hollow may penetrate the side of the thermoelectric leg. In one embodiment, the hollow may be formed inside and closed off the thermoelectric leg. In one embodiment, the hollow may penetrate the thermoelectric leg vertically. By forming the hollow as described above, the thermoelectric leg can optimize its thermal and electrical properties in various directions. Such diverse hollow structures can be customized according to the size and shape of the element to provide a design and performance suitable for specific applications. For example, thermoelectric elements suitable for electronic devices that need to be miniaturized or for devices that operate in high-temperature environments can be manufactured. Furthermore, such structural diversity can increase flexibility in the manufacturing process and help in developing thermoelectric elements that suit diverse environmental conditions and application fields.

[0033] In particular, in one embodiment, if the hollow is shaped to penetrate the thermoelectric leg vertically, the thermoelectric leg may further include an insert spacer located within the hollow. The insert spacer can provide electrical or mechanical complementation. Such structural improvements allow the element to maintain performance even in extreme environments or under high mechanical stress. Furthermore, such a design expands the applicability by enabling the thermoelectric element to operate efficiently over a wider temperature range and in a variety of operating environments. The insert spacer can also optimize the flow and distribution of material during the manufacturing process of the thermoelectric element, making the manufacturing process more efficient and economical. This can be an important factor in increasing the commercial applicability of the thermoelectric element.

[0034] As long as it performs the functions described above, the specific shape of the insertion spacer is not particularly limited. In one embodiment, the insertion spacer may be formed in a tubular shape including a sub-hollow that penetrates the insertion spacer vertically. In one embodiment, the insertion spacer may be formed in an I-beam shape with an I-shaped cross-section. The diverse shapes of the insertion spacer offer diverse possibilities to suit the performance and application field of the thermoelectric element. A tubular insertion spacer, including a sub-hollow, can provide additional thermal management and structural support. Such a configuration can help optimize heat flow within the thermoelectric element and maintain uniform electrical properties. I-beam type insertion spacers can also provide strong mechanical support and stability, which is advantageous in application fields where mechanical stability is particularly important, as it allows the element to withstand physical stress better.

[0035] In one embodiment, the insertion spacer may have the same height as the hollow spacer. This can help improve the overall structural consistency and performance of the thermoelectric leg. Such a structure can enhance the overall stability and efficiency of performance. Furthermore, having the insertion spacer and the hollow spacer at the same height allows for a balance between mechanical strength and rigidity within the element, thereby improving the durability and reliability of the device.

[0036] In one embodiment, the semiconductor may include one or more semiconductor materials selected from the group including BiTeSe, BiSbTe, Bi2Te3, PbTe, SiGe, GeTe, Sb2Te3, AgSbTe2, Cu2Se, InSb, MgSi, and Zn2Sb, but this is a non-limiting example and the scope of the present invention is not limited thereto. Each of these semiconductor materials has unique thermoelectric properties and can be used selectively depending on the specific application field and operating conditions. This can be useful in customizing thermoelectric elements to suit a variety of environments and requirements, making an important contribution to maximizing efficiency and performance.

[0037] On the other hand, a thermoelectric element according to an embodiment of the present invention may include: a plurality of p-type and n-type thermoelectric legs; a plurality of conductors in contact with at least a portion of the p-type and n-type thermoelectric legs; a first electrode in contact with at least a portion of the conductors; and a second electrode in contact with at least a portion of the conductors and separated from the first electrode. In one embodiment, at least a portion of the thermoelectric legs may be thermoelectric legs according to the embodiments of the present invention described above.

[0038] On the other hand, the thermoelectric leg manufacturing method according to an embodiment of the present invention provides a thermoelectric leg manufacturing method comprising: a basic sintering step of sintering a powder of a soluble substance or a powder of a semiconductor substance in a hot-pressing step in a mold; an additional sintering step of performing a step of additional sintering the sintered solid and the powder of the soluble substance or the powder of the semiconductor substance in another mold one or more times to form a sintered solid for dissolution containing all of the soluble substance and the semiconductor substance; and a hollow forming step of exposing the soluble substance in the sintered solid for dissolution to a solvent and selectively removing it to form a hollow.

