WO2013027662A1 - Thermoelectric conversion element, thermoelectric conversion module, and methods of manufacturing same - Google Patents

Abstract

Provided are a thermoelectric conversion element, a thermoelectric conversion module employing the thermoelectric conversion element, and methods of manufacturing the thermoelectric conversion element and the thermoelectric conversion module, which have high manufacturability allowing efficient production without requiring a firing, heat processing, etc., step. A curable resin is applied to or infused into a formed body including a thermoelectric conversion material powder formed from an intermetallic compound and a metallic powder, and the curable resin is cured thereafter. A silicide is used as the intermetallic compound. At least one substance selected from the group of magnesium silicide, manganese silicide, or iron silicide is chosen as the silicide.

Description

Thermoelectric conversion element, thermoelectric conversion module, and manufacturing method thereof

The present invention relates to a thermoelectric conversion element, a thermoelectric conversion module using the thermoelectric conversion element, a thermoelectric conversion element, and a method for manufacturing the thermoelectric conversion module.

In recent years, the reduction of carbon dioxide has become an important issue in order to prevent global warming, and thermoelectric conversion elements that can directly convert heat into electricity have attracted attention as an effective waste heat utilization technology. ing.

And, as a conventional thermoelectric conversion element, for example, in a FeSi ₂ thermoelectric power generation element obtained by bonding a FeSi ₂ raw material powder adjusted to p-type or n-type with a binder, degreasing, sintering, and heat treatment, An FeSi ₂ thermoelectric power generation element using a Cu-containing resin in which a Cu component is uniformly dispersed in a resin and a manufacturing method thereof have been proposed (see Patent Document 1).

In this FeSi ₂ thermoelectric generator, α (metal phase) -FeSi ₂ raw material powder adjusted to p-type or n-type is mixed and agitated with a binder made of a resin containing Cu particles and pressed into a predetermined shape. In addition to molding the green compact, the resin component is degreased from the green compact, and then the compact is sintered and solidified, and heat treated to form a β (semiconductor phase). It is said that the use of a resin containing can promote the transformation from the α layer (metal phase) to the β layer (semiconductor phase), so that the heat treatment time will be greatly shortened.

In addition, as a method for manufacturing a thermoelectric conversion module, in a sintering mold, each thermoelectric conversion semiconductor raw material powder made of FeSi ₂ -based p-type and n-type, and a plate or powder made of a predetermined metal at least at one end thereof A method of manufacturing a thermoelectric conversion module by putting them in and sintering and joining them in one step by a discharge plasma sintering method has been proposed (see Patent Document 2).
This Patent Document 2 further shows that Cr or Co is mixed into the FeSi ₂ raw material powder.

According to the invention of this Patent Document 2, it becomes possible to sinter and bond a predetermined metal together with p-type and n-type raw material powders in one step, so that the manufacturing cost of the thermoelectric conversion module is greatly reduced. It is supposed to be possible.

However, in the manufacturing method of the thermoelectric generator of Patent Document 1 described above and the manufacture of the thermoelectric conversion module of Patent Document 2, the manufacturing process requires sintering, heat treatment, etc., and the process is complicated and the manufacturing process. It takes time and costs increase.

JP-A-8-139368 JP 2010-34508 A

The present invention has been made in view of the above circumstances, and can be efficiently manufactured without requiring steps such as baking and heat treatment at a high temperature, and a highly productive thermoelectric conversion element, and the thermoelectric conversion element An object of the present invention is to provide a thermoelectric conversion module using the above, and a method of manufacturing such a thermoelectric conversion element and thermoelectric conversion module.

In order to solve the above problems, the thermoelectric conversion element of the present invention is
It contains a thermoelectric conversion material powder made of an intermetallic compound and a metal powder, and is held in a predetermined shape by a resin.

In the thermoelectric conversion element of the present invention, the intermetallic compound is preferably silicide.

The silicide is preferably at least one selected from the group consisting of magnesium silicide, manganese silicide, and iron silicide.

The manufacturing method of the thermoelectric conversion element of the present invention is:
It is a manufacturing method of the above-mentioned thermoelectric conversion element of the present invention,
Applying or impregnating a curable resin to a molded body containing a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder; and
And a step of curing the curable resin.

