JP2003304006A - Thermoelectric conversion module and heat exchanger using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a module using thermoelements usable under temperatures above 300°C, and a heat exchanger using the module. <P>SOLUTION: A thermoelectric conversion module has p-type thermoelectric conversion element bodies (11) and n-type thermoelectric conversion element bodies (12), which are connected to each other in series via electrode members (13, 14) and are arranged to be opposite to each other so as to constitute a first plane on a high temperature side and a second plane on a low temperature side. The p-type thermoelectric conversion element bodies (11) are composed of p-type cobalt-antimony based semiconductors, and the n-type thermoelectric conversion element bodies (12) are composed of n-type cobalt-antimony based semiconductors. A thin film layer is formed between each electrode member (13, 14) and thermoelectric conversion element body. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric conversion module using a semiconductor type thermoelectric element and a heat exchanger using the same.

[0002]

2. Description of the Related Art Today, when resources are expected to be exhausted in the 21st century, how to effectively use energy has become an extremely important issue, and various systems have been devised. Among them, the thermoelectric element is expected as a means for recovering energy that has been wasted in the environment as waste heat. Such a thermoelectric conversion element is used as a module in which a p-type semiconductor and an n-type semiconductor are connected to each other in series.

Conventionally, in order to achieve high thermoelectric conversion efficiency, many thermoelectric conversion semiconductor materials have been studied, and much attention has been paid particularly to improvement of power generation efficiency.

However, looking at thermoelectric materials from a practical standpoint, the one currently in practical use is bismuth (Bi)-
Tellurium (Te) series (including Sb and selenium (Se) as the third element), and other materials have a track record of being manufactured for special purposes, but are not on an industrial production base. .

By the way, conventionally, the waste heat boiler is designed only for the purpose of selecting steam or hot water through a heat exchanger, and electric power related to its operation is externally supplied. However, in recent years, attempts have been made to incorporate a thermoelectric conversion module into this waste heat boiler to extract electric power from the waste heat. In that case, from the viewpoint that a higher temperature heat source can be utilized, the thermoelectric conversion element to be used is more desirable as the usable temperature is higher, and it can be said that it is particularly preferable to have a usable temperature of 300 ° C. or higher.

However, the conventional Bi-Te-based thermoelectric conversion element has an operating temperature of at most 200 ° C., and cannot meet this requirement. Moreover, the bonding material and bonding method with the underlying electrode material or substrate material that fixes the semiconductor material is a conventional bonding method using a brazing material, etc. It was not possible to obtain electric power, which was a big problem for practical use.

[0007]

In the conventional thermoelectric conversion element, the operating temperature of the semiconductor material itself is limited to 200 ° C. or lower, and the semiconductor material and the base electrode material or the substrate material in a high operating temperature range are used. The joining of was not sufficient, and a large electromotive force could not be stably obtained.

Therefore, the present invention improves the semiconductor material, the bonding material and the bonding method between this semiconductor material and the electrode material of the underlying layer, and exhibits a sufficient thermoelectric conversion function for a long time even at a temperature of 300 ° C. or higher. An object is to provide a module and a heat exchanger using the same.

[0009]

In order to achieve the above-mentioned object, the present inventors have focused on a filled skutterudite thermoelectric conversion semiconductor which can be used at a temperature of 300 ° C. or higher. However, it can withstand the use of high temperature above 300 ℃,
Conventionally, there has been no means for joining an electrode material or a heat conductive plate that does not change the performance of the element. In addition, even if the thermoelectric conversion semiconductor element and the electrode material can be joined, a large thermal stress is generated in the thermoelectric conversion module that requires a large temperature difference if there is a difference in the coefficient of thermal expansion between the element and the electrode. As a result, it was found that there was a problem that the element was destroyed or the junction was destroyed.

