JP5105718B2 - Thermal-electrical direct conversion device - Google Patents

Description

  The present invention relates to a thermal-electrical direct conversion device, and more particularly to a thermal-electrical direct conversion device that can maintain good conversion efficiency.

In recent years, the amount of energy consumed by mankind has rapidly increased at an unprecedented rate. As a result, the problem of global warming caused by greenhouse gases such as carbon dioxide (CO ₂ ) has emerged, and the global environment is preserved. Therefore, development of an energy source capable of suppressing CO ₂ generation as much as possible is craved all over the world. Under such circumstances, mainly from the viewpoint of energy saving, the use of large-scale waste heat has been progressing, and the reuse of medium-to-small-scale waste heat is now attracting attention.

  However, with regard to medium- and small-scale waste heat, even if the quality of the waste heat is high, the amount of heat itself is relatively small. For example, in a power generator for large-scale waste heat such as a steam turbine, the amount of heat is large. As a result, the power generation efficiency is extremely low, and there is a problem that the amount of electricity corresponding to the modification of existing facilities and the maintenance and repair costs cannot be obtained.

  In addition, due to the small amount of heat, the use of heat, such as the use of hot water, is often forgotten, and the use of medium- and small-scale waste heat is difficult to progress worldwide. Therefore, the development and practical application of a direct heat-electricity conversion device that can convert electric energy from the energy of waste heat of medium and small scales with a simple and small device system is awaited.

  In order to cope with such technical demands, development of a direct thermal-electric conversion device that directly converts thermal energy into electrical energy using a semiconductor has been in progress (see, for example, Patent Document 1).

  In general, this type of direct heat-electric conversion device is composed of a combination of p-type and n-type direct heat-electric conversion semiconductors (thermoconduction elements) that use thermoelectric effects such as the Thomson effect, Peltier effect, and Seebeck effect. Is done. A general structure is shown in FIG. That is, in the conventional direct thermo-electric conversion device 100, the p-type thermo-electric direct conversion semiconductor chip (p-type semiconductor) 2 and the n-type thermo-electric direct conversion semiconductor chip (n-type semiconductor) 3 include the high temperature side electrode 5. And a low temperature side insulating plate 8 having a low temperature side electrode 6. The p-type semiconductor 2 and the n-type semiconductor 3 form a thermal-electrical direct conversion semiconductor pair (semiconductor pair) 4, and many thermal-electrical direct conversion semiconductor pairs are connected electrically and thermally in the entire conversion device. .

  The p-type semiconductor 2 and the n-type semiconductor 3 are connected to the high temperature side electrode 5, and the p type semiconductor 2 and the n type semiconductor 3 are joined to the low temperature side electrode 6 via the low temperature side junction 12.

  In the heat-electricity direct conversion device 1 configured as described above, when the heat flow 13 is supplied to the high temperature side electrode 5, the heat is transferred to the p-type semiconductor 2 and the n-type semiconductor 3, and the p-type and n-type semiconductors. Along the heat flow 14 passing through 2 and 3, holes 16 that are semiconductor carriers are formed inside the p-type semiconductor 2, and electrons 17 that are semiconductor carriers are formed inside the p-type semiconductor 3, and the p-type semiconductor 2 or n It moves toward the low temperature side electrode 6 joined to the mold semiconductor 3 via the low temperature side joint 12.

  On the other hand, the heat flow 14 that passes through the p-type and n-type semiconductors 2 and 3 becomes a heat flow 15 that passes through the low-temperature side electrode 6 and is released from the low-temperature side electrode. Here, an appropriate electrical load 19 is connected to the electrode-current extraction means 9 installed in the thermal-electrical direct conversion device 100 outside the thermal-electrical direct conversion device 1 and the current connected thereto. By being electrically connected to the thermal-electrical direct conversion device 1 via the extraction means 10, the movement of the semiconductor carrier is taken out of the thermal-electrical direct conversion device 100 and used as a current flow 18. be able to.

  In this way, the thermal-electrical direct conversion device can convert the temperature difference between the high-temperature side electrode and the low-temperature side electrode directly into electricity using a thermal-electrical direct conversion semiconductor and take it out as power outside the device. However, on the contrary, heat can be transferred from the low temperature side to the high temperature side or from the high temperature side to the low temperature side by applying an electric current from the outside.

  In addition, various types of direct thermal-electric conversion devices have been proposed. For example, Patent Document 2 discloses a configuration in which thermal-electrical direct conversion semiconductor pairs are linearly arranged and a strain relaxation electrode mainly composed of carbon is formed at the junction between the thermal-electrical direct conversion semiconductor pair and the electrode. Is disclosed.

Patent Document 3 discloses a technique for forming a high temperature side insulating plate from a composite film made of a resin and an inorganic powder.
JP 2004-1119833 A JP 2000-188429 A JP 11-340523 A

  FIG. 5 is a cross-sectional view showing one embodiment of the structure of a conventional direct thermal-electric conversion device 100. Generally, the power generation efficiency increases as the temperature difference between the high temperature side and the low temperature side of the thermoelectric direct conversion semiconductor pair 4 increases. Further, in the case where a current is applied to the thermo-electric direct conversion device 100 to cause a temperature difference between the high temperature side electrode and the low temperature side electrode, a larger temperature difference can be obtained as the applied current is larger. .

