JPH10163537A - Thermoelectric converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric converter which is easy to assemble, for which no stress is applied to electrical connections of thermoelectric elements against the expansion and shrinkage of heat-exchange boards. SOLUTION: A thermoelectric converter has two opposed approximately flat plate-like heat-exchange boards 11, thermoelectric elements 2, each composed a pair of a P and N-type semiconductors compression-welded and arranged between the heat-exchange boards 11 and electrodes 31, 32 which connect and bond the P and N-type semiconductors of the thermoelectric elements 2 disposed on the boards 11. The elements 2 are each formed in a spherical shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoelectric converter.

[0002]

2. Description of the Related Art Conventionally, there is a thermoelectric conversion device that converts electric energy into heat using the Peltier effect and converts heat into electric energy using the Seebeck effect. As the thermoelectric conversion device, a Peltier element used for a temperature controller, a portable cool box, a small dehumidifier, or the like is well known. As shown in FIGS. 6 and 7, for example, the Peltier elements are heat-exchange substrates 11 and 12 formed of two opposed substantially flat ceramic materials such as alumina ceramics.
And P which is pressed and arranged between the heat exchange substrates 11 and 12
Element 2 formed of a pair of semiconductors of N-type and N-type
And P of the thermoelectric element provided on the heat exchange substrates 11 and 12
And an electrode 3 that connects and joins the N-type and N-type in series.

[0003] The above-mentioned Peltier device comