JP2006032723A - Heat/electricity direct converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat/electricity direct converter capable of inhibiting the progress of a deterioration due to the oxidation or the like of a component, and capable of excellently maintaining a conversion efficiency for a prolonged term. <P>SOLUTION: The heat/electricity direct converter 1a is constituted while having heat/electricity direct conversion semiconductors 2 and 3 directly converting a thermal energy to an electrical energy or the electrical energy to the thermal energy, and an airtight box body 30 interrupting the heat/electricity direct conversion semiconductors 2 and 3 from the outside air. In the heat/electricity direct converter 1a, the airtight box body 30 has a metallic cover 20 covering a high-temperature side substrate 7 joined with the high-temperature side ends of the heat/electricity direct conversion semiconductors 2 and 3, a metallic frame 21 surrounding the peripheries of the heat/electricity direct conversion semiconductors 2 and 3, and a means for extracting a current to the outside of the airtight box body 30. Further, the converter is composed of a low-temperature side substrate 22 joined with the low-temperature side ends of the heat/electricity direct conversion semiconductors 2 and 3. In the converter 1a, the inside of the airtight box body 30 is adjusted in a vacuum or an inert-gas atmosphere. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal-electrical direct conversion device, and more particularly to a thermal-electrical direct conversion device capable of suppressing the progress of deterioration due to oxidation or the like of components of the conversion device and maintaining good conversion efficiency over a long period of time.

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 due to 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 conventionally, and at present, the reuse of medium-scale waste heat has been 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 / repair cost 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 converts thermal energy directly into electrical energy using a semiconductor has been in progress (see, for example, Patent Document 1 and Non-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, the conventional thermo-electric direct conversion device 1 includes a p-type thermo-electric direct conversion semiconductor chip 2 and an n-type thermo-electric direct conversion semiconductor chip 3 having a high temperature side insulating plate (high temperature side substrate) having a high temperature side electrode 5. ) 7 and a low temperature side insulating plate (low temperature side substrate) 8 having the low temperature side electrode 6. The p-type thermal-electrical direct conversion semiconductor chip 2 and the n-type thermal-electrical direct conversion semiconductor chip 3 form a thermal-electrical direct conversion semiconductor pair 4, and a large amount of heat is electrically and thermally generated in the entire conversion device. An electrical direct conversion semiconductor pair is connected.

  The p-type heat-electric direct conversion semiconductor chip 2 and the n-type heat-electric direct conversion semiconductor chip 3 are joined via the high-temperature side electrode 5 and the high-temperature side electrode-semiconductor chip junction 11, and further p-type heat-electric direct The conversion semiconductor chip 2 and the n-type thermal-electrical direct conversion semiconductor chip 3 are joined via the low temperature side electrode 6 and the low temperature side electrode-semiconductor chip junction 12.

  In the heat-electrical 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 directly converted to the p-type heat-electricity via the high temperature side electrode-semiconductor chip junction 11. The semiconductor carrier 2 and the n-type direct thermal-electric conversion semiconductor chip 3 are transferred to the semiconductor chip 2 and 3 and pass through the semiconductor chip 2, 3. The holes 16 and the electrons 17 which are semiconductor carriers inside the n-type heat-electric direct conversion semiconductor chip 3 are transferred to the p-type heat-electric direct conversion semiconductor chip 2 or the n-type heat-electric direct conversion semiconductor chip 3 on the low temperature side. It moves toward the low temperature side electrode 6 joined via the electrode-semiconductor chip junction 12.

  On the other hand, the heat flow 14 that passes through the semiconductor chips 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 means installed in the heat-electricity direct conversion device 1 outside the heat-electricity 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 1 as a current flow 18 and used. Can do.

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, heat can also 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 not shown.
JP 2004-1119833 A "Thermoelectric conversion engineering-basics and applications-" Realize p. 349-363 (2001).

  Thus, when a heat difference is added to the thermo-electric direct conversion device to convert heat into electricity, the higher the high temperature side electrode temperature and the lower the low temperature side electrode temperature of the thermo-electric direct conversion device, That is, the greater the temperature difference between the electrodes, the greater the heat conversion efficiency. In addition, when a current is applied to the thermal-electrical direct conversion device to convert electricity into heat, the higher temperature or lower temperature of the thermal-electrical direct conversion device increases as the applied current increases. For this reason, in the conventional direct thermal-electric conversion device having the configuration shown in FIG. 1, when used in the atmosphere, components such as electrodes and semiconductor chips are likely to deteriorate due to oxidation, nitridation, etc. There was a problem that the ability to convert electricity or electricity to heat decreased with time, and it was difficult to ensure good conversion performance over a long period of time.

  In order to solve the above problems, the present inventors can shut off the conventional thermal-electric direct conversion device having the configuration shown in FIG. 1 from the atmosphere by enclosing it in a casing made of metal or ceramics as it is. A configuration that can prevent deterioration of parts due to oxidation is realized. However, since the heat flow supplied to the device passes not only through the semiconductor chip but also through the housing, the rate of heat to be converted is reduced, and the ability to convert from heat to electricity or from electricity to heat It became clear that there was a significant drop.