  On the other hand, when the temperature difference between the high temperature side and the low temperature side of the thermoelectric direct conversion semiconductor pair 4 increases, the difference in the amount of thermal deformation between the constituent members on the high temperature side and the low temperature side also increases.

  In order to absorb this difference in the amount of thermal deformation, the high temperature side electrode (high temperature side electrode 5) is not fixed to the heat-electric direct conversion semiconductor pair 4, but is placed so as to straddle the heat-electric direct conversion semiconductor pair 4. Form may be taken. By unfixing the high temperature side electrode 5 and the heat-electricity direct conversion semiconductor pair 4, it becomes possible to absorb the amount of thermal deformation, and damage to the heat-electricity direct conversion semiconductor pair 4, the low temperature side junction 12, etc. It can be prevented to some extent.

  At this time, the cover member 27 having a bathtub-like box structure is arranged so as to cover the high temperature side electrode 5 so that the high temperature side electrode 5 does not move due to vibration or the like. Due to the presence of the cover member 27, even if the high temperature side electrode 5 and the thermoelectric direct conversion semiconductor pair 4 are not fixed, the high temperature side electrode 5 moves from the position of the high temperature side end face of the thermoelectric direct conversion semiconductor pair. Or avoiding misalignment.

  However, in the above structure, when thermal deformation occurs due to the temperature difference between the high temperature side and the low temperature side, a frictional force due to the difference in thermal expansion is generated on the contact surface between the high temperature side electrode 5 and the thermoelectric direct conversion semiconductor pair. The frictional force causes the heat-electric direct conversion semiconductor pair 4, the high temperature side electrode 5, or the low temperature side junction 12 (hereinafter referred to as the heat-electric direct conversion semiconductor pair 4 etc.) to be pulled or compressed. -There is a possibility that the electric direct conversion semiconductor pair 4 or the like may be damaged or damaged, resulting in a decrease in power generation performance.

  The present invention has been made in view of the above circumstances, and even when a displacement due to thermal deformation occurs between the high-temperature side electrode and the thermo-electric direct conversion semiconductor pair, the high-temperature side electrode and the thermo-electric direct To provide a thermal-electrical direct conversion device capable of reducing friction between the conversion semiconductor pair, thereby preventing scratches and breakage of the thermal-electrical direct conversion semiconductor pair and avoiding a decrease in power generation efficiency. Objective.

In order to solve the above-described problems, a direct thermal-electric conversion device according to the present invention includes a plurality of thermal-electrical direct conversion semiconductor pairs composed of a p-type semiconductor and an n-type semiconductor, and the thermal-electrical direct conversion semiconductor pair. A plurality of low-temperature side electrodes that electrically connect the p-type semiconductor and the n-type semiconductor at a low-temperature side end portion, and the plurality of thermo-electrical direct conversion semiconductor pairs via the plurality of low-temperature side electrodes; A plurality of high-temperature sides formed of a net-like metal member that electrically connects the p-type semiconductor and the n-type semiconductor at the low-temperature side insulating plate to be connected and the high-temperature side end of the thermo-electric direct conversion semiconductor pair An electrode, a plurality of cover members covering each of the plurality of high temperature side electrodes, and a high temperature thermally connected to the plurality of heat-electrical direct conversion semiconductor pairs via the plurality of high temperature side electrodes and the cover member and the side insulating plate, wherein each hot side electrode Serial a sliding member provided between the first sliding member provided, wherein each hot side electrodes wherein each n-type semiconductor between the p-type semiconductor, and the first sliding member Each of the first and second sliding members is in non-fixed contact with the first and second sliding members, and the first and second sliding members are in contact with each other . 2 and the high temperature side electrode formed of the mesh metal member are also in a non-fixed state.

  According to the thermo-electric direct conversion device according to the present invention, even if a displacement due to thermal deformation occurs between the high-temperature side electrode and the thermo-electric direct conversion semiconductor pair, the high-temperature side electrode and the thermo-electric direct Friction between the conversion semiconductor pair can be reduced, thereby preventing damage and breakage of the thermal-electrical direct conversion semiconductor pair and avoiding a decrease in power generation efficiency.

  An embodiment of a direct thermal-electric conversion device according to the present invention will be described with reference to the accompanying drawings.

(1) First Embodiment FIG. 1A is a cross-sectional view schematically showing the structure of a thermoelectric direct conversion device 1 according to a first embodiment.

  The thermal-electrical direct conversion device 1 has a plurality of thermal-electrical direct conversion semiconductor pairs 4 composed of a p-type semiconductor 2 and an n-type semiconductor 3, and the plurality of thermal-electrical direct conversion semiconductor pairs 4 are high-temperature side insulating plates. 7 and the low-temperature side substrate 22.

  In FIG. 1A, the heat-electricity direct conversion semiconductor pair 4 is a high temperature side to which heat is applied, and the lower side is a low temperature side to dissipate heat.

  The low temperature side end of the thermoelectric direct conversion semiconductor pair 4 is electrically and thermally connected to the low temperature side electrode 6 via the low temperature side junction 12. The low temperature side electrode 6 electrically connects the low temperature side end of the p-type semiconductor 2 and the low temperature side end of the n-type semiconductor 3 of the adjacent direct thermal-electric conversion semiconductor pair 4.

  On the other hand, the high temperature side electrode 5 is placed on the high temperature side end of the thermoelectric direct conversion semiconductor pair 4, and the p type semiconductor 2 and the n type semiconductor 3 constituting one thermoelectric direct conversion semiconductor pair 4 are arranged. The space is electrically connected by the high temperature side electrode 5.

