WO2009093642A1 - Thermoelectric material and thermoelectric conversion module - Google Patents

Thermoelectric material and thermoelectric conversion module Download PDF

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WO2009093642A1
WO2009093642A1 PCT/JP2009/050947 JP2009050947W WO2009093642A1 WO 2009093642 A1 WO2009093642 A1 WO 2009093642A1 JP 2009050947 W JP2009050947 W JP 2009050947W WO 2009093642 A1 WO2009093642 A1 WO 2009093642A1
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thermoelectric conversion
conversion material
type semiconductor
semiconductor element
type
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PCT/JP2009/050947
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French (fr)
Japanese (ja)
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Takanori Nakamura
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Murata Manufacturing Co., Ltd.
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    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/45—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on copper oxide or solid solutions thereof with other oxides
    • C04B35/4504—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on copper oxide or solid solutions thereof with other oxides containing rare earth oxides
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/10—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects
    • H10N10/17—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects operating with only the Peltier or Seebeck effects characterised by the structure or configuration of the cell or thermocouple forming the device
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N10/00—Thermoelectric devices comprising a junction of dissimilar materials, i.e. devices exhibiting Seebeck or Peltier effects
    • H10N10/80—Constructional details
    • H10N10/85—Thermoelectric active materials
    • H10N10/851—Thermoelectric active materials comprising inorganic compositions
    • H10N10/855—Thermoelectric active materials comprising inorganic compositions comprising compounds containing boron, carbon, oxygen or nitrogen
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
    • C04B2235/3208—Calcium oxide or oxide-forming salts thereof, e.g. lime
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
    • C04B2235/3213—Strontium oxides or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3205—Alkaline earth oxides or oxide forming salts thereof, e.g. beryllium oxide
    • C04B2235/3215—Barium oxides or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
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    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C04B2235/3227—Lanthanum oxide or oxide-forming salts thereof
    • C—CHEMISTRY; METALLURGY
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    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3224—Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
    • C04B2235/3229—Cerium oxides or oxide-forming salts thereof

Definitions

  • the present invention relates to a thermoelectric conversion material and a thermoelectric conversion module configured using the same, and particularly relates to an improvement for improving the output factor of the thermoelectric conversion material.
  • thermoelectric conversion material composed of a compound having a layered perovskite structure represented by the general formula Ln 2 MO 4 (Ln is a rare earth element and M is a transition metal element)
  • Ln 2 MO 4 Ln is a rare earth element and M is a transition metal element
  • thermoelectric conversion material a composition formula (Nd 1-z M z ) 2 CuO 4 (where M is Zr or Pr, and z is 0 ⁇ z ⁇ 1 is satisfied.).
  • a thermoelectric conversion material represented by the composition when Nd is doped with Pr that is, the composition formula (Nd 1 ⁇ z Pr z ) 2 CuO 4 .
  • FIG. 4 and FIG. 5 of Patent Document 1 show changes in Seebeck coefficient, changes in electrical resistivity, and output factors due to changes in the doping amount z of Pr in (Nd 1-z Pr z ) 2 CuO 4 .
  • Each change in (power factor) is shown. From FIG. 2 of Patent Document 1, it can be seen that the Seebeck coefficient slightly decreases as the Pr doping amount z increases. From FIG. 4 of Patent Document 1, the electrical resistivity is almost the same as the case where the doping amount z is 0 until the doping amount z of Pr is 0.05, but the doping amount z is 0.05. It can be seen that it decreases as it exceeds and increases to 0.10. Further, FIG. 5 of Patent Document 1 shows that the output factor is improved as the doping amount z of Pr is increased.
  • Patent Document 2 describes a thermoelectric conversion material represented by a composition formula (Ln 1-x A x ) 2 CuO 4 (Ln is La or Y, A is Ba or Sr, 0 ⁇ x ⁇ 1). ing. Regarding this thermoelectric conversion material, Patent Document 2 describes that a large figure of merit can be given from around room temperature to a low temperature of 100K or less.
  • thermoelectric conversion material described in Patent Document 2 still has room for improvement in the value of the output factor, and it is unclear whether it can be used up to a high temperature range of, for example, about 500 ° C. without deterioration in characteristics.
  • an object of the present invention is to provide a thermoelectric conversion material capable of further improving the output factor, and a thermoelectric conversion module configured using the thermoelectric conversion material.
  • the present invention is first directed to a p-type thermoelectric conversion material.
  • P-type thermoelectric conversion material a rare earth having a layered perovskite structure - a transition metal oxide, represented by formula (Ln 2-x A1 x) A2B 2 O 6, Ln is La, Pr , Nd, Sm and Gd, A1 is at least one selected from Ca, Sr and Ba, A2 is at least one selected from Ca, Sr and Ba, B Is at least one selected from Co, Cu and Ni, and x is in the range of 0 ⁇ x ⁇ 0.2.
  • Ln is more preferably at least one selected from La, Pr and Nd.
  • B is more preferably Cu.
  • x is in the range of 0 ⁇ x ⁇ 0.2, that is, a part of Ln is at least one selected from Ca, Sr and Ba. Is preferably substituted with.
  • the present invention is also directed to a thermoelectric conversion module configured using the p-type thermoelectric conversion material according to the present invention.
  • the thermoelectric conversion module includes a p-type semiconductor element including a p-type thermoelectric conversion material, an n-type semiconductor element including an n-type thermoelectric conversion material, one end of the p-type semiconductor element, and n A first electrode commonly connected to one end of the n-type semiconductor element; a second electrode connected to the other end of the p-type semiconductor element; and a third electrode connected to the other end of the n-type semiconductor element; It has.
  • the p-type thermoelectric conversion material is a p-type thermoelectric conversion material according to the present invention.
  • thermoelectric conversion module in the second embodiment, includes a p-type semiconductor element including a p-type thermoelectric conversion material, and an n-type semiconductor element including an n-type thermoelectric conversion material bonded to the p-type semiconductor element.
  • the p-type semiconductor element and the n-type semiconductor element are directly joined at a part of the junction, and are joined via an insulator at the remaining part of the junction.
  • the p-type thermoelectric conversion material is a p-type thermoelectric conversion material according to the present invention.
  • thermoelectric conversion module the p-type semiconductor element, the n-type semiconductor element, and the insulator are preferably obtained by sintering at the same time.
  • the output factor can be improved and the dimensionless figure of merit ZT can also be improved, as will be apparent from the experimental examples described later.
  • the p-type thermoelectric conversion material according to the present invention does not contain toxic elements and has high safety. Further, excellent thermoelectric characteristics can be exhibited in a temperature range from room temperature to about 500 ° C., particularly in a temperature range of 300 ° C. or more.
  • thermoelectric conversion material when a part of Ln is substituted with at least one selected from Ca, Sr and Ba, the rare-earth element which is a rare element is maintained while maintaining excellent thermoelectric properties.
  • the amount used can be reduced.
  • thermoelectric conversion module 1 by 1st Embodiment of this invention. It is a perspective view which shows the thermoelectric conversion module 11 by 2nd Embodiment of this invention. It is a figure which shows the Seebeck (Seebeck) coefficient about the sample produced in Experimental example 1. FIG. It is a figure which shows the output factor about the sample produced in Experimental example 1. FIG. It is a figure which shows the dimensionless figure of merit ZT about the sample produced in example 1 of an experiment.
  • P-type thermoelectric conversion material according to the present invention are those represented by the composition formula (Ln 2-x A1 x) A2B 2 O 6.
  • Ln is at least one selected from La, Pr, Nd, Sm, and Gd
  • A1 is at least one selected from Ca, Sr, and Ba
  • A2 is selected from Ca, Sr, and Ba.
  • At least one selected, and B is at least one selected from Co, Cu and Ni.
  • X is in the range of 0 ⁇ x ⁇ 0.2.
  • Ln is at least one selected from La, Pr and Nd, and B is Cu.
  • x is in a range of 0 ⁇ x ⁇ 0.2, that is, a part of Ln is substituted with A1 which is at least one selected from Ca, Sr and Ba.
  • the starting element includes the element to be Ln, the element to be A1, the element to be A2, and the element to be B.
  • Raw materials are prepared.
  • oxides are usually used for Ln and B, and carbonates are used for A1 and A2.
  • oxide or carbonate it is not limited to such an oxide or carbonate,
  • other inorganic materials such as a hydroxide, and organometallic compounds, such as an acetylacetonate complex, may be used.
  • the above-mentioned starting materials are weighed so as to give a desired composition ratio, and then pulverized and mixed.
  • a pulverization and mixing treatment for example, a wet ball mill using a dispersion medium as water is used. In this way, a mixed powder of starting materials is obtained.
  • water is used as a dispersion medium, an operation for evaporating water is then performed.
  • the mixed powder of the starting material is heat-treated in the atmosphere at a temperature of 900 ° C. for 8 hours, for example.
  • the target p-type thermoelectric conversion material powder is obtained.
  • the unreacted part may remain in the thermoelectric conversion material powder.
  • the p-type thermoelectric conversion material powder described above is, for example, press-molded in a state where a binder is mixed with the p-type thermoelectric conversion material powder, and then the compact is fired in the atmosphere at a temperature of, for example, 1000 to 1100 ° C. for 2 hours.
  • a sintered body of the p-type thermoelectric conversion material is produced.
  • the p-type thermoelectric conversion material powder is dispersed in a slurry containing a binder, and after the slurry is formed into a sheet shape, the p-type thermoelectric conversion material powder may be fired to produce a sintered body of the p-type thermoelectric conversion material.
  • the relative density of the sintered body is preferably 80% or more, and more preferably 90% or more.
  • the relative density usually depends on the firing temperature. However, since the optimal firing temperature varies depending on, for example, the composition of the thermoelectric conversion material, it is necessary to adjust according to the composition of the thermoelectric conversion material.
  • thermoelectric conversion module configured using the p-type thermoelectric conversion material according to the present invention will be described.
  • FIG. 1 is a cross-sectional view showing a thermoelectric conversion module 1 according to a first embodiment of the present invention.