The thermoelectric conversion module of the present invention is
A thermoelectric conversion module having a structure in which one side element and the other side element are connected via a conductive resin,
(a) the thermoelectric conversion element according to any one of claims 1 to 3 is used as the one-side element;
(b) The thermoelectric conversion element according to any one of claims 1 to 3, wherein a thermoelectric conversion element different from the one side element or a metal element made of metal is used as the other side element. It is said.

Moreover, the manufacturing method of the thermoelectric conversion module of the present invention is:
A method for manufacturing a thermoelectric conversion module having a structure in which one side element and the other side element are connected via a conductive resin,
(a) a molded body containing a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder; and (b) a molded body comprising a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder. The other side molded body, which is a molded body different from the one side molded body, or a molded body made of metal, is arranged so as to have a predetermined arrangement of the thermoelectric conversion modules, and is connected via a conductive resin. Forming a structure;
When a molded body made of the metal is used as the other side molded body, a thermoelectric conversion material powder made of an intermetallic compound and a metal powder are used as the other side molded body. And a step of applying or impregnating a curable resin to the one side molded body and the other side molded body when a molded body different from the one side molded body is used. ,
By curing the curable resin, a thermoelectric conversion material powder made of an intermetallic compound and a metal powder, one side element held in a predetermined shape by the cured resin, and a molded body made of metal A thermoelectric conversion material powder made of an intermetallic compound, and the other element containing a metal powder and held in a predetermined shape by a cured resin is a predetermined arrangement of thermoelectric conversion modules. And a step of forming a thermoelectric conversion module having a structure that is arranged so as to be connected via a conductive resin.

Moreover, the manufacturing method of the thermoelectric conversion module of the present invention is:
A method for manufacturing a thermoelectric conversion module having a structure in which one side element and the other side element are connected via a conductive resin,
(a) using the thermoelectric conversion element according to any one of claims 1 to 3 as the one-side element;
(b) The thermoelectric conversion element according to any one of claims 1 to 3, wherein a thermoelectric conversion element different from the one side element, or a metal element made of metal is used as the other side element,
(c) The one side element and the other side element are arranged so as to form a predetermined arrangement of thermoelectric conversion modules, and are connected by a conductive resin.

The thermoelectric conversion element of the present invention contains a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder, is held in a predetermined shape by a resin, and uses an oxide semiconductor or an intermetallic compound as a thermoelectric conversion material. In some cases, it can be produced without the need for a sintering step. As a result, it is possible to provide a thermoelectric conversion element that is low in production cost and excellent in mass productivity.

Also, by mixing metal powder, which is a material with lower resistance, into the thermoelectric conversion material powder, it is possible to reduce the resistivity of the thermoelectric conversion element, and it is possible to provide a thermoelectric conversion element with high power generation capacity become.

Furthermore, the thermoelectric conversion element of the present invention can easily cope with a complicated shape and can easily segment a plurality of materials.

Further, by using silicide as the intermetallic compound, it becomes possible to obtain a thermoelectric conversion material having high thermoelectric conversion efficiency without requiring a sintering process at a high temperature, and the present invention is more effective. It can be tightened.

Furthermore, by using at least one selected from the group consisting of magnesium silicide, manganese silicide, and iron silicide as the silicide, it is possible to obtain a thermoelectric conversion element having good characteristics and excellent economy.

In addition, the method for producing a thermoelectric conversion element of the present invention includes applying a curable resin to or impregnating a curable resin on a molded body containing a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder, and then applying the curable resin. Since it is made to harden | cure, a thermoelectric conversion element can be manufactured efficiently and at low cost, without passing through the process of sintering.
Moreover, in the case of the above-mentioned method, it is easy to cope with a complicated shape and it is easy to segment a plurality of materials.

The thermoelectric conversion module of the present invention is a thermoelectric conversion module having a structure in which one side element and the other side element are connected via a conductive resin, and the thermoelectric conversion element of the present invention is used as the one side element. The thermoelectric conversion element of the present invention is a thermoelectric conversion element different from the one side element, or a metal element made of metal is used as the other side element, and at least one side element has a low resistance, Since the thermoelectric conversion element of the present invention having good characteristics is used, it is possible to provide a thermoelectric conversion module having excellent productivity and good characteristics.

In addition, the method for producing a thermoelectric conversion module of the present invention includes (a) a one-side molded body that is a molded body including a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder, and (b) a thermoelectric composed of an intermetallic compound. The molded body containing the conversion material powder and the metal powder, and the molded body different from the one-side molded body, or the other-side molded body that is a molded body made of metal is arranged in a predetermined array of thermoelectric conversion modules. If a molded body made of metal is used as the other side molded body after forming a structure that is arranged in a row and connected via a conductive resin, the other side molded body When a molded body containing a thermoelectric conversion material powder composed of an intermetallic compound as a body and a metal powder and a molded body different from the one-side molded body is used, the one-side molded body and the other-side molded body Apply curable resin. Alternatively, since the curable resin is cured after impregnation, the above-described thermoelectric conversion element of the present invention can be efficiently produced.

In addition, the manufacturing method of the thermoelectric conversion module of the present invention uses (a) the thermoelectric conversion element of the present invention as one side element, and (b) the thermoelectric conversion element of the present invention which is different from the one side element. An element or a metal element made of metal is used as the other side element, and (c) the one side element and the other side element are arranged so as to be in a predetermined arrangement of the thermoelectric conversion modules and connected by a conductive resin. Even in this case, the thermoelectric conversion element of the present invention described above can be efficiently manufactured.

Further, the thermoelectric conversion module manufactured by the method of the present invention can be further molded with a resin.

It is a perspective view which shows the external appearance structure of the thermoelectric conversion element concerning Example 1 of this invention. It is front sectional drawing which shows typically the internal structure of the thermoelectric conversion element concerning Example 1 of this invention. It is a principal part enlarged view of FIG. 2, Comprising: It is a figure which shows typically the state by which metal powder was added to the thermoelectric conversion material in the thermoelectric conversion element of this invention, and the shape was hold | maintained with resin. It is a figure which shows the relationship between the resistivity of the thermoelectric conversion element produced in Example 1 of this invention, and the addition amount of metal powder (Ni powder). It is a figure which shows the relationship between the dimensionless figure of merit ZT of the thermoelectric conversion element produced in Example 1 of this invention, and the addition amount of metal powder (Ni powder). It is a figure explaining the structure of the thermoelectric conversion module concerning Example 2 of this invention. It is a figure which shows the maximum output at the time of adjusting the external load so that the output voltage of a thermoelectric conversion module concerning Example 2 of this invention and no output may become the maximum. It is a figure explaining the basic composition and the function of a thermoelectric conversion module.

Embodiments of the present invention will be described below, and the features of the present invention will be described in more detail.

For example, as shown in FIG. 8, one p-type thermoelectric conversion material 1 and one n-type thermoelectric conversion material 2 are provided, and the p-type thermoelectric conversion material 1 and the n-type thermoelectric conversion material 2 are end surfaces on the high temperature side. 3a, via the high temperature side connection electrode 4, and on the low temperature side end surfaces 3b of the p-type thermoelectric conversion material 1 and the n-type thermoelectric conversion material 2, electrodes (extraction electrodes) 5 are respectively disposed. When considering a thermoelectric conversion element 10 of a type, if a temperature difference is given between the high temperature side end surface 3 a and the low temperature side end surface 3 b, an electromotive force is generated due to the Seebeck effect, and electric power is extracted through the electrode (extraction electrode) 5.

In addition, the Seebeck coefficient of the p-type thermoelectric conversion material is plus and the Seebeck coefficient of the n-type thermoelectric conversion material is minus, and a large thermoelectromotive force can be obtained by using a plurality of pairs of pn junctions.

However, the thermoelectric conversion module is not limited to a combination of a p-type thermoelectric conversion material and an n-type thermoelectric conversion material, but a combination of a p-type thermoelectric conversion material and a metal material, or a combination of an n-type thermoelectric conversion material and a metal material. The thermoelectric conversion module that generates a predetermined electromotive force can also be configured.