[0039] The aforementioned basic sintering stage is a stage in which the core solid that forms the basis of the thermoelectric leg manufacturing process can be formed. In this stage, the basic structure of the thermoelectric element is formed by sintering a powder of a soluble substance or semiconductor material through a pressing process. In the additional sintering stage, in addition to the solid formed in the basic sintering stage, other forms of soluble substances or semiconductor materials are additionally sintered to create a complex structure. This process is necessary to meet the complex structural requirements of the thermoelectric element and to achieve specific thermoelectric properties. Finally, in the hollow formation stage, a hollow is formed by exposing the soluble substance formed in the sintered solid for melting to a solvent and selectively removing it.

[0040] In one embodiment, the pressing process may be an SPS (Spark Plasma Sintering) process. In the context of this specification, an SPS process is a process of sintering a sintered body by applying pressure, voltage, and current, and means a method of rapidly sintering a material in powder form at high pressure and temperature. This process can only serve to optimize the structural properties and electrical performance of a thermoelectric element by forming a uniform density and strong bond within the material. The rapid sintering rate of the SPS process increases production efficiency and reduces the risk of deformation and damage that the material can experience at high temperatures, which can contribute to saving overall manufacturing costs and improving product quality. Furthermore, the SPS process can be applied to the sintering of various types of materials and composite materials, and can play an important role in expanding the performance and application range of thermoelectric elements.

[0041] As described above, the form in which the hollow is formed is not particularly limited, as long as the hollow performs the aforementioned function, and the soluble substance can be arranged and sintered by the desired hollow. In one embodiment, the soluble substance can be arranged such that the hollow formed in the hollow formation stage penetrates the side surface of the thermoelectric leg. In one embodiment, the soluble substance can be arranged such that the hollow formed in the hollow formation stage is closed inside the thermoelectric leg. However, in one embodiment, when the soluble substance is arranged such that the hollow is closed inside the thermoelectric leg, one or more holes can be formed in the sintered portion of the semiconductor material powder so that the soluble substance is exposed to the solvent. In one embodiment, the sintered solid formation step can be performed two or more times such that the additional sintering step is inserted into the portion where the soluble substance has been sintered.

[0042] Figure 1 is a cross-sectional diagram illustrating an example of a thermoelectric leg manufacturing method according to an embodiment of the present invention. In Figure 1, light gray represents the soluble substance, and dark gray represents the semiconductor substance; a similar pattern is observed in subsequent diagrams. The example in Figure 1 is a method for simply manufacturing a cell with a hollow structure. As shown in the left diagram, a core of the soluble substance is formed in the basic sintering stage, and then, as shown in the center diagram, a semiconductor substance surrounding the core is formed in the additional sintering stage. Finally, as shown in the right diagram, the soluble substance is exposed to a solvent and removed, thereby manufacturing a cell with a hollow structure.

[0043] In one embodiment, the solid obtained by sintering the semiconductor material may be formed in a tubular or I-beam shape.

[0044] Figure 2 is a cross-sectional drawing illustrating another example of a thermoelectric leg manufacturing method according to an embodiment of the present invention. The example in Figure 2 is a method for manufacturing a cell in which a tubular insertion spacer is additionally inserted inside. Starting from the left, a core can be sintered with a soluble material, then a semiconductor material can be formed to completely surround it, another soluble material can be formed to completely surround it, and yet another semiconductor material can be formed to completely surround it. If the soluble material is removed by exposing it to a solvent in this state, a tubular insertion spacer can be formed within the semiconductor, and a cell with complementary mechanical properties can be manufactured. Depending on the purpose, the sintered solid may be pre-fixed to an electrode or substrate before the removal of the soluble material.

[0045] Referring in part to Figure 2, the tubular insertion spacer may be a pre-formed steel body. A soluble substance can be placed inside the tubular spacer and sintered, and the sintered shape can be surrounded by a thermoelectric material (semiconductor material). In this case, the tubular insertion spacer can be formed without going through the sintering process.

[0046] Figure 3 is a cross-sectional drawing illustrating another example of a thermoelectric leg manufacturing method according to an embodiment of the present invention. The example in Figure 3 is a method for manufacturing a cell in which an I-beam type insertion spacer is additionally inserted inside. Starting from the left, a core can be sintered with a semiconductor material, then soluble material can be sintered on both sides, then semiconductor material can be sintered on the other orthogonal sides, then soluble material can be sintered around the whole, and finally semiconductor material can be sintered around the whole again. In this state, if the soluble material is exposed to a solvent and removed, an I-beam type insertion spacer can be formed in the semiconductor, and a cell with complementary mechanical properties can be manufactured. Depending on the purpose, the sintered solid may be pre-fixed to an electrode or substrate before the removal of the soluble material.