  When heat is applied to the high temperature side end of the thermoelectric direct conversion semiconductor pair 4 and a temperature difference occurs between the high temperature side end and the low temperature side end, inside the p-type semiconductor 2 from the high temperature side to the low temperature side On the contrary, current flows from the low temperature side to the high temperature side inside the n-type semiconductor 3.

  Since the plurality of thermal-electrical direct conversion semiconductor pairs 4 are sequentially connected via the high-temperature side electrode 5 and the low-temperature side electrode 6, respectively, each thermal-electrical direct conversion semiconductor pair 4 is electrically connected in series. Will generate electrical energy. Of the heat-electricity direct conversion semiconductor pairs 4 connected in series, electric energy can be taken out from the heat-electricity direct conversion semiconductor pairs 4 located at both ends via the current extraction unit 10.

  In addition, by applying a current to the current extraction unit 10, the thermal-electrical direct conversion device 1 can also function as a conversion device from electrical energy to heat.

  The low temperature side substrate 22 includes the low temperature side electrode 6, the low temperature side insulating plate 8, and a heat release portion 24 to the low temperature system.

  More specifically, the low temperature side insulating plate 8 is formed of, for example, a ceramic plate, and the low temperature side electrode 6 and the heat release unit 24 to the low temperature system are integrated by bonding metal plates to both sides of the ceramic plate. Formed. At this time, the plurality of low temperature side electrodes 6 are divided from each other and bonded in a patch form on the low temperature side insulating plate 8 via the low temperature side insulating plate bonding portion 23. On the other hand, the metal plate forming the heat release portion 24 to the low temperature system is formed over substantially the entire low temperature side of the low temperature insulating plate 8.

  In this way, the low-temperature side substrate 22 is integrally formed on the surface of the low-temperature-side insulating plate 8 in advance by joining the low-temperature-side electrode 6 and the heat-dissipating part 24 to the low-temperature-side system, so The assembly work of 1 is simplified. Further, since the bonding strength between the low temperature side insulating plate 8 and the low temperature side electrode 6 and the heat release part 24 to the low temperature side system is high and the degree of adhesion between them can be high, the heat-electricity direct conversion device having excellent durability. 1 is obtained.

  In addition, as a material of the metal plate which forms the low temperature side electrode 6 and the heat release part 24 to the low temperature side system, from the viewpoint of heat resistance and electrical conductivity or thermal conductivity, copper, silver, aluminum, tin, iron base It is preferably made of at least one selected from alloys, nickel, nickel-base alloys, titanium, and titanium-base alloys.

  Further, the material of the ceramic plate forming the low-temperature side insulating plate 8 includes alumina or a ceramic containing alumina, a metal containing alumina powder dispersedly, silicon nitride or silicon nitride from the viewpoint of stability of insulation resistance. At least one selected from ceramics, ceramics containing aluminum nitride or aluminum nitride, ceramics containing zirconia or zirconia, ceramics containing yttria or yttria, ceramics containing silica or silica, ceramics containing beryllia or beryllia It is preferable that it is comprised.

  On the other hand, the configuration of the high temperature side end of the thermoelectric direct conversion semiconductor pair 4 is slightly different from the low temperature side.

  FIG. 1B is a diagram showing components on the high temperature side of the thermoelectric direct conversion semiconductor pair 4. As shown in FIG. 1B, sliding members 28 a and 28 b are provided at the high temperature side end of the thermoelectric direct conversion semiconductor pair 4. The sliding members 28a, 28b and the thermal-electrical direct conversion semiconductor pair 4 are in contact with each other in an unfixed state, and the sliding member 28a is placed on the high temperature side end of the p-type semiconductor 2, and the sliding member 28b. Is placed on the high temperature side end of the n-type semiconductor 3.

  From the top of the sliding members 28a, 28b, the high temperature side electrode 5 is placed so as to straddle the sliding members 28a, 28b. At this time, the state between the thermoelectric direct conversion semiconductor pair 4 and the high temperature side electrode 5 is also not fixed. The high temperature side electrode 5 receives a predetermined pressure from the upper side in FIG. 1 and is pressed in the direction of the heat-electric direct conversion semiconductor pair 4, and by this pressing, the high temperature side electrode 5 and the heat-electric direct conversion semiconductor pair 4 are pressed. A thermal and electrical connection between them is ensured.

  On the other hand, when the sliding members 28a and 28b and the high temperature side electrode 5 are brought into contact with the thermoelectric direct conversion semiconductor pair 4 in an unfixed state, the thermoelectric direct conversion semiconductor pair 4 is thermally deformed. However, it is possible to absorb the thermal deformation and prevent the thermal-electrical direct conversion semiconductor pair 4 and the low-temperature side connection portion 12 from being damaged.

  The sliding members 28 a and 28 b are members provided to reduce the frictional force generated due to the difference in thermal expansion between the high temperature side electrode 5 and the thermo-electric direct conversion semiconductor pair 4.

  In the case where the sliding members 28a and 28b are not provided, the high temperature side electrode 5 and the thermoelectric direct conversion semiconductor pair 4 come into contact with one contact surface. When a frictional force resulting from a difference in thermal expansion occurs on this contact surface, even if the high temperature side electrode 5 and the thermoelectric direct conversion semiconductor pair 4 are in an unfixed state, absorption of thermal deformation becomes insufficient. . In particular, as will be described later, when the high temperature side electrode 5 is formed of a mesh metal member, the surface of the high temperature side electrode 5 is rough. 4 and it becomes difficult to slip each other. For this reason, the frictional force of the contact surface is relatively large and the thermal deformation is not sufficiently absorbed.