  The present invention has been made to solve the above-described problems, and provides a direct thermal-electric conversion device capable of suppressing the progress of deterioration due to oxidation or the like of constituent members and maintaining good conversion efficiency over a long period of time. Objective. It is another object of the present invention to provide a hermetic heat-electrical direct conversion device that can easily flow heat flow to a semiconductor chip and maintain high conversion efficiency.

  In order to achieve the above object, a thermal-electrical direct conversion device according to the present invention includes a thermal-electrical direct conversion semiconductor that directly converts thermal energy into electrical energy or electrical energy into thermal energy, and the thermal-electrical direct thereof. An airtight housing that shields the conversion semiconductor from outside air, the airtight housing covering a high temperature side substrate joined to a high temperature side end of the thermal-electrical direct conversion semiconductor, and the heat- It is composed of a metal frame that surrounds the periphery of the electrical direct conversion semiconductor, and a low temperature side substrate that is provided with means for taking out the current outside the hermetic housing and is joined to the low temperature side end of the thermal direct electrical conversion semiconductor. The inside of the airtight housing is adjusted to a vacuum or an inert gas atmosphere.

  According to the thermal-electrical direct conversion device, the metal lid that covers the high-temperature side substrate, the metal frame that surrounds the periphery of the thermal-electrical direct conversion semiconductor, and the low-temperature side end of the thermal-electrical direct conversion semiconductor are joined. The heat-electricity direct conversion semiconductor is cut off from the outside air by an airtight housing composed of a low temperature side substrate, and the inside of the airtight housing is adjusted to a vacuum or an inert gas atmosphere, so that components such as semiconductors It is possible to obtain a direct thermal-electric conversion device that can effectively prevent deterioration due to oxidation or the like and maintain high conversion efficiency over a long period of time.

  Further, in the above direct heat-electric conversion device, the metal lid is formed such that at least a portion in contact with the high temperature side substrate incorporated in the hermetic casing is higher than the peripheral portion and protrudes in the heat input direction. It is preferable.

  As described above, at least the metal lid portion that comes into contact with the high temperature side substrate built in the hermetic casing is formed so as to protrude higher in the heat input direction than the peripheral portion, thereby contacting the protruding metal lid. Since heat input is intensively propagated to the high temperature side substrate, heat is easily concentrated on the semiconductor chip, and the heat-electric conversion efficiency can be increased. On the other hand, the amount of heat received by the peripheral portion of the metal lid is relatively reduced as compared with the central portion, and thus the amount of heat dissipated wastefully through the metal frame is reduced.

  Further, in the thermal-electrical direct conversion device, the metal lid itself and the heat of the metal frame connected to the metal lid itself are formed on a portion of the metal lid that is not in contact with the high-temperature side substrate built in the hermetic casing. It is preferable to provide thermal expansion absorbing means for absorbing expansion.

  As described above, by providing the thermal expansion absorbing means in the portion of the metal lid that is not in contact with the high temperature side substrate built in the hermetic housing, the thermal expansion of the metal lid itself and the metal frame connected thereto is suppressed. It becomes possible to absorb effectively, a thermal stress is relieved effectively, and the converter excellent in durability is obtained. In particular, since the thermal expansion absorbing means is provided in a portion of the metal lid that is not in contact with the high temperature side substrate built in the airtight housing, the thermal expansion occurs and the metal lid is displaced. However, there is little possibility that the metal lid interferes with the semiconductor chip.

  Further, in the thermal-electrical direct conversion device, a flange mechanism that lengthens a heat transfer path from the metal lid to the low-temperature side substrate via the metal frame may be disposed on at least one of the metal lid and the metal frame. preferable.

  As described above, by providing the flange mechanism in the heat transfer path, it is possible to lengthen the heat transfer path (heat path) from the metal lid to the low temperature side substrate via the metal frame, and the airtight housing In particular, the heat transfer resistance in the metal frame can be increased to suppress the amount of heat passing, and the amount of heat involved in the heat-electric conversion can be increased relatively through the semiconductor chip. Therefore, the thermal-electric conversion efficiency in the semiconductor chip can be increased.

  Furthermore, in the said thermo-electric direct conversion apparatus, it is preferable that at least one part of the outer peripheral surface of the said metal frame is formed in the curved surface form.

  As described above, by forming at least a part of the outer peripheral surface of the metal frame into a curved shape, for example, each corner of the metal frame that has been formed into a rectangular tube shape is rounded to form a curved shape. This makes it possible to reduce the cross-sectional area of the metal frame and reduce the amount of heat passing through the metal frame, while increasing the amount of heat that passes through the semiconductor chip and participates in the heat-electrical conversion. Therefore, the thermal-electric conversion efficiency in the semiconductor chip can be increased.

  Moreover, it is preferable that the thermal-electrical direct conversion device includes a thermal expansion absorbing unit that absorbs thermal expansion of the metal frame in the height direction of the metal frame. As a specific configuration example of the thermal expansion absorbing means, a structure in which one or two or more stages where the cross section of the metal frame is bent can be adopted. The bent portion may have a shape in which a plane is bent, or may have a shape bent in an arc shape.

  As described above, by providing the thermal expansion absorbing means in the height direction of the metal frame, the thermal expansion of the metal frame can be effectively absorbed, the thermal stress is effectively relieved, and the heat of the airtight housing is reduced. Fatigue failure due to stress can be effectively prevented, and a converter having excellent durability can be obtained.

  Furthermore, in the thermal-electrical direct conversion device, the metal lid and the metal frame are welded or integrally formed, while the low temperature side substrate and the metal frame are welded, soldered, or brazed. Bonding, diffusion bonding, or bonding with an adhesive is preferable.

  The joining method of the metal lid, the metal frame, and the low temperature side substrate is not particularly limited, but according to the joining method, the joining operation is simple and sufficient joining strength can be obtained. In particular, by integrally molding the metal lid and the metal frame, the number of device parts is reduced and the device can be easily assembled.

  In the thermal-electrical direct conversion device, the inert gas atmosphere in the hermetic casing is preferably composed of at least one gas selected from nitrogen, helium, neon, argon, krypton, and xenon.

  By sealing the non-oxidizing gas in an airtight housing and deactivating the internal atmosphere, it is possible to effectively prevent components such as semiconductor chips from deteriorating due to oxidation, etc., and maintain high conversion efficiency over a long period of time. A direct heat-electric conversion device is obtained.

  Furthermore, in the thermal-electrical direct conversion device, it is preferable that the pressure of the inert gas atmosphere is set to be lower than the external pressure at room temperature.

  As described above, by setting the pressure of the inert gas atmosphere in the hermetic casing to be lower than the external pressure, it is possible to effectively prevent moisture from remaining in the inert gas atmosphere in the hermetic casing. Chip degradation damage can be effectively suppressed. Further, since the thermal conductivity in the gas atmosphere in the hermetic casing 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.

  In the thermal-electric direct conversion device, the metal lid and the metal frame are preferably made of a heat-resistant metal or a heat-resistant alloy that can withstand the high temperature side temperature of the heat-electric direct conversion device. Specifically, the heat-resistant alloy includes nickel or a nickel-base alloy, an iron-base alloy selected from carbon steel and stainless steel, an iron-base alloy containing chromium, an iron-base alloy containing silicon, an alloy containing cobalt, copper It is preferable that it is either of the alloys containing.

  According to the metal lid and metal frame made of the above heat-resistant metal or heat-resistant alloy, excellent durability can be exhibited with little deterioration even in a high temperature use environment.

  Furthermore, in the thermal-electrical direct conversion device, the low-temperature side substrate includes a ceramic plate and a metal plate bonded to at least one surface of the ceramic plate, and the metal plate includes copper, silver, aluminum, tin, It is preferably made of at least one selected from iron-based alloys, nickel, nickel-based alloys, titanium, and titanium-based alloys.

  As described above, by using the low temperature side substrate in which the metal plate is bonded to at least one surface of the ceramic plate, the low temperature side substrate in which the metal plate as the low temperature side electrode is bonded to the insulating substrate in advance is obtained, and the conversion device Assembling becomes easy. Since the bonding strength between the ceramic plate and the metal plate is high and the degree of adhesion between the two is also high, a converter having excellent durability can be obtained.

  Further, in the direct thermal-electric conversion device, the ceramic plate used for the low-temperature side substrate is alumina or ceramic containing alumina, metal containing alumina powder dispersedly, silicon nitride or ceramic containing silicon nitride, Consists of at least one selected from aluminum nitride or ceramic containing aluminum nitride, ceramic containing zirconia or zirconia, yttria or ceramic containing yttria, silica or ceramic containing silica, beryllia or ceramic containing beryllia It is preferred that

  According to the low temperature side substrate made of the above ceramic plates, since the insulation resistance is stable and excellent, a highly reliable thermo-electric direct conversion device capable of exhibiting a high thermoelectric effect over a long period of time can be obtained.

  Furthermore, in the thermal-electrical direct conversion device, the thermal-electrical direct conversion semiconductor comprises a p-type semiconductor and an n-type semiconductor, and these semiconductors are rare earth elements, actinoids, cobalt, iron, rhodium, ruthenium, palladium. At least 3 selected from platinum, nickel, antimony, titanium, zirconium, hafnium, nickel, tin, cobalt, silicon, manganese, zinc, boron, carbon, nitrogen, gallium, germanium, indium, vanadium, niobium, barium, magnesium A thermal-electric direct conversion semiconductor composed of seed elements is preferred.

  According to the thermo-electric direct conversion semiconductor composed of the at least three elements, a thermo-electric direct conversion device that can exhibit a good thermoelectric effect over a long period of time and has high thermoelectric conversion efficiency is provided. can get.

  Further, in the thermo-electric direct conversion device, the crystal structure of the p-type or n-type thermo-electric direct conversion semiconductor is a skutterudite structure, a filled skutterudite structure, a Heusler structure, a half-Heusler structure, or a clathrate structure. It is preferable that any one of them.

  According to the semiconductor chip having each of the above crystal structures, a thermoelectric direct conversion device having a good thermoelectric effect and high thermoelectric conversion efficiency can be obtained.

