JP7313660B2 - Thermoelectric conversion module - Google Patents

Description

The present invention relates to a thermoelectric conversion module, particularly to a thermoelectric conversion module used for thermoelectric power generation.

BACKGROUND ART Conventionally, thermoelectric conversion modules for thermoelectric power generation have been known. Such a thermoelectric conversion module generally includes a plurality of thermoelectric elements (n-type semiconductor elements and p-type semiconductor elements), a plurality of metal electrodes for electrically connecting the plurality of thermoelectric elements, and a pair of insulating substrates (for example, ceramic substrates) sandwiching the plurality of thermoelectric elements and the plurality of metal electrodes.

In a thermoelectric conversion module for thermoelectric power generation, power is generated by providing a predetermined temperature difference (for example, about 300° C.) between a high temperature surface (high temperature side insulating substrate) and a low temperature surface (low temperature side insulating substrate).

A conventional thermoelectric conversion module has a flat plate shape with a wide surface perpendicular to the heat flow direction and a thin thickness in the heat flow direction. As a result, the temperature of the low-temperature surface rises and a sufficient temperature difference cannot be ensured. Therefore, in a conventional thermoelectric conversion module, a heat sink is attached to the low-temperature surface, and the heat sink is forcedly air-cooled to ensure the temperature difference necessary for power generation between the high-temperature surface and the low-temperature surface.

However, since the thermoelectric conversion module and the heat sink are usually bonded via thermally conductive grease or the like, there is a large thermal resistance in the heat transfer path from the low temperature surface to the atmosphere (for example, air at about 25° C.), which reduces the cooling efficiency.

Japanese Patent Application Laid-Open No. 8-46248 discloses a configuration in which a heat radiating plate and a heat absorbing plate are adhered to the outside of the thermoelectric element with silicone grease or the like in order to enhance the performance of the thermoelectric element, which has a structure in which an n-type thermoelectric material and a p-type thermoelectric material are sandwiched between a pair of insulating ceramic substrates on which metal electrodes are patterned.

JP-A-8-46248 (paragraph 0002, FIG. 10)

An object of the present invention is to provide a thermoelectric conversion module capable of improving the cooling efficiency on the low temperature side of thermoelectric elements.

A first thermoelectric conversion module according to the present invention is a thermoelectric conversion module having at least one thermoelectric power generation section, wherein the thermoelectric power generation section includes a thermoelectric element and a low temperature side conductive section connected to a low temperature end of the thermoelectric element, and the low temperature side conductive section has a Seebeck coefficient of the same polarity as that of the thermoelectric element.

In this case, a high temperature side conductive portion connected to the high temperature end of the thermoelectric element may be further provided. In this case, the high-temperature-side conductive portion may have a Seebeck coefficient opposite in polarity to that of the thermoelectric element.

A second thermoelectric conversion module according to the present invention is a thermoelectric conversion module having at least one thermoelectric power generation unit, wherein the thermoelectric power generation unit includes a pair of thermoelectric elements having high temperature ends electrically connected to each other, and a pair of low temperature side conductive portions connected to low temperature ends of the pair of thermoelectric elements, and each of the pair of low temperature side conductive portions has a Seebeck coefficient of the same polarity as that of the corresponding thermoelectric element.

In the above case, a plurality of thermoelectric generators may be provided.

A third thermoelectric conversion module according to the present invention is a thermoelectric conversion module including a plurality of thermoelectric power generation units, each of the plurality of thermoelectric power generation units comprising a thermoelectric element, a low temperature side conductive portion connected to the low temperature end of the thermoelectric element, and a high temperature side conductive portion connected to the high temperature end of the thermoelectric element, and the low temperature side conductive portion functions as a heat sink.

A fourth thermoelectric conversion module according to the present invention is a thermoelectric conversion module comprising a plurality of thermoelectric power generation units, each of the plurality of thermoelectric power generation units comprising a pair of thermoelectric elements having high temperature ends electrically connected to each other, and a pair of low temperature side conductive portions connected to low temperature ends of the pair of thermoelectric elements, respectively, and each of the pair of low temperature side conductive portions functioning as a heat sink.

In the above case, the low-temperature-side conductive portion may be composed of an electric wire.

Further, in the first or third thermoelectric conversion module, the high-temperature-side conductive portion may be composed of an electric wire.