The present inventors have spent many experiments to solve these various problems, have found a filled skutterudite thermoelectric conversion element that can be used at high temperatures, and have a foil or thin plate of Al or Al alloy. the filled skutterudite thermoelectric conversion element and the thermal expansion coefficient of approximately the thermal expansion coefficient is heated to 8x10 ^-6 / ℃ ~16x10 ^-6 / ℃ above insert 550 ° C. between the electrode plates made of an iron-based material is the temperature when It has been found that high bonding strength can be obtained without affecting the thermoelectric properties of the device.

Further, an iron material as an electrode material, particularly JIS
The thermal expansion coefficient of martensitic stainless steel typified by SUS410 is 12 × 10 ^-6 / ° C in the temperature range up to 500 ° C, so that it is almost equal to the thermal expansion coefficient of the filled skutterudite material and the thermal stress Is a size that does not occur or does not matter even if it occurs.

The present invention is based on these findings.

That is, according to the present invention, in order to solve the above-mentioned problems, the thermoelectric conversion module according to claim 1 is configured by an electrode member so as to form a first plane on the high temperature side and a second plane on the low temperature side. A p-type thermoelectric conversion element body, which is connected to each other in series and arranged to face each other, is provided, and the p-type thermoelectric conversion element body is p-type cobalt.
(Co) -antimony (Sb) based semiconductor,
Type thermoelectric conversion element body is composed of an n-type Co-Sb based semiconductor, and the electrode member has a thermal expansion coefficient of 8 × 10 ⁻⁶ / ° C. to 1
A thin film layer containing aluminum (Al) as a main component, which is made of a material in the range of ⁶ × 10 ⁻⁶ / ° C. and is pressure-welded between the thermoelectric conversion element body and the electrode member, is bonded. Here, the thin film layer contains aluminum (Al) as a main component, contains pure aluminum, and is an element that alloys with aluminum at 5 wt% or less of aluminum, for example, Si, Cu, Ni, Co, Fe, etc. Alternatively, it may include a metal or semiconductor that is inevitably contained.

The thermoelectric conversion module according to claim 2 is the thermoelectric conversion module according to claim 1, wherein the thin film layer has a bonding pressure of 200 kg / cm 2.
It is characterized by being formed by pressure welding at a joining temperature of 500 ° C to 600 ° C.

A thermoelectric conversion module according to a third aspect of the present invention is the thermoelectric conversion module according to the first aspect, wherein an insulating heat conducting plate made of ceramics or silicon rubber is provided in one or both of the first plane and the second plane. Is characterized by.

A thermoelectric conversion module according to a fourth aspect is the thermoelectric conversion module according to any one of the first to third aspects, wherein the n-type thermoelectric conversion element body and the p-type thermoelectric conversion element body have a skutterudite type crystal structure. It is a compound having a filled skutterudite structure in which voids in a CoSb ₃ -based compound crystal are filled with an element.

A thermoelectric conversion module according to a fifth aspect is a heat exchanger having a heating surface and a cooling surface, and the thermoelectric conversion module according to the first aspect is provided between the heating surface and the cooling surface. A heat exchanger characterized by the above.

The ceramic insulating heat conductive plate can be made of aluminum nitride, silicon nitride, silicon carbide or alumina.

Further, in the present invention, the above-mentioned electrode member is made of an iron-based electrode material, and an Al-Sb alloy layer having a thickness of 10 μm or less is present at the joint between the thermoelectric conversion element body and the electrode member. Is preferred.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

FIG. 1 is a schematic sectional view showing a thermoelectric conversion module according to an embodiment of the present invention.