  According to the thermal-electrical direct conversion device according to the present invention, the metal lid that covers the high-temperature side substrate, the metal frame that surrounds the thermal-electrical direct conversion semiconductor, and the low-temperature side end of the thermal-electrical direct conversion semiconductor The heat-electrical direct conversion semiconductor is cut off from the outside air by an airtight housing composed of a low temperature side substrate to be joined, and the inside of the airtight housing is adjusted to a vacuum or an inert gas atmosphere. It is possible to effectively prevent the component parts from being deteriorated due to oxidation or the like and to obtain a thermal-electric direct conversion device capable of maintaining high conversion efficiency over a long period of time.

  Next, modes for carrying out the present invention will be described based on the following embodiments with reference to the accompanying drawings.

Example 1
FIG. 1 is a view showing an embodiment of a direct heat-electric conversion device according to the present invention using an airtight housing that cuts off a semiconductor chip from the outside air, and FIG. 1A is a direct view of heat-electric direct according to the present invention. It is a perspective view which shows the structure of one Example of a converter, FIG.1 (b) is BB arrow sectional drawing of the thermoelectric direct conversion apparatus (thermoelectric direct conversion module) shown to Fig.1 (a). is there.

  As shown in FIG. 1, a thermal-electrical direct conversion device 1a according to this embodiment includes a thermal-electrical direct conversion semiconductor 4 that directly converts thermal energy into electrical energy or electrical energy into thermal energy, and its thermal- The airtight housing 30 is configured to block the electric direct conversion semiconductor 4 from the outside air, and the airtight housing 30 covers the high temperature side substrate 7 joined to the high temperature side end of the heat-electrical direct conversion semiconductor 4. A metal lid 20, a metal frame 21 surrounding the heat-electric direct conversion semiconductor 4, and a means 10 for taking out current from the hermetic casing are joined to the low-temperature end of the heat-electric direct conversion semiconductor. The inside of the airtight housing 30 is adjusted to a vacuum or an inert gas atmosphere.

The thermo-electric direct conversion semiconductor 4 is constituted by a pair of a p-type thermo-electric direct conversion semiconductor chip 2 and an n-type thermo-electric direct conversion semiconductor chip 3 having a skutterudite structure. The low temperature side substrate 8 and the high temperature side substrate 7 are made of alumina (Al ₂ O ₃ ), while the low temperature side substrate 8 is made of an AlN base ceramic substrate. Further, the metal lid 20 and the metal frame 21 constituting the hermetic casing 30 are made of a nickel-based alloy.

  When heat is converted into electricity by supplying heat to the heat-electric direct conversion device configured as described above and adding a temperature difference to the input / output ends, the high temperature side temperature of the heat-electric direct conversion device is increased. The lower the temperature on the lower temperature side, that is, the larger the temperature difference between the input and output ends, the higher the thermal-electric conversion efficiency. That is, in order to increase the conversion efficiency, it is effective to operate the input end of the thermo-electric direct conversion device under a high temperature condition.

  However, when the direct thermal-electric conversion device is operated under high temperature conditions in the atmosphere, components such as electrodes and semiconductor chips are easily oxidized and nitrided, and deterioration is likely to proceed. In order to suppress the progress of deterioration of these structural members, suppress the decrease in conversion efficiency from heat to electricity, or from electricity to heat, and ensure good conversion performance over a long period, As shown, it is effective to use an airtight casing that shields the thermal-electrical direct conversion device from outside air.

  As shown in FIG. 1, in the thermal-electric direct conversion device according to the present embodiment, a plurality of thermal-electrical units composed of a p-type thermal-electrical direct conversion semiconductor chip 2 and an n-type thermal-electrical direct conversion semiconductor chip 3. The low temperature side end of the direct conversion semiconductor pair 4 is bonded to the low temperature side substrate 22 via the low temperature side electrode-semiconductor chip junction 23, while the high temperature side end connects the high temperature side electrode-semiconductor chip junction 11. And mechanically connected to a high-temperature side substrate (high-temperature side insulating plate) 7.

  The thermoelectric direct conversion device directly converts the temperature difference between the metal lid 20 on the side to which waste heat is supplied and the low temperature side substrate 22 into electricity and takes it out of the device as power, or the device input end from the outside Current is supplied to the heat source to cause heat transfer from the low temperature side system to the high temperature side system. Since the portion in contact with the metal lid 20 inside the apparatus to which heat is supplied becomes high temperature, it is necessary to protect the conversion element such as a semiconductor chip and the electrode from oxidation under a high temperature environment.

  Therefore, in this embodiment, in order to fill the inside of the apparatus with an oxidation-resistant gas such as nitrogen and seal the inside of the apparatus, the metal lid 20 and the metal frame 21 are integrally bonded and fixed to the low-temperature side substrate 22 so as to be airtight. A housing 30 is formed. On the outside of the hermetic casing 30, there is provided a current extraction means 10 that maintains an internal sealing property and performs electrical connection with the outside. The connection means 9 with the electrode-current extraction means 10. Thus, the electrodes 5 and 6 inside the apparatus are electrically connected to the outside.

  Although the case where the current extraction means 10 provided outside the housing 30 is a thin plate-shaped terminal is illustrated in FIG. 1, in order to protect the terminal portion from external force, it is possible to have a shape other than the thin plate. .

