JP2005317629A - Thermoelectric conversion module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoelectric conversion module which suppresses the generation of thermal stress at a bonding portion between a semiconductor and an electrode forming a thermoelectric element, and prevents cracking of the semiconductor. <P>SOLUTION: The thermoelectric conversion module 10 is formed by connecting a plurality of pairs of thermoelectric elements in series, wherein a pair of cylindrical or prismatic p-type and n-type semiconductors 13 and 13a are arranged side by side, between first and second insulators 11 and 11a facing each other in nearly parallel by means of electrodes 14 that are respectively provided on the first and second insulators 11 and 11a. The end of the thermoelectric element 12 to be connected with the electrode 14 of the first insulator 11 or the second insulator 11a is provided with a thread 15 made of the same material as that of the electrode 14 or a different material, and a tapped hole 16 with the screwed thread 15 is provided in the electrode 14. The thread 15 is screwed in the tapped hole 16 to electrically connect the thermoelectric element 12 with the electrode 14, and a clearance 17 is formed between the thread 15 and the tapped hole 16 so that they may mutually move horizontally. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermoelectric conversion module that can act as cooling or heating by power generation due to a temperature difference or supply of DC power.

  As shown in FIG. 3, a conventional thermoelectric conversion module 50 includes a thermoelectric element 52 composed of a pair of semiconductors of a P-type semiconductor 51 and an N-type semiconductor 51a as a plate-like ceramic substrate, a resin substrate, or a film-like resin sheet. The P-type semiconductor 51 and the N-type semiconductor 51a are alternately and continuously connected with a conductive resin or a bonding material 55 such as solder through electrodes 54 formed on the first and second insulators 53 and 53a. They are joined and connected in series, and are clamped with a clamp 56 or the like so as to be sandwiched between the first and second insulators 53 and 53a from both sides. For example, for use as a thermoelectric generator, the first insulator 53 on the high temperature side is connected to the first insulator 53 via a heat sink plate 57 that can efficiently transmit the high temperature. The first heat transfer body 58 is brought into contact with the other second insulator 53a on the low temperature side, whereby the second heat transfer body 58a is brought into contact with the thermoelectric element from the first and second heat transfer bodies 58 and 58a. Power is generated by the Seebeck effect that causes the thermoelectric element 52 to generate a potential having a magnitude proportional to the temperature difference between the temperatures transmitted to the respective terminal portions 52, and the generated power is connected to both ends of the electrode 54. , 59a. In addition, as a device using the thermoelectric conversion module 50, cooling of the first heat transfer body 58 and heating of the second heat transfer body 58a by the Peltier effect by supplying power from the lead wires 59 and 59a to the thermoelectric element 52, or The first heat transfer body 58 and the second heat transfer body 58a opposite to the above can be heated and cooled. When a conductive resin is used for the bonding material 55 between the thermoelectric element 52 and the electrode 54, the heat resistance of the conductive resin is low, so that the heating temperature after bonding is limited, and the use as the thermoelectric conversion module 50 is limited. Will be.

When the thermoelectric conversion module is used as a thermoelectric power generation device, if the electric power extracted from the thermoelectric element is increased, the temperature of the high temperature side heat transfer body is increased to increase the temperature difference from the low temperature side heat transfer body. There is a need. In this case, solder is usually used for bonding the semiconductor and the electrode. However, when low-temperature solder that is soft solder is used, the heat resistance of the solder is as low as about 150 ° C., which hinders improvement in power generation efficiency. It has become. Therefore, it is conceivable to use high-temperature solder instead of low-temperature solder. In this case, although the temperature of the heat transfer body on the high temperature side can be increased, the components of the high-temperature solder are contained in the semiconductor constituting the thermoelectric element. In addition, since Sn and Pb of the solder component have high affinity with Cu of the electrode, Cu diffuses into the semiconductor through the high-temperature solder, and the thermoelectric conversion efficiency of the semiconductor itself is lowered over time. . In view of this, there has been proposed a structure in which an intervening layer is provided and bonded between a semiconductor and electrodes constituting a thermoelectric element (see, for example, Patent Document 1). In addition, stress is applied to the bonding portion between the semiconductor and the electrode constituting the thermoelectric element due to the thermal expansion on the high temperature side and the thermal contraction on the low temperature side, and cracks may occur due to long-term use. In view of this, it has been proposed that the semiconductor constituting the thermoelectric element has a spherical shape and is not easily subjected to stress (see, for example, Patent Document 2).
JP-A-9-293906 JP-A-10-163537

However, the conventional thermoelectric conversion module as described above has the following problems.
In the case where the semiconductor constituting the thermoelectric element and the electrode are joined by soldering, even if an intervening layer is provided between the semiconductor and the electrode, the solder joining is a rigid joining, so heating during operation Further, it is impossible to absorb the thermal stress of the joint due to cooling at the time of stopping, and it is impossible to completely prevent cracks generated in a semiconductor having brittle characteristics due to this stress. Similarly, even when the semiconductor is made spherical, as long as it is a rigid solder joint, the thermal stress of the semiconductor cannot be absorbed, so that the cracks generated in the semiconductor cannot be completely prevented. The semiconductor has a markedly reduced thermoelectric performance due to the occurrence of cracks.
The present invention has been made in view of such circumstances, and provides a thermoelectric conversion module that prevents the occurrence of cracks in a semiconductor by preventing the occurrence of thermal stress at the junction between a semiconductor and an electrode constituting a thermoelectric element. For the purpose.

A thermoelectric conversion module according to the present invention that meets the above-described object is provided by arranging a pair of cylindrical and polygonal P-type semiconductors and N-type semiconductors between first and second insulators facing each other in a plane substantially parallel to each other. In a thermoelectric conversion module in which a plurality of sets of thermoelectric elements provided are formed by electrically connecting a P-type semiconductor and an N-type semiconductor in series via electrodes provided on the first and second insulators, respectively. The end of the thermoelectric element connected to the electrode of the first insulator or the second insulator has a screw made of the same or different material as the thermoelectric element, and has a screw hole for screwing in the electrode. The thermoelectric element is electrically connected by screwing the screw into the screw hole, and there is a clearance that allows the screw and the screw hole to move horizontally between the screw and the screw hole.
Here, in the thermoelectric conversion module, it is preferable that conductive grease is applied to the joint portion between the screw and the screw hole.

  The thermoelectric conversion module according to claim 1 and claim 2 dependent thereon has a screw made of the same or different material as the thermoelectric element at the end of the thermoelectric element connected to the electrode of the first or second insulator. In addition, a screw hole is provided in the electrode, the screw is screwed into the screw hole, the thermoelectric element is electrically connected, and the screw and the screw hole have a clearance that can move horizontally between the screw and the screw hole. Therefore, electrical conduction can be secured between the thermoelectric element and the electrode by screwing with a screw and a screw hole, and the difference between the semiconductor and the insulator constituting the thermoelectric element can be ensured by the clearance between the screw and the screw hole. Since differences in thermal expansion and contraction between materials can be absorbed, the generation of thermal stress can be prevented and the occurrence of cracks in the semiconductor can be prevented.

  Particularly, in the thermoelectric conversion module according to claim 2, since the conductive grease is applied to the joint portion between the screw and the screw hole, the stability of the electrical connection and the heat conductive connection at the joint portion can be obtained. it can.

Subsequently, the best mode for carrying out the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.
Here, FIG. 1 is an explanatory diagram of a thermoelectric conversion module according to an embodiment of the present invention, and FIGS.

  As shown in FIG. 1, a thermoelectric conversion module 10 according to an embodiment of the present invention includes a plate-shaped ceramic substrate, such as aluminum nitride or alumina, or a plate-shaped resin, facing each other substantially in parallel with each other. A plurality of thermoelectric elements 12 are provided between the first insulator 11 made of a substrate, a film-like resin sheet, or a combination thereof, and the second insulator 11a. The thermoelectric element 12 is formed of a pair of a P-type semiconductor 13 and an N-type semiconductor 13a made of a cylindrical body or a polygonal cylinder, for example, bismuth-tellurium-based, cobalt-antimony-based, etc., or a joined body thereof. ing. Each of the P-type semiconductor 13 and the N-type semiconductor 13a configured as a pair is formed of, for example, copper, molybdenum, or an alloy thereof provided in each of the first insulator 11 and the second insulator 11a. A plurality of sets of thermoelectric elements 12 composed of a pair of P-type semiconductor 13 and N-type semiconductor 13a are continuously and electrically connected in series through electrodes 14 and in series.

  An end portion of the thermoelectric element 12 composed of the P-type semiconductor 13 and the N-type semiconductor 13a is electrically connected to the electrode 14 of the first insulator 11 or the second insulator 11a, and the electrode 14 is connected to the thermoelectric element. In order to attach 12, the thermoelectric element 12 is made of the same material, that is, a semiconductor, and has a screw 15 extending from the end of the thermoelectric element 12. The electrode 14 has a screw hole 16 for screwing and joining the screw 15, and the screw 15 is screwed by the screw hole 16. By this screwing, the thermoelectric element 12 composed of the P-type semiconductor 13 and the N-type semiconductor 13a can be electrically connected in series. Further, the thermoelectric element 12 composed of the P-type semiconductor 13 and the N-type semiconductor 13a. By connecting a plurality of sets arranged in a matrix in plan view, the whole can be electrically connected in series. Moreover, between the screw 15 and the screw hole 16, when the screw 15 is screwed into the screw hole 16, the screw 15 does not fall out of the screw hole 16, and at the same time, the screw 15 and the screw hole 16 can move horizontally. Clearance 17 is provided. Due to this clearance 17, the thermoelectric element 12 and the electrode 14 are joined not by a rigid joint such as a solder joint, but by joining the joint between the screw 15 and the screw hole 16 with a margin. Therefore, it is possible to absorb the thermal stress concentration at the joint and to prevent the generation of cracks that are likely to occur in the semiconductor that is the thermoelectric element 12.

  As shown in FIG. 2A, the thermoelectric conversion module 10 according to an embodiment of the present invention includes an end portion of a thermoelectric element 12 composed of a P-type semiconductor 13 and an N-type semiconductor 13a, In order to connect the electrode 14 of the insulator 11 or the second insulator 11a, a screw 15a made of a material different from the semiconductor that is the thermoelectric element 12, for example, a metal such as copper or molybdenum, is connected to the thermoelectric element 12 by soldering or the like. Some are formed by bonding with the bonding material 20. Further, as shown in FIG. 2B, the thermoelectric conversion module 10 according to one embodiment of the present invention includes an end portion of the thermoelectric element 12, and the first insulator 11 or the second insulator 11a. In order to connect the electrode 14, one side of the screw 15 b that is made of the same material as the semiconductor that is the thermoelectric element 12 or a different material from the semiconductor that is the thermoelectric element 12 and can be screwed on both sides of the joint surface is the thermoelectric element 12. There are some which are formed by screwing into a screw hole 16a for joining provided at the end of each. In the case of this screwing, it is sufficient that the screw 15b can be fitted to the screw hole 16a between the screw 15b and the screw hole 16a, and it is not necessary to provide a special clearance. The electrode 14 has a screw hole 16 for screwing and screwing the screws 15a and 15b, and by screwing the screws 15a and 15b with the screw holes 16, the P-type semiconductor 13 A plurality of sets of thermoelectric elements 12 made of N-type semiconductor 13a are electrically in series. Between the screws 15 a and 15 b and the screw hole 16, when the screws 15 a and 15 b are screwed into the screw hole 16, the screws 15 a and 15 b do not fall out of the screw hole 16, and at the same time, the screws 15 a and 15 b and the screw hole 16. Have a clearance 17 that can move horizontally with respect to each other.

  Here, in the thermoelectric conversion module 10, conductive grease is preferably applied to a joint portion between the screws 15, 15 a, 15 b and the screw hole 16. Since this conductive grease can have both electrical conductivity and thermal thermal conductivity, electrical connection at the joint between the screws 15, 15a, 15b and the screw hole 16 and heat conduction can be achieved. Stabilization of the mechanical joint can be promoted.