  By providing the sliding members 28a and 28b between the high temperature side electrode 5 and the thermoelectric direct conversion semiconductor pair 4, there are two contact surfaces between the high temperature side electrode 5 and the thermoelectric direct conversion semiconductor pair 4. Can be formed. For this reason, the slidable contact surface is increased by one, and thermal deformation of the heat-electrical direct conversion semiconductor pair 4 and the like is easily absorbed.

  Further, when the high temperature side electrode 5 is formed of a net-like metal member, the contact surface between the high temperature side electrode 5 and the sliding members 28a and 28b becomes less slippery, but the sliding members 28a and 28b and the heat -Since the contact surface with the electrical direct conversion semiconductor pair 4 can maintain smoothness, the frictional force can be reduced as a whole.

  Thus, by providing the sliding members 28a and 28b, absorption of thermal deformation of the heat-electric direct conversion semiconductor pair 4 and the like can be facilitated, and damage to the heat-electric direct conversion semiconductor pair 4 can be prevented. As a result, the power generation efficiency of the heat-electricity direct conversion device 1 can be maintained satisfactorily.

  On the other hand, since the high temperature side electrode 5 and the sliding members 28a and 28b are not fixed, it is necessary to take measures to prevent movement due to inclination, vibration, or the like. The cover member 27 is a member for this purpose, and is disposed from above the high temperature side electrode 5 so as to cover the high temperature side electrode 5. The cover member 27 is formed of a bathtub-like box-shaped member having an opening on the surface facing the high temperature side electrode 5. The cover member 27 accommodates the high temperature side electrode 5 inside the cover member 27 and prevents the high temperature side electrode 5 from being largely moved by vibration or the like.

  The sliding members 28 a, 28 b, the high temperature side electrode 5, the cover member 27, and the high temperature side insulating plate 7 convert the heat applied to the thermo-electric direct conversion device 1 to the high temperature side end of the thermo-electric direct conversion semiconductor pair 4. In order to transmit with high efficiency, it is necessary to form with a material with high thermal conductivity. Further, since these components are used in a high temperature environment, for example, at about 500 ° C. or higher, high heat resistance is also required. The materials and detailed structures of these components will be described below.

  The sliding members 28a and 28b are formed of nickel, cobalt, carbon, tantalum, titanium, aluminum, zinc, copper, stainless steel, a thermal-electric direct conversion semiconductor material, or a combination thereof.

  By using nickel, cobalt, carbon, tantalum, titanium, aluminum, zinc, copper, and stainless steel as the sliding members 28a and 28b, high heat resistance can be secured, and since these materials have low electrical resistance, p-type Loss of power flowing from the semiconductor 2 to the n-type semiconductor 3 can be kept low. When nickel, cobalt, carbon, tantalum, titanium, aluminum, zinc, copper, or stainless steel is used as the sliding members 28a and 28b, the same material is used for the sliding member 28a and the sliding member 28b. .

  In addition, by using a material that forms a thermo-electric direct conversion semiconductor as the sliding members 28a and 28b, it becomes possible to perform direct thermo-electric conversion also by the sliding members 28a and 28b themselves, It becomes possible to minimize the loss of direct thermal-electric conversion due to the insertion of 28b. At this time, the polarity (p-type or n-type) of the heat-electric direct conversion semiconductor constituting the sliding members 28a, 28b needs to match the polarity of the heat-electric direct conversion semiconductor pair 4 with which it contacts. That is, the sliding member 28 a needs to be formed of the same material as that of the p-type semiconductor 2, and the sliding member 28 b needs to be formed of the same material as that of the n-type semiconductor 3.

  The thermal-electrical direct conversion semiconductor material is formed of the same material as that of the p-type semiconductor 2 or the n-type semiconductor 3 described later.

  Specifically, from the viewpoint of thermoelectric conversion efficiency and from the viewpoint that a good thermoelectric effect can be maintained for a long time, rare earth elements, actinoids, cobalt, iron, rhodium, ruthenium, palladium, platinum, nickel, antimony, Heat composed of at least three elements selected from titanium, zirconium, hafnium, nickel, tin, silicon, manganese, zinc, boron, carbon, nitrogen, gallium, germanium, indium, vanadium, niobium, barium and magnesium An electric direct conversion semiconductor is preferable.

  Similarly, from the viewpoint of thermoelectric change efficiency and thermoelectric effect sustainability, the p-type semiconductor 2 and the n-type semiconductor 3 constituting the thermo-electric direct conversion semiconductor pair 4 are (i) copper oxide, carbon, boron, sodium. And a layered composite oxide of cobalt and one substance selected from calcium, (b) aluminum nitride, (c) uranium nitride, (d) silicon nitride, (e) molybdenum disulfide, (f) skutter A thermoelectric conversion material having a cobalt antimonide compound having a diete-type crystal structure as a main phase, a thermoelectric conversion material having (to) a clathrate compound as a main phase, and (h) a thermoelectric conversion material having a half-Heusler compound as a main phase, One substance selected from each of the substances, a compound comprising two or more kinds of the substances, a mixture comprising two or more kinds of the substances, or a solid solution comprising two or more kinds of the substances. It may be formed. In this case, the half-Heusler compound is a thermo-electric direct containing at least one of titanium, zirconium, hafnium, nickel, tin, cobalt, antimony, vanadium, chromium, niobium, tantalum, molybdenum, palladium, and rare earth elements. A conversion semiconductor material is preferred.

  In addition, the crystal structure of the main phase of the p-type semiconductor 2 and the n-type semiconductor 3 is selected from among a skutterudite structure, a filled skutterudite structure, a Heusler structure, a half-Heusler structure, and a clathrate structure from the viewpoint of a good thermoelectric effect. Any one of these or a mixed phase thereof is preferable.

  The high temperature side electrode 5 electrically connects the p-type semiconductor 2 and the n-type semiconductor 3 and requires high electrical conductivity. For this reason, it forms with metal materials, such as copper, for example.

  On the other hand, as described above, the end portions of the high temperature side electrode 5 and the p-type semiconductor 2 or the n-type semiconductor 3 are in an unfixed state, so that it is necessary to further increase the adhesion of the connection portion and reduce the electrical resistance. . Therefore, the high temperature side electrode 5 according to the present embodiment is formed using a net-like metal member in which fine metal wires such as copper wires are densely knitted. The high-temperature side electrode 5 and the p-type semiconductor 2 or n are bonded to the high-temperature side electrode 5 formed of the mesh-like metal member by pressing the high-temperature-side insulating plate 7 through the cover member 27 by the elasticity of the mesh-like metal member. Adhesion with the end portion with the mold semiconductor 3 is improved, and high electrical conductivity can be secured. Moreover, thermal conductivity can also be improved by this improvement in adhesion.

  Furthermore, by forming the high temperature side electrode 5 with a net-like metal member, it is possible to absorb errors in the height direction of the thermo-electrical direct conversion semiconductor pair 4 (including variations between single and individual). In general, the height of the thermo-electric direct conversion semiconductor pair 4 causes a certain error due to a manufacturing error, nonuniformity of applied heat, and the like, but these errors cause the high temperature side electrode 5 and the thermo-electric direct conversion semiconductor. Adhesiveness between the pair 4 is impaired, which causes a decrease in thermal conductivity and electrical conductivity. These errors can be absorbed by the high temperature side electrode 5 formed of a mesh metal member, and high thermal conductivity and electrical conductivity can be ensured.

  The cover member 27 is not required to have electrical conductivity, but is required to have high thermal conductivity and heat resistance. For this reason, a metal material may be used. In this case, since the cover member 27 has electrical conductivity as a result, the surface of the cover member 27 is secured in order to ensure electrical insulation with the cover member 27 of the adjacent heat-electrical direct conversion semiconductor pair 4. An electrical insulating layer (not shown) may be provided on the surface.

The high temperature side insulating plate 7 is provided so as to be in pressure contact with each other so as to substantially cover the entirety of the plurality of cover members 27. Since heat is directly applied to the high temperature side surface of the high temperature side insulating plate 7, high heat resistance is required. Further, high heat conductivity is required to efficiently transmit the applied heat to the heat-electricity direct conversion semiconductor pair 4. Furthermore, it is necessary to ensure electrical insulation between each thermal-electrical direct conversion semiconductor pair 4. For this reason, the high temperature side insulating plate 7 is formed of a ceramic substrate using a material having electrical insulation properties such as alumina (Al ₂ O ₃ ), high thermal conductivity, and excellent heat resistance. The

  In order to further increase the thermal conductivity of the high temperature side insulating plate 7, a metal film (foil) having a high thermal conductivity may be formed on both surfaces of the high temperature side insulating plate 7. For example, a first metal film 7a is provided on almost the entire high temperature side surface of the high temperature side insulating plate 7, and a plurality of second metal films 7b on the patch are provided on the opposite surface (the surface in contact with the cover member 27). Form.

  By providing the first and second metal films 7a and 7b, the adhesiveness between the high temperature side insulating plate 7 and the components in contact with both surfaces thereof is increased, and the thermal conductivity can be improved.

  The second metal film 7b has a patch shape that substantially corresponds to the shape of the cover member 27, and ensures separation between the adjacent patches, thereby ensuring electrical insulation between the thermo-electric direct conversion semiconductor pairs 4. I have to.

  The p-type semiconductor 2 and the n-type semiconductor 3 constituting the thermo-electric direct conversion semiconductor pair 4 are rare earth elements and actinoids from the viewpoint of thermoelectric conversion efficiency and from the viewpoint of maintaining a good thermoelectric effect for a long period of time. , Cobalt, iron, rhodium, ruthenium, palladium, platinum, nickel, antimony, titanium, zirconium, hafnium, nickel, tin, silicon, manganese, zinc, boron, carbon, nitrogen, gallium, germanium, indium, vanadium, niobium, barium And a thermo-electric direct conversion semiconductor composed of at least three elements selected from magnesium and magnesium.