Moreover, in the second or fourth thermoelectric conversion module, the thermoelectric power generation section may further include a high temperature side electrode that electrically connects the high temperature ends of the pair of thermoelectric elements.

In the above case, the thermoelectric generator may further include an insulating substrate arranged on the high temperature side of the thermoelectric generator.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to improve the cooling efficiency of the low temperature side of a thermoelectric element.

FIG. 3 is a diagram for explaining the configuration of a thermoelectric generator according to the present invention; FIG. 5 is a diagram for explaining the configuration of another thermoelectric generator according to the present invention; It is a figure for demonstrating the structure of the thermoelectric conversion module by this invention. FIG. 4 is a diagram (part 1) for explaining a state when the thermoelectric conversion module 300 is used; FIG. 11 is a diagram (part 2) for explaining a state when the thermoelectric conversion module 300 is used; 3 is a diagram (3) for explaining a state when the thermoelectric conversion module 300 is used; FIG. FIG. 4 is a diagram for explaining the configuration of another thermoelectric conversion module according to the present invention; FIG. 11 is a diagram (part 1) for explaining a state when the thermoelectric conversion module 700 is used; FIG. 11 is a diagram (part 2) for explaining a state when the thermoelectric conversion module 700 is used; 3 is a diagram (3) for explaining a state when the thermoelectric conversion module 700 is used; FIG. It is a figure for demonstrating the structure of the produced thermoelectric-generation part. It is a figure which shows a measurement result.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<<First embodiment>>
FIG. 1 is a diagram for explaining the configuration of a thermoelectric generator according to the present invention.

As shown in the figure, the first thermoelectric generator 100 according to the present invention includes a thermoelectric element 110 , a low temperature side conductive portion 120 and a high temperature side conductive portion 130 .

The thermoelectric element 110 has a predetermined (for example, rectangular parallelepiped) shape, and when a temperature difference is applied to both ends of the thermoelectric element 110, it generates an electromotive force due to the Seebeck effect. Examples of materials for the thermoelectric element 110 include magnesium silicide (Mg ₂ Si), iron silicide (FeSi ₂ ), manganese silicide (MnSi _1.73 ), and the like.

The low-temperature-side conductive part 120 is connected to the low-temperature end of the thermoelectric element 110 to take out the electric power generated by the thermoelectric element 110, and in this embodiment, it is composed of an electric wire (metal wire). The low temperature side conductive portion 121 is joined to the low temperature end of the thermoelectric element 110 by, for example, brazing.

The low-temperature-side conductive portion 120 is made of a material having a thermoelectromotive force (Seebeck coefficient) of the same polarity as the thermoelectric element 110 . That is, when the thermoelectric element 110 has a negative Seebeck coefficient, it is made of a material with a negative Seebeck coefficient (e.g., alumel, constantan, etc.).

The high-temperature-side conductive part 130 is connected to the high-temperature end of the thermoelectric element 110 to take out the electric power generated by the thermoelectric element 110, and in this embodiment, it is composed of electric wires. The hot-side conductive portion 130 is joined to the hot ends of the thermoelectric elements 110 by, for example, brazing.

The high-temperature-side conductive portion 130 is made of a material having a thermoelectromotive force (Seebeck coefficient) of opposite polarity to that of the thermoelectric element 110 . That is, when the Seebeck coefficient of the thermoelectric element 110 has a negative value, it is made of a material with a positive Seebeck coefficient (e.g., copper, iron, chromel, etc.).

The low-temperature-side conductive portion 120 and the high-temperature-side conductive portion 130 are configured to have a sufficient length, and the low-temperature-side conductive portion 120 also functions as a heat sink (heat dissipation portion) for cooling the low-temperature end of the thermoelectric element 110. By configuring the low-temperature-side conductive portion 120 and the high-temperature-side conductive portion 130 to have a sufficient length, it is possible to secure a necessary temperature difference between the high temperature end and the low temperature end of the thermoelectric element 110 without forced air cooling.

In addition, in the thermoelectric power generation unit 100, the thermoelectric element 110 and the low temperature side conductive part 120 functioning as a heat sink (heat dissipation part) are directly bonded without interposing an insulating substrate or thermally conductive grease. Therefore, compared with a conventional thermoelectric conversion module, the thermal resistance on the low temperature side of the thermoelectric element 110 is reduced, and the cooling efficiency on the low temperature side of the thermoelectric element 110 can be improved.