  • a thermoelectric conversion module 1 includes a p-type semiconductor element 2 including a p-type thermoelectric conversion material, an n-type semiconductor element 3 including an n-type thermoelectric conversion material, one end of the p-type semiconductor element 2, and n A first electrode 4 commonly connected to one end of the p-type semiconductor element 3, a second electrode 5 connected to the other end of the p-type semiconductor element 2, and a second electrode 5 connected to the other end of the n-type semiconductor element 3. And a third electrode 6.
  • the p-type thermoelectric conversion material according to the present invention is used as the p-type thermoelectric conversion material constituting the p-type semiconductor element 2.
  • thermoelectric conversion module 1 for example, a high-temperature heat source is disposed on the first electrode 4 side, and a temperature difference is generated between one end side and the other end side of each of the p-type semiconductor element 2 and the n-type semiconductor element 3. Is generated, an electromotive force is generated between the first electrode 4 and the second and third electrodes 5 and 6. Therefore, when a load is connected between the second and third electrodes 5 and 6, a current flows and can be taken out as electric power.
  • thermoelectric conversion module 1 configured as shown in FIG. 1, in an actual product, for example, alumina is formed on one end side and the other end side of each of the p-type semiconductor element 2 and the n-type semiconductor element 3.
  • the first and second insulating substrates are arranged, and the p-type semiconductor element 2 and the n-type semiconductor element 3 are sandwiched between the first and second insulating substrates.
  • the first electrode 4 is formed by baking a conductive paste printed on the first insulating substrate, and the second and third electrodes 5 and 6 are formed on the second insulating substrate. It is formed by baking a printed conductive paste.
  • thermoelectric conversion module 1 a plurality of p-type semiconductor elements 2 and n-type semiconductor elements 3 are disposed between the first and second insulating substrates, respectively. Electrodes 4 to 6 may be formed to connect element 2 and n-type semiconductor element 3 in series. Alternatively, in order to increase the allowable current that can flow to the thermoelectric conversion module 1, a plurality of p-type semiconductor elements 2 and n-type semiconductor elements 3 are disposed between the first and second insulating substrates, respectively. Electrodes 4 to 6 may be formed to connect p-type semiconductor element 2 and n-type semiconductor element 3 in parallel.
  • FIG. 2 is a perspective view showing a thermoelectric conversion module 11 according to a second embodiment of the present invention.
  • thermoelectric conversion module 11 includes a plurality of p-type semiconductor elements 12 including a p-type thermoelectric conversion material, and a plurality of n-type thermoelectric conversion materials bonded to each of p-type semiconductor elements 12. and an n-type semiconductor element 13.
  • the p-type thermoelectric conversion material constituting the p-type semiconductor element 12 the p-type thermoelectric conversion material according to the present invention is used.
  • thermoelectric conversion module 1 it is necessary to provide an insulating void layer between the p-type semiconductor element and the n-type semiconductor element 3. In the thermoelectric conversion module 11, it is necessary to provide such a void layer. Absent. Therefore, since the area of the thermoelectric conversion material occupying per unit area can be increased, the power generation capacity per unit area of the thermoelectric conversion module can be increased.
  • the p-type semiconductor element 12, the n-type semiconductor element 13, and the insulator 14 described above are obtained by sintering at the same time. This is because highly reliable joints can be obtained between each other.
  • power extraction electrodes 15 and 16 are formed at the lower end portions of the p-type semiconductor element 12 and the n-type semiconductor element 13 located at the respective end portions in the drawing.
  • thermoelectric conversion module 11 for example, when a high-temperature heat source is arranged on the upper end side in the figure and a temperature difference is given between the upper end side and the lower end side, an electromotive force is generated between the power extraction electrodes 15 and 16. Will occur. Therefore, when a load is connected between the power extraction electrodes 15 and 16, a current flows and can be extracted as electric power.
  • sample symbol such as “LaCa-1” or “LaSr” shown in Table 1 above
  • the “La” portion and the “Ca” or “Sr” portion are represented by the composition formula (Ln 2-x A1 x )
  • Each element constituting the “Ln” portion and the “A2” portion in A2Cu 2 O 6 is shown.
  • the number “1” at the end of the “sample symbol” such as “LaCa-1” is attached to distinguish between samples that share the “Ln” portion and the “A2” portion. Is.
  • the “comparative example” does not include “A2” in the composition formula (Ln 2 ⁇ x A1 x ) A2B 2 O 6 .
  • the starting materials weighed as described above were pulverized and mixed by a wet ball mill using water as a dispersion medium. And water was evaporated from the obtained slurry to obtain a mixed powder of starting materials.
  • the mixed powder of the starting material was heat-treated in the atmosphere at a temperature of 900 ° C. for 8 hours to obtain a target thermoelectric conversion material powder.
  • the organic binder was mixed with the thermoelectric conversion material powder at a ratio of 5% by weight with respect to each powder, and pulverized and mixed with a wet ball mill using water as a dispersion medium.
  • thermoelectric conversion material powder mixed with the organic binder was sufficiently dried, a compact was produced by applying a pressure of 10 MPa using a single screw press.
  • the molded body was fired in the atmosphere at a temperature in the range of 1000 to 1100 ° C. for 2 hours to obtain a sintered body of the thermoelectric conversion material according to each sample.
  • the firing temperature was adjusted according to the composition of the thermoelectric conversion material according to each sample, and was set so that the relative density of the sintered body was 80% or more.
  • the crystal structure of the sintered body according to each sample was identified by X-ray diffraction. As a result, it was found that all the samples had a crystal structure mainly composed of a layered perovskite structure. Table 2 shows the generation phase in the sintered body according to each sample together with the ratio.
  • a Seebeck coefficient was obtained.
  • the sintered body of each sample is placed in a temperature vessel set to 50 to 550 ° C, the temperature at both ends of the sample is adjusted so that a temperature difference is obtained between the high temperature part and the low temperature part, The electromotive force obtained in the meantime was measured and calculated from the measured electromotive force and the measured temperature difference.
  • the output factor was calculated
  • a dimensionless figure of merit (ZT) was obtained.
  • the sintered body of each sample was placed in a temperature bath set to 50 to 550 ° C., and the specific heat and thermal diffusivity were measured by the laser flash method.
  • the thermal conductivity is calculated by taking into account the size and weight of the measurement sample, and from this thermal conductivity ( ⁇ ) and measurement temperature T (absolute temperature) and the output factor (P) obtained as described above.
  • FIG. 3 shows Seebeck coefficients for sample LaCa-1, sample LaCa-3, sample LaCa-7, sample LaCa-9, sample PrSr and sample NdSr, and a comparative example. From FIG. 3, it was first found that each sample was a thermoelectric conversion material having p-type polarity. Further, it was found that the sample LaCa-1, sample LaCa-3, sample LaCa-7, sample LaCa-9, sample PrSr, and sample NdSr can provide a higher Seebeck coefficient than the comparative example.
  • FIG. 4 shows output factors for sample LaCa-1, sample LaCa-3, sample LaCa-7 and sample LaCa-9, and a comparative example. From FIG. 4, it was found that the sample LaCa-1, the sample LaCa-3, the sample LaCa-7, and the sample LaCa-9 can obtain characteristics that exceed the comparative example with respect to the output factor.
  • FIG. 5 shows dimensionless figure of merit (ZT) for sample LaCa-1, sample LaCa-3, sample LaCa-7, sample LaCa-9, and comparative example.
  • FIG. 5 shows that the sample LaCa-1, the sample LaCa-3, the sample LaCa-7, and the sample LaCa-9 have higher values for the dimensionless figure of merit (ZT) than the comparative example.
  • ZT dimensionless figure of merit
  • a decrease in output in a high temperature range of 300 ° C. or higher is suppressed, and it is more advantageous when used in a wide temperature range. It was found to be a working material.
  • thermoelectric conversion module having a structure as shown in FIG. 1 was produced.
  • thermoelectric conversion as a comparative example was performed under the same conditions as in the above example, except that the sintered body of the comparative example prepared in Experimental Example 1 was used instead of the sintered body of the sample LaCa-3. A module was produced.
  • thermoelectric conversion module is heated to 200 ° C. and 400 ° C., and the lower end is also water-cooled to 20 ° C.
  • the electromotive force and the maximum output at no load obtained from the thermoelectric conversion module were measured using an electronic load device. The results are shown in Table 3.
  • the power generation characteristics according to the example are about 1.17 times higher when the high temperature part is 200 ° C. and about 1.34 times higher when the high temperature part is 400 ° C. In particular, it showed high characteristics in the high temperature range.
  • thermoelectric conversion module having a structure as shown in FIG. 2 was produced.
  • La 2 O 3 , SrCO 3 , CaCO 3 and the starting materials thereof are used so that the composition of the sample LaCa-3 prepared in Experimental Example 1 is obtained.
  • Each powder of CuO was weighed, and these weighed powders were mixed with a ball mill for 16 hours while using pure water as a dispersion medium.
  • the obtained slurry was dried, and then calcined at a temperature of 900 ° C. in the air to obtain a calcined powder.
  • each of La 2 O 3 , SrCO 3, and CuO serving as the starting materials is used so as to have the composition of the comparative example manufactured in Experimental Example 1.
  • the powder was weighed and subjected to the same operation as above to obtain a calcined powder.
  • thermoelectric conversion module comprising the thermoelectric conversion module according to each of Examples and Comparative Examples, so as to have the composition of (Nd 1.95 Ce 0.05) CuO 4 , a, the starting materials Nd 2
  • Each powder of O 3 , CeO 2 and CuO was weighed and subjected to the same operation as above to obtain a calcined powder.
  • each of the above-mentioned three types of calcined powders was pulverized by a ball mill for 40 hours, and pure water, a binder, and the like were added to the processed powder and mixed to form a slurry. Then, the obtained slurry is formed into a sheet shape by a doctor blade method, whereby a p-type thermoelectric conversion material sheet having a thickness of 50 ⁇ m to be a p-type semiconductor element and a thickness of 50 ⁇ m to be an n-type semiconductor element are obtained. Each n-type thermoelectric conversion material sheet was obtained.