  When the thermoelectric conversion module 10 is used as a thermoelectric power generation device which is a kind of thermoelectric conversion device, for example, a heat sink plate 18 made of copper, molybdenum, or an alloy thereof is provided on the first insulator 11 side. In addition, the first transmission made of a hollow body or the like that can pass a high-temperature gas such as exhaust gas, high-temperature gas such as waste heat, or high-temperature liquid such as waste water after cooling the high-temperature body. A heating element 19 is provided. Further, on the second insulator 11a side, for example, a second heat transfer body 19a made of a hollow body or the like through which a cooling medium or a low-temperature medium such as cold air can pass is provided. The heat sink plate 18 is provided in order to efficiently transfer high-temperature heat obtained from a high-temperature gas, a high-temperature liquid, or the like to the thermoelectric element 12. Further, in order to allow the first heat transfer body 19 and the second heat transfer body 19a to be in contact with the first insulator 11 and the second insulator 11a, the first heat transfer body 19 and the second heat transfer body 19a are tightened with a tightening tool 21. In this way, heat conduction is strengthened. The thermoelectric power generator configured as described above has a potential proportional to the temperature difference between the temperatures transmitted from the first heat transfer body 19 and the second heat transfer body 19a to the respective terminal portions of the thermoelectric element 12. Is generated by the Seebeck effect generated by the thermoelectric element 12, and the generated power is taken out from the lead wires 22 and 22a extending from the electrodes 14 at both ends where the thermoelectric elements 12 are connected in series. ing.

  Further, in the thermoelectric conversion device using the thermoelectric conversion module 10, the cooling on the first heat transfer body 19 side and the second heat transfer body are performed by the Peltier effect by supplying power from the lead wires 22 and 22 a to the thermoelectric element 12. Heating and cooling of the contacted object that can be moved by heat to heat the 19a side or heat the first heat transfer body 19 and cool the second heat transfer body 19a As a device for this, various applications can be made. When a ceramic substrate is used for the first insulator 11 and / or the second insulator 11a, each heat medium can be effectively utilized by using, for example, an aluminum nitride substrate having a high thermal conductivity. Or the object to be heated or the object to be cooled can be efficiently heated or cooled.

  The thermoelectric conversion module of the present invention can obtain a large electric power without causing a defect in a semiconductor as a thermoelectric element even if a temperature difference between a high temperature side and a low temperature side becomes large, and generates power using waste heat or the like. Thermoelectric power generators that can be used, and even if the temperature difference between the high-temperature side and the low-temperature side is increased by flowing high power, high temperatures and cold, hot air heaters, heating that can draw out low temperatures without causing defects in the semiconductor that is the thermoelectric element It can be used for a cooling device, various devices for supplying power for use in a narrow place or a severe place, an economical power generator for circulating a heat medium, and the like.

It is explanatory drawing of the thermoelectric conversion module which concerns on one embodiment of this invention. (A), (B) is an expansion explanatory drawing of the modification of the junction part of the thermoelectric conversion module, respectively. It is explanatory drawing of the conventional thermoelectric conversion module.

Explanation of symbols

  10: thermoelectric conversion module, 11: first insulator, 11a: second insulator, 12: thermoelectric element, 13: P-type semiconductor, 13a: N-type semiconductor, 14: electrode, 15, 15a, 15b: screw 16, 16a: screw holes, 17: clearance, 18: heat sink plate, 19: first heat transfer body, 19a: second heat transfer body, 20: bonding material, 21: clamping tool, 22, 22a: lead line

Claims (2)

A plurality of sets of thermoelectric elements in which a pair of a P-type semiconductor and an N-type semiconductor in the form of a cylinder or a polygonal column are arranged in parallel between first and second insulators facing each other in a plane substantially parallel to each other. And a thermoelectric conversion module formed by electrically connecting the P-type semiconductor and the N-type semiconductor in series via electrodes provided on each of the second insulator and the second insulator,
The end of the thermoelectric element connected to the electrode of the first insulator or the second insulator has a screw made of the same or different material as the thermoelectric element, and a screw hole for screwing the screw And the thermoelectric element is electrically connected by screwing the screw into the screw hole, and the screw and the screw hole move horizontally between the screw and the screw hole. A thermoelectric conversion module characterized by having a possible clearance.   The thermoelectric conversion module according to claim 1, wherein conductive grease is applied to a joint portion between the screw and the screw hole.

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