  According to the thermal-electrical direct conversion device according to the present embodiment, the inside of the housing 30 in which the constituent members such as the electrodes 6 and 7 and the semiconductor chip pair 4 are installed is kept airtight, and the inside is vacuum or inert gas. It becomes possible to maintain the atmosphere. Thereby, even when operated in a high temperature environment, it is possible to effectively suppress the progress of deterioration due to oxidation, nitridation, or the like of the constituent members installed inside the casing of the thermal-electrical direct conversion device. .

(Example 2)
In FIG. 3, the amount of heat passing through the metal frame 21 is reduced and the conversion performance is improved by making the portion in contact with the high temperature side insulating plate 7 of the metal lid 20 of the thermo-electric direct conversion device higher than the other portions. 1 shows an embodiment of a thermal-electrical direct conversion device.

  That is, in the thermal-electrical direct conversion device according to the present embodiment, in addition to the configuration of the first embodiment, the metal lid 20 is in contact with at least the high temperature side substrate 7 built in the hermetic housing 30. The part is formed so as to protrude in the heat input direction higher than the peripheral part.

  According to the thermal-electrical direct conversion device according to the present embodiment, the heat transfer path from the metal lid 20 to the low temperature side substrate 22 via the metal frame 21 is brought into contact with the high temperature side insulating plate 7 of the metal lid 20. Compared to the case where the height of the other portion is equal to the height of the other portion, the length can be made longer, and the heat supplied to the apparatus can be received intensively at the central portion of the metal lid 20, so that the heat-electricity direct Heat can be intensively introduced into the conversion semiconductor pair 4 and the thermoelectric conversion efficiency can be increased. In particular, since the heat transfer path can be lengthened and the heat transfer resistance of the path can be relatively increased, the high temperature side insulating plate 7, the high temperature side electrode 5, and the thermo-electric direct The amount of heat passing through the semiconductor pair 4 and the low temperature side electrode 6 to the low temperature side substrate 22 can be increased, and the performance of the direct thermoelectric conversion device can be improved.

  The heat transfer path from the metal lid 20 to the low temperature side substrate 22 via the metal frame 21 is only a step-shaped path 31 at the peripheral edge of the metal lid 20 as shown in FIGS. 3 and 6A. It is not limited to. For example, as shown in FIG. 6B, a structure in which an arc-shaped path 32 is provided in the peripheral edge of the metal lid 20, a structure in which the arc-shaped path is formed in multiple stages, or a structure shown in FIG. Thus, it is also possible to adopt a structure in which the bent portion 33 having a V-shaped cross section is formed on the peripheral portion of the metal lid 20 or a structure in which the bent portions 34 are formed in multiple stages as shown in FIG. . The step-shaped path 31, the arc-shaped path 32, and the bent portions 33, 34 are also a thermal stress absorbing mechanism that absorbs the displacement and suppresses the generation of thermal stress even when the metal lid 20 is thermally expanded. Useful because it works.

Example 3
FIG. 4 shows the thermal expansion of the metal lid 20 itself and the metal frame 21 connected to the portion not in contact with the high temperature side insulating plate (high temperature side substrate) 7 of the metal lid 20 of the thermal-electrical direct conversion device. An embodiment of a direct thermal-electric conversion device provided with a mechanism for relaxing thermal stress generated in the metal lid 20 and the metal frame 21 by providing means for absorbing is shown.

  That is, in the direct thermal-electric conversion device according to the present embodiment shown in FIG. 4, in addition to the configuration of the first embodiment, the high temperature side substrate built in the hermetic casing 30 of the metal lid 20 is further included. 7 is provided with a thermal expansion absorbing means 35 that absorbs thermal expansion of the metal lid 20 itself and the metal frame 21 connected to the metal lid 20 itself.

  In the thermal-electrical direct conversion device according to this embodiment, in order to relieve the thermal stress generated in the metal lid 20 and the metal frame 21 connected to the metal lid 20 and the stress generated in other parts due to those stresses. By providing the thermal expansion absorbing means 35 having a V-shaped cross section in a portion of the metal lid 20 that is not in contact with the high temperature side insulating plate 7, the metal lid 20 and the metal frame 21 connected to the metal lid 20 are generated. Thermal expansion and thermal deformation can be absorbed.

  In addition to the V-shaped cross section shown in FIG. 4 and FIG. 6 (c), the cross section of the thermal expansion absorbing means 35 has an arc cross section as shown in FIG. It is possible to adopt a multi-stage or a V-shaped cross section formed in two or more stages as shown in FIG. 6 (d), both of which are effective for thermal expansion and thermal deformation of the constituent members. Can be absorbed.

Example 4
In FIG. 5, the amount of heat passing through the metal frame 21 is suppressed by providing means for extending the heat transfer path from the metal lid 20 of the thermo-electric direct conversion device to the low temperature side substrate 22 via the metal frame 21, An embodiment of a thermo-electric direct conversion device that suppresses a decrease in the amount of heat passing through the thermo-electric direct semiconductor pair due to the provision of the metal frame 21 and improves the thermoelectric conversion performance will be described.