  • an insulator Mg 2 SiO 4 powder, glass powder, varnish and solvent were mixed, and an insulating paste was produced using a roll machine. Then, this insulating paste was printed with a thickness of 10 ⁇ m on each of the p-type thermoelectric conversion material sheet and the n-type thermoelectric conversion material sheet obtained as described above.
  • thermoelectric conversion material sheets not printed with insulating paste After that, four p-type thermoelectric conversion material sheets not printed with insulating paste, one p-type thermoelectric conversion material sheet printed with insulating paste, and four n-type thermoelectric conversion material sheets not printed with insulating paste
  • the stacking process is performed so that a combination of 20 pairs of p-type semiconductor elements and n-type semiconductor elements is formed in the order of one sheet of n-type thermoelectric conversion material printed with an insulating paste,. Got.
  • the laminate was pressed at a pressure of 200 MPa by an isotropic isostatic pressing method, and then cut into a predetermined size with a dicing saw to obtain a raw module body to be a thermoelectric conversion module body.
  • the raw module body was degreased at a temperature of 480 ° C., and then fired in the atmosphere at a temperature of 900 to 1050 ° C. to obtain a sintered module body.
  • the sintered module body is polished, and Ag paste is printed on the lower ends of both side surfaces, and baked at a temperature of about 700 ° C. to form an electrode for power extraction.
  • the thermoelectric conversion module which concerns on each was produced.
  • thermoelectric conversion modules according to the above examples and comparative examples were evaluated by the same method as in Experimental Example 2. The results are shown in Table 4.
  • the power generation characteristics according to the example are about 1.25 times higher when the high temperature part is 200 ° C. and about 1.31 times higher when the high temperature part is 400 ° C. In particular, it showed high characteristics in the high temperature range.

Abstract

Disclosed is a p-type thermoelectric material having improved output factor and dimensionless performance index ZT. Specifically disclosed is a p-type thermoelectric material represented by the following composition formula: (Ln2-xA1x)A2B2O6, wherein Ln represents at least one element selected from the group consisting of La, Pr, Nd, Sm and Gd; A1 represents at least one element selected from the group consisting of Ca, Sr and Ba; A2 represents at least one element selected from the group consisting of Ca, Sr and Ba; B represents at least one element selected from the group consisting of Co, Cu and Ni; and x is a number within the range of 0 ≤ x ≤ 0.2. The p-type thermoelectric material can be advantageously used as a material for a p-type semiconductor device (2) included in a thermoelectric conversion module (1).

Description

熱電変換材料および熱電変換モジュールThermoelectric conversion material and thermoelectric conversion module
　この発明は、熱電変換材料およびそれを用いて構成される熱電変換モジュールに関するもので、特に、熱電変換材料の出力因子を向上させるための改良に関するものである。 The present invention relates to a thermoelectric conversion material and a thermoelectric conversion module configured using the same, and particularly relates to an improvement for improving the output factor of the thermoelectric conversion material.
　一般式Ｌｎ２ＭＯ４（Ｌｎは希土類元素、Ｍは遷移金属元素）で表される層状ペロブスカイト構造を有する化合物からなる熱電変換材料において、そのＬｎサイトに異種元素をドーピングすることによって特性を改善することが、たとえば、特開２０００－１２９１４号公報（特許文献１）および特公平６－１７２２５号公報（特許文献２）に記載されている。 In a thermoelectric conversion material composed of a compound having a layered perovskite structure represented by the general formula Ln 2 MO 4 (Ln is a rare earth element and M is a transition metal element), the characteristics are improved by doping the Ln site with a different element. This is described, for example, in Japanese Patent Application Laid-Open No. 2000-12914 (Patent Document 1) and Japanese Patent Publication No. 6-17225 (Patent Document 2).
　より具体的には、上記特許文献１には、熱電変換材料として、組成式（Ｎｄ１－ｚＭｚ）２ＣｕＯ４（ただし、Ｍは、ＺｒまたはＰｒであり、ｚは、０＜ｚ≦１を満足する。）で表わされるものが記載されている。この発明にとって特に興味があるのが、Ｎｄに対してＰｒをドープした場合の組成、すなわち組成式（Ｎｄ１－ｚＰｒｚ）２ＣｕＯ４で表わされる熱電変換材料である。 More specifically, in Patent Document 1, as a thermoelectric conversion material, a composition formula (Nd 1-z M z ) 2 CuO 4 (where M is Zr or Pr, and z is 0 <z ≦ 1 is satisfied.). Of particular interest to the present invention is a thermoelectric conversion material represented by the composition when Nd is doped with Pr, that is, the composition formula (Nd 1−z Pr z ) 2 CuO 4 .
　この特許文献１の図２、図４および図５には、（Ｎｄ１－ｚＰｒｚ）２ＣｕＯ４におけるＰｒのドープ量ｚの変化による、ゼーベック係数の変化、電気抵抗率の変化および出力因子（パワーファクター）の変化がそれぞれ示されている。この特許文献１の図２から、Ｐｒのドープ量ｚの増加に伴って、ゼーベック係数が若干低下することがわかる。また、この特許文献１の図４から、電気抵抗率については、Ｐｒのドープ量ｚが０．０５までは、ドープ量ｚが０の場合とほとんど変わらないが、ドープ量ｚが０．０５を超え、０．１０にまで増加するに従って、低下することがわかる。また、特許文献１の図５から、出力因子については、Ｐｒのドープ量ｚの増加に伴って向上することがわかる。 2, FIG. 4 and FIG. 5 of Patent Document 1 show changes in Seebeck coefficient, changes in electrical resistivity, and output factors due to changes in the doping amount z of Pr in (Nd 1-z Pr z ) 2 CuO 4 . Each change in (power factor) is shown. From FIG. 2 of Patent Document 1, it can be seen that the Seebeck coefficient slightly decreases as the Pr doping amount z increases. From FIG. 4 of Patent Document 1, the electrical resistivity is almost the same as the case where the doping amount z is 0 until the doping amount z of Pr is 0.05, but the doping amount z is 0.05. It can be seen that it decreases as it exceeds and increases to 0.10. Further, FIG. 5 of Patent Document 1 shows that the output factor is improved as the doping amount z of Pr is increased.
　上述したゼーベック係数（Ｓ）、電気抵抗率（ρ）および出力因子（Ｐ）の間には、Ｐ＝Ｓ２／ρの関係がある。ここで、出力因子（Ｐ）を向上させるには、電気抵抗率（ρ）をより低くしながら、ゼーベック係数（Ｓ）をより大きくしなければならない。しかしながら、特許文献１に記載された（Ｎｄ１－ｚＰｒｚ）２ＣｕＯ４の組成の場合、前述したように、Ｐｒのドープ量ｚの増加に伴って、ゼーベック係数（Ｓ）が低下するので、出力因子（Ｐ）の向上をそれほど望めない。 There is a relationship of P = S 2 / ρ among the Seebeck coefficient (S), the electrical resistivity (ρ), and the output factor (P) described above. Here, in order to improve the output factor (P), it is necessary to increase the Seebeck coefficient (S) while lowering the electrical resistivity (ρ). However, in the case of the composition of (Nd 1-z Pr z ) 2 CuO 4 described in Patent Document 1, the Seebeck coefficient (S) decreases as the Pr doping amount z increases, as described above. The improvement of the output factor (P) cannot be expected so much.
　また、特許文献２には、組成式（Ｌｎ１－ｘＡｘ）２ＣｕＯ４（ＬｎはＬａまたはＹ、ＡはＢａまたはＳｒ、０＜ｘ＜１）で表される熱電変換材料が記載されている。この熱電変換材料に関して、特許文献２では、室温付近から１００Ｋ以下の低温まで大きな性能指数を与えることができると記載されている。 Patent Document 2 describes a thermoelectric conversion material represented by a composition formula (Ln 1-x A x ) 2 CuO 4 (Ln is La or Y, A is Ba or Sr, 0 <x <1). ing. Regarding this thermoelectric conversion material, Patent Document 2 describes that a large figure of merit can be given from around room temperature to a low temperature of 100K or less.
　しかしながら、特許文献２に記載される熱電変換材料は、出力因子の値について未だ改善の余地があり、また、たとえば５００℃程度の高い温度域まで特性低下なしに使用できるかどうかが不明である。
特開２０００－１２９１４号公報 特公平６－１７２２５号公報 However, the thermoelectric conversion material described in Patent Document 2 still has room for improvement in the value of the output factor, and it is unclear whether it can be used up to a high temperature range of, for example, about 500 ° C. without deterioration in characteristics.
JP 2000-12914 A Japanese Patent Publication No. 6-17225
　そこで、この発明の目的は、出力因子のさらなる向上が可能な熱電変換材料、およびそれを用いて構成される熱電変換モジュールを提供しようとすることである。 Therefore, an object of the present invention is to provide a thermoelectric conversion material capable of further improving the output factor, and a thermoelectric conversion module configured using the thermoelectric conversion material.
　この発明はｐ型熱電変換材料にまず向けられる。この発明に係るｐ型熱電変換材料は、層状ペロブスカイト構造を有する希土類－遷移金属酸化物であって、組成式（Ｌｎ２－ｘＡ１ｘ）Ａ２Ｂ２Ｏ６で示され、Ｌｎは、Ｌａ、Ｐｒ、Ｎｄ、ＳｍおよびＧｄから選ばれる少なくとも１種であり、Ａ１は、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であり、Ａ２は、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であり、Ｂは、Ｃｏ、ＣｕおよびＮｉから選ばれる少なくとも１種であり、ｘは、０≦ｘ≦０．２の範囲にあることを特徴としている。 The present invention is first directed to a p-type thermoelectric conversion material. P-type thermoelectric conversion material according to the present invention, a rare earth having a layered perovskite structure - a transition metal oxide, represented by formula (Ln 2-x A1 x) A2B 2 O 6, Ln is La, Pr , Nd, Sm and Gd, A1 is at least one selected from Ca, Sr and Ba, A2 is at least one selected from Ca, Sr and Ba, B Is at least one selected from Co, Cu and Ni, and x is in the range of 0 ≦ x ≦ 0.2.