[0047] Referring partially to Figure 3, the I-beam type insertion spacer may be a pre-formed steel body. A soluble material can be placed around the I-beam type spacer and sintered, and the sintered shape can be surrounded by a thermoelectric material (semiconductor material). In this case, the I-beam type insertion spacer can be formed without going through the sintering process.

[0048] The insertion spacers mentioned in Figures 2 and 3 do not necessarily have to be formed from semiconductors; instead, they may be made from pre-formed steel bodies. Such insertion spacers may be made of materials that not only have high strength and rigidity but also low thermal conductivity and thermal expansion coefficient. This can play an important role in reinforcing the structural stability and performance of the thermoelectric element. Non-limiting examples include materials such as glass fabric, which can help optimize the thermal and electrical properties within the thermoelectric element. The use of materials such as glass fabric can enable the thermoelectric element to operate stably even in extreme environments, providing long-term durability and reliability.

[0049] The examples given above illustrate specific shapes and materials of insertion spacers, but the structure, shape, and material of insertion spacers inserted into hollow spaces are not limited thereto, as long as they provide electrical or mechanical complementation.

[0050] As long as the aforementioned functions are performed, the material of the soluble substance is not particularly limited. In one embodiment, the soluble substance may include sodium chloride (NaCl). This is a non-limiting example, but the soluble substance used in the present invention is required to have high solubility in a specific solvent and can be easily sintered throughout the process. Sodium chloride is highly soluble and can be easily removed during the hollow formation process, which enables the precise fabrication of thermoelectric legs with complex structures. Through such sintering and hollow formation processes, the weight of the thermoelectric element can be reduced, manufacturing costs can be lowered, and efficiency can be improved. In addition, other soluble substances besides NaCl can be used, which provides further flexibility in the manufacturing process and can help in developing elements suitable for diverse environmental conditions and application fields.

[0051] The following describes embodiments of the present invention. However, the embodiments described below represent only a part of the present invention, and the scope of the present invention is not limited to these embodiments.

[0052] Manufacturing example

[0053] Figure 4 is a diagram showing an example of the manufacturing of a thermoelectric leg according to an embodiment of the present invention. Referring to Figure 4, the manufacturing example is as follows: as shown in (1), NaCl in the mold is sintered to form a core; as shown in (2), n-type or p-type semiconductor powder is filled around it, and then sintered again. Sintering is carried out in an SPS process, with the following conditions: pressure of 50.0 MPa, temperature of 450.0 °C, and time range of 10-10 minutes. As semiconductor materials used in the manufacturing process, BiTeSe is selected as the n-type semiconductor and BiSbTe as the p-type semiconductor. These materials are used to form the n-type and p-type legs of the thermoelectric element, respectively. NaCl is also used, and a purity of 99% is selected. NaCl is a soluble substance used to form a hollow space, and as shown in (3), by exposing it to a solvent after the sintering process to remove it, it contributes to creating a precise space within the thermoelectric element. Through such a manufacturing process, a thermoelectric leg with high efficiency and lightweight properties can be produced.

[0054] Comparison of manufacturing costs and power generation costs

[0055] Figure 5 is a diagram comparing the manufacturing costs of a conventional thermoelectric leg and a thermoelectric leg according to an embodiment of the present invention. As shown at the bottom of Figure 5, the p-type semiconductor used as the thermoelectric material is Bi 0.5 S 1.5 Te 3.0 n-type semiconductors are Bi 2.0 Te 2.7 Se 0.3 Using the formula, the costs of Bi, Ti, Se, Sb, and NaCl were determined to be 2.430, 2.607, 5.185, 0.105, and 0.002 (unit cost), respectively. As shown at the top of Figure 5, the manufacturing cost of a conventional thermoelectric leg is 5.791, while the thermoelectric leg according to the embodiment of the present invention has a manufacturing cost of 3.221, confirming a 44.4% reduction compared to the conventional technology.