  Similarly, from the viewpoint of thermoelectric change efficiency and thermoelectric effect sustainability, the p-type semiconductor 2 and the n-type semiconductor 3 constituting the thermo-electric direct conversion semiconductor pair 4 are (i) copper oxide, carbon, boron, sodium. And a layered composite oxide of cobalt and one substance selected from calcium, (b) aluminum nitride, (c) uranium nitride, (d) silicon nitride, (e) molybdenum disulfide, (f) skutter A thermoelectric conversion material having a cobalt antimonide compound having a diete-type crystal structure as a main phase, a thermoelectric conversion material having (to) a clathrate compound as a main phase, and (h) a thermoelectric conversion material having a half-Heusler compound as a main phase, One substance selected from each of the substances, a compound comprising two or more kinds of the substances, a mixture comprising two or more kinds of the substances, or a solid solution comprising two or more kinds of the substances. It may be formed. In this case, the half-Heusler compound is a thermo-electric direct containing at least one of titanium, zirconium, hafnium, nickel, tin, cobalt, antimony, vanadium, chromium, niobium, tantalum, molybdenum, palladium, and rare earth elements. A conversion semiconductor material is preferred.

  In addition, the crystal structure of the main phase of the p-type semiconductor 2 and the n-type semiconductor 3 is selected from among a skutterudite structure, a filled skutterudite structure, a Heusler structure, a half-Heusler structure, and a clathrate structure from the viewpoint of a good thermoelectric effect. Any one of these or a mixed phase thereof is preferable.

  According to the heat-electric direct conversion device 1 configured as described above, the components on the high temperature side of the heat-electric direct conversion semiconductor pair 4, that is, the sliding members 28 a and 28 b, the high temperature side electrode 5, and the cover member 27. The high temperature side insulating plate 7 is made of a material having high thermal conductivity and heat resistance, and can achieve high thermal adhesion, so that the heat applied to the surface of the high temperature side insulating plate 7 is efficient. It is often transmitted to the thermo-electric direct conversion semiconductor pair 4 to ensure high thermoelectric conversion efficiency.

  Moreover, since the high temperature side electrode 5 and the cover member 27 are configured to be mounted in a non-fixed manner on the thermoelectric direct conversion semiconductor pair 4, even when the thermoelectric direct conversion semiconductor pair 4 is thermally deformed, stress is applied to the joint portion. Concentration does not occur, and damage to the thermal-electrical direct conversion semiconductor pair 4 or the like can be prevented.

  Furthermore, by providing the sliding members 28a and 28b between the high temperature side electrode 5 and the heat-electric direct conversion semiconductor pair 4, the frictional force on the contact surface of the heat-electric direct conversion semiconductor pair 4 can be reduced. It becomes possible, and it becomes possible to prevent more effectively the damage by thermal deformation of the thermoelectric direct conversion semiconductor pair 4 grade | etc.,.

(2) Second Embodiment FIG. 2 is a perspective view showing an external appearance of a thermoelectric direct conversion device 1a according to a second embodiment. 3 is a cross-sectional view of the thermoelectric direct conversion device 1a shown in FIG.

  The thermal-electrical direct conversion device 1a according to the second embodiment is a form in which a plurality of thermal-electrical direct conversion semiconductor pairs 4 and their peripheral components are accommodated in an airtight casing 30.

  The hermetic housing 30 includes a metal lid 20 that covers the high temperature side insulating plate 7 that is thermally connected to the high temperature side ends of the plurality of heat-electric direct conversion semiconductor pairs 4, and a plurality of heat-electric direct conversion semiconductor pairs 4. And a low temperature side substrate 22 that is thermally connected to the low temperature side end portions of the plurality of thermal-electrical direct conversion semiconductor pairs 4. The hermetic casing 30 shields internal components including the plurality of direct heat-electric conversion semiconductor pairs 4 from the outside air, and holds the inside of the hermetic casing 30 in a vacuum or an inert gas atmosphere.

  The inert gas is preferably composed of a gas selected from nitrogen, helium, neon, argon, krypton and xenon. Or these mixed gas may be sufficient. By encapsulating these non-oxidizing gases in the airtight housing 30 and deactivating the internal atmosphere, it is possible to effectively prevent deterioration of components such as semiconductor chips due to oxidation or the like, and high conversion over a long period of time. The direct thermal-electric conversion device 1a that can maintain the efficiency is obtained.

  Moreover, in the thermal-electrical direct conversion device 1a, it is preferable that the pressure of the inert gas atmosphere is set to be lower than the external pressure at normal temperature. By setting the pressure of the inert gas atmosphere in the hermetic casing 30 to be lower than the external pressure, damage due to an increase in the internal pressure at a high temperature is prevented, and moisture remains in the inert gas atmosphere in the hermetic casing 30. It can be effectively prevented, and deterioration damage of the semiconductor chip due to moisture can be effectively suppressed. Furthermore, since the thermal conductivity in the gas atmosphere in the hermetic casing 30 is lowered, it is possible to prevent heat from being dissipated from the semiconductor chip in the direction of the metal frame, and to improve the heat-electric conversion efficiency.

  The metal lid 20 and the metal frame 21 constituting the hermetic casing 30 are made of a heat-resistant alloy such as a nickel base alloy or a heat-resistant metal, for example. As the heat-resistant alloy or heat-resistant metal forming the metal lid 20 and the metal frame 21, from the viewpoint of durability in a high temperature use environment, in addition to a nickel-based alloy, an iron-based alloy containing nickel, carbon steel, stainless steel, chromium, It is preferably selected from any of an iron-base alloy containing silicon, an alloy containing cobalt, or an alloy containing nickel or copper.

  The metal lid 20 and the metal frame 21 are joined by welding, for example. In addition, the metal lid 20 and the metal frame 21 may be integrally formed. By integrally forming the metal lid 20 and the metal frame 21, the number of parts is reduced and the assembling work is simplified.