　この発明に係るｐ型熱電変換材料において、Ｌｎは、より限定的に、Ｌａ、ＰｒおよびＮｄから選ばれる少なくとも１種であることが好ましい。また、Ｂは、より限定的に、Ｃｕであることが好ましい。 In the p-type thermoelectric conversion material according to the present invention, Ln is more preferably at least one selected from La, Pr and Nd. Further, B is more preferably Cu.
　また、この発明に係るｐ型熱電変換材料において、ｘが０＜ｘ≦０．２の範囲にあること、すなわち、Ｌｎの一部が、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であるＡ１で置換されることが好ましい。 In the p-type thermoelectric conversion material according to the present invention, x is in the range of 0 <x ≦ 0.2, that is, a part of Ln is at least one selected from Ca, Sr and Ba. Is preferably substituted with.
　この発明は、この発明に係るｐ型熱電変換材料を用いて構成される熱電変換モジュールにも向けられる。 The present invention is also directed to a thermoelectric conversion module configured using the p-type thermoelectric conversion material according to the present invention.
　この発明に係る熱電変換モジュールは、第１の実施態様では、ｐ型熱電変換材料を含むｐ型半導体素子と、ｎ型熱電変換材料を含むｎ型半導体素子と、ｐ型半導体素子の一端およびｎ型半導体素子の一端に共通に接続される第１の電極と、ｐ型半導体素子の他端に接続される第２の電極と、ｎ型半導体素子の他端に接続される第３の電極とを備えている。そして、上記ｐ型熱電変換材料が、この発明に係るｐ型熱電変換材料であることを特徴としている。 In the first embodiment, the thermoelectric conversion module according to the present invention includes a p-type semiconductor element including a p-type thermoelectric conversion material, an n-type semiconductor element including an n-type thermoelectric conversion material, one end of the p-type semiconductor element, and n A first electrode commonly connected to one end of the n-type semiconductor element; a second electrode connected to the other end of the p-type semiconductor element; and a third electrode connected to the other end of the n-type semiconductor element; It has. The p-type thermoelectric conversion material is a p-type thermoelectric conversion material according to the present invention.
　この発明に係る熱電変換モジュールは、第２の実施態様では、ｐ型熱電変換材料を含むｐ型半導体素子と、ｐ型半導体素子に接合される、ｎ型熱電変換材料を含むｎ型半導体素子とを備え、ｐ型半導体素子とｎ型半導体素子とは、その接合部の一部において、直接接合され、その接合部の残部において、絶縁体を介して接合されている。そして、上記ｐ型熱電変換材料が、この発明に係るｐ型熱電変換材料であることを特徴としている。 In the second embodiment, a thermoelectric conversion module according to the present invention includes a p-type semiconductor element including a p-type thermoelectric conversion material, and an n-type semiconductor element including an n-type thermoelectric conversion material bonded to the p-type semiconductor element. The p-type semiconductor element and the n-type semiconductor element are directly joined at a part of the junction, and are joined via an insulator at the remaining part of the junction. The p-type thermoelectric conversion material is a p-type thermoelectric conversion material according to the present invention.
　上記第２の実施態様に係る熱電変換モジュールにおいて、ｐ型半導体素子とｎ型半導体素子と絶縁体とは、同時に焼結させて得られたものであることが好ましい。 In the thermoelectric conversion module according to the second embodiment, the p-type semiconductor element, the n-type semiconductor element, and the insulator are preferably obtained by sintering at the same time.
　この発明に係るｐ型熱電変換材料によれば、後述する実験例から明らかになるように、出力因子を向上させることができ、さらに、無次元性能指数ＺＴをも向上させることができる。また、この発明に係るｐ型熱電変換材料は、毒性元素を含まず、安全性が高い。また、室温から５００℃程度の温度域において、特に３００℃以上の温度域において、優れた熱電特性を示すものとすることができる。 According to the p-type thermoelectric conversion material according to the present invention, the output factor can be improved and the dimensionless figure of merit ZT can also be improved, as will be apparent from the experimental examples described later. Moreover, the p-type thermoelectric conversion material according to the present invention does not contain toxic elements and has high safety. Further, excellent thermoelectric characteristics can be exhibited in a temperature range from room temperature to about 500 ° C., particularly in a temperature range of 300 ° C. or more.
　この発明に係るｐ型熱電変換材料において、Ｌｎの一部が、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種で置換されると、優れた熱電特性を維持しながら、希少元素である希土類元素の使用量を低減することができる。 In the p-type thermoelectric conversion material according to the present invention, when a part of Ln is substituted with at least one selected from Ca, Sr and Ba, the rare-earth element which is a rare element is maintained while maintaining excellent thermoelectric properties. The amount used can be reduced.
この発明の第１の実施形態による熱電変換モジュール１を示す断面図である。It is sectional drawing which shows the thermoelectric conversion module 1 by 1st Embodiment of this invention. この発明の第２の実施形態による熱電変換モジュール１１を示す斜視図である。It is a perspective view which shows the thermoelectric conversion module 11 by 2nd Embodiment of this invention. 実験例１において作製された試料についてのゼーベック（Seebeck）係数を示す図である。It is a figure which shows the Seebeck (Seebeck) coefficient about the sample produced in Experimental example 1. FIG. 実験例１において作製された試料についての出力因子を示す図である。It is a figure which shows the output factor about the sample produced in Experimental example 1. FIG. 実験例１において作製された試料についての無次元性能指数ＺＴを示す図である。It is a figure which shows the dimensionless figure of merit ZT about the sample produced in example 1 of an experiment.
符号の説明Explanation of symbols
　１，１１　熱電変換モジュール
　２，１２　ｐ型半導体素子
　３，１３　ｎ型半導体素子
　４，５，６，１５，１６　電極
　１４　絶縁体 DESCRIPTION OF SYMBOLS 1,11 Thermoelectric conversion module 2,12 p-type semiconductor element 3,13 n- type semiconductor element 4,5,6,15,16 Electrode 14 Insulator
　この発明に係るｐ型熱電変換材料は、組成式（Ｌｎ２－ｘＡ１ｘ）Ａ２Ｂ２Ｏ６で示されるものである。ここで、Ｌｎは、Ｌａ、Ｐｒ、Ｎｄ、ＳｍおよびＧｄから選ばれる少なくとも１種であり、Ａ１は、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であり、Ａ２は、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であり、Ｂは、Ｃｏ、ＣｕおよびＮｉから選ばれる少なくとも１種である。また、ｘは、０≦ｘ≦０．２の範囲にある。 P-type thermoelectric conversion material according to the present invention are those represented by the composition formula (Ln 2-x A1 x) A2B 2 O 6. Here, Ln is at least one selected from La, Pr, Nd, Sm, and Gd, A1 is at least one selected from Ca, Sr, and Ba, and A2 is selected from Ca, Sr, and Ba. At least one selected, and B is at least one selected from Co, Cu and Ni. X is in the range of 0 ≦ x ≦ 0.2.
　好ましくは、Ｌｎは、Ｌａ、ＰｒおよびＮｄから選ばれる少なくとも１種であり、Ｂは、Ｃｕである。 Preferably, Ln is at least one selected from La, Pr and Nd, and B is Cu.
　また、ｘが０＜ｘ≦０．２の範囲にあること、すなわち、Ｌｎの一部が、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であるＡ１で置換されることが好ましい。 Further, it is preferable that x is in a range of 0 <x ≦ 0.2, that is, a part of Ln is substituted with A1 which is at least one selected from Ca, Sr and Ba.
　このようなｐ型熱電変換材料を製造するため、好ましい実施形態では、上記Ｌｎとなるべき元素、上記Ａ１となるべき元素、上記Ａ２となるべき元素、および上記Ｂとなるべき元素をそれぞれ含む出発原料が用意される。これら出発原料のうち、通常、ＬｎおよびＢについては、酸化物が用いられ、Ａ１およびＡ２については、炭酸塩が用いられる。しかしながら、このような酸化物または炭酸塩に限定されるものではなく、たとえば水酸化物などの他の無機材料や、アセチルアセトナート錯体のような有機金属化合物が用いられてもよい。 In order to produce such a p-type thermoelectric conversion material, in a preferred embodiment, the starting element includes the element to be Ln, the element to be A1, the element to be A2, and the element to be B. Raw materials are prepared. Of these starting materials, oxides are usually used for Ln and B, and carbonates are used for A1 and A2. However, it is not limited to such an oxide or carbonate, For example, other inorganic materials, such as a hydroxide, and organometallic compounds, such as an acetylacetonate complex, may be used.
　次に、上述した出発原料は、所望の組成比を与え得るように秤量され、次いで粉砕混合処理される。この粉砕混合処理には、たとえば、分散媒を水とした湿式ボールミルが用いられる。このようにして、出発原料の混合粉末が得られる。水を分散媒とする場合には、次いで、水を蒸発させるための操作が実施される。 Next, the above-mentioned starting materials are weighed so as to give a desired composition ratio, and then pulverized and mixed. For this pulverization and mixing treatment, for example, a wet ball mill using a dispersion medium as water is used. In this way, a mixed powder of starting materials is obtained. When water is used as a dispersion medium, an operation for evaporating water is then performed.
　次に、出発原料の混合粉末は、大気中にて、たとえば９００℃の温度で８時間熱処理される。これによって、目的とするｐ型熱電変換材料粉末が得られる。なお、上述の熱処理を終えたとき、熱電変換材料粉末中に未反応部分が残存していてもよい。 Next, the mixed powder of the starting material is heat-treated in the atmosphere at a temperature of 900 ° C. for 8 hours, for example. Thereby, the target p-type thermoelectric conversion material powder is obtained. In addition, when the above-mentioned heat processing is completed, the unreacted part may remain in the thermoelectric conversion material powder.