The thermoelectric conversion module 10 of FIG.
P-type cobalt-antimony type thermoelectric conversion element body 11 made of type cobalt-antimony type semiconductor and n-type cobalt-antimony type thermoelectric conversion element body 12 made of a plurality of n-type cobalt-antimony type semiconductors are alternately arranged on the same plane. Are arranged side by side on a matrix. An n-type thermoelectric element body 12 is adjacent to one p-type thermoelectric element body 11. As the cobalt-antimony-based semiconductor forming the p-type thermoelectric element body 11 and the n-type thermoelectric element body 12, CoSb ₃ , RhSb ₃ , IrSb ₃ or the like having a skutterudite structure can be used. CoAs ₃ has a similar structure, but since arsenic is highly toxic, it is desirable to use a semiconductor material that does not contain arsenic. Fe, R for p-type semiconductors
Co is replaced with p-type impurities such as u and Os, and with n-type impurities such as Pd, Pt, and Ni for n-type semiconductors. Further, it is preferable that the thermoelectric element body has a small thermal conductivity in order to improve the characteristics.
Therefore, it is preferable to fill the intracavity voids of the compound having the skutterudite crystal structure with a heavy element. By doing so, the lattice vibration is scattered by the filled heavy element, the thermal conductivity is lowered, and the thermoelectric conversion characteristics are improved.

A first electrode member 13 for connecting the one p-type thermoelectric element body 11 and one n-type thermoelectric element body 12 adjacent thereto is provided on the upper side, while one p-type thermoelectric element body 12 is provided.
A second electrode member 14 is provided below the type thermoelectric element body 11 and one n-type thermoelectric element body 12 adjacent to the type thermoelectric element body 11 to connect them in common. The first electrode member 13 and the second electrode member 14 are provided in a state of being displaced by one element. In this way, both thermoelectric element bodies 11 and 12 are electrically connected in series. In the present embodiment, both electrode members 13 and 14 are both made of an iron-based electrode (metal) material. The iron-based metal material, but martensitic stainless represented by SUS410 of JIS is preferred, as long as the thermal expansion coefficient is in the range of ^{8x10 -6 / ℃ ~16x10 -6 / ℃} , carbon steel, alloy Steel etc. may be used.

The iron-based electrode members 13 and 14 can be formed by a technique such as vapor deposition or thermal spraying. However, it is most preferable to use a plate of ferrous material. Between the iron-based electrode members 13 and 14 and the p-type thermoelectric conversion element body 11 and the n-type thermoelectric conversion element body 12, these electrode members 13 and 14 and the p-type thermoelectric conversion element body 11 and the n-type thermoelectric conversion element are provided. A thin film layer 17 containing aluminum (Al) as a main component is bonded to the main body 12 under pressure. Due to the formation of this thin film layer 17,
Since the brazing material used for joining is not used, the joining becomes more reliable, and the thermal and electrical loss at the joining interface in a high temperature state exceeding 200 ° C is reduced.

As another embodiment, it is also possible to use an Al-coated iron and steel plate in which the surface of the electrode material is coated with Al, in which case the Al-iron joint is formed before being processed into the electrode shape. Since the plate-like electrode material is already sufficient, the bonding strength between the thin film layer 17 and the electrode members 13 and 14 does not change due to the pressure welding process.

Usually, on the outside of the first common electrode member 13,
Upper insulating heat conductive plate commonly joined to these electrode members 13
15 are provided. On the other hand, on the outside of the second common electrode member 14, a lower insulating heat conductive plate 16 jointly joined to the electrode members 14 is provided. Both heat-conducting plates 15 and 16 can be made of ceramics, preferably aluminum nitride, silicon nitride, silicon carbide or alumina, which have good thermal conductivity. The silver-based metal material forming the electrode members 13 and 14 uses frit glass to achieve good bonding to the ceramic heat conductive plates 15 and 16.

In the thermoelectric conversion module having the structure shown in FIG. 1, the upper insulating heat conducting plate 15 side is set to a low temperature (L) and the lower insulating heat conducting plate 16 side is set to a low temperature (H), and the upper and lower insulating heat conducting plates are arranged. If a temperature difference is applied between 15 and 16, the first electrode member 13
A potential difference is generated between the second electrode member 14 and the second electrode member 14, and when a load is connected to the end of the electrode, electric power can be taken out.

The thermoelectric conversion module of this embodiment can be incorporated in a heat exchanger. Basically, this heat exchanger has a heating surface and a cooling surface, and has a structure in which the thermoelectric conversion module of the present invention is incorporated between the heating surface and the cooling surface. An example of the heat exchanger is shown in FIG. This heat exchanger 20
Has a gas passage 21 in the center and a peripheral device 22 around it.
Is installed. Further, a thermoelectric conversion module 10 of the present invention having a structure shown in FIG. 1 (for example, detailed structure of an electrode material is omitted for processing) is provided in contact with the gas passage 21.
The thermoelectric conversion module 10 is surrounded by an envelope 22 together with the gas passage 21, and a water flow path 23 is formed between the envelope 22 and the thermoelectric conversion module 10, for example. In the gas passage 21, for example, high-temperature exhaust gas from a refuse incinerator is introduced,
On the other hand, cooling water is introduced into the water flow path 23 from one end thereof via a water introduction pipe 24. The heat of the high-temperature exhaust gas is taken by the thermoelectric conversion module 10 to heat the water flowing in the water flow path 23, and as a result, the water is taken out from the water discharge pipe 25 as hot water. At this time, one surface of the thermoelectric conversion module 10 becomes a low temperature side due to the water flowing in the water flow path 23, and the other surface becomes a high temperature due to the high temperature exhaust gas flowing in the gas passage 21. Therefore, as described above, electric power is extracted from the thermoelectric conversion module 10.

FIG. 3 shows an example of a refuse incineration facility provided with the heat exchanger 20 of the present invention. The waste incineration facility 30 shown in FIG.
Waste incinerator 31, forced draft fan 32, forced draft fan 32 to incinerator
Ordinary heat exchanger 33 for heating the combustion air supplied to 31,
And a secondary forced air blower 34. In the heat exchanger 33, the high-temperature exhaust gas from the incinerator 31 is line L1 and branch line L2.
Air introduced via the blower fan 32 and introduced into the heat exchanger 33 via the line L4 is heated by the high-temperature gas and introduced into the bottom of the incinerator 31 via the line L3.

The exhaust gas line L1 from the incinerator 31 is connected to the heat exchanger 20 of the present invention, in which hot water is generated by the exhaust gas and electric power is generated by the thermoelectric conversion module, as described above. The exhaust gas that has passed through the heat exchanger 33 flows into the electrostatic precipitator 35 through the line L5, and the dust is removed there. The exhaust gas passing through the heat exchanger 20 joins the line L5 via the line L6, and flows into the dust collector 35 together with the exhaust gas passing through the heat exchanger 33. The exhaust gas cleaned by the dust collector 35 is discharged to the outside of the system. The exhaust gas from the incinerator 31 flows through the system by the action of the induced draft fan 36.

Further, the heat exchanger of the present invention is installed on the surface of a boiler inner water pipe or a water pipe fin of a brackish water thermal power plant, and the high temperature side is the inside of the boiler and the low temperature side is the water pipe side, so that power and a steam turbine are provided. The steam to be sent can be obtained at the same time and the efficiency of the brackish water thermal power plant can be improved.

[0032]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. (Example 1) (Production of p-type thermoelectric material sintered body) Co having a purity of 99.998% and a purity of 99.
Raw materials were 999% Sb, 99.99% purity Ce, and 99.99% purity Fe metal. This was weighed so that the composition formula was Ce (Fe _0.75 Co _0.25 ) ₄ Sb ₁₂ . However, since Sb is vaporized in the next arc melting process, Sb was weighed so as to be 3% by weight more than the predetermined ratio. The above-mentioned weighing raw material was loaded into a water-cooled copper hearth in an arc furnace, and after vacuuming to a vacuum degree of 2 × 10 ^-3 Pa, high-purity Ar with a purity of 99.999% was introduced up to 60 kPa. The arc was dissolved in a reduced pressure Ar atmosphere. After melting, the metal block obtained by quenching with a water-cooled copper hearth,
A quartz tube was vacuum-sealed under a high vacuum of 10 ^-4 Pa or less and heat-treated at 973K for 30 hours. The obtained metal lump was crushed in a nitrogen atmosphere and molded at a pressure of 100 MPa using a mold having an inner diameter of 20 mm. This molded body was filled in a carbon mold having an inner diameter of 20 mm and pressure-sintered at 100 MPa and 680 ° C. for 1 hour in an Ar atmosphere to obtain a disc-shaped sintered body having a diameter of 20 mm. Resistivity at 400 ℃ 1.5 × 10 ^-3 Ωcm,
The Seebeck coefficient was 215 μV / K and the thermal conductivity was 1.5 W / mK. (Manufacture of n-type thermoelectric material sintered body) Co with a purity of 99.998% and a purity of 99.
The raw materials were 999% Sb, 99.99% purity Ce, and 99.99% purity Pd metal. This was weighed so that the composition formula was Ce _0.2 (Pd _0.03 Co _0.97 ) ₄ Sb ₁₂ . However, since Sb is vaporized in the next arc melting process, Sb was weighed so as to be 3% by weight more than the predetermined ratio. After loading the above weighing raw material into a water-cooled copper hearth in an arc furnace and vacuuming to a vacuum degree of 2 × 10 ^-3 Pa, high-purity 99.999% pure Ar was introduced up to 60 kPa. Then, a reduced pressure Ar atmosphere was created and the arc was dissolved. After melting, the metal ingot obtained by quenching with a water-cooled copper hearth was vacuum-sealed in a quartz tube at a high vacuum of 10 ^-4 Pa or less, and at 973K.
Heat treated for 30 hours. The obtained metal lump was crushed in a nitrogen atmosphere and molded at a pressure of 100 MPa using a mold having an inner diameter of 20 mm. Fill this molded body into a carbon mold with an inner diameter of 20 mm, and
In the atmosphere, pressure sintering at 100MPa, 680 ℃ for 1 hour, diameter 20mm
A disc-shaped sintered body was obtained. Resistivity at 400 ℃ 1.1 × 10 ^-3 Ωc
m, Seebeck coefficient-250 μV / K, and thermal conductivity 3.6 W / mK. (Production of Thermoelectric Conversion Module) A rectangular parallelepiped element having a side length of 3 mm and a length of 10 mm was cut out from the p-type thermoelectric material sintered body and the n-type thermoelectric material sintered body. A ply type and an n type are alternately placed in a lattice in which stainless steel plates with a width of 3 mm and a thickness of 1 mm are arranged at an interval of 3 mm, and a total of 72 sets of 12 rows and 12 columns in length are set.
144 pieces were arranged in a square. 3mm x 7mm thickness 10 so that a series circuit is formed on the upper and lower surfaces of the element that emerge from the mesh
A pure Al foil with a thickness of μm is arranged, and 3 mm is placed at the same position as the Al foil.
A SUS410 plate with a thickness of x7 mm and a thickness of 0.5 mm was provided. The electrode material is formed from this SUS410 plate. This was placed in a hot press, a pressure of 300 kg / cm 2 was applied, and the treatment was performed at 550 ° C. for 1 hour in an argon atmosphere. After cooling, the laminated body was taken out of the furnace and the stainless steel plate was removed. As a result, a thermoelectric conversion module having the shape described in FIG. 1 and in which all layers were bonded with sufficient strength was formed. It was Here, the p-type thermoelectric conversion element body 11 and the n-type thermoelectric conversion element body 12 are formed from the p-type thermoelectric material sintered body and the n-type thermoelectric material sintered body.

Regarding the thermoelectric conversion module, the high temperature side is 50
When the thermoelectric characteristics were measured under a matched load condition with 0 ° C., 25 ° C. on the low temperature side, a load having the same resistance value as the module internal resistance was connected as a load, the generated voltage was 3.6 V, and the power was 11 W. After continuously operating for 1000 hours under these conditions, the temperature was returned to room temperature and the operation was performed again under the same conditions. The performance did not change even after 10 times or more of this repetition for a total operating time of 10,000 hours or more, and there was no damage or change in shape. Such a thermoelectric conversion module was ranked A. Also, in the same test, if this performance is reduced 8 to less than 10 times and the performance is degraded, it will operate even if it is set to B rank and the high temperature side is set to 300 ° C or higher, but the performance is degraded if it is less than 8 times. What caused the above was designated as C rank.

Regarding the above-mentioned thermoelectric conversion module of this embodiment, a thin film containing aluminum (Al) as a main component, which is pressed against the electrode members 13 and 14 and the p-type thermoelectric conversion element body 11 and the n-type thermoelectric conversion element body 12. Although the layer 17 is bonded, the thermoelectric conversion module was formed by changing the bonding temperature and the bonding pressure, which are the pressure welding conditions, and the results of examining the performance are shown in Table 1.
Is.

[0035]

[Table 1] From Table 1, it was possible to find the conditions under which the thin film layer 17 could firmly bond the electrode members 13, 14 to the p-type thermoelectric conversion element body 11 and the n-type thermoelectric conversion element body 12.

That is, the basic conditions are 600 ° C. or lower (desirably 575 ° C.) or 500 ° C. or higher (desirably 525) which does not significantly react with Sb which is the main component of skutterudite.
(Above ℃) bonding temperature, above 200kg / cm2, 90
A thermoelectric conversion module of rank B or higher can be provided by applying a bonding pressure of 0 kg / cm 2 or lower. Especially, 575 ℃
Hereinafter, a high-performance thermoelectric conversion module of rank A can be provided by applying a joining temperature of 525 ° C. or more and a joining pressure of 300 kg / cm ² or more and 700 kg / cm ² or less.

The above results are the results when the bonding time is set to 2 hours, but similar results can be obtained when the bonding time is in the range of 5 minutes to 3 hours.

Further, under the above conditions, it is also a great merit that the Al-coated iron and steel plate and the insulating material AlN or Si3N4 are well bonded and all the bonding can be performed at once.

In the above examples, a module using a filled skutterudite power generation element, which has been desired to be modularized, can be manufactured, and thermoelectric conversion with practically sufficient durability and characteristics is possible. Modules are provided. Therefore, by incorporating the module into the heat exchanger, it is possible to provide a highly efficient heat exchanger for cogeneration, and if it is used in the boiler of a refuse incinerator, it is possible to recover a large amount of energy that was previously discarded, reducing the environmental load. It will make a great contribution. (Embodiment 2) In the following embodiment, the description will focus on the parts different from the first embodiment, but the detailed description of the same configuration will be omitted. The thermoelectric conversion modules of Example 1 were arranged between a heat-resistant steel plate and a corrosion-resistant steel plate, and an AlN insulating plate having a thickness of 0.5 mm was sandwiched between the heat-resistant steel plate on the high temperature side and the corrosion-resistant steel plate on the low temperature side. 0.5mm thick high thermal conductivity silicone rubber (for example, Shin-Etsu Chemical trade name TC-50TX)
A laminated plate was prepared by sandwiching and sandwiching the plate and fixing it with both flat plates. At this time, the output terminals from each module were connected in series. As a result, a heat exchanger with a thermoelectric conversion module was obtained in which the heat-resistant steel side of the laminate was the high temperature part and the corrosion-resistant steel side was the cooling part. This heat exchanger with thermoelectric conversion module is provided with, for example, a flow path 23 for circulating water on the cooling side as shown in FIG. 2, and this is provided with a waste incinerator as shown in FIG.
By installing in 31, the boiler can obtain steam and hot water and can generate electricity. Here, 32 is a forced draft blower, 33 is a normal heat exchanger, 34 is a secondary forced draft blower,
Reference numeral 35 is a dust collector, and 36 is an induced draft fan. Further, L1 is a heat exchanger with a thermoelectric conversion module for the exhaust gas from the incinerator 31.
20 is a gas pipeline, L2 is a pipeline that introduces the exhaust gas from the incinerator 31 into a normal heat exchanger 33, and L3 is a heat exchanger 33.
L4, a gas line for introducing the air heated in the incinerator 31
Is a conduit for introducing air from the blower 32 into the heat exchanger 33, L
Reference numeral 5 is a conduit for introducing the exhaust gas that has passed through the heat exchanger 33 into the dust collector 35. In FIG. 3, the thermoelectric generator module of the present invention may be installed directly on the heat exchanger 33. (Embodiment 3) The heat exchanger of Embodiment 2 is installed on the surface of a boiler inner water pipe or water pipe fin of a steam-fired power plant, and the heat-resistant steel flat plate side is the inside of the boiler and the cooling water is the water pipe side, so that power and steam can be obtained. The steam sent to the turbine was obtained at the same time, and the steam-fired power generation facility with improved efficiency could be obtained. That is, if the power generation efficiency of the brackish water power generation facility that generates power only by the steam turbine is ηα and the thermoelectric conversion efficiency of the heat exchanger is ητ, then ηα = ητ + (1-ητ ) ηρ, and by installing a heat exchanger with a thermoelectric conversion efficiency of ητ in a brackish water power plant with a power generation efficiency of ηρ, (1-ητ
The power generation efficiency can be improved by ρ) ητ.

[0040]

With the above structure, it is possible to provide a thermoelectric conversion module that exhibits a sufficient thermoelectric conversion function for a long time even at a temperature of 300 ° C. or higher, and a heat exchanger using the same.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a thermoelectric conversion module according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing an example of a heat exchanger of the present invention.

FIG. 3 is a schematic configuration diagram of a refuse incinerator in which the heat exchanger of the present invention is installed.

[Explanation of symbols]

10 ... Thermoelectric conversion module 11 ... p type thermoelectric conversion element body 12 ... n type thermoelectric conversion element body 13 ... First electrode member 14 ... Second electrode member 15, 16… Insulating heat conductive plate 17 ... Bonding layer 20 ... Heat exchanger 21 ... Gas passage 22 ... Enclosure 23 ... Channel 24 ... Introduction pipe 25 ... Discharge pipe 31 ... Garbage incinerator 32 ... Push blower 33 ... Ordinary heat exchanger 34 ... Secondary forced air blower 35 ... dust collector 36 ... Induction fan

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01L 35/34 H01L 35/34 H02N 11/00 H02N 11/00 A

Claims (5)

[Claims] 1. A p-type thermoelectric conversion element body, which is connected in series with each other by electrode members so as to form a first plane on the high temperature side and a second plane on the low temperature side, and is arranged to face each other, and n. Type thermoelectric conversion element body, the p-type thermoelectric conversion element body is made of p-type cobalt (Co) -antimony (Sb) based semiconductor, and the n-type thermoelectric conversion element body is n-type Co-Sb.
Is constituted by a system semiconductor, aluminum said electrode member, the coefficient of thermal expansion is made of a material in the range of ^{8x10 -6 / ℃ ~16x10 -6 / ℃} , is pressed between the electrode members and the thermoelectric conversion element main body A thermoelectric conversion module, wherein a thin film layer containing (Al) as a main component is joined. 2. The thin film layer has a bonding pressure of 200 kg / cm2.
The thermoelectric conversion module according to claim 1, wherein the thermoelectric conversion module is formed by pressure welding at a joining temperature of 500 ° C to 600 ° C at a joining temperature of about 900 Kg / cm 2. 3. The thermoelectric generator according to claim 1, wherein an insulating heat conducting plate made of ceramics or silicon rubber is provided in either or both of the first plane and the second plane. Conversion module. 4. The n-type thermoelectric conversion element body and the p-type thermoelectric conversion element body have a skutterudite type crystal structure.
The thermoelectric conversion module according to any one of claims 1 to 3, which is a compound having a filled skutterudite structure in which the voids in the CoSb ₃ -based compound crystal are filled with an element. 5. A heat exchanger having a heating surface and a cooling surface, comprising the thermoelectric conversion module according to any one of claims 1 to 4 between the heating surface and the cooling surface. A heat exchanger characterized by the above.