In addition, in the thermoelectric power generation section 100, the low temperature side conductive section 120 is made of a material having a thermoelectromotive force (Seebeck coefficient) of the same polarity as that of the thermoelectric element 110. Therefore, due to the temperature difference between both ends of the low temperature side conductive section 120, an electromotive force in the same direction as that of the thermoelectric element 110 is generated in the low temperature side conductive section 120, and the electromotive force in the entire thermoelectric generation section 100 can be increased accordingly.

<<Second embodiment>>
FIG. 2 is a diagram for explaining the configuration of another thermoelectric generator according to the present invention.

As shown in the figure, the second thermoelectric generator 200 according to the present invention includes a pair of thermoelectric elements 211 and 212 , a pair of low temperature side conductive parts 221 and 222 and a high temperature side electrode 230 .

The thermoelectric elements 211 and 212 have a predetermined (for example, rectangular parallelepiped) shape, and generate an electromotive force by the Seebeck effect when a temperature difference is applied to both ends thereof. In this embodiment, one thermoelectric element 211 is composed of an n-type semiconductor, and the other thermoelectric element 212 is composed of a p-type semiconductor. Examples of materials for the thermoelectric elements 211 and 212 include magnesium silicide (Mg ₂ Si), iron silicide (FeSi ₂ ), manganese silicide (MnSi _1.73 ), and the like.

The low temperature side conductive parts 221 and 222 are connected to the low temperature ends of the thermoelectric elements 211 and 212, respectively, and are for extracting the electric power generated by the thermoelectric elements 211 and 212 to the outside. The low temperature side conductive parts 221, 222 are joined to the low temperature ends of the thermoelectric elements 211, 212 by, for example, brazing.

The low-temperature-side conductive portions 221 and 222 are made of a material having the same polarity thermoelectromotive force (Seebeck coefficient) as the corresponding thermoelectric elements 211 and 212, respectively. That is, the low-temperature-side conductive portion 221 connected to the thermoelectric element 211 made of an n-type semiconductor is made of a material having a negative Seebeck coefficient (e.g., alumel, constantan, etc.), and the low-temperature-side conductive portion 222 connected to the thermoelectric element 212 made of a p-type semiconductor is made of a material having a positive Seebeck coefficient (e.g., copper, iron, chromel, etc.).

The high-temperature side electrode 230 is connected to the high-temperature ends of the thermoelectric elements 211 and 212 to electrically connect the high-temperature ends of the thermoelectric elements 211 and 212. In the present embodiment, the high temperature side electrode 230 is made of a conductive plate-like member (metal plate). The thermoelectric elements 211 and 212 and the high temperature side electrode 230 constitute a π-type thermoelectric element. The hot-side electrode 230 is made of a metal with high electrical conductivity (eg, copper), and is joined to the hot ends of the thermoelectric elements 211 and 212 by, for example, brazing.

The low temperature side conductive portions 221 and 222 are configured to have a sufficient length, and the low temperature side conductive portions 221 and 222 also function as heat sinks (radiating portions) for cooling the low temperature ends of the corresponding thermoelectric elements 211 and 212, respectively. By configuring the low temperature side conductive parts 221 and 222 to have a sufficient length, it is possible to secure a necessary temperature difference between the high temperature end and the low temperature end of the thermoelectric elements 211 and 212 without forced air cooling.

In addition, in the thermoelectric power generation unit 200, the thermoelectric elements 211 and 212 and the low temperature side conductive parts 221 and 222 functioning as heat sinks (radiating parts) are directly bonded without intervening an insulating substrate or thermally conductive grease. Therefore, compared with a conventional thermoelectric conversion module, the thermal resistance on the low temperature side of the thermoelectric elements 211 and 212 is reduced, and the cooling efficiency on the low temperature side of the thermoelectric elements 211 and 212 can be improved.

In addition, in the thermoelectric power generation unit 200, the low-temperature-side conductive parts 221 and 222 are made of a material having a thermoelectromotive force (Seebeck coefficient) of the same polarity as that of the corresponding thermoelectric elements 211 and 212. Therefore, due to the temperature difference occurring between both ends of the low-temperature-side conductive parts 221 and 222, the low-temperature-side conductive parts 221 and 222 also generate an electromotive force in the same direction as the corresponding thermoelectric elements 211 and 212. The electromotive force of the entire power generation section 200 can be increased.

<<Third Embodiment>>
Next, a thermoelectric conversion module using the first thermoelectric generator 100 described above will be described.

FIG. 3 is a diagram for explaining the configuration of the thermoelectric conversion module according to the present invention.

As shown in the figure, the first thermoelectric conversion module 300 according to the present invention comprises a plurality (five in the example shown in the figure) of thermoelectric generators 100 a to 100 e and an insulating substrate 340 .

For the sake of simplicity, FIG. 1 shows a case in which a plurality of thermoelectric power generation units 100a to 100e are arranged in parallel in a straight line.

Each of the plurality of thermoelectric generators 100a to 100e has the same configuration as the thermoelectric generator 100 described above, and includes thermoelectric elements 110a to 110e, low temperature side conductive parts 120a to 120e, and high temperature side conductive parts 130a to 130e.

Since each of the plurality of thermoelectric power generation units 100a to 100e has the same configuration as the thermoelectric power generation unit 100 described above, the same effects as those of the thermoelectric power generation unit 100 described above can be obtained.

The insulating substrate 340 is joined to the high temperature sides of the plurality of thermoelectric generators 100a to 100e to constitute the high temperature surface of the thermoelectric conversion module 300, and is made of ceramics, for example.

The thermoelectric conversion module 300 having the configuration as described above is used in a state in which the ends of the low temperature side conductive portions 120a to 120e and the high temperature side conductive portions 130a to 130e are appropriately electrically connected according to the specifications of the voltage and current required as a power source, and the plurality of thermoelectric power generation portions 100a to 100e are appropriately connected in series or parallel.

4 to 6 are diagrams for explaining the state when the thermoelectric conversion module 300 is used.

FIG. 4 shows an example in which the five thermoelectric power generation units 100a to 100e provided in the thermoelectric conversion module 300 are connected in series, FIG. 5 shows an example in which the four thermoelectric power generation units 100a to 100d provided in the thermoelectric conversion module 300 are connected in series, and FIG. .

In the example shown in FIG. 4, the low temperature side conductive portion 120a of the thermoelectric power generation unit 100a and the high temperature side conductive portion 130b of the thermoelectric power generation unit 100b are connected by wiring 401, the low temperature side conductive portion 120b of the thermoelectric power generation unit 100b and the high temperature side conductive portion 130c of the thermoelectric power generation unit 100c are connected by wiring 402, and the low temperature side conductive portion 120c of the thermoelectric power generation unit 100c and the thermoelectric power generation unit 1 are connected. 00d is connected by a wiring 403, the low temperature side conductive portion 120d of the thermoelectric generator 100d and the high temperature side conductive portion 130e of the thermoelectric generator 100e are connected by a wiring 404, the low temperature side conductive portion 120e of the thermoelectric generator 100e and one terminal of the load 450 are connected by a wiring 405, and the other terminal of the load 450 and the high temperature side of the thermoelectric generator 100a are connected. The wiring 406 is connected to the conductive portion 130a.

Further, in the example shown in FIG. 5, the low temperature side conductive portion 120a of the thermoelectric generation section 100a and the high temperature side conductive portion 130b of the thermoelectric generation section 100b are connected by wiring 501, the low temperature side conductive section 120b of the thermoelectric generation section 100b and the high temperature side conductive section 130c of the thermoelectric generation section 100c are connected by wiring 502, and the low temperature side conductive section 120c of the thermoelectric generation section 100c and the thermoelectric generation are connected. The high-temperature-side conductive portion 130d of the thermoelectric generator 100d is connected by a wiring 503, the low-temperature-side conductive portion 120d of the thermoelectric generator 100d and one terminal of the load 550 are connected by a wiring 504, and the other terminal of the load 550 and the high-temperature-side conductive portion 130a of the thermoelectric generator 100a are connected by a wiring 505.

Further, in the example shown in FIG. 6, the low temperature side conductive portion 120a of the thermoelectric generation section 100a and the high temperature side conductive portion 130b of the thermoelectric generation section 100b are connected by wiring 501, the low temperature side conductive section 120b of the thermoelectric generation section 100b and the high temperature side conductive section 130c of the thermoelectric generation section 100c are connected by wiring 502, and the low temperature side conductive section 120c of the thermoelectric generation section 100c and thermoelectric generation are connected. The high-temperature side conductive portion 130e of the portion 100e is connected with the wiring 506, the low-temperature side conductive portion 120e of the thermoelectric power generation portion 100e and one terminal of the load 550 are connected with the wiring 507, and the other terminal of the load 550 and the high temperature side conductive portion 130a of the thermoelectric power generation portion 100a are connected with the wiring 505.