　次に、上述のｐ型熱電変換材料粉末は、これにバインダを混合した状態で、たとえばプレス成形され、次いで、成形体が大気中において、たとえば１０００～１１００℃の温度で２時間焼成され、それによって、ｐ型熱電変換材料の焼結体が作製される。なお、ｐ型熱電変換材料粉末は、バインダを含むスラリー中に分散され、スラリーをシート状に成形した後、焼成され、ｐ型熱電変換材料の焼結体が作製されることもある。 Next, the p-type thermoelectric conversion material powder described above is, for example, press-molded in a state where a binder is mixed with the p-type thermoelectric conversion material powder, and then the compact is fired in the atmosphere at a temperature of, for example, 1000 to 1100 ° C. for 2 hours. Thus, a sintered body of the p-type thermoelectric conversion material is produced. The p-type thermoelectric conversion material powder is dispersed in a slurry containing a binder, and after the slurry is formed into a sheet shape, the p-type thermoelectric conversion material powder may be fired to produce a sintered body of the p-type thermoelectric conversion material.
　上記焼結体は、相対密度が８０％以上であることが好ましく、９０％以上であることがより好ましい。相対密度は、通常、焼成温度によって左右される。しかしながら、最適な焼成温度は、たとえば、熱電変換材料の組成によって異なるため、熱電変換材料の組成に応じて調整する必要がある。 The relative density of the sintered body is preferably 80% or more, and more preferably 90% or more. The relative density usually depends on the firing temperature. However, since the optimal firing temperature varies depending on, for example, the composition of the thermoelectric conversion material, it is necessary to adjust according to the composition of the thermoelectric conversion material.
　以下に、この発明に係るｐ型熱電変換材料を用いて構成される熱電変換モジュールについて説明する。 Hereinafter, a thermoelectric conversion module configured using the p-type thermoelectric conversion material according to the present invention will be described.
　図１は、この発明の第１の実施形態による熱電変換モジュール１を示す断面図である。 FIG. 1 is a cross-sectional view showing a thermoelectric conversion module 1 according to a first embodiment of the present invention.
　図１を参照して、熱電変換モジュール１は、ｐ型熱電変換材料を含むｐ型半導体素子２と、ｎ型熱電変換材料を含むｎ型半導体素子３と、ｐ型半導体素子２の一端およびｎ型半導体素子３の一端に共通に接続される第１の電極４と、ｐ型半導体素子２の他端に接続される第２の電極５と、ｎ型半導体素子３の他端に接続される第３の電極６とを備えている。そして、上記ｐ型半導体素子２を構成するｐ型熱電変換材料として、この発明に係るｐ型熱電変換材料が用いられる。 Referring to FIG. 1, a thermoelectric conversion module 1 includes a p-type semiconductor element 2 including a p-type thermoelectric conversion material, an n-type semiconductor element 3 including an n-type thermoelectric conversion material, one end of the p-type semiconductor element 2, and n A first electrode 4 commonly connected to one end of the p-type semiconductor element 3, a second electrode 5 connected to the other end of the p-type semiconductor element 2, and a second electrode 5 connected to the other end of the n-type semiconductor element 3. And a third electrode 6. The p-type thermoelectric conversion material according to the present invention is used as the p-type thermoelectric conversion material constituting the p-type semiconductor element 2.
　このような熱電変換モジュール１において、たとえば、第１の電極４側に高温熱源が配置され、ｐ型半導体素子２およびｎ型半導体素子３の各々の一端側と他端側との間に温度差が与えられると、第１の電極４と第２および第３の電極５および６との間に起電力が発生する。したがって、第２および第３の電極５および６間に負荷を接続すると、電流が流れ、これを電力として取り出すことができる。 In such a thermoelectric conversion module 1, for example, a high-temperature heat source is disposed on the first electrode 4 side, and a temperature difference is generated between one end side and the other end side of each of the p-type semiconductor element 2 and the n-type semiconductor element 3. Is generated, an electromotive force is generated between the first electrode 4 and the second and third electrodes 5 and 6. Therefore, when a load is connected between the second and third electrodes 5 and 6, a current flows and can be taken out as electric power.
　なお、図１に示すような構成の熱電変換モジュール１を実現するため、実際の製品では、ｐ型半導体素子２およびｎ型半導体素子３の各々の一端側および他端側に、たとえばアルミナからなる第１および第２の絶縁性基板が配置され、ｐ型半導体素子２およびｎ型半導体素子３は、これら第１および第２の絶縁性基板によって挟まれた状態とされる。そして、第１の電極４は、第１の絶縁性基板上に印刷された導電性ペーストを焼き付けることによって形成され、第２および第３の電極５および６は、第２の絶縁性基板上に印刷された導電性ペーストを焼き付けることによって形成される。 In order to realize the thermoelectric conversion module 1 configured as shown in FIG. 1, in an actual product, for example, alumina is formed on one end side and the other end side of each of the p-type semiconductor element 2 and the n-type semiconductor element 3. The first and second insulating substrates are arranged, and the p-type semiconductor element 2 and the n-type semiconductor element 3 are sandwiched between the first and second insulating substrates. The first electrode 4 is formed by baking a conductive paste printed on the first insulating substrate, and the second and third electrodes 5 and 6 are formed on the second insulating substrate. It is formed by baking a printed conductive paste.
　また、熱電変換モジュール１の出力を大きくするため、上記第１および第２の絶縁性基板間に各々複数のｐ型半導体素子２およびｎ型半導体素子３を配置しながら、これら複数のｐ型半導体素子２およびｎ型半導体素子３を直列に接続するように電極４～６が形成されることがある。あるいは、熱電変換モジュール１に流れ得る許容電流を大きくするため、上記第１および第２の絶縁性基板間に各々複数のｐ型半導体素子２およびｎ型半導体素子３を配置しながら、これら複数のｐ型半導体素子２およびｎ型半導体素子３を並列に接続するように電極４～６が形成されることがある。 Further, in order to increase the output of the thermoelectric conversion module 1, a plurality of p-type semiconductor elements 2 and n-type semiconductor elements 3 are disposed between the first and second insulating substrates, respectively. Electrodes 4 to 6 may be formed to connect element 2 and n-type semiconductor element 3 in series. Alternatively, in order to increase the allowable current that can flow to the thermoelectric conversion module 1, a plurality of p-type semiconductor elements 2 and n-type semiconductor elements 3 are disposed between the first and second insulating substrates, respectively. Electrodes 4 to 6 may be formed to connect p-type semiconductor element 2 and n-type semiconductor element 3 in parallel.
　図２は、この発明の第２の実施形態による熱電変換モジュール１１を示す斜視図である。 FIG. 2 is a perspective view showing a thermoelectric conversion module 11 according to a second embodiment of the present invention.
　図２を参照して、熱電変換モジュール１１は、ｐ型熱電変換材料を含む複数のｐ型半導体素子１２と、ｐ型半導体素子１２の各々に接合される、ｎ型熱電変換材料を含む複数のｎ型半導体素子１３とを備えている。上記ｐ型半導体素子１２を構成するｐ型熱電変換材料として、この発明に係るｐ型熱電変換材料が用いられる。 Referring to FIG. 2, thermoelectric conversion module 11 includes a plurality of p-type semiconductor elements 12 including a p-type thermoelectric conversion material, and a plurality of n-type thermoelectric conversion materials bonded to each of p-type semiconductor elements 12. and an n-type semiconductor element 13. As the p-type thermoelectric conversion material constituting the p-type semiconductor element 12, the p-type thermoelectric conversion material according to the present invention is used.
　ｐ型半導体素子１２とｎ型半導体素子１３とは、互いの間の接合部の一部において、直接接合され、その接合部の残部において、絶縁体１４を介して接合される。より詳細には、絶縁体１４は、各接合部において、図による上端側と下端側とに交互に配置されるように形成される。前述の熱電変換モジュール１では、ｐ型半導体素子とｎ型半導体素子３との間に、絶縁用の空隙層を設ける必要があるが、熱電変換モジュール１１では、このような空隙層を設ける必要がない。したがって、単位面積当たりに占める熱電変換材料の面積を大きくとることができるので、熱電変換モジュールの単位面積当たりの発電能力を高めることができる。 The p-type semiconductor element 12 and the n-type semiconductor element 13 are directly joined at a part of the junction between them, and are joined via the insulator 14 at the remaining part of the junction. More specifically, the insulator 14 is formed so as to be alternately arranged on the upper end side and the lower end side in the drawing at each joint portion. In the thermoelectric conversion module 1 described above, it is necessary to provide an insulating void layer between the p-type semiconductor element and the n-type semiconductor element 3. In the thermoelectric conversion module 11, it is necessary to provide such a void layer. Absent. Therefore, since the area of the thermoelectric conversion material occupying per unit area can be increased, the power generation capacity per unit area of the thermoelectric conversion module can be increased.
　上述したｐ型半導体素子１２とｎ型半導体素子１３と絶縁体１４とは、同時に焼結させて得られたものであることが好ましい。互いの間で信頼性の高い接合部を得ることができるからである。 It is preferable that the p-type semiconductor element 12, the n-type semiconductor element 13, and the insulator 14 described above are obtained by sintering at the same time. This is because highly reliable joints can be obtained between each other.
　また、各端部に位置するｐ型半導体素子１２およびｎ型半導体素子１３の各々の図による下端部には、電力取出し用電極１５および１６が形成される。 Further, power extraction electrodes 15 and 16 are formed at the lower end portions of the p-type semiconductor element 12 and the n-type semiconductor element 13 located at the respective end portions in the drawing.
　このような熱電変換モジュール１１において、たとえば、図による上端側に高温熱源が配置され、上端側と下端側との間に温度差が与えられると、電力取出し用電極１５および１６の間に起電力が発生する。したがって、電力取出し用電極１５および１６間に負荷を接続すると、電流が流れ、これを電力として取り出すことができる。 In such a thermoelectric conversion module 11, for example, when a high-temperature heat source is arranged on the upper end side in the figure and a temperature difference is given between the upper end side and the lower end side, an electromotive force is generated between the power extraction electrodes 15 and 16. Will occur. Therefore, when a load is connected between the power extraction electrodes 15 and 16, a current flows and can be extracted as electric power.