  The joining method of the metal frame 21 and the low temperature side substrate 22 is not particularly limited, but is preferably joined by welding, soldering or brazing, diffusion joining, or an adhesive from the viewpoint of joining strength. .

  The low temperature side substrate 22 constituting the hermetic casing 30 is basically the same as that of the first embodiment. However, the current extraction means 10 for extracting current from the thermal-electrical direct conversion device 1a is connected to the thermal-electrical direct conversion semiconductor pair 4 (thermal-electrical direct connected in series) via the connection means 9 penetrating the low temperature side substrate 22. The conversion semiconductor pair 4 is connected to the thermal-electrical direct conversion semiconductor pair 4) located at both ends, so that the confidentiality of the airtight housing 30 is maintained.

  The thermal-electrical direct conversion semiconductor pair 4, the high temperature side electrode 5, the sliding members 28 a and 28 b, the cover member 27, and the high temperature side insulating plate 7 housed in the airtight housing 30 are all the same as in the first embodiment. belongs to.

  According to the second embodiment, in addition to obtaining the same effect as the first embodiment, by providing the airtight housing 30, the direct thermal-electric conversion device 1a is installed in the air, Even when operated in a high temperature environment for a long time, it is possible to effectively suppress deterioration due to oxidation or nitridation of internal components, and high thermoelectric conversion efficiency can be maintained over a long period of time.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the components without departing from the scope of the invention in the implementation stage. Moreover, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be appropriately combined.

(A) is sectional drawing which shows typically the structure of 1st Embodiment of the thermoelectric direct conversion apparatus which concerns on this invention, (b) is a figure which shows the detail and assembly procedure of the high temperature side component . The perspective view which shows the external appearance of 2nd Embodiment of the thermoelectric direct conversion apparatus which concerns on this invention. Sectional drawing which shows typically the structure of 2nd Embodiment of the thermoelectric direct conversion apparatus which concerns on this invention. Explanatory drawing which shows the general structure and operation | movement concept of a thermal-electrical direct conversion apparatus. Sectional drawing which shows typically the structure of the conventional thermal-electrical direct conversion apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Thermal-electrical direct conversion apparatus 2 P-type semiconductor 3 N-type semiconductor 4 Thermal-electrical direct conversion semiconductor pair 5 High temperature side electrode 6 Low temperature side electrode 7 High temperature side insulating plate 7a 1st metal film 7b 2nd metal film 8 Low temperature side insulating plate 10 Current extraction means 12 Low temperature side joint portion 20 Metal lid 21 Metal frame 22 Low temperature side substrate 23 Low temperature side insulating plate joint portion 24 Heat release portion 27 to the low temperature side system Cover members 28a, 28b Sliding member 30 Airtight enclosure

Claims (15)