By the way, when a metal oxide semiconductor material is used as the p-type and n-type thermoelectric conversion materials as described above, the metal oxide semiconductor material is usually a metal compound raw material (oxide, carbonate, etc.). After mixing at a compounding ratio, heat treatment is performed to synthesize raw material powder having the desired composition, and further cut out a thermoelectric conversion material manufactured through a process of sintering by a method such as pressure sintering into a predetermined shape. The thermoelectric conversion material (p-type thermoelectric conversion element and n-type thermoelectric conversion element) is manufactured, for example, by electrical connection so as to have a π-type junction structure as shown in FIG. Therefore, in order to produce a p-type thermoelectric conversion material (element) and an n-type thermoelectric conversion material (element), a sintering process is essential, which not only increases the energy cost but also complicates the manufacturing process.

In contrast, in the present invention, magnesium silicide produced by a method such as a melting method or an intermetallic compound of manganese silicide is used as the thermoelectric conversion material. A thermoelectric conversion element can be obtained without the need.

That is, the thermoelectric conversion element of the present invention applies a curable resin to or impregnates a molded body containing a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder, and then cures the curable resin. Therefore, it can be efficiently manufactured without requiring a sintering process at a high temperature.

The intermetallic compound (metal-based semiconductor thermoelectric conversion material) used for the thermoelectric conversion material of the present invention is not particularly limited, but metal-based compounds such as silicide-based materials, Heusler-based materials, half-Heusler-based materials, and skutterudite-based materials A semiconductor thermoelectric conversion material is preferably used, and a silicide material such as magnesium silicide (eg, Mg ₂ Si), manganese silicide (eg, MnSi _1.7 ), iron silicide (eg, FeSi ₂ ) is more preferably used.
Moreover, in the thermoelectric conversion element of this invention, it is also possible to use the material suitable for the temperature distribution inside an element by stacking in the serial direction.

Moreover, in the thermoelectric conversion element of this invention, the metal powder which is a material whose resistivity is lower than this thermoelectric conversion material is mixed with the thermoelectric conversion material powder which consists of intermetallic compounds.
The added metal powder only needs to have a lower resistivity than the thermoelectric conversion material, and there is no particular restriction on the type thereof. Moreover, a metal powder may be used individually by 1 type, and 2 or more types may be mixed and used for it. Moreover, it is desirable to use a metal powder having a particle size smaller than that of the thermoelectric conversion material powder, and it is usually preferable to add the powder in a powder state.

In the present invention, Ni powder is preferable as the metal powder mixed with the n-type thermoelectric conversion material powder, and Cu powder is preferable as the metal powder mixed with the p-type thermoelectric conversion material powder.
The amount of metal powder added is preferably such that the ratio of metal powder to the total amount of metal powder and thermoelectric conversion material powder is in the range of 0.1 to 50 vol%. This is because when the added amount of the metal powder is less than 0.1 vol%, the effective resistivity does not decrease, and when the added amount of the metal powder exceeds 50 vol%, the Seebeck coefficient decreases, and the power generation characteristics Due to the low.

The thermoelectric conversion element of the present invention does not require a sintering step such as pressure sintering, for example, and can be manufactured by molding by a method such as pressure molding.
There is no particular limitation on the particle size when classifying the thermoelectric conversion material powder before molding, and the abundance ratio of the thermoelectric conversion material powder of each particle size, so long as it is a particle size that can maintain the shape of the thermoelectric conversion element, For example, particles having a particle size of 300 μm or more may be included. In addition, each classified product may be appropriately mixed and used.

In addition, the pressure in the case of pressure molding with a biaxial press may be a pressure that can reach a density at which the molded body can maintain a predetermined shape, and examples thereof include a pressure of 100 MPa, It is not limited to this.

In producing the thermoelectric conversion element of the present invention, for example, after applying or impregnating a curable resin on the surface of a molded body of thermoelectric conversion material powder and metal powder (for example, a molded body by pressure molding). The curable resin is cured. Thereby, a thermoelectric conversion element is obtained.
Note that the mechanical strength of the thermoelectric conversion element is insufficient only by molding such as pressure molding, but the mechanical strength is increased by applying or impregnating the curable resin and then curing to increase the reliability. Can be improved.
Moreover, moisture resistance can be improved by covering the element surface with a curable resin.
As described above, since the thermoelectric conversion element of the present invention does not require a process such as pressure sintering, it is possible to reduce energy consumed in the manufacturing process, and it is economical and excellent in productivity. A thermoelectric conversion element can be provided.
In addition, it is possible to easily perform complicated shape processing, and since it becomes easy to segment materials having different temperature characteristics, it is possible to improve thermoelectric conversion efficiency.
Moreover, by mixing metal powder (low resistance material) with the thermoelectric conversion material powder, it is possible to reduce the resistivity of the thermoelectric conversion element, and it is possible to increase the power generation capacity.