　以下に、この発明による効果を確認するために実施した実験例について説明する。 Hereinafter, experimental examples conducted to confirm the effects of the present invention will be described.
　１．実験例１
　組成式（Ｌｎ２－ｘＡ１ｘ）Ａ２Ｂ２Ｏ６において、ＢとしてＣｕを用いながら、ＬｎとしてＬａ、ＰｒまたはＮｄを用い、Ａ１としてＳｒを用い、Ａ２としてＣａ、ＳｒまたはＢａを用いて、表１に示すような組成となるように、各原料を秤量した。ここで、Ｌａ、Ｐｒ、ＮｄおよびＣｕの各原料については、各々の酸化物粉末を用い、Ｃａ、ＳｒおよびＢａの各々の原料については、各々の炭酸塩粉末を用いた。 1. Experimental example 1
In the composition formula (Ln 2-x A1 x) A2B 2 O 6, while using the Cu as the B, La, Pr, or Nd is used as Ln, Sr is used as A1, with Ca, Sr, or Ba as A2, Each raw material was weighed so as to have a composition as shown in Table 1. Here, the respective oxide powders were used for the respective raw materials of La, Pr, Nd, and Cu, and the respective carbonate powders were used for the respective raw materials of Ca, Sr, and Ba.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　上記表１に示す、たとえば「ＬａＣａ－１」または「ＬａＳｒ」のような「試料記号」における「Ｌａ」の部分および「Ｃａ」または「Ｓｒ」の部分は、組成式（Ｌｎ２－ｘＡ１ｘ）Ａ２Ｃｕ２Ｏ６における「Ｌｎ」の部分および「Ａ２」の部分を構成する各元素をそれぞれ示している。また、たとえば「ＬａＣａ－１」のような「試料記号」における末尾の数字「１」等は、「Ｌｎ」の部分および「Ａ２」の部分を共通にする試料間で互いに区別するために付したものである。 In the “sample symbol” such as “LaCa-1” or “LaSr” shown in Table 1 above, the “La” portion and the “Ca” or “Sr” portion are represented by the composition formula (Ln 2-x A1 x ) Each element constituting the “Ln” portion and the “A2” portion in A2Cu 2 O 6 is shown. In addition, for example, the number “1” at the end of the “sample symbol” such as “LaCa-1” is attached to distinguish between samples that share the “Ln” portion and the “A2” portion. Is.
　また、「比較例」は、組成式（Ｌｎ２－ｘＡ１ｘ）Ａ２Ｂ２Ｏ６における「Ａ２」を含んでいない。 Further, the “comparative example” does not include “A2” in the composition formula (Ln 2−x A1 x ) A2B 2 O 6 .
　次に、前述のように秤量された出発原料を、分散媒に水を用いた湿式ボールミルで粉砕混合した。そして、得られたスラリーから水を蒸発させ、出発原料の混合粉末を得た。 Next, the starting materials weighed as described above were pulverized and mixed by a wet ball mill using water as a dispersion medium. And water was evaporated from the obtained slurry to obtain a mixed powder of starting materials.
　次に、出発原料の混合粉末を、大気中にて、９００℃の温度で８時間熱処理し、目的とする熱電変換材料粉末を得た。 Next, the mixed powder of the starting material was heat-treated in the atmosphere at a temperature of 900 ° C. for 8 hours to obtain a target thermoelectric conversion material powder.
　次に、上記熱電変換材料粉末に、有機バインダを各粉末に対し５重量％の割合で混合し、水を分散媒とした湿式ボールミルで粉砕混合した。 Next, the organic binder was mixed with the thermoelectric conversion material powder at a ratio of 5% by weight with respect to each powder, and pulverized and mixed with a wet ball mill using water as a dispersion medium.
　次に、上記有機バインダを混合した熱電変換材料粉末を十分に乾燥させた後、１軸プレス機を用い、１０ＭＰａの圧力を加えて成形体を作製した。 Next, after the thermoelectric conversion material powder mixed with the organic binder was sufficiently dried, a compact was produced by applying a pressure of 10 MPa using a single screw press.
　次に、上記成形体を、大気中にて、１０００～１１００℃の範囲の温度で２時間焼成し、各試料に係る熱電変換材料の焼結体を得た。ここで、焼成温度は、各試料に係る熱電変換材料の組成により調整し、焼結体の相対密度が８０％以上となるように設定した。 Next, the molded body was fired in the atmosphere at a temperature in the range of 1000 to 1100 ° C. for 2 hours to obtain a sintered body of the thermoelectric conversion material according to each sample. Here, the firing temperature was adjusted according to the composition of the thermoelectric conversion material according to each sample, and was set so that the relative density of the sintered body was 80% or more.
　このようにして作製された各試料に係る焼結体について、次のような評価を行なった。 The following evaluations were performed on the sintered bodies according to the samples thus prepared.
　まず、各試料に係る焼結体の結晶構造をＸ線回折により同定した。その結果、すべての試料について、層状ペロブスカイト構造を主成分とする結晶構造を有していることがわかった。表２に、各試料に係る焼結体での生成相がその比率とともに示されている。 First, the crystal structure of the sintered body according to each sample was identified by X-ray diffraction. As a result, it was found that all the samples had a crystal structure mainly composed of a layered perovskite structure. Table 2 shows the generation phase in the sintered body according to each sample together with the ratio.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２において、生成相のうち、「Ｌｎ２ＡＣｕ２Ｏ６」構造を有するものについては四角枠で囲んでいる。 In Table 2, the product phase having the “Ln 2 ACu 2 O 6 ” structure is surrounded by a square frame.
　組成式（Ｌｎ２－ｘＡ１ｘ）Ａ２Ｃｕ２Ｏ６における「Ｌｎ」と「Ａ１」と「Ａ２」とを「Ｌｎ－Ａ１－Ａ２」で表したとき、所望する「Ｌｎ２ＡＣｕ２Ｏ６」構造を有するものは、試料ＬａＣａ－１の組成である「Ｌａ－なし－Ｃａ」、試料ＬａＣａ－２～ＬａＣａ－９の組成である「Ｌａ－Ｓｒ－Ｃａ」、試料ＬａＳｒの組成である「Ｌａ－なし－Ｓｒ」、試料ＬａＢａの組成である「Ｌａ－なし－Ｂａ」、試料ＰｒＳｒの組成である「Ｐｒ－なし－Ｓｒ」、ならびに試料ＮｄＳｒの組成である「Ｎｄ－なし－Ｓｒ」において得られた。 When “Ln”, “A1” and “A2” in the composition formula (Ln 2−x A1 x ) A2Cu 2 O 6 are represented by “Ln-A1-A2”, the desired “Ln 2 ACu 2 O 6 ” Those having a structure include “La-None-Ca” as the composition of sample LaCa-1, “La-Sr—Ca” as the composition of samples LaCa-2 to LaCa-9, and “La-Sr—Ca” as the composition of sample LaSr. -None-Sr "," La-None-Ba "which is the composition of sample LaBa," Pr-None-Sr "which is the composition of sample PrSr, and" Nd-None-Sr "which is the composition of sample NdSr. It was.
　なお、この実験例では開示していないが、上記「Ｌａ－なし－Ｓｒ」、「Ｌａ－なし－Ｂａ」、「Ｐｒ－なし－Ｓｒ」、および「Ｎｄ－なし－Ｓｒ」の各組成において、Ｌａ、ＰｒまたはＮｄの一部をＡ１であるＣａ、ＳｒまたはＢａで置換した組成でも、所望の「Ｌｎ２ＡＣｕ２Ｏ６」構造が得られることを確認している。 Although not disclosed in this experimental example, in each of the compositions of “La-None-Sr”, “La-None-Ba”, “Pr-None-Sr”, and “Nd-None-Sr”, It has been confirmed that the desired “Ln 2 ACu 2 O 6 ” structure can be obtained even with a composition in which a part of La, Pr or Nd is substituted with Ca, Sr or Ba which is A1.
　また、Ｌｎとして、この実験例で開示したＬａ、ＰｒおよびＮｄ以外のＳｍおよびＧｄを用いた場合にも、さらには、Ｂとして、この実験例で開示したＣｕ以外のＣｏおよびＮｉを用いた場合にも、所望の「Ｌｎ２ＡＣｕ２Ｏ６」構造が得られることを確認している。 In addition, when Sm and Gd other than La, Pr and Nd disclosed in this experimental example are used as Ln, and Co and Ni other than Cu disclosed in this experimental example are used as B. In addition, it has been confirmed that the desired “Ln 2 ACu 2 O 6 ” structure is obtained.
　また、図３に示すように、ゼーベック（Seebeck）係数を求めた。ゼーベック係数は、各試料に係る焼結体を、５０～５５０℃に設定した温度槽内に配置し、高温部と低温部とに温度差が得られるように試料両端の温度を調整し、試料間に得られる起電力を測定し、この測定された起電力と測定温度差とから算出した。 Also, as shown in FIG. 3, a Seebeck coefficient was obtained. For the Seebeck coefficient, the sintered body of each sample is placed in a temperature vessel set to 50 to 550 ° C, the temperature at both ends of the sample is adjusted so that a temperature difference is obtained between the high temperature part and the low temperature part, The electromotive force obtained in the meantime was measured and calculated from the measured electromotive force and the measured temperature difference.