[0056] Figure 6 is a diagram comparing the power output and power production costs of a conventional thermoelectric leg and a thermoelectric leg according to an embodiment of the present invention. Conv represents a conventional thermoelectric leg, as shown on the left side of Figure 5; NaCl_1 represents a thermoelectric leg with hollows formed at the top and bottom, as shown at the middle of Figure 5; and NaCl_2 represents a thermoelectric leg with a hollow formed through the side, as shown on the right side of Figure 5. In the case of the NaCl_1 structure, the manufacturing cost is the lowest, the performance is the best, and it can be confirmed that the power generation cost is reduced by 54.7% compared to the conventional structure. In the case of the NaCl_2 structure, the power generation performance is similar to the existing shape (conv), but due to the significant reduction in manufacturing costs, it can be confirmed that the power generation cost is reduced by 41.8% compared to the conventional structure.

[0057] Figure 7 is a drawing showing a cell for a thermoelectric element leg according to an embodiment of the present invention that includes a closed hollow or an additional spacer. Referring to Figure 7, embodiments of the present invention can also include a closed hollow to enhance electrical properties or a tubular or I-beam type insertion spacer to enhance mechanical properties. The closed hollow shape can increase the contact area between the thermoelectric leg and the electrode, thereby reducing electrical resistance, which can help improve electrical properties. On the other hand, embodiments using a tubular or I-beam type insertion spacer serve to increase the mechanical strength and rigidity of the thermoelectric element. Such insertion spacers can help ensure that the thermoelectric element operates stably under a variety of environmental conditions, contributing to improved durability. The external and internal dimensions (5.3(A) × 10.0(H) mm / 3.4(A) × 10.0(H) mm / 2.4(A) × 10.0(H) mm) and β value (0.54) presented in Figure 7 can serve as important reference material for evaluating the actual impact of such designs.

[0058] Figures 8 and 9 are graphs showing the manufacturing cost, power generation cost, and power generation amount of the conventional thermoelectric leg described above and the thermoelectric leg according to the embodiment of the present invention. In the drawings, as shown in Figure 7, Fully filled means a conventional thermoelectric leg, Hollow means a cell with only a through-hole formed, Closed air means a closed cell, Spacer Inserted Hollow means a cell with a tubular insertion spacer formed, and I-Beam Inserted means a cell with an I-beam type insertion spacer formed. Referring to Figures 8 and 9, although hollow and closed air thermoelectric elements show superior performance in terms of power generation cost, they have the problem of being difficult to apply to actual designs due to their weakness in mechanical strength and rigidity. To solve this, a method of inserting a spacer made of a material that can reinforce the mechanical properties inside (Spacer Inserted Hollow, I-Beam Inserted) is proposed. Such spacer insertion can improve the structural integrity of the thermoelectric element and increase its strength and rigidity, compensating for the weaknesses of hollow and closed structures. In particular, the "Spacer Inserted Hollow" embodiment, which offers the best structural integrity, provides the potential to further reduce power generation costs by designing the thermoelectric element to be thinner. Such approaches can help increase the practicality of thermoelectric elements and improve their economics in large-scale production and commercial applications.

[0059] Figure 10 shows how to calculate the β value, a parameter related to the power generation cost of a thermoelectric leg. Figure 11 shows the power generation cost based on β. Referring to Figures 10 and 11 together, the fact that the thinner the thickness (β) of the thermoelectric element, the greater the effect of reducing the power generation cost ($ / W) is significant. According to conventional technology, the performance at a β value of 0.54 was used as the baseline. However, in the case of Spacer Inserted Hollow and I-Beam Inserted shapes, it was confirmed that structural integrity is best in the Spacer Inserted Hollow shape in particular. This means that it is possible to further reduce the β value of the thermoelectric element, which in other words suggests that power generation costs can be further reduced.

[0060] Marketability

[0061] Thermoelectric power generation elements produced using this manufacturing method can be manufactured using conventional process equipment, which is expected to significantly reduce power generation costs. Such savings have the potential to accelerate the commercialization of thermoelectric devices, which can be widely used in various industrial fields. In particular, this device, which can produce electricity using temperature differences, can be used in waste heat recovery systems where waste heat is generated, such as in automobiles, ships, and power plants, and can help reduce carbon emissions through energy recycling. It can also be applied to various high-tech fields such as space generators, aerospace thermal control devices, military infrared detectors, guided missile coolers, constant temperature baths for medical equipment, and blood refrigerators, greatly expanding the scope and efficiency of such technologies. Such diverse applicability can make an important contribution to the innovation of thermoelectric technology and the development of sustainable energy solutions.