As the curable resin to be applied or impregnated into the molded body, a thermosetting resin such as an epoxy resin may be used, or a type that is cured by a photocurable resin, a curing accelerator or a catalyst. It is also possible to use a resin such as a resin. Further, the application state and the impregnation state of the curable resin may be at least a state in which the molded body can maintain its shape, and the reach distance from the surface of the molded body to the inside is particularly limited. It is not a thing.

Further, as long as the molded body can maintain its shape, the curable resin may be present so as to cover the surface with almost no penetration into the molded body.

The ratio of the curable resin in the thermoelectric conversion element may be appropriately selected so that the thermoelectric conversion element made of the thermoelectric conversion material powder and the metal powder has a predetermined strength.

FIG. 1 is a perspective view of a thermoelectric conversion element according to an embodiment of the present invention, FIG. 2 is a front sectional view, and FIG. 3 is an enlarged view of a main part of FIG.

As shown in FIGS. 2 and 3, in the thermoelectric conversion element A according to this embodiment, the inside from the surface 10 a (FIG. 3) of the molded body 10 including the thermoelectric conversion material powder 11 made of an intermetallic compound and the metal powder 12. The curable resin 13 is impregnated toward the surface, and the molded body 10 is maintained in a predetermined shape (substantially cubic shape) by the curable resin 13.

1 to 3 are manufactured through a process in which the molded body 10 is immersed in a curable resin in an uncured state, pulled up, vacuumed to remove bubbles, and then cured. is there.

It is possible to further infiltrate the resin by adjusting the immersion time and the subsequent vacuum suction time.

Further, when the resin is stopped on the surface layer of the molded body 10, the resin may be applied and cured. Even in that case, the shape retaining property of holding the thermoelectric conversion element in a predetermined shape can be ensured. *

Moreover, as an example of the thermoelectric conversion module of this invention, it forms using the thermoelectric conversion element (p-type thermoelectric conversion element and n-type thermoelectric conversion element) of this invention comprised as mentioned above, and it shows in FIG. Such a π-type thermoelectric conversion module can be exemplified.

For example, in manufacturing a thermoelectric conversion module having a plurality of junction pairs of a p-type thermoelectric conversion element and an n-type thermoelectric conversion element, the p-type thermoelectric conversion element and the n-type thermoelectric conversion element are combined with a predetermined arrangement of thermoelectric conversion modules. A thermoelectric conversion module having a plurality of pn junction pairs efficiently by arranging and connecting with a conductive resin, and then applying or impregnating a curable resin and then curing the thermosetting resin. Can be manufactured.

In addition, the thermoelectric conversion element of the present invention obtained by curing a curable resin that has been coated or impregnated has excellent moisture resistance, and improves the reliability of a thermoelectric conversion module that is produced using the thermoelectric conversion element. Can do.

In addition, in the thermoelectric conversion module, it is desirable that the thermoelectric conversion elements are electrically connected by a single conductive resin, but metal wires, foils, bars, plates, etc. may be connected by a conductive resin. Good.

Hereinafter, the present invention will be described in more detail with reference to examples of the present invention. In Example 1, a thermoelectric conversion element using Mg ₂ Si, which is an intermetallic compound, as a metal-based semiconductor thermoelectric material was prepared and the characteristics thereof were examined by the following procedure.

First, Mg ₂ Si produced by a melting method was prepared as a metal-based semiconductor thermoelectric material, and this was pulverized in a mortar, and then the particle size was classified to 50 μm to 300 μm.
Next, Ni powder having an average particle size of 0.9 μm is weighed into the classified thermoelectric material powder (Mg ₂ Si powder) so as to have the volume fraction shown in Table 1, and acetone is used as a solvent for over 10 minutes. Sonic dispersion was performed to obtain a slurry.
Then, after removing the solvent component from the slurry, the slurry was dried in an oven at 40 ° C. for 1 hour, and a thermoelectric conversion material powder for pressure molding was obtained through a sieve having an opening of 30 μm.