As shown in FIGS. 4 and 5, in the thermoelectric conversion module 300, a plurality of thermoelectric power generation units 100a to 100e can be freely combined and used by switching the external connections, so that it is possible to flexibly meet the voltage and current specifications required as a power supply.

Further, even if some of the plurality of thermoelectric power generation units 100a to 100e (for example, the thermoelectric power generation unit 100d) are damaged, as shown in FIG. 5, if there is an unused thermoelectric power generation unit (for example, the thermoelectric power generation unit 100e), it is possible to continue using the thermoelectric conversion module 300 simply by partially changing the external wiring as shown in FIG.

<<Fourth embodiment>>
Next, a thermoelectric conversion module using the second thermoelectric generator 200 described above will be described.

FIG. 7 is a diagram for explaining the configuration of another thermoelectric conversion module according to the present invention.

As shown in the figure, the second thermoelectric conversion module 700 according to the present invention comprises a plurality (five in the example shown in the figure) of thermoelectric generators 200 a to 200 e and an insulating substrate 740 .

For the sake of simplicity, FIG. 1 shows a case in which a plurality of thermoelectric power generation units 200a to 200e are arranged in parallel in a straight line.

Each of the plurality of thermoelectric power generation units 200a to 200e has the same configuration as the thermoelectric power generation unit 200 described above, and includes a pair of thermoelectric elements 211a to 211e and 212a to 212e, a pair of low temperature side conductive portions 221a to 221e and 222a to 222e, and high temperature side electrodes 230a to 230e.

Since each of the plurality of thermoelectric power generation units 200a to 200e has the same configuration as the thermoelectric power generation unit 200 described above, the same effects as those of the thermoelectric power generation unit 200 described above can be obtained.

The insulating substrate 740 is joined to the high temperature sides of the plurality of thermoelectric generators 200a to 200e to constitute the high temperature surface of the thermoelectric conversion module 700, and is made of ceramics, for example.

Like the thermoelectric conversion module 300, the thermoelectric conversion module 700 configured as described above is used in a state in which the ends of the low-temperature side conductive portions 221a to 221e and 222a to 222e are appropriately electrically connected according to the specifications of the voltage and current required as a power source, and the plurality of thermoelectric power generation portions 200a to 200e are appropriately connected in series or parallel.

8 to 10 are diagrams for explaining the state when the thermoelectric conversion module 700 is used.

FIG. 8 shows an example in which the five thermoelectric power generation units 200a to 200d provided in the thermoelectric conversion module 700 are connected in series, FIG. 9 shows an example in which the four thermoelectric power generation units 200a to 200d provided in the thermoelectric conversion module 700 are connected in series, and FIG. are

In the example shown in FIG. 8 , the low-temperature side conductive portion 221 a of the thermoelectric generation section 200 a and the low-temperature side conductive portion 222 b of the thermoelectric generation section 200 b are connected by wiring 801 , the low-temperature side conductive section 221 b of the thermoelectric generation section 200 b and the low-temperature side conductive section 222 c of the thermoelectric generation section 200 c are connected by wiring 802 , and the low-temperature side conductive section 221 c of the thermoelectric generation section 200 c and the thermoelectric generation section 2 are connected. 00d is connected by a wiring 803, the low temperature side conductive portion 221d of the thermoelectric generator 200d and the low temperature side conductive portion 222e of the thermoelectric generator 200e are connected by a wiring 804, the low temperature side conductive portion 221e of the thermoelectric generator 200e and one terminal of the load 850 are connected by a wiring 805, and the other terminal of the load 850 and the low temperature side of the thermoelectric generator 200a are connected. The wiring 806 is connected to the conductive portion 222a.

In the example shown in FIG. 9, the low-temperature side conductive portion 221a of the thermoelectric generation section 200a and the low-temperature side conductive portion 222b of the thermoelectric generation section 200b are connected by wiring 901, the low-temperature side conductive section 221b of the thermoelectric generation section 200b and the low-temperature side conductive section 222c of the thermoelectric generation section 200c are connected by wiring 902, and the low-temperature side conductive section 221c of the thermoelectric generation section 200c and thermoelectric generation are connected. The low-temperature-side conductive portion 222d of the thermoelectric generator 200d is connected with the wiring 903, the low-temperature-side conductive portion 221d of the thermoelectric generator 200d and one terminal of the load 950 are connected with the wiring 904, and the other terminal of the load 950 and the low-temperature-side conductive portion 222a of the thermoelectric generator 200a are connected with the wiring 905.