　また、図４に示すように、出力因子を求めた。出力因子を求めるため、まず、各試料に係る焼結体を、５０～５５０℃に設定した温度槽内に配置し、直流４端子法により、各試料に係る焼結体の抵抗値を各測定温度にて測定し、この測定された抵抗値と測定試料の寸法とから、抵抗率を求めた。そして、この抵抗率（ρ）と前述のようにして求められたゼーベック係数（Ｓ）とから、出力因子（Ｐ）を、Ｐ＝Ｓ２／ρの式により算出した。 Moreover, as shown in FIG. 4, the output factor was calculated | required. In order to obtain the output factor, first, the sintered body related to each sample is placed in a temperature bath set to 50 to 550 ° C., and the resistance value of the sintered body related to each sample is measured by the direct current four-terminal method. The measurement was performed at temperature, and the resistivity was obtained from the measured resistance value and the dimension of the measurement sample. Then, from this resistivity (ρ) and the Seebeck coefficient (S) obtained as described above, the output factor (P) was calculated by the equation P = S 2 / ρ.
　また、図５に示すように、無次元性能指数（ＺＴ）を求めた。無次元性能指数（ＺＴ）を求めるため、まず、各試料に係る焼結体を、５０～５５０℃に設定した温度槽内に配置し、レーザフラッシュ法により比熱および熱拡散率を測定し、これらに測定試料の寸法および重量を加味して、熱伝導率を算出し、この熱伝導率（κ）および測定温度Ｔ（絶対温度）と上述のようにして求められた出力因子（Ｐ）とから、無次元性能指数（ＺＴ）を、ＺＴ＝（Ｐ／κ）×Ｔの式により算出した。 Further, as shown in FIG. 5, a dimensionless figure of merit (ZT) was obtained. In order to obtain the dimensionless figure of merit (ZT), first, the sintered body of each sample was placed in a temperature bath set to 50 to 550 ° C., and the specific heat and thermal diffusivity were measured by the laser flash method. The thermal conductivity is calculated by taking into account the size and weight of the measurement sample, and from this thermal conductivity (κ) and measurement temperature T (absolute temperature) and the output factor (P) obtained as described above. The dimensionless figure of merit (ZT) was calculated by the formula ZT = (P / κ) × T.
　図３には、試料ＬａＣａ－１、試料ＬａＣａ－３、試料ＬａＣａ－７、試料ＬａＣａ－９、試料ＰｒＳｒおよび試料ＮｄＳｒ、ならびに比較例についてのゼーベック係数が示されている。図３から、まず、各試料はｐ型の極性を持つ熱電変換材料であることがわかった。また、試料ＬａＣａ－１、試料ＬａＣａ－３、試料ＬａＣａ－７、試料ＬａＣａ－９、試料ＰｒＳｒおよび試料ＮｄＳｒによれば、比較例より高いゼーベック係数が得られることがわかった。 FIG. 3 shows Seebeck coefficients for sample LaCa-1, sample LaCa-3, sample LaCa-7, sample LaCa-9, sample PrSr and sample NdSr, and a comparative example. From FIG. 3, it was first found that each sample was a thermoelectric conversion material having p-type polarity. Further, it was found that the sample LaCa-1, sample LaCa-3, sample LaCa-7, sample LaCa-9, sample PrSr, and sample NdSr can provide a higher Seebeck coefficient than the comparative example.
　図４には、試料ＬａＣａ－１、試料ＬａＣａ－３、試料ＬａＣａ－７および試料ＬａＣａ－９、ならびに比較例についての出力因子が示されている。図４から、試料ＬａＣａ－１、試料ＬａＣａ－３、試料ＬａＣａ－７および試料ＬａＣａ－９によれば、出力因子について、比較例を上回る特性が得られることがわかった。 FIG. 4 shows output factors for sample LaCa-1, sample LaCa-3, sample LaCa-7 and sample LaCa-9, and a comparative example. From FIG. 4, it was found that the sample LaCa-1, the sample LaCa-3, the sample LaCa-7, and the sample LaCa-9 can obtain characteristics that exceed the comparative example with respect to the output factor.
　図５には、試料ＬａＣａ－１、試料ＬａＣａ－３、試料ＬａＣａ－７および試料ＬａＣａ－９、ならびに比較例についての無次元性能指数（ＺＴ）が示されている。図５から、試料ＬａＣａ－１、試料ＬａＣａ－３、試料ＬａＣａ－７および試料ＬａＣａ－９によれば、無次元性能指数（ＺＴ）について、比較例より高い値を示すことがわかった。特に、試料ＬａＣａ－１、試料ＬａＣａ－３、試料ＬａＣａ－７および試料ＬａＣａ－９によれば、３００℃以上の高温域における出力低下が抑制されており、広い温度範囲での使用でより有利に作用する材料であることがわかった。 FIG. 5 shows dimensionless figure of merit (ZT) for sample LaCa-1, sample LaCa-3, sample LaCa-7, sample LaCa-9, and comparative example. FIG. 5 shows that the sample LaCa-1, the sample LaCa-3, the sample LaCa-7, and the sample LaCa-9 have higher values for the dimensionless figure of merit (ZT) than the comparative example. In particular, according to sample LaCa-1, sample LaCa-3, sample LaCa-7, and sample LaCa-9, a decrease in output in a high temperature range of 300 ° C. or higher is suppressed, and it is more advantageous when used in a wide temperature range. It was found to be a working material.
　２．実験例２
　実験例２では、図１に示したような構造を有する熱電変換モジュールを作製した。 2. Experimental example 2
In Experimental Example 2, a thermoelectric conversion module having a structure as shown in FIG. 1 was produced.
　実験例１で作製した試料ＬａＣａ－３の焼結体を、長さ５ｍｍ、幅５ｍｍおよび高さ６ｍｍの寸法に切り出したｐ型半導体素子と、ｎ型熱電変換材料である（Ｎｄ１．９５Ｃｅ０．０５）ＣｕＯ４の焼結体を、長さ５ｍｍ、幅５ｍｍおよび高さ６ｍｍの寸法に切り出したｎ型半導体素子とを、アルミナ基板上で銀ペーストを介して１６対直列となるように接続し、銀ペーストを大気中において８００℃の温度で焼き付け、実施例としてのいわゆるπ型の熱電変換モジュールを作製した。 A p-type semiconductor element obtained by cutting the sintered body of the sample LaCa-3 prepared in Experimental Example 1 into dimensions of 5 mm in length, 5 mm in width, and 6 mm in height, and an n-type thermoelectric conversion material (Nd 1.95 Ce 0.05 ) An n-type semiconductor element obtained by cutting a sintered body of CuO 4 into dimensions of 5 mm in length, 5 mm in width, and 6 mm in height so that 16 pairs are connected in series via a silver paste on an alumina substrate. Then, the silver paste was baked at a temperature of 800 ° C. in the atmosphere to prepare a so-called π-type thermoelectric conversion module as an example.
　他方、実験例１で作製した比較例の焼結体を、上記試料ＬａＣａ－３の焼結体の代わりに用いたことを除いて、上記実施例と同様の条件で、比較例としての熱電変換モジュールを作製した。 On the other hand, a thermoelectric conversion as a comparative example was performed under the same conditions as in the above example, except that the sintered body of the comparative example prepared in Experimental Example 1 was used instead of the sintered body of the sample LaCa-3. A module was produced.
　次に、上記実施例および比較例に係る熱電変換モジュールの発電特性を評価するため、熱電変換モジュールの上端を２００℃および４００℃の各温度に加熱し、同じく下端を２０℃に水冷した状態で、熱電変換モジュールから得られる無負荷時の起電力および最大出力を、電子負荷装置を用いて測定した。その結果が表３に示されている。 Next, in order to evaluate the power generation characteristics of the thermoelectric conversion modules according to the above examples and comparative examples, the upper end of the thermoelectric conversion module is heated to 200 ° C. and 400 ° C., and the lower end is also water-cooled to 20 ° C. The electromotive force and the maximum output at no load obtained from the thermoelectric conversion module were measured using an electronic load device. The results are shown in Table 3.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３からわかるように、実施例による発電特性は、比較例によるものと比較して、高温部が２００℃のときで約１．１７倍、４００℃のときで約１．３４倍と高くなっており、特に高温度領域で高い特性を示した。 As can be seen from Table 3, the power generation characteristics according to the example are about 1.17 times higher when the high temperature part is 200 ° C. and about 1.34 times higher when the high temperature part is 400 ° C. In particular, it showed high characteristics in the high temperature range.
　３．実験例３
　実験例３では、図２に示したような構造を有する熱電変換モジュールを作製した。 3. Experimental example 3
In Experimental Example 3, a thermoelectric conversion module having a structure as shown in FIG. 2 was produced.
　実施例に係る熱電変換モジュールに備えるｐ型半導体素子を得るため、実験例１で作製した試料ＬａＣａ－３の組成となるように、その出発原料となるＬａ２Ｏ３、ＳｒＣＯ３、ＣａＣＯ３およびＣｕＯの各粉末を秤量し、純水を分散媒としながら、これら秤量した粉末を、１６時間、ボールミルで混合した。得られたスラリーを乾燥させ、その後、大気中において、９００℃の温度で仮焼し、仮焼粉末を得た。 In order to obtain a p-type semiconductor element included in the thermoelectric conversion module according to the example, La 2 O 3 , SrCO 3 , CaCO 3 and the starting materials thereof are used so that the composition of the sample LaCa-3 prepared in Experimental Example 1 is obtained. Each powder of CuO was weighed, and these weighed powders were mixed with a ball mill for 16 hours while using pure water as a dispersion medium. The obtained slurry was dried, and then calcined at a temperature of 900 ° C. in the air to obtain a calcined powder.
　他方、比較例に係る熱電変換モジュールに備えるｐ型半導体素子を得るため、実験例１で作製した比較例の組成となるように、その出発原料となるＬａ２Ｏ３、ＳｒＣＯ３およびＣｕＯの各粉末を秤量し、上記と同様の操作を経て、仮焼粉末を得た。 On the other hand, in order to obtain a p-type semiconductor element included in the thermoelectric conversion module according to the comparative example, each of La 2 O 3 , SrCO 3, and CuO serving as the starting materials is used so as to have the composition of the comparative example manufactured in Experimental Example 1. The powder was weighed and subjected to the same operation as above to obtain a calcined powder.