Then, this thermoelectric conversion material powder was subjected to pressure molding at a pressure of 100 MPa using a biaxial press to produce a molded body (molded body) having a size of 24 mm × 4 mm × 3.5 mmt.

Next, this compact was hydrostatically pressed at a pressure of 1 GPa to produce compacts having different relative densities.
Then, an epoxy resin was applied as a curable resin to this molded body, and vacuum deaeration was performed to impregnate the epoxy resin from the surface of the molded body into the internal space.

Then, the resin-impregnated molded body was allowed to stand at room temperature for 24 hours to solidify the epoxy resin and then cut with a dicing saw to obtain a thermoelectric conversion element (n-type thermoelectric conversion element) having a length of 12 mm.
About the obtained thermoelectric conversion element, relative density, resistivity, Seebeck coefficient, thermal conductivity, and fracture strength were examined.

The resistivity (Ω · cm) was examined by measuring the electric resistance at room temperature of the thermoelectric conversion element by the four-terminal method.
Further, the Seebeck coefficient (μV / K) was calculated by measuring the thermoelectromotive force generated when a temperature difference of 5 to 30 ° C. was given to both ends of the thermoelectric conversion element.
Furthermore, the thermal conductivity (W / mK) was measured by a laser fresh method.
Further, the breaking strength (Mpa) was evaluated by a three-point bending test for samples before and after impregnation with a curable resin (epoxy resin) and after application, impregnation and curing.

Moreover, the output factor (PF) which is the characteristic of the thermoelectric conversion material was calculated | required from following formula (1).
P. F. (W / K ² m) = α ² / ρ (1)
α: Seebeck coefficient ρ: Resistivity (electric resistance)

Furthermore, the dimensionless figure of merit ZT, which is a value obtained by dividing the output factor by the thermal conductivity and multiplying by the absolute temperature, was obtained.

Table 2 shows the relative density, resistivity, Seebeck coefficient, output factor, thermal conductivity, dimensionless figure of merit ZT, and breaking strength of the thermoelectric conversion element produced in this example.
The properties other than the breaking strength are values measured for a sample obtained by curing the impregnated curable resin.

4 and 5 show changes in resistivity and dimensionless figure of merit ZT of the thermoelectric conversion element produced in this example.

As shown in Table 2, among the samples of sample numbers 1 to 7, Ni is added, and in the thermoelectric conversion elements of sample numbers 2 to 7 satisfying the requirements of the present invention, Ni is any volume fraction. In this case, the dimensionless figure of merit ZT is improved. For example, in the sample number 5, the dimensionless figure of merit ZT is 0.0258, which is about twice the characteristic of the sample of the sample number 1 with no Ni powder added. It was confirmed that

In addition, regarding the breaking strength, the breaking strength of the sample cured after applying and impregnating the curable resin is greatly improved compared to the sample before applying and impregnating the curable resin. Was confirmed. For example, regarding the sample of sample number 5, in the case of the sample not impregnated with the resin, the fracture strength is 5.2 MPa, whereas in the case of the sample impregnated with the resin and cured, 79.1 MPa is about 15 It has been confirmed that double strength can be obtained.

Further, from the above examples, as in the sample of sample number 1, when only the thermoelectric conversion material powder is molded without compounding the metal powder (Ni powder), the output factor is small and the power generation characteristics are low. It was confirmed that the power generation capability was improved by adding metal powder (Ni powder) as in samples Nos. 2 to 7, and that effective fracture strength was obtained by impregnating and curing the resin. It was.

Moreover, according to the method for manufacturing a thermoelectric conversion element of the present invention, since a heat treatment step (sintering step) at a high temperature is not required, it is possible to reduce the energy cost required for manufacturing the thermoelectric conversion element. The time required for the manufacturing process can be shortened.

