JPH0555640A - Manufacture of thermoelectric converter and thermoelectric converter manufactured by the same - Google Patents

Abstract

PURPOSE:To improve the mechanical and thermal strengths of a thermoelectric converter and to avoid the damage on the converter by disposing powder of semiconductor and a metal material for an electrode having high heat resistance and small reactivity with the semiconductor in a layer state, and simultaneously integrally molding the semiconductor and the electrode by using a plasma active sintering method. CONSTITUTION:Sintering powder 3 of a material is filled in a sintering jig 2 in a chamber 1, the powder 3 is held by an upper punch 4 and a lower punch 5, and a predetermined pressure is applied from both sides by a pressurizing mechanism 6. Pulse currents are supplied from a sintering power source 9 to an upper punch electrode 7 connected to the punch 4 and a lower punch electrode 8 connected to the punch 5, a plasma discharge is generated among the particles of the powder 3 to be sintered. Thus, since the powder of the semiconductor is finely introduced into the air gaps of the powder of the metal, the connecting strength of the semiconductor and the electrode can be enhanced. As a result, the mechanical and thermal strengths of a thermoelectric converter are improved, and the damage of the converter can be avoided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a thermoelectric conversion element and a thermoelectric conversion element produced by the production method. More specifically, the present invention relates to a P type and N type using a plasma activated sintering method.
TECHNICAL FIELD The present invention relates to a method for manufacturing a thermoelectric semiconductor element of a mold and a thermoelectric conversion element manufactured by the manufacturing method.

[0002]

2. Description of the Related Art A thermoelectric conversion element is a thermoelectric generation element that directly takes out heat by making use of a temperature difference to take out electricity, and, conversely, an electric cooling is used to make a temperature difference on both sides of the element to cool it. There are two types of elements. In general, the effect of generating electricity when a temperature difference is applied to both ends of a semiconductor element is called Seebeck effect, and the effect of causing a temperature difference between both ends of an element when electricity is applied to a semiconductor is called Peltier effect.

At present, thermoelectric generators are energy-saving technologies such as recovery of waste heat from factories and automobiles, energy-saving technologies such as small generators using heating elements, or alternative energy, against the backdrop of global environmental problems and energy resource problems. Has been attracting attention as one of the.
Further, the electronic cooling element is drawing attention as a cooling technique that does not use a refrigerant such as CFC, and is used for cooling and temperature control of electronic parts, dehumidifiers, small refrigerators, and the like.

For example, the thermoelectric conversion in the case of electronic cooling is P
This is done by applying direct current electricity to a circuit formed by joining type and N type semiconductors with electrodes, whereby heat is absorbed on one side of the joint and heat is generated on the other side.
Also, this phenomenon is reversed when the direction of electricity flowing through the circuit is changed.

The thermoelectric conversion element is used by arranging a plurality of pairs of these P-type and N-type semiconductors electrically in series and thermally in parallel.

[0006]

Conventional methods for producing thermoelectric conversion elements include various crystal growth methods, atmospheric pressure powder sintering methods by cold pressing, hot pressing sintering methods such as hot pressing methods. There is. In addition, there are thick film method, thin film method, etc., but these are unfinished from a technical point of view, and there are almost no examples currently used.

Generally, the crystal growth method provides better characteristics than the powder sintering method by cold pressing or the hot pressing method. However, the crystal growth method is disadvantageous in that it requires a long time for manufacturing, has a cleavage property, has a low mechanical strength, and has a low device yield, resulting in a high manufacturing cost.

On the other hand, the powder sintering method by cold pressing is a method in which the raw material powder is put into a mold and press-molded, and then heat treatment is carried out, and the mechanical strength of the element is increased and the yield is improved. The device characteristics are inferior to the crystal growth method. Moreover, in order to carry out pressing, it is necessary to granulate the powdered raw material again to an appropriate size or remove the fine powder, and it cannot be said that the raw material yield is poor and the productivity is excellent. Is the current situation. Further, oxides and adsorbed gases mixed in the raw material deteriorate the characteristics of the thermoelectric conversion element, and therefore it is necessary to remove them, and the management of the raw material is important.

The hot pressing method is the closest manufacturing method to the plasma activated sintering method. However, since the raw material powder is directly pressed and simultaneously heated to be sintered, a very high pressure is required to increase the sintering density. -High temperature conditions are required and a long sintering time is required. In addition, it is necessary to properly control the purity of the raw material powder.

The thermoelectric conversion element has been attracting attention from the viewpoints of environmental problems and energy saving, but in order to popularize the thermoelectric conversion element, it is necessary to solve the cost problem caused by the current low productivity method.

Conventionally, in the case of thermoelectric conversion elements used for thermoelectric power generation, materials used at a relatively low temperature of 300 ° C. or lower such as bismuth tellurium compounds and antimony tellurium compounds, and PbTe and GeTe compounds. Materials used at temperatures up to around 600 ℃, such as SiGe and iron silicide
Materials that can be used near 1000 ℃ are roughly divided into three categories. However, when these materials are put to practical use for thermoelectric power generation, the target materials are limited in terms of power generation efficiency and cost.

The efficiency η of thermoelectric power generation is expressed by the following equation.

Η = η _o / [2 + η _o · {4 / (Z · ΔT) −0.5}] where η _o is the Carnot efficiency and is determined by the temperature conditions used.

In this equation, the only way to increase the power generation efficiency η is to increase Z and ΔT. Z is called a figure of merit and indicates the ability of the thermoelectric conversion material, and is a coefficient determined by the material. Further, ΔT is a temperature difference between the heating side and the heat radiating side, and the higher the heat resistance of the material, the larger the ΔT can be.

The performance index Z of the BiTe system, the SbTe system, and their compound systems is very high at around room temperature as compared with other materials, and Z = 2.0 to 2.6 × 10 ⁻³ / K.
However, the melting point of the material is around 600 ° C., and the characteristics also drastically drop in the high temperature region, so ΔT cannot be taken very large (ΔT = ˜300 ° C.), and the power generation efficiency η is about 5-6%.

The iron silicide system has a heat resistance of about 1200 ° C. and thus has a large ΔT (ΔT = ˜).
1000 ° C.), the figure of merit Z is as small as 1/5 or less of that of BiTe system, and the conversion efficiency η is very small at several%.

On the other hand, the lead tellurium-based material has a melting point of 920 ° C.
Since the operating temperature range can be used in the vicinity of ~ 600 ° C, the temperature difference can be 500 ° C or more. Also, the figure of merit Z is 1.5 ×× 10 ^-3 /
Above K, power generation efficiency can exceed 10%.

From these viewpoints, the lead tellurium-based material is the most practical thermoelectric power material, but some practical problems must be solved for practical use. One is bonding with an electrode that has heat resistance (withstanding use at 600 ° C or higher), and the other is sufficient strength under the condition that the temperature cycle of heating and cooling is repeated at a temperature difference of near 500 ° C.・
This is the development of an element or unit structure having heat stress resistance.

Since the bismuth tellurium-based material is used in a relatively low temperature range, a normal solder or heat-resistant solder, for example, a lead-based (melting point 327 ° C.) or zinc-based (melting point 419 ° C.) metal is used as the joining method. It was possible to mount relatively easily, and even if the element performance deteriorates due to the diffusion of the bonding material into the element (or the diffusion in the opposite direction), a thickness of several μm can be applied by plating, vapor deposition, sputtering, etc. The diffusion could be stopped by forming a metal barrier layer such as nickel.

Further, since the melting point of FeSi ₂ system (iron silicide system) is high, the bonding at high temperature is performed by silver brazing (MP = 6).
A high temperature brazing material (50 to 850 ° C.) is used, or, as seen in many documents, a method of directly joining P-type and N-type without using an electrode is adopted.

However, in the PbTe system, the operating temperature range is around 600 ° C. and the melting point of the material is 9 ° C.
Since it is around 00 ℃, normal high temperature solder cannot be used,
In addition, since the working temperature of the high-temperature brazing material is close to the melting point of lead tellurium, the brazing material easily diffuses into the lead tellurium, and diffusion by normal plating or sputtering film at the working temperature is prevented. It's difficult. In addition, when rigidly fixed to a large temperature difference and thermal stress caused by a temperature cycle, element breakdown is likely to occur.

The cause of this is considered to be stress due to the difference in expansion coefficient among the substrate, electrode and element and stress due to the change in temperature difference. It can be considered that the same problem will occur in all cases where power generation is performed with a large temperature difference, and the FeSi ₂ system also has the same problem. Therefore, a method of mechanically pressing the thermoelectric power generating element against the electrode with a spring such as a spring has been devised, but the apparatus becomes large and not suitable for practical use.

A first object of the present invention is to improve the productivity of the thermoelectric conversion element, improve the yield, reduce the production cost, and improve the characteristics of the element as much as the crystal growth method. It is to provide a manufacturing method and a thermoelectric conversion element manufactured by the manufacturing method.

A second object of the present invention is to improve the mechanical strength and thermal strength of the thermoelectric conversion element to avoid element destruction, and a method for manufacturing the thermoelectric conversion element, and a thermoelectric conversion manufactured by the manufacturing method. It is to provide an element.

[0025]

According to the present invention, the first object is to provide a method for producing a thermoelectric conversion element for producing a semiconductor for a thermoelectric conversion element using a plasma activated sintering method, and a method for producing the same. This is achieved by the manufactured thermoelectric conversion element.

According to the present invention, the second object is to arrange the semiconductor powder and a metal material for electrodes, which has high heat resistance and low reactivity with the semiconductor, for example, metal powder, in layers, The present invention is achieved by a method for manufacturing a thermoelectric conversion element in which a semiconductor and an electrode are simultaneously molded integrally by using a plasma activated sintering method, and a thermoelectric conversion element manufactured by the manufacturing method.

The plasma activated sintering method is a kind of powder sintering method generally called plasma activated sintering (PAS) or spark plasma sintering (SPS).

[0028]

According to the first manufacturing method of the present invention and the thermoelectric conversion element manufactured by the manufacturing method, a semiconductor for a thermoelectric conversion element is manufactured by using a plasma activated sintering method utilizing plasma discharge as a heating method. Because it is manufactured, the raw material powder can be sintered at low pressure and low temperature in a short time, and by controlling the pressure and temperature during molding, it is possible to use the conventional raw material powder or a raw material of lower purity and to perform the crystal growth method. Equivalent characteristics can be obtained, and since the oxide on the surface of the raw material powder is removed and the adsorbed gas is desorbed by plasma, the control of the raw material can be simplified, and as a result, the productivity of the thermoelectric conversion element is improved. Along with that, the yield can be improved, the production cost can be reduced, and
The characteristics of the device can be improved to the same level as the crystal growth method.

According to the second manufacturing method of the present invention and the lead-tellurium-based thermoelectric conversion element manufactured by the manufacturing method, the semiconductor powder and the metal powder for the electrode are arranged in layers and plasma activated sintering is performed. Since it is integrally molded using the method, the electrode can be bonded to the semiconductor in the temperature range of sintering conditions (650 ° C or higher), so electrode bonding with heat resistance can be achieved. A porous portion may be formed between the substrate, the electrode, and the element, and the stress due to the difference in expansion coefficient between the substrate and the element and the stress due to the temperature difference may be absorbed in this porous portion. Since the semiconductor powder finely penetrates into the obstacle, the bonding strength between the semiconductor and the electrode can be increased, and as a result, the mechanical strength and the thermal strength of the thermoelectric conversion element can be improved and element destruction can be avoided.

In the plasma activated sintering method, a voltage is directly applied to a raw material powder to be molded to generate discharge plasma between powder particles, and the particle surfaces are activated to remove an oxide layer or an adsorbed gas adhering to the surfaces. It is a method of removing and advancing sintering at low pressure in a short time.

This plasma activated sintering method has been conventionally used for sintering metals, joining dissimilar metals or joining magnetic materials and ceramics, but it is necessary to control a very small amount of impurities in a normal semiconductor. It was not thought that a sintering method such as plasma sintering could be applied to the production of
It was never used in the manufacture of semiconductors.

However, the thermoelectric conversion element is a semiconductor having a very high impurity concentration among the semiconductors, has a lower sensitivity to impurities and is easier to manage than a general semiconductor, and
It was considered possible to apply the plasma activated sintering method.

[0033]

[Examples] Focusing on short-time sintering at low pressure and low temperature, which is an advantage of the plasma activated sintering method, various moldings were performed using raw powders of thermoelectric semiconductors, and the pressure and temperature during molding were controlled. Then, it was found that the same characteristics as those obtained by the crystal growth method can be obtained by using the conventional raw material powder.

With respect to productivity, one general plasma sintering apparatus was able to obtain a productivity about 5 to 10 times that of a crystal or powder pressing apparatus of the same price.

Another feature is that the raw material does not need to be strictly controlled because of the effects of removing oxides in the raw material by plasma and desorption of adsorbed gas.

A schematic structure of the plasma sintering apparatus is shown in FIG.

In the chamber 1, the sintering powder 3 as a raw material is put into the sintering jig 2, and the powder 3 is placed in the upper punch 4.
And a lower punch 5, and while applying a predetermined pressure by a pressure mechanism 6 from both, the upper punch electrode 7 connected to the upper punch 4 and the lower punch electrode 8 connected to the lower punch 5 are connected to the sintering power source 9 Then, a pulse current is applied to cause a plasma discharge between the particles of the powder 3 to sinter.

It is also possible to superimpose a metal electrode, for example, a metal plate or metal powder on the temporarily pressed sintering powder 3 and put it in the sintering jig 2 to integrally mold the electrode simultaneously with the sintering of the semiconductor. Is.

The pressurizing mechanism 6 and the sintering power source 9 are connected to a control device 10 for controlling the pressure and pulse current applied to the powder 3, and the control device 10 includes a position measuring mechanism 11, an atmosphere control mechanism 12, It is connected to the water cooling mechanism 13, the temperature measuring device 14, and the like. This plasma-activated sintering method can be used not only for sintering semiconductors and integrally molding semiconductors and electrodes, but also for bonding semiconductors and conductors and bonding semiconductors and insulators.

As an example of thermoelectric conversion in the thermoelectric conversion element, the principle of thermoelectric conversion in the case of electronic cooling will be described with reference to FIG.

One end of the P-type semiconductor 15 and one end of the N-type semiconductor 16 are joined by the electrode 17, and the other end of the P-type semiconductor 15 is connected to the minus side of the power source 19 via the electrode 18 and the other end of the N-type semiconductor 16 is connected. The electrode
A circuit 21 is formed by connecting to the positive side of the power source 19 via 20 and when a direct current is passed from the power source 19 to the circuit 21, heat is absorbed at the joint with the electrode 17 and the joint with the electrode 18 and the electrode 20. Generates heat.

The amount of heat Qab that can be absorbed when a direct current is passed through the circuit 21 is determined by the heat absorption amount Qp due to the Peltier effect as shown in the following equation. Heat quantity returning to the side 1/2 I ² ·
It is the amount obtained by subtracting the heat quantity Qc returned from the high temperature side to the low temperature side by heat conduction due to the temperature difference between R and both ends of the thermoelectric conversion element.

[0043] ^{Qab = Qp -1 / 2I 2 ·} R-Qc Incidentally, when the direction of the DC current flowing through the circuit 21 to the opposite, heat absorption and release phenomenon described above is reversed.