  In other words, in addition to the configuration of the first embodiment, the heat-electric direct conversion device according to the present embodiment shown in FIG. 5 further includes a heat transfer path from the metal lid 20 to the low temperature side substrate via the metal frame 21. A flange mechanism 36 for increasing the length of the metal cover 20 is provided on at least one of the metal lid 20 and the metal frame 21.

  In the thermal-electrical direct conversion device according to the embodiment shown in FIG. 5, as means for taking a long heat transfer path, a flange is provided in the middle of the heat transfer path from the metal lid 20 to the low temperature side substrate 22 via the metal frame 21. This is an example where a mechanism 36 is provided. In this embodiment, a flange mechanism 36 is formed by combining a flange 36 a extending outward from the outer peripheral edge of the metal lid 20 and a flange 36 b extending outward from the upper end of the metal frame 21. Then, the flange 36b provided on the metal frame 21 and the flange 36a provided on the metal lid 20 are sealed and welded so that the joining portion is on the outer peripheral side of the flange, whereby the heat transfer path between the metal lid 20 and the metal frame 21 is achieved. The length is increased by an amount corresponding to the distance (width) of the flange.

  By using this structure, the heat transfer path length from the metal lid 20 to the low temperature side substrate 22 via the metal frame 21 is increased, and the heat transfer resistance is increased to make it difficult for heat to propagate. The amount of heat passing through the heat transfer path from the high temperature side insulating plate 7, the high temperature side electrode 5, the thermoelectric direct semiconductor pair 4 and the low temperature side electrode 6 to the low temperature side substrate 22 can be relatively increased. The thermoelectric conversion performance in the direct thermo-electric converter can be improved.

  In addition, as another means for ensuring the heat transfer path long, a structure in which the shape of the peripheral edge of the metal lid 20 is arcuate as shown in FIG. 6B, a structure in which the arcuate path is multi-staged, By adopting a path structure having a V-shaped cross section as shown in FIG. 6C and a structure in which a path having a V-shaped cross section is formed in multiple stages as shown in FIG. 6D, the heat transfer path is made longer. Is also possible.

  Further, as another means for ensuring a long heat transfer path, a metal frame 21 having a bent portion whose section is bent in a V shape as shown in FIG. Further, as shown in FIG. 8B, a metal frame 21 in which a bent portion whose section is refracted into a V-shape is formed in two or more stages may be adopted. Furthermore, as shown in FIG. 8C, a metal frame 21 provided with a bent portion having an arc-shaped cross section may be employed. Further, as shown in FIG. 8D, a metal frame 21 in which bent portions having an arcuate cross section are formed in two or more stages may be employed. Furthermore, a metal frame 21 provided with a bent portion having an S-shaped cross section as shown in FIG. In either case, it is possible to ensure a long heat transfer path.

(Example 5)
FIG. 7 shows an embodiment of a direct heat-electric conversion device in which the cross-sectional area is reduced by forming the four corners of the cross section of the metal frame 21 into a curved surface in order to reduce the amount of heat passing through the metal frame 21.

  That is, in the thermo-electric direct conversion device according to the present embodiment shown in FIG. 7, in addition to the configuration of the first embodiment, at least a part of the outer peripheral surface of the metal frame 21 is formed in a curved shape. It is characterized by.

  In the thermal-electrical direct conversion device according to the present embodiment, as shown in FIG. 7A, the metal lid 20, the metal frame 21, and the low-temperature side substrate 22 are integrally joined to form an airtight casing 30. Has been. However, with respect to the cross-sectional shape of the metal frame 21, from the state of the metal frame 21 having a conventional general rectangular cross section as shown on the left side of FIG. The metal frame 21 subjected to (R processing) is used.

  According to the direct thermal-electric conversion device according to the present embodiment, the cross-sectional area of the metal frame 21 can be reduced as compared with a conventional metal frame having a rectangular cross section without a curved surface portion, and heat passing through the metal frame 21 is achieved. Since the amount can be reduced, heat from the metal lid 20 to the low temperature side substrate 22 via the high temperature side insulating plate 7, the high temperature side electrode 5, the thermoelectric direct semiconductor pair 4 and the low temperature side electrode 6. The amount of passage can be increased relatively, and the thermoelectric conversion performance in the thermo-electric direct conversion device can be improved.

  As another means for reducing the cross-sectional area of the cross section of the metal frame 21, it is possible to perform chamfering at four corners in the cross section. Moreover, you may reduce the cross-sectional area of the metal frame 21 by processing so that it may have the curved surface which a curvature changes continuously instead of the curved surface which has a fixed curvature.

(Example 6)
Next, there is provided a means for absorbing thermal expansion of the metal frame 21 of the thermal-electrical direct conversion device, and one of the thermal-electrical direct conversion devices provided with a mechanism for relaxing the thermal stress generated in the metal lid 20 and the metal frame 21. An embodiment is shown in FIG.

  That is, in the thermal-electrical direct conversion device according to the present embodiment shown in FIG. 8, in addition to the configuration of the first embodiment, the thermal expansion further absorbs the thermal expansion of the metal frame 21 in the height direction of the metal frame 21. The absorption means 37 is provided.