In Example 1, Ni powder having the same Seebeck coefficient polarity as Mg ₂ Si is used as the metal powder to be added. That is, Ni ₂ powder, which is a thermoelectric conversion material, has a negative Seebeck coefficient and a lower resistivity than Mg ₂ Si, and is used as the metal powder.
Thus, when the intermetallic compound (Mg ₂ Si in this example), which is a thermoelectric conversion material, and the polarity of the Seebeck coefficient of the metal powder are matched, the resistivity can be reduced while suppressing the reduction of the Seebeck coefficient. It is preferable when trying.

For example, when using Mg ₂ Si as the thermoelectric conversion material, it is desirable to use a metal powder having a negative Seebeck coefficient and a resistivity lower than Mg ₂ Si as the metal powder to be added. Examples of the metal include Pt and Al, and examples of the alloy include constantan.

A thermoelectric conversion element (p-type thermoelectric conversion element in this example 2) was used in the same manner as in Example 1 except that MnSi _1.7 was used as the metal-based semiconductor thermoelectric material and Cu powder having an average particle diameter of 0.75 μm was used as the metal powder. )
That is, Cu powder was weighed into the classified thermoelectric material powder (MnSi _1.7 powder) so as to have the volume fraction shown in Table 3, and the thermoelectric conversion element (p-type) was obtained in the same manner as in Example 1 above. Thermoelectric conversion element) was produced.

The relative density, resistivity, Seebeck coefficient, thermal conductivity, and fracture strength of the obtained thermoelectric conversion element were examined, and the output factor (PF) and the dimensionless figure of merit ZT were obtained. The results are shown in Table 4.

As shown in Table 4, although not as much as in Example 1, among the samples (thermoelectric conversion elements) of sample numbers 11 to 17 in the samples of sample numbers 12 to 17 satisfying the requirements of the present invention to which Cu powder was added The dimensionless figure of merit ZT is improved regardless of the volume fraction of Cu. For example, in the sample number 16, the dimensionless figure of merit ZT is 0.0075, and the sample number with no addition of Cu powder. It was confirmed that about 1.2 times the characteristics of 11 samples were obtained.

As a p-type thermoelectric conversion element, a thermoelectric conversion material powder having the composition of sample number 16 prepared in Example 2 was pressure-molded to prepare a p-type thermoelectric conversion element having a size of 5 mm □ × height of 6 mm.

Further, as the n-type thermoelectric conversion element, the thermoelectric conversion material powder having the composition of Sample No. 3 prepared in Example 1 was pressure-molded to prepare an n-type thermoelectric conversion element having a size of 5 mm □ × height of 6 mm.

Next, as shown in FIG. 6, conductive resin 22 was applied to alumina substrate 21, and a plurality of p-type pn junction pairs of p-type thermoelectric conversion element 1 and n-type thermoelectric conversion element 2 were connected in series. It mounted on the conductive resin 22 so that it might become a predetermined | prescribed arrangement | sequence of a thermoelectric conversion module, and the conductive resin 22 was hardened.

Next, although not particularly illustrated, another alumina substrate coated with a conductive resin so that the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion element 2 are connected in series is connected to the p-type thermoelectric conversion element 1 and the n-type thermoelectric conversion. A series π-type thermoelectric conversion module was fabricated by placing the conductive resin on the upper surface side of the element 2 and curing the conductive resin. And electric wiring was performed to the both terminal parts of this series pi type thermoelectric conversion module.

Next, a temperature difference of 80 ° C. is applied to the upper and lower surfaces of the series π-type thermoelectric conversion module to examine the output voltage at no load, and the external load is adjusted so that the output is maximized, and this series π-type thermoelectric conversion is performed. The maximum output of the module was examined. The result is shown in FIG.
As shown in FIG. 7, the output voltage with no load was 0.16 V, and the maximum output adjusted for the external load was 14 mW.

Thus, in the π-type thermoelectric conversion module of Example 3 using the thermoelectric conversion element of the present invention, an effective power generation amount was obtained, and it was confirmed that the thermoelectric conversion module functions.

In addition, also when manufacturing the thermoelectric conversion module of this Example 3, since the heat processing process (sintering process) at high temperature is not required, it becomes possible to shorten the time which a manufacturing process requires, and to manufacture The energy required can be reduced.