In the example shown in FIG. 10, the low-temperature side conductive portion 221a of the thermoelectric generation section 200a and the low-temperature side conductive portion 222b of the thermoelectric generation section 200b are connected by wiring 901, the low-temperature side conductive section 221b of the thermoelectric generation section 200b and the low-temperature side conductive section 222c of the thermoelectric generation section 200c are connected by wiring 902, and the low-temperature side conductive section 221c of the thermoelectric generation section 200c and the thermoelectric generator are connected. The low temperature side conductive portion 222e of the power generation section 200e is connected by a wiring 906, the low temperature side conductive portion 221e of the thermoelectric generation section 200e and one terminal of the load 950 are connected by a wiring 907, and the other terminal of the load 950 and the low temperature side conductive portion 222a of the thermoelectric generation section 200a are connected by a wiring 905.

As shown in FIGS. 8 and 9, in the thermoelectric conversion module 700, a plurality of thermoelectric power generation units 200a to 200e can be freely combined and used by appropriately changing the external connection state. Therefore, it is possible to flexibly respond to the voltage and current specifications required as a power supply.

Further, even if some of the plurality of thermoelectric power generation units 200a to 200e (for example, the thermoelectric power generation unit 200d) are damaged, as shown in FIG. 9, if there is an unused thermoelectric power generation unit (for example, the thermoelectric power generation unit 200e), it is possible to continue using the thermoelectric conversion module 700 only by partially changing the external wiring as shown in FIG.

Although the embodiments of the present invention have been described above, the embodiments of the present invention are, of course, not limited to the above. For example, in the second embodiment and the fourth embodiment described above, the hot ends of a pair of thermoelectric elements are electrically connected via the high temperature side electrodes, but it is also conceivable to directly join the hot ends of the pair of thermoelectric elements.

Next, an embodiment of the thermoelectric generator according to the present invention will be described.

First, an n-type thermoelectric element made of magnesium silicide (Mg ₂ Si) was produced as follows.

First, magnesium (Mg) powder with a purity of 99.9% and a particle size of 180 μm, silicon (Si) powder with a purity of 99.9% and a particle size of 180 μm, and antimony (Sb) powder with a purity of 99.999% and a particle size of 180 μm were weighed so that the stoichiometric ratio would be Mg _2.02 Si _0.99 Sb _0.01 .

Next, the raw material powders were uniformly mixed, placed in a semi-sealable carbon container with a lid, placed in an electric furnace, and heat-treated at 700° C. for 1 hour in an argon gas atmosphere to obtain a solid solution of a Mg _Si- based thermoelectric material.

Next, the obtained solid solution was pulverized with an automatic mortar so as to have a particle size of 30 μm or less.

Next, the obtained solid solution powder was filled in a 30φ cylindrical jig for spark plasma sintering, placed in a spark plasma sintering apparatus, and sintered under the conditions of a sintering temperature of 850 ° C., a sintering pressure of 30 MPa, and a sintering time of 25 minutes.

After that, the resulting sintered body was naturally cooled to room temperature and processed into a rectangular parallelepiped of 10×10×17 mm to obtain a final thermoelectric element.

Next, a thermoelectric generator was produced using the obtained thermoelectric element.

FIG. 11 is a diagram for explaining the configuration of the fabricated thermoelectric generator.

As shown in the figure, the thermoelectric power generating section 1100 includes an n-type thermoelectric element 1110, copper wires 1121 and alumel wires 1122 as low temperature side conductive portions, and copper wire 1130 as high temperature side conductive portions.

In this embodiment, two low-temperature-side conductive portions 1121 and 1122 made of different materials are electrically connected to the low-temperature end of one thermoelectric element 1100 for convenience.

A thermoelectric generator 1100 having a configuration as shown in the figure was produced as follows.

First, both ends (copper wire joints) of the thermoelectric element 1110 were roughened with SiC abrasive paper, and then coated with a special solder (Cerasolza Eco) manufactured by Kuroda Techno Co., Ltd. (Kohoku Ward, Yokohama City, Kanagawa Prefecture) using an ultrasonic soldering device.