  In this embodiment, in order to relieve the thermal stress generated in the metal lid 20 and the metal frame 21 connected to the metal lid 20, the metal frame 21 has a V-shaped cross section as shown in FIG. A bent portion is provided as the thermal expansion absorbing means 37. The thermal expansion absorbing means 37 having a bent portion having a V-shaped cross section easily absorbs thermal expansion and thermal deformation generated in the metal lid 20 and the metal frame 21 connected to the metal lid 20. The cross-sectional shape of the thermal expansion absorbing means 37 may be a structure in which V-shaped bent portions are provided in two or more stages as shown in FIG. Moreover, as shown in FIG.8 (c), it can also be set as the structure which provided the circular-arc-shaped bending part. Furthermore, as shown in FIG. 8D and FIG. 8E, arc-shaped bent portions may be provided in multiple stages.

  Further, the thermal expansion absorbing means is configured by appropriately combining with the passing heat amount reducing mechanism shown in Example 2, the stress relaxation mechanism shown in Example 3, the flange mechanism shown in Example 4, and the metal frame shape shown in Example 5. It is also possible.

(Example 7)
An example of a joining structure between the metal lid 20 and the metal frame 21 and an example of a joining structure between the metal frame 21 and the low temperature side substrate 22 are shown in FIG. FIG. 9A shows a state in which the metal lid 20 and the metal frame 21 are joined by welding, while FIG. 9B shows an embodiment in which the metal lid 20 and the metal frame 21 are integrally formed. On the other hand, the metal frame 21 and the low temperature side substrate 22 are bonded via a low temperature substrate-metal frame bonding portion 25. The joining operation is performed by welding, soldering or brazing, diffusion joining, or a joining method using an adhesive.

  According to the above joining method, the joining operation is simple and sufficient joining strength can be obtained. In particular, by integrally molding the metal lid and the metal frame, the number of device parts is reduced and the device can be easily assembled.

The structure of the thermoelectric direct conversion apparatus which concerns on Example 1 is shown, (a) is a perspective view which shows the external appearance of an apparatus, (b) is BB arrow sectional drawing in Fig.1 (a). The perspective view which shows the structural example of the conventional thermoelectric direct conversion apparatus, and the schematic diagram which expands and shows the principal part. Sectional drawing of the principal part of the thermoelectric direct conversion apparatus which concerns on Example 2. FIG. Sectional drawing of the principal part of the thermoelectric direct conversion apparatus which concerns on Example 3. FIG. Sectional drawing of the principal part of the thermoelectric direct conversion apparatus which concerns on Example 4. FIG. It is sectional drawing of the principal part of the thermoelectric direct conversion apparatus which concerns on Example 5, (a) shows the structural example which provided the step-shaped path | route, (b) showed the structural example which provided the circular arc-shaped path | route. (C) shows the example of composition which provided the bent part, and (d) is a sectional view showing the example of composition which provided the bent part in multiple stages. The thermal-electrical direct conversion apparatus which concerns on Example 6 is shown, (a) is a perspective view which shows the external appearance of an apparatus, (b) is a plane sectional view which shows the cross-sectional shape of a metal frame. It is sectional drawing of the principal part of the thermoelectric direct conversion apparatus which concerns on Example 7, (a) shows the structural example which formed the bending part which has a V-shaped cross section in the metal frame as a thermal expansion absorption means, (b ) Shows a configuration example in which a thermal expansion absorbing means having multiple bent portions formed on a metal frame is formed on the metal frame, and (c) shows a configuration example in which a bent portion having an arc-shaped cross section is formed on the metal frame as a thermal expansion absorbing means. (D) shows a configuration example in which a bent portion having an arc-shaped cross section is formed in two steps to form a thermal expansion absorbing means, and (e) shows a bent portion having an arc-shaped cross section coupled in an S shape. FIG. 5 is a cross-sectional view showing a configuration example of a thermal expansion absorbing unit. It is sectional drawing which shows the principal part of the thermoelectric direct conversion apparatus which concerns on Example 8, (a) is sectional drawing which shows the state which joined the metal lid | cover 20 and the metal frame 21 by welding, (b). FIG. 3 is a cross-sectional view showing an embodiment in which a metal lid 20 and a metal frame 21 are integrally formed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Thermal-electrical direct conversion apparatus 2 P-type thermal-electrical direct conversion semiconductor chip 3 N-type thermal-electrical direct conversion semiconductor chip 4 Thermal-electrical direct conversion semiconductor pair 5 High temperature side electrode 6 Low temperature side electrode 7 High temperature side insulating plate (High temperature side substrate)
8 Low temperature side insulating plate (low temperature side substrate)
9 Electrode-Means with Current Extraction Means 10 Current Extraction Means 11 High Temperature Side Electrode-Semiconductor Chip Junction 12 Low Temperature Side Electrode-Semiconductor Chip Junction 13 Heat Flow 14 Supplyed to High Temperature Side Electrode 14 Heat Flow 15 Passing through Semiconductor Chip Heat flow emitted from the low temperature side electrode 16 Hole 17 Electron 18 Current flow 19 Electrical load 20 Metal lid 21 Metal frame 22 Low temperature side substrate 23 Low temperature side electrode-low temperature side insulating plate junction 24 Heat release to the low temperature side system Part 25 low temperature substrate-metal frame joint part 26 current extraction part insulation means 30 airtight housing 31 stepped path 32 arcuate path 33 bent part 34 multi-stage bent part 35 thermal expansion absorbing means 36 flange mechanisms 36a, 36b flange 37 thermal expansion absorption means