[0062] Figure 12 is a diagram illustrating the various shapes of thermoelectric legs and their effects on the β value. The β value represents the material volume ratio of the thermoelectric leg, and this is one of the important factors determining the power generation cost of a thermoelectric element. This diagram presents four types of thermoelectric leg shapes: "FF (Fully filled)", "Hollow", "SI (Support Inserted)", and "HSI (Hollow Support Inserted)". Referring to Figure 12, it can be seen that the amount of thermoelectric material required decreases as the β value decreases, from the fully filled FF form to the hollow form with an internal support, to the SI form with an internal support inserted, and finally to the HSI form which has a hollow space along with the support, thereby reducing material costs. This shows the potential to reduce power generation costs. In particular, the SI form, which fills the interior with an insulating material such as glass fabric, and the HSI form, which has an internal space with a support inserted, are shown to be effective in reducing material usage and lowering power generation costs while maintaining mechanical strength. Such structural deformations can reduce power generation costs while also enhancing the reliability and durability of thermoelectric elements.

[0063] Figure 13 is a diagram containing graphs showing the electrical resistance of different thermoelectric unit couple devices. These graphs compare the electrical resistance values ​​of various thermoelectric leg shapes: "FF (β=1.0)", "Hollow (β=0.8, 0.6, 0.4)", "SI (β=0.2)", and "HSI (β=0.2)". Referring to Figure 13, it can be seen that the fully filled "FF" configuration exhibits the lowest electrical resistance, while the "Hollow" unit, with its hollow structure, tends to show increasing electrical resistance as the β value decreases.

[0064] Figure 14 is a diagram showing the results of measuring the temperature difference between the high-temperature and low-temperature parts of various thermoelectric unit couple devices based on the input heat quantity (Q_in). Experimental results are shown as points, and ANSYS simulation results are shown as lines. Referring to Figure 14, it can be seen that the fully filled "FF (β=1.0)" configuration shows the lowest temperature difference, while the "Hollow_0.4 (β=0.4)" and "HSI (β=0.2)" configurations show a much higher temperature difference than the FF.

[0065] Figure 15 is a diagram showing the results of measuring the power output (P_out) for various thermoelectric unit couple devices based on the input heat quantity (Q_in). Experimental results are shown as dots, and ANSYS simulation results are shown as lines. Referring to Figure 15, it can be seen that the "Hollow_0.4 (β=0.4)" configuration shows a higher power output than the FF. This can be interpreted as the effect of increasing temperature difference overwhelming the effect of increasing electrical resistance, thus increasing the power output. On the other hand, in the "SI (β=0.2)" and "HSI (β=0.2)" configurations, even if the temperature difference increases, the increase in electrical resistance has a greater effect, and the power output tends to decrease.

[0066] Figure 16 is a diagram showing the relative weights of other thermoelectric unit couple devices normalized against the "FF (β=1.0)" type. This graph shows the weight ratio for each thermoelectric leg configuration. Referring to Figure 16, the "FF" type is the heaviest, and the weight of the "Hollow" type thermoelectric leg decreases with increasing β value. In the case of "SI (β=0.2)" and "HSI (β=0.2)", the weight of the thermoelectric material decreases, but this decrease is offset by the weight of the supporter. This indicates an advantage in application fields where high performance and weight reduction are required simultaneously.

[0067] Figure 17 is a diagram showing the power output per unit weight of each thermoelectric unit couple device, normalized to the unit weight, with the "FF (β=1.0)" type as the baseline. The data points shown are values ​​calculated based on experiments, and the performance of thermoelectric units with different β values ​​was compared and analyzed. Referring to Figure 17, the "Hollow_0.4 (β=0.4)" configuration shows the highest power output relative to its weight, while the "FF" and "HSI (β=0.2)" configurations show lower values. This result shows that power production efficiency can be increased while reducing weight, suggesting that when applied to vehicles and ships, it is possible to reduce the impact on fuel consumption and load weight while increasing power output.

[0068] Figure 18 shows the cost per unit volume ($ / cm^3) of p-type (Bi_0.5Sb_1.5Te_3) and n-type (Bi_2Te_2.7Se_0.3) thermoelectric materials compared to the costs of glass fabric and NaCl, which are used as support materials. Referring to Figure 18, it can be seen that the costs of p-type and n-type thermoelectric materials are considerably higher than those of glass fabric and NaCl. In particular, the cost of n-type thermoelectric material is the highest, suggesting that designing to minimize the amount of thermoelectric material used plays an important role in reducing the overall cost of thermoelectric elements. Glass fabric is relatively inexpensive but provides structural support and insulation, while NaCl can be used at a very low cost.