a plurality of direct thermal-electric conversion semiconductor pairs consisting of a p-type semiconductor and an n-type semiconductor;
A plurality of low-temperature side electrodes that electrically connect the p-type semiconductor and the n-type semiconductor at a low-temperature side end of the thermo-electric direct conversion semiconductor pair;
A low temperature side insulating plate thermally connected to the plurality of thermal-electrical direct conversion semiconductor pairs via the plurality of low temperature side electrodes;
A plurality of high-temperature side electrodes formed of a mesh metal member that electrically connects the p-type semiconductor and the n-type semiconductor at a high-temperature side end of the thermo-electric direct conversion semiconductor pair;
A plurality of cover members covering each of the plurality of high temperature side electrodes;
A high temperature side insulating plate thermally connected to the plurality of thermal-electrical direct conversion semiconductor pairs via the plurality of high temperature side electrodes and the cover member;
A first sliding member provided between each high temperature side electrode and each p-type semiconductor ;
A sliding member provided between each of the high temperature side electrodes and each of the n-type semiconductors, the second sliding member being divided from the first sliding member;
With
The first and second sliding members and the thermoelectric direct conversion semiconductor pair are in contact in an unfixed state,
The first and second sliding members and the high temperature side electrode formed of the mesh metal member are also in contact with each other in an unfixed state.
A direct heat-electric conversion device. a plurality of direct thermal-electric conversion semiconductor pairs consisting of a p-type semiconductor and an n-type semiconductor;
A plurality of low-temperature side electrodes that electrically connect the p-type semiconductor and the n-type semiconductor at a low-temperature side end of the thermo-electric direct conversion semiconductor pair;
A low temperature side insulating plate thermally connected to the plurality of thermal-electrical direct conversion semiconductor pairs via the plurality of low temperature side electrodes;
A plurality of high-temperature side electrodes formed of a mesh metal member that electrically connects the p-type semiconductor and the n-type semiconductor at a high-temperature side end of the thermo-electric direct conversion semiconductor pair;
A plurality of cover members covering each of the plurality of high temperature side electrodes;
A high temperature side insulating plate thermally connected to the plurality of thermal-electrical direct conversion semiconductor pairs via the plurality of high temperature side electrodes and the cover member;
A metal lid that covers the high-temperature side insulating plate, a metal frame that surrounds the plurality of thermal-electrical direct conversion semiconductor pairs, and the low-temperature side insulating plate are formed, and the plural thermal-electrical direct conversion semiconductor pairs are formed. An airtight housing that shields from the outside air and keeps the interior in a vacuum or inert gas atmosphere;
A first sliding member provided between each high temperature side electrode and each p-type semiconductor ;
A sliding member provided between each of the high temperature side electrodes and each of the n-type semiconductors, the second sliding member being divided from the first sliding member;
With
The first and second sliding members and the thermoelectric direct conversion semiconductor pair are in contact in an unfixed state,
The first and second sliding members and the high temperature side electrode formed of the mesh metal member are also in contact with each other in an unfixed state.
A direct heat-electric conversion device. The first and second sliding members may be nickel, cobalt, carbon, tantalum, titanium, aluminum, zinc, copper, stainless steel, a thermal-electric direct conversion semiconductor material, or a combination thereof. The direct thermal-electric conversion device according to claim 1 or 2. 4. The thermal-electrical direct conversion device according to claim 3, wherein the thermal-electrical direct conversion semiconductor material has the same polarity as the thermal-electrical direct conversion semiconductor pair that it contacts. The thermal-electrical direct conversion semiconductor materials are rare earth elements, actinides, cobalt, iron, rhodium, ruthenium, palladium, platinum, nickel, antimony, titanium, zirconium, hafnium, nickel, tin, silicon, manganese, zinc, boron, carbon. The thermo-electric direct conversion device according to claim 3, comprising at least three elements selected from the group consisting of nitrogen, gallium, germanium, indium, vanadium, niobium, barium and magnesium. The crystal structure of the main phase of the thermo-electric direct conversion semiconductor material is any one of a skutterudite structure, a filled skutterudite structure, a Heusler structure, a half-Heusler structure, and a clathrate structure, or a mixed phase thereof. The direct thermal-electric conversion device according to claim 3. The thermal-electrical direct conversion semiconductor material is:
(A) A layered composite oxide of cobalt and one substance selected from copper oxide, carbon, boron, sodium and calcium,
(B) aluminum nitride, (c) uranium nitride, (d) silicon nitride, (e) molybdenum disulfide,
(F) a thermoelectric conversion material whose main phase is a cobalt antimonide compound having a skutterudite-type crystal structure;
(G) a thermoelectric conversion material having a clathrate compound as a main phase, and (h) a thermoelectric conversion material having a half-Heusler compound as a main phase,
One substance selected from each of the above substances, a compound composed of two or more kinds of the respective substances, a mixture composed of two or more kinds of the respective substances, or a solid solution composed of two or more kinds of the respective substances. The thermal-electrical direct conversion device according to claim 3. The half-Heusler compound is a thermal-electrical direct conversion semiconductor material containing at least one of titanium, zirconium, hafnium, nickel, tin, cobalt, antimony, vanadium, chromium, niobium, tantalum, molybdenum, palladium, and rare earth elements. 8. The thermal-electrical direct conversion device according to claim 7, wherein the thermal-electrical direct conversion device is provided. The p-type semiconductor and the n-type semiconductor are rare earth elements, actinides, cobalt, iron, rhodium, ruthenium, palladium, platinum, nickel, antimony, titanium, zirconium, hafnium, nickel, tin, silicon, manganese, zinc, boron, 3. The direct thermal-electric conversion semiconductor material composed of at least three elements of carbon, nitrogen, gallium, germanium, indium, vanadium, niobium, barium and magnesium. Direct heat-electric conversion device. The crystal structure of the main phase of the p-type semiconductor and the n-type semiconductor is any one of a skutterudite structure, a filled skutterudite structure, a Heusler structure, a half-Heusler structure, and a clathrate structure, or a mixed phase thereof. The thermal-electrical direct conversion device according to claim 1 or 2, characterized in that. The material forming the p-type semiconductor and the n-type semiconductor is:
(A) A layered composite oxide of cobalt and one substance selected from copper oxide, carbon, boron, sodium and calcium,
(B) aluminum nitride, (c) uranium nitride, (d) silicon nitride, (e) molybdenum disulfide,
(F) a thermoelectric conversion material whose main phase is a cobalt antimonide compound having a skutterudite-type crystal structure;
(G) a thermoelectric conversion material having a clathrate compound as a main phase; and (h) a thermoelectric conversion material having a half-Heusler compound as a main phase;
One substance selected from each of the above substances, a compound composed of two or more kinds of the respective substances, a mixture composed of two or more kinds of the respective substances, or a solid solution composed of two or more kinds of the respective substances. The direct thermal-electric conversion device according to claim 1 or 2. The half-Heusler compound is a thermal-electrical direct conversion semiconductor material containing at least one of titanium, zirconium, hafnium, nickel, tin, cobalt, antimony, vanadium, chromium, niobium, tantalum, molybdenum, palladium, and rare earth elements. The thermal-electrical direct conversion device according to claim 11, wherein the thermal-electrical direct conversion device is provided. The high temperature side insulating plate is provided with a foil made of a material having high thermal conductivity on the surface on the high temperature side, and the foil is provided on the surface on the low temperature side only at a position in contact with the cover member. The direct thermal-electric conversion device according to claim 1 or 2. The metal lid and the metal frame are formed of nickel, nickel-base alloy, carbon steel, stainless steel, iron-base alloy containing chromium, iron-base alloy containing silicon, alloy containing cobalt, or alloy containing nickel or copper. The thermal-electrical direct conversion device according to claim 2, wherein: 3. The heat − according to claim 2, wherein the inert gas includes at least one gas selected from nitrogen, helium, neon, argon, krypton, and xenon, and has a pressure lower than atmospheric pressure at room temperature. Electric direct conversion device.

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