In Example 3, MnSi _1.7 produced by the melting method is used as the p-type thermoelectric conversion material, and Mg ₂ Si also produced by the melting method is used as the n-type thermoelectric conversion material. In addition to magnesium silicide and manganese silicide, iron silicide or the like can be used as the intermetallic compound.

Moreover, in the said Example, although Ni powder is used as a metal powder used with n-type thermoelectric conversion material powder and Cu powder is used as a metal powder used with p-type thermoelectric conversion material powder, as a metal powder, resistance It is possible to use various metal powders whose rate is lower than that of intermetallic compounds. In this case, as described above, it is desirable that the polarities of the Seebeck coefficients of the intermetallic compound as the thermoelectric conversion material and the metal constituting the metal powder are the same.

In addition, the present invention is not limited to the above-described embodiments in other respects. The number of junction pairs of the p-type thermoelectric conversion element and the n-type thermoelectric conversion element in the thermoelectric conversion module, the specifics of both are specifically described. Various applications and modifications can be made within the scope of the invention with respect to the connection mode and the like.

DESCRIPTION OF SYMBOLS 1 p-type thermoelectric conversion element 2 n-type thermoelectric conversion element 10 Molded object 10a Surface of molded object 11 Thermoelectric conversion material powder 12 Metal powder 13 Curable resin 21 Alumina substrate 22 Conductive resin A Thermoelectric conversion element M Thermoelectric conversion module

Claims (7)

A thermoelectric conversion element comprising a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder, and being held in a predetermined shape by a resin. The thermoelectric conversion element according to claim 1, wherein the intermetallic compound is silicide. The thermoelectric conversion element according to claim 2, wherein the silicide is at least one selected from the group consisting of magnesium silicide, manganese silicide, and iron silicide. A method for producing a thermoelectric conversion element according to any one of claims 1 to 3,
Applying or impregnating a curable resin to a molded body containing a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder; and
And a step of curing the curable resin. A method for manufacturing a thermoelectric conversion element. A thermoelectric conversion module having a structure in which one side element and the other side element are connected via a conductive resin,
(a) the thermoelectric conversion element according to any one of claims 1 to 3 is used as the one-side element;
(b) The thermoelectric conversion element according to any one of claims 1 to 3, wherein a thermoelectric conversion element different from the one side element or a metal element made of metal is used as the other side element. Thermoelectric conversion module. A method for manufacturing a thermoelectric conversion module having a structure in which one side element and the other side element are connected via a conductive resin,
(a) a molded body containing a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder; and (b) a molded body comprising a thermoelectric conversion material powder composed of an intermetallic compound and a metal powder. The other side molded body, which is a molded body different from the one side molded body, or a molded body made of metal, is arranged so as to have a predetermined arrangement of the thermoelectric conversion modules, and is connected via a conductive resin. Forming a structure;
When a molded body made of the metal is used as the other side molded body, a thermoelectric conversion material powder made of an intermetallic compound and a metal powder are used as the other side molded body. And a step of applying or impregnating a curable resin to the one side molded body and the other side molded body when a molded body different from the one side molded body is used. ,
By curing the curable resin, a thermoelectric conversion material powder made of an intermetallic compound and a metal powder, one side element held in a predetermined shape by the cured resin, and a molded body made of metal A thermoelectric conversion material powder made of an intermetallic compound, and the other element containing a metal powder and held in a predetermined shape by a cured resin is a predetermined arrangement of thermoelectric conversion modules. And forming a thermoelectric conversion module having a structure arranged so as to be connected via a conductive resin. A method of manufacturing a thermoelectric conversion module, comprising: A method for manufacturing a thermoelectric conversion module having a structure in which one side element and the other side element are connected via a conductive resin,
(a) the thermoelectric conversion element according to any one of claims 1 to 3 is used as the one-side element;
(b) The thermoelectric conversion element according to any one of claims 1 to 3, wherein a thermoelectric conversion element different from the one side element, or a metal element made of metal is used as the other side element,
(c) The method for manufacturing a thermoelectric conversion module, wherein the one side element and the other side element are arranged so as to form a predetermined arrangement of thermoelectric conversion modules and are connected by a conductive resin.

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