[0069] Figure 19 is a normalized diagram showing the power generation cost ($ / W) of thermoelectric unit couple devices based on the "FF (β=1.0)" type. The values ​​shown as dots represent data calculated based on experiments. Referring to Figure 19, it can be seen that the "Hollow_0.4 (β=0.4)" configuration shows the lowest power generation cost, and that the "HSI (β=0.2)" configuration can also significantly reduce the power generation cost compared to "FF". This data shows that structural improvements to the thermoelectric element are effective in minimizing power generation costs. It shows that "Hollow_0.4" can achieve a power generation cost reduction of approximately 79-83% compared to "FF", and "HSI" can achieve a power generation cost reduction of approximately 71-76%.

[0070] While preferred embodiments of the present invention have been described above with reference to those who are ordinary skill in the art, it should be understood that the present invention can be modified and altered in various ways without departing from the spirit and scope of the invention as set forth in the appended claims.

Claims

1. Including semiconductors, A thermoelectric leg comprising at least one hollow formed in the semiconductor.

2. The thermoelectric leg according to claim 1, wherein the hollow penetrates the side surface of the thermoelectric leg.

3. The thermoelectric leg according to claim 1, wherein the hollow is formed inside the thermoelectric leg and closed off.

4. The thermoelectric leg according to claim 1, wherein the hollow portion penetrates the thermoelectric leg vertically.

5. The thermoelectric leg according to claim 3, further comprising an insertion spacer located within the hollow space.

6. The thermoelectric leg according to claim 5, wherein the insertion spacer is formed in a tubular shape including a sub-hollow that penetrates the insertion spacer vertically.

7. The thermoelectric leg according to claim 5, wherein the insertion spacer is formed in the shape of an I-beam, with an I-shaped cross-section.

8. The thermoelectric leg according to claim 6 or 7, wherein the insertion spacer has the same height as the hollow space.

9. The aforementioned semiconductors are BiTeSe, BiSbTe, and Bi ２ Te ３ , PbTe, SiGe, GeTe, Sb ２ Te ３ AgSbTe ２ ,Cd ２ Se, InSb, MgSi, and Zn ２ The thermoelectric leg according to claim 1, comprising one or more semiconductor materials selected from the group including Sb.

10. Multiple p-type and n-type thermoelectric legs, A plurality of conductors in contact with at least a portion of the p-type and n-type thermoelectric legs, A first electrode that contacts at least a portion of the conductor, A second electrode that is in contact with at least a portion of the conductor and separated from the first electrode, Includes, At least a portion of the thermoelectric leg is a thermoelectric leg according to claim 1. Thermoelectric element.

11. A sintered solid formation step includes a basic sintering step in which a powder of a soluble substance or a powder of a semiconductor substance is sintered in a hot-pressing step within a mold, and an additional sintering step in which the sintered solid and the powder of the soluble substance or the powder of the semiconductor substance are further sintered in a hot-pressing step within another mold one or more times to form a sintered solid for dissolution that contains all of the soluble substance and the semiconductor substance. A hollow formation step is performed in which the soluble substance is exposed to the solvent in the aforementioned sintered solid for dissolution and selectively removed to form a hollow, A method for manufacturing thermoelectric legs, including the method described above.

12. The method for manufacturing a thermoelectric leg according to claim 11, wherein the soluble substance is arranged such that the hollow formed in the hollow formation step penetrates the side surface of the thermoelectric leg.

13. The soluble substance is arranged such that the hollow formed in the hollow formation step is closed inside the thermoelectric leg. The thermoelectric leg manufacturing method according to claim 11, wherein one or more pores are formed in the sintered portion of the semiconductor material powder so that the soluble substance is exposed to the solvent.

14. The thermoelectric leg manufacturing method according to claim 11, wherein the sintered solid formation step involves forming a sintered solid for melting with an insertion spacer placed inside.

15. The semiconductor material is BiTeSe, BiSbTe, Bi ２ Te ３ , PbTe, SiGe, GeTe, Sb ２ Te ３ , AgSbTe ２ , Cu ２ Se, InSb, MgSi, and Zn ２ The method for manufacturing a thermoelectric leg according to claim 11, comprising one or more semiconductor materials selected from the group containing Sb.

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