As shown in FIG. 3, the thermoelectric conversion element is used by arranging a plurality of pairs of a P-type semiconductor 15 and an N-type semiconductor 16 electrically in series and thermally in parallel.

An example of manufacturing a thermoelectric conversion element using the plasma activated sintering method will be shown below. Here, as a numerical value indicating the characteristic of the thermoelectric conversion element, the following performance index Z (figure)
of merit).

[0046] As the material for the thermoelectric conversion element, a bismuth tellurium-based material, (Bi · Sb) ₂ (Te · Se) ₃ , was used, and this raw material powder was sintered with a plasma sintering device (Sumitomo Coal Industry Dr. Sinter). Then, a fixed amount was put into the sample, and the sample was temporarily pressed and fixed, and then plasma sintered. The ingots produced by changing the pressure and temperature conditions during sintering were cut, and their characteristics were measured.

Table 1 shows the pressure and temperature conditions during sintering and the characteristic values of the thermoelectric conversion element.

Table 1 (Bi · Sb) 2 (Te · Se) 3 Sintering pressure Sintering temperature Performance index (kg / cm ² ) (° C.) Z (10 ⁻³ ) Plasma sintering method 1 250 300 0.7 2 300 300 1.3 3 3 350 300 2.1 4 400 300 2.0 5 500 300 300 1.8 6 300 250 0.6 0.6 7 300 350 350 2.2 8 300 400 1.9 9 500 400 0.8 Crystal growth Method (conventional method) 2.2 Powder pressing method (conventional method) 1.6.

From this, it can be seen that the sintering conditions for obtaining the predetermined characteristic values include proper pressure and proper temperature. Further, these are also affected by the raw material composition, raw material shape, and the like. If the temperature and the pressure are insufficient, the mechanical strength of the ingot is also lowered, and problems such as delamination occur. By the way, the yield of the thermoelectric conversion element from the ingot obtained in Sample 7 exceeds about 95%.

The size of the ingot that can be manufactured by the current plasma sintering apparatus is 35 mm in diameter × 30 mm or more in thickness,
One ingot can be manufactured in 10 minutes. In the case of the crystal growth method, it takes about 40 to 50 hours with a diameter of 35 mm and a thickness of 200 mm, and thus the plasma activated sintering method has a productivity 40 times that of the crystal growth method.

Moreover, it is considered that this manufacturing method can be applied to sintering of all thermoelectric conversion element materials, not limited to bismuth tellurium type materials.

The present inventor has also tried sintering experiments of various thermoelectric materials by the plasma sintering method, and as a result, P-type or N-type powders of thermoelectric materials, or P-type and N-type powders and the When simultaneously filling and sintering electrically insulating oxide powders such as glass powders, etc., which are separated from each other, when a metal material serving as an electrode of the thermoelectric conversion element, for example, metal powders is simultaneously sintered, it has excellent heat resistance and extremely high strength. Moreover, it was found that a thermoelectric conversion element resistant to heat stress can be obtained.

In this method, first, a predetermined amount of metal powder to be an electrode is placed on a jig for plasma sintering, and P of thermoelectric material is placed on the metal powder.
Type or N type powder, or P type and N type powder at the same time with a predetermined amount filled with electrically insulating powder such as glass powder, and as it is, or as a layered metal powder to be a counter electrode. It is placed at the position where plasma sintering is performed.

Here, the metal material used as the electrode has heat resistance and has a thermal expansion coefficient similar to that of the thermoelectric conversion element, and it is difficult to react with the thermoelectric conversion element at high temperature, and even if a reaction product is formed. The material must be stable under the conditions of thermoelectric power generation. Further, it must be a material that does not impair the electrical characteristics of the thermoelectric conversion element in the state of being bonded to the thermoelectric material.