　また、実施例および比較例の各々に係る熱電変換モジュールに備えるｎ型半導体素子を得るため、（Ｎｄ１．９５Ｃｅ０．０５）ＣｕＯ４の組成となるように、その出発原料となるＮｄ２Ｏ３、ＣｅＯ２およびＣｕＯの各粉末を秤量し、上記と同様の操作を経て、仮焼粉末を得た。 In addition, in order to obtain a n-type semiconductor device comprising the thermoelectric conversion module according to each of Examples and Comparative Examples, so as to have the composition of (Nd 1.95 Ce 0.05) CuO 4 , a, the starting materials Nd 2 Each powder of O 3 , CeO 2 and CuO was weighed and subjected to the same operation as above to obtain a calcined powder.
　次に、上記の３種類の仮焼粉末の各々について、４０時間、ボールミルで粉砕処理し、処理後の粉末に、純水、バインダ等を添加して混合し、スラリー化した。そして、得られたスラリーを、ドクターブレード法によりシート状に成形することによって、ｐ型半導体素子となるべき厚みが５０μｍのｐ型熱電変換材料シート、およびｎ型半導体素子となるべき厚みが５０μｍのｎ型熱電変換材料シートをそれぞれ得た。 Next, each of the above-mentioned three types of calcined powders was pulverized by a ball mill for 40 hours, and pure water, a binder, and the like were added to the processed powder and mixed to form a slurry. Then, the obtained slurry is formed into a sheet shape by a doctor blade method, whereby a p-type thermoelectric conversion material sheet having a thickness of 50 μm to be a p-type semiconductor element and a thickness of 50 μm to be an n-type semiconductor element are obtained. Each n-type thermoelectric conversion material sheet was obtained.
　他方、絶縁体を形成するため、Ｍｇ２ＳｉＯ４粉末、ガラス粉末、ワニスおよび溶剤を混合し、ロール機を用いて、絶縁ペーストを作製した。そして、上記のようにして得られたｐ型熱電変換材料シートおよびｎ型熱電変換材料シートの各々上に、この絶縁ペーストを厚み１０μｍで印刷した。 On the other hand, in order to form an insulator, Mg 2 SiO 4 powder, glass powder, varnish and solvent were mixed, and an insulating paste was produced using a roll machine. Then, this insulating paste was printed with a thickness of 10 μm on each of the p-type thermoelectric conversion material sheet and the n-type thermoelectric conversion material sheet obtained as described above.
　その後、絶縁ペーストを印刷していないｐ型熱電変換材料シートを４枚、絶縁ペーストを印刷したｐ型熱電変換材料シートを１枚、絶縁ペーストを印刷していないｎ型熱電変換材料シートを４枚、絶縁ペーストを印刷したｎ型熱電変換材料シートを１枚、…、といった順序で、２０対のｐ型半導体素子およびｎ型半導体素子の組み合わせが形成されるように積層工程を実施し、積層体を得た。 After that, four p-type thermoelectric conversion material sheets not printed with insulating paste, one p-type thermoelectric conversion material sheet printed with insulating paste, and four n-type thermoelectric conversion material sheets not printed with insulating paste The stacking process is performed so that a combination of 20 pairs of p-type semiconductor elements and n-type semiconductor elements is formed in the order of one sheet of n-type thermoelectric conversion material printed with an insulating paste,. Got.
　次に、上記積層体を、等方静水圧プレス法にて２００ＭＰａの圧力でプレスした後、所定の大きさにダイシングソーにて切断し、熱電変換モジュール本体となるべき生のモジュール本体を得た。次いで、この生のモジュール本体を、４８０℃の温度で脱脂し、その後、大気中において、９００～１０５０℃の温度で焼成して、焼結したモジュール本体を得た。 Next, the laminate was pressed at a pressure of 200 MPa by an isotropic isostatic pressing method, and then cut into a predetermined size with a dicing saw to obtain a raw module body to be a thermoelectric conversion module body. . Next, the raw module body was degreased at a temperature of 480 ° C., and then fired in the atmosphere at a temperature of 900 to 1050 ° C. to obtain a sintered module body.
　次に、上記焼結したモジュール本体を研磨し、両側面の下端部に、Ａｇペーストを印刷し、約７００℃の温度で焼き付けることにより、電力取出し用電極を形成し、実施例および比較例の各々に係る熱電変換モジュールを作製した。 Next, the sintered module body is polished, and Ag paste is printed on the lower ends of both side surfaces, and baked at a temperature of about 700 ° C. to form an electrode for power extraction. The thermoelectric conversion module which concerns on each was produced.
　次に、上記実施例および比較例に係る熱電変換モジュールの発電特性を、実験例２の場合と同様の方法により評価した。その結果が表４に示されている。 Next, the power generation characteristics of the thermoelectric conversion modules according to the above examples and comparative examples were evaluated by the same method as in Experimental Example 2. The results are shown in Table 4.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４からわかるように、実施例による発電特性は、比較例によるものと比較して、高温部が２００℃のときで約１．２５倍、４００℃のときで約１．３１倍と高くなっており、特に高温度領域で高い特性を示した。 As can be seen from Table 4, the power generation characteristics according to the example are about 1.25 times higher when the high temperature part is 200 ° C. and about 1.31 times higher when the high temperature part is 400 ° C. In particular, it showed high characteristics in the high temperature range.

Claims (7)

  1. 　組成式（Ｌｎ２－ｘＡ１ｘ）Ａ２Ｂ２Ｏ６で示される熱電変換材料であって、
    　前記Ｌｎは、Ｌａ、Ｐｒ、Ｎｄ、ＳｍおよびＧｄから選ばれる少なくとも１種であり、前記Ａ１は、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であり、前記Ａ２は、Ｃａ、ＳｒおよびＢａから選ばれる少なくとも１種であり、前記Ｂは、Ｃｏ、ＣｕおよびＮｉから選ばれる少なくとも１種であり、前記ｘは、０≦ｘ≦０．２の範囲にある、
    ｐ型熱電変換材料。     A thermoelectric conversion material represented by the composition formula (Ln 2-x A1 x) A2B 2 O 6,
    The Ln is at least one selected from La, Pr, Nd, Sm and Gd, the A1 is at least one selected from Ca, Sr and Ba, and the A2 is selected from Ca, Sr and Ba. At least one selected, and B is at least one selected from Co, Cu and Ni, and x is in a range of 0 ≦ x ≦ 0.2.
    p-type thermoelectric conversion material.
  2. 　前記Ｌｎは、Ｌａ、ＰｒおよびＮｄから選ばれる少なくとも１種である、請求項１に記載のｐ型熱電変換材料。 The p-type thermoelectric conversion material according to claim 1, wherein the Ln is at least one selected from La, Pr and Nd.
  3. 　前記Ｂは、Ｃｕである、請求項１に記載のｐ型熱電変換材料。 The p-type thermoelectric conversion material according to claim 1, wherein B is Cu.
  4. 　前記ｘは、０＜ｘ≦０．２の範囲にある、請求項１に記載のｐ型熱電変換材料。 The p-type thermoelectric conversion material according to claim 1, wherein x is in a range of 0 <x ≦ 0.2.
  5. 　ｐ型熱電変換材料を含むｐ型半導体素子と、
    　ｎ型熱電変換材料を含むｎ型半導体素子と、
    　前記ｐ型半導体素子の一端および前記ｎ型半導体素子の一端に共通に接続される第１の電極と、
    　前記ｐ型半導体素子の他端に接続される第２の電極と、
    　前記ｎ型半導体素子の他端に接続される第３の電極と
    を備え、
    　前記ｐ型熱電変換材料は、請求項１ないし４のいずれかに記載のｐ型熱電変換材料である、熱電変換モジュール。     a p-type semiconductor element containing a p-type thermoelectric conversion material;
    an n-type semiconductor element containing an n-type thermoelectric conversion material;
    A first electrode commonly connected to one end of the p-type semiconductor element and one end of the n-type semiconductor element;
    A second electrode connected to the other end of the p-type semiconductor element;
    A third electrode connected to the other end of the n-type semiconductor element,
    The thermoelectric conversion module, wherein the p-type thermoelectric conversion material is the p-type thermoelectric conversion material according to any one of claims 1 to 4.
  6. 　ｐ型熱電変換材料を含むｐ型半導体素子と、
    　前記ｐ型半導体素子に接合される、ｎ型熱電変換材料を含むｎ型半導体素子と
    を備え、
    　前記ｐ型半導体素子と前記ｎ型半導体素子とは、その接合部の一部において、直接接合され、その接合部の残部において、絶縁体を介して接合されていて、
    　前記ｐ型熱電変換材料は、請求項１ないし４のいずれかに記載のｐ型熱電変換材料である、熱電変換モジュール。     a p-type semiconductor element containing a p-type thermoelectric conversion material;
    An n-type semiconductor element including an n-type thermoelectric conversion material joined to the p-type semiconductor element,
    The p-type semiconductor element and the n-type semiconductor element are directly joined at a part of the junction, and are joined via an insulator at the remaining part of the junction,
    The thermoelectric conversion module, wherein the p-type thermoelectric conversion material is the p-type thermoelectric conversion material according to any one of claims 1 to 4.
  7. 　前記ｐ型半導体素子と前記ｎ型半導体素子と前記絶縁体とは、同時に焼結させて得られたものである、請求項６に記載の熱電変換モジュール。 The thermoelectric conversion module according to claim 6, wherein the p-type semiconductor element, the n-type semiconductor element, and the insulator are obtained by sintering at the same time.
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003298128A (en) * 2002-03-28 2003-10-17 Shizuoka Prefecture Method of manufacturing thermoelectric conversion element
JP2004356476A (en) * 2003-05-30 2004-12-16 Japan Science & Technology Agency Composite oxide with outstanding thermoelectric transformation performance

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003298128A (en) * 2002-03-28 2003-10-17 Shizuoka Prefecture Method of manufacturing thermoelectric conversion element
JP2004356476A (en) * 2003-05-30 2004-12-16 Japan Science & Technology Agency Composite oxide with outstanding thermoelectric transformation performance

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