Claims (15)

A heat-electric direct conversion semiconductor that directly converts thermal energy into electrical energy or electric energy into thermal energy, and an airtight housing that blocks the heat-electrical direct conversion semiconductor from outside air. The body takes out a metal lid that covers the high-temperature side substrate joined to the high-temperature side end of the thermo-electric direct conversion semiconductor, a metal frame that surrounds the thermo-electric direct conversion semiconductor, and current out of the hermetic casing. And a low-temperature side substrate bonded to the low-temperature side end of the thermoelectric direct conversion semiconductor, and the inside of the hermetic casing is adjusted to a vacuum or an inert gas atmosphere. A direct heat-electric conversion device. 2. The heat according to claim 1, wherein the metal lid is formed such that at least a portion in contact with a high temperature side substrate built in the hermetic casing is higher than a peripheral portion and protrudes in a heat input direction. -Electric direct conversion device. Of the metal lid, a thermal expansion absorbing means for absorbing thermal expansion of the metal lid itself and a metal frame connected to the metal lid itself is provided in a portion not in contact with the high temperature side substrate built in the hermetic casing. The thermal-electrical direct conversion device according to claim 1 or 2, wherein the thermal-electrical direct conversion device is provided. 4. A flange mechanism for elongating a heat transfer path from the metal lid to a low temperature side substrate through a metal frame is disposed on at least one of the metal lid and the metal frame. The thermal-electrical direct conversion apparatus in any one. 5. The direct thermoelectric conversion device according to claim 1, wherein at least a part of an outer peripheral surface of the metal frame is formed in a curved shape. 6. The thermal-electrical direct conversion device according to claim 1, further comprising thermal expansion absorption means for absorbing thermal expansion of the metal frame in a height direction of the metal frame. The metal lid and the metal frame are welded or integrally formed, while the low-temperature side substrate and the metal frame are bonded by welding, soldering, brazing, diffusion bonding, or an adhesive. The thermal-electrical direct conversion device according to any one of claims 1 to 6, wherein the thermal-electrical direct conversion device is provided. The thermo-electricity according to any one of claims 1 to 7, wherein the inert gas atmosphere comprises at least one gas selected from nitrogen, helium, neon, argon, krypton, and xenon. Direct conversion device. 9. The direct thermoelectric conversion device according to claim 1, wherein a pressure of the inert gas atmosphere is set to be lower than an external pressure at normal temperature. 10. The heat-of any one of claims 1 to 9, wherein the metal lid and the metal frame are made of a heat-resistant metal or heat-resistant alloy that can withstand a high temperature side temperature of a heat-electrical direct conversion device. Electric direct conversion device. The heat-resistant alloy is an iron-based alloy selected from nickel or a nickel-based alloy, carbon steel, and stainless steel, an iron-based alloy containing chromium, an iron-based alloy containing silicon, an alloy containing cobalt, and an alloy containing copper. The direct thermal-electric conversion device according to claim 10, which is any one of the above. The low-temperature side substrate comprises a ceramic plate and a metal plate bonded to at least one surface of the ceramic plate. The metal plate is copper, silver, aluminum, tin, iron-base alloy, nickel, nickel-base alloy, titanium. The thermal-electrical direct conversion device according to any one of claims 1 to 11, wherein the thermal-electric direct conversion device comprises at least one selected from titanium-based alloys. The ceramic plate used for the low temperature side substrate is alumina or a ceramic containing alumina, a metal containing alumina powder dispersedly, a ceramic containing silicon nitride or silicon nitride, a ceramic containing aluminum nitride or aluminum nitride, zirconia 13. The heat according to claim 12, comprising at least one selected from zirconia-containing ceramics, yttria or yttria-containing ceramics, silica or silica-containing ceramics, beryllia or beryllia-containing ceramics. -Electric direct conversion device. The thermal-electrical direct conversion semiconductor comprises a p-type semiconductor and an n-type semiconductor, and these semiconductors are rare earth elements, actinoids, cobalt, iron, rhodium, ruthenium, palladium, platinum, nickel, antimony, titanium, zirconium, Thermo-electric direct composed of at least three elements selected from hafnium, nickel, tin, cobalt, silicon, manganese, zinc, boron, carbon, nitrogen, gallium, germanium, indium, vanadium, niobium, barium, magnesium The thermal-electrical direct conversion device according to any one of claims 1 to 13, wherein the thermal-electrical direct conversion device is a conversion semiconductor. The crystal structure of the p-type or n-type direct thermal-electric conversion semiconductor is any one of a skutterudite structure, a filled skutterudite structure, a Heusler structure, a half-Heusler structure, and a clathrate structure. The thermal-electrical direct conversion apparatus of Claim 14.

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