Next, one end of a copper wire (diameter: 2.0 mm, length: 470 mm) was joined to each of the two ends of the thermoelectric element 1110 coated with a special solder, using tar-free Pb-free solder.

Next, one end (copper wire joint portion) of the alumel wire (diameter 2.3 mm, length 470 mm) was coated with the above special solder, and the end was joined to the low temperature side copper wire 1121 in the vicinity of the low temperature end of the thermoelectric element 1110 with Pb-free solder.

Finally, a Y-shaped terminal was connected as an output terminal to the other ends of the copper wires 1121 and 1130 and the alumel wire 1122 .

Next, the power generation performance of the produced thermoelectric power generation unit 1100 was measured as follows.

First, with the hot end of the thermoelectric element 1110 heated on a hot plate, the temperatures of the hot end of the thermoelectric element 1110 and the output end of the copper wire 1121 were measured with thermocouples, and the voltage between the output ends of the copper wires 1121 and 1130 was measured with a digital voltmeter.

Similarly, while the hot end of the thermoelectric element 1110 was heated on a hot plate, the temperatures of the hot end of the thermoelectric element 1110 and the output end of the alumel wire 1122 were measured with thermocouples, and the voltage between the output ends of the alumel wire 1122 and the copper wire 1130 was measured with a digital voltmeter.

FIG. 12 is a diagram showing measurement results. In the figure, “Th” represents the temperature (unit: °C) of the high temperature end of the thermoelectric element 1110, “Tc” represents the temperature (unit: °C) of the output ends of the low temperature side conductive parts 1121 and 1122, “Vout” represents the voltage between the output terminals (unit: μV), and “αout” represents the output voltage (Vout/(Th−Tc)) per degree of temperature difference (unit: μV/°C).

As shown in the figure, a larger output voltage can be obtained when the alumel wire is used as the low temperature side conductive portion than when the copper wire is used.

Thermoelectric element 1110 is an n-type semiconductor and has a negative Seebeck coefficient. On the other hand, copper wire has a positive Seebeck coefficient and alumel wire has a negative Seebeck coefficient. In other words, when the alumel wire having the same polarity (that is, negative) Seebeck coefficient as that of the thermoelectric element 1110 is used as the low temperature side conductive portion, a larger output voltage is obtained than when the copper wire having the opposite polarity (that is, positive) Seebeck coefficient to that of the thermoelectric element 1110 is used.

100, 100a to 100e Thermoelectric power generation section 110, 110a to 110e Thermoelectric element 120, 120a to 120e Low temperature side conductive section 130, 130a to 130e High temperature side conductive section 200, 200a to 200e Thermoelectric power generation section 211, 211a to 211e, 212, 212a to 212e Thermoelectric elements 221, 221a to 221e, 222, 222a to 222e Low temperature side conductive parts 230, 230a to 230e High temperature side electrode 300 Thermoelectric conversion module 340 Insulating substrate 401 to 406 Wiring 450 Load 501 to 507 Wiring 550 Load 700 Thermoelectric converting module 740 Insulating substrate 801 ~806 Wiring 850 Load 901~907 Wiring 950 Load 1100 Thermoelectric generator 1110 Thermoelectric element 1121 Low temperature side copper wire 1122 Alumel wire 1130 High temperature side copper wire

Claims (5)

A thermoelectric conversion module comprising at least one thermoelectric generator,
The thermoelectric power generation unit is
a pair of thermoelectric elements having hot ends electrically connected;
a pair of low-temperature-side conductive portions connected to the low-temperature ends of the pair of thermoelectric elements,
A thermoelectric conversion module, wherein each of the pair of low-temperature-side conductive parts has a Seebeck coefficient of the same polarity as that of a corresponding thermoelectric element. 2. The thermoelectric conversion module according to claim 1 , comprising a plurality of said thermoelectric generators. 3. The thermoelectric conversion module according to claim 1 , wherein the low-temperature-side conductive portion is composed of an electric wire. 4. The thermoelectric conversion module according to any one of claims 1 to 3, wherein the thermoelectric generator further comprises a high temperature side electrode electrically connecting the high temperature ends of the pair of thermoelectric elements. 5. The thermoelectric conversion module according to any one of claims 1 to 4 , further comprising an insulating substrate arranged on the high temperature side of said thermoelectric generator.

Images