Generally, in the case of a thermoelectric conversion element used at room temperature, metals used as electrodes include copper, nickel, aluminum, etc., but when used at 500 ° C. or higher, the following is used. The target is metal. For example, iron, nickel,
It is titanium, stainless steel, molybdenum, tungsten, or an alloy containing a trace amount of lead or tellurium in these metals.

As a result of the examination, in the case of the lead tellurium thermoelectric material,
If you try to sinter the metal powder that will become the electrode at the same time, the materials that can be sintered within the upper limit of the sintering temperature of lead tellurium powder (up to 750 ℃) are iron, nickel, titanium, etc.
Materials around 00 ° C are suitable.

Regarding nickel, when co-sintering with lead-tellurium, a nickel / tellurium intermetallic compound is formed and very good bonding is obtained, but a rapid reaction occurs at sintering at 650 ° C. or higher. Progresses, the joint melts,
Even if the joined body at about 600 ℃ is kept at about 500 ℃ for a long period of time, the joint will swell, which makes it unsuitable for use above 500 ℃.

Titanium forms a titanium / tellurium compound, which is very stable, at 750 ° C-500.
No change was observed in the joint even with time.

Further, iron hardly reacts with lead tellurium,
Bonding strength is extremely weak for plate-shaped iron. However, when iron powder is sintered in the sintering density range of 70-98%, a porous iron electrode is formed, and lead tellurium finely penetrates into the air gap of the iron, increasing the bonding strength between the element and the electrode. Also, the porous portion effectively acts to absorb the thermal stress caused by the difference in expansion coefficient.

In the case of simultaneously sintering and joining different materials having different melting points as described above, in plasma sintering, the punch material and the grain size of the sintered material are made different so that the temperature gradient can be easily applied. In addition, it has a unique feature that the sintering density can be easily and reproducibly controlled. Therefore, when sintering a thermoelectric material and a metal material having a different melting point at the same time, it is necessary to use plasma sintering.

An example of manufacturing an electrode-integrated thermoelectric conversion element using plasma sintering will be described.

As shown in FIG. 4, with the lower punch 5 installed on the sintering jig 2, a metal material to be an electrode, for example, iron powder 22 (325 mesh electrolytic iron) in this case is quantitatively placed. Then, a predetermined amount of lead tellurium powder 23 is filled on it and flattened.

Further, iron powder 22 is placed thereon. Then, the ingot of the thermoelectric conversion element in which the metal electrodes are joined on both sides can be prepared by mounting on the plasma sintering apparatus of FIG. 1 and sintering at a sintering temperature of 500 to 800 ° C. in vacuum.

To use as a module, this element may be cut and used by brazing the substrate with a high temperature brazing material such as silver brazing.

Another production example of the electrode-integrated thermoelectric conversion element using plasma sintering will be described.

As shown in FIG. 5, the plasma sintering jig 2 is used.
Then, the metal powder 25 is filled in the same manner as above. Then, P-type and N-type lead tellurium powders 26 and 27 are filled in a state where an oxide powder 28 having an insulating property and a low thermal conductivity is sandwiched between the powders 26 and 27, and further on top of that. The metal powder 25 is placed and plasma sintering is performed.

The insulating powder 28 preferably has a melting point of 700 ° C. or higher. For example, glass-based powder, alumina-silica-based, alumina-silica-magnesia-based mixed powder is preferable.

The thickness of the insulating layer formed by sintering the powder 28 of the insulating material is preferably 0.5 mm or less in consideration of the heat flow, but the composition has a high melting point and can maintain a porous state under the sintering conditions of PbTe. If it is a product, there is no problem even if the thickness is 1 mm or more.

By sintering the powders 28 of the insulating material together, as shown in FIG. 6, an ingot 29 having P-type and N-type lead tellurium sintered and bonded to the same electrode is completed.

By slicing this ingot 29 to form a P / N pair of thermoelectric power generating elements 30, and mounting only the low temperature side of the thermoelectric power generating element 30 as shown in FIG. A bare module 31 can be created.

Similarly, by sintering a plurality of basic structures composed of P-type and N-type powders and insulating powders,
It is also possible to obtain many element pairs at one time.

At the time of mounting, for example, an inorganic adhesive having a high thermal conductivity is applied to the heat exchanging portion on the high temperature side and the electrode surface is adhered for use, or it is joined to an electrically insulating substrate by a similar method to form a module. To use as.

[0073]

According to the first manufacturing method of the present invention and the thermoelectric conversion element manufactured by the manufacturing method, since the semiconductor for the thermoelectric conversion element is manufactured by using the plasma activated sintering method, the raw material powder is used. Can be sintered at low pressure and low temperature in a short time, and by controlling the pressure and temperature during molding, it is possible to obtain the same characteristics as the crystal growth method using the conventional raw material powder,
Further, since the oxide in the raw material is removed by plasma and the adsorbed gas is desorbed, the management of the raw material can be simplified, and as a result, the productivity of the thermoelectric conversion element is improved, the yield is improved, and the production cost is reduced. At the same time, the characteristics of the element can be improved to the same level as the crystal growth method, and therefore, the market of thermoelectric conversion elements, which has been hindered from spreading due to high production cost, can be expanded,
It can play a part in solving environmental problems.

According to the second manufacturing method of the present invention and the thermoelectric conversion element manufactured by the manufacturing method, the semiconductor powder and the metal material for the electrodes having different melting points are integrated by using the plasma activated sintering method. Since it is molded, a porous portion can be formed between the semiconductor and the electrode, and the stress caused by the difference in the expansion coefficient between the substrate, the electrode and the element and the stress caused by the temperature difference are absorbed in this porous portion. In addition, since the semiconductor powder finely penetrates into the air gap of the metal powder, the bonding strength between the semiconductor and the electrode can be increased, and as a result, the mechanical strength and thermal strength of the thermoelectric conversion element can be improved to improve the element. You can avoid destruction.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a plasma sintering apparatus used for manufacturing a thermoelectric conversion element of the present invention.

FIG. 2 is an explanatory view of the principle of thermoelectric conversion in the case of electronic cooling.

FIG. 3 is a perspective view of a thermoelectric conversion element.

FIG. 4 is an explanatory diagram of a manufacturing example of a thermoelectric conversion element integrated with an electrode using plasma sintering.

FIG. 5 is an explanatory view of another example of manufacturing a thermoelectric conversion element integrated with an electrode using plasma sintering.

FIG. 6 is a perspective view of an ingot obtained by integrally sintering insulating powder.

FIG. 7 is a perspective view of a module in which an ingot obtained by integrally sintering insulating powder is mounted.

[Explanation of symbols]

 1 Chamber 2 Sintering Jig 3 Sintering Powder 4 Upper Punch 5 Lower Punch 6 Pressing Mechanism 7 Upper Punch Electrode 8 Lower Punch Electrode 9 Sintering Power Supply 10 Controller 15 P-type Semiconductor 16 N-type Semiconductor 17 Electrode 18 Electrode 19 Power supply 20 Electrode 21 Circuit 22 Iron powder 23 Lead tellurium powder 25 Metal powder 26 P-type lead tellurium powder 27 N-type lead tellurium powder 28 Insulator powder 29 Ingot 30 Thermoelectric generator 31 Module

Claims (5)

[Claims] 1. A method of manufacturing a thermoelectric conversion element, which comprises manufacturing a semiconductor for a thermoelectric conversion element using a plasma activated sintering method. 2. The method for manufacturing a thermoelectric conversion element according to claim 1, wherein the electrodes are integrally molded at the same time when the semiconductor is manufactured. 3. A thermoelectric conversion element manufactured by the manufacturing method according to claim 1. 4. A method for manufacturing a thermoelectric conversion element, in which semiconductor powder and a metal material for an electrode are arranged in layers and the semiconductor and the electrode are integrally molded using a plasma activated sintering method. 5. A thermoelectric conversion element manufactured by the manufacturing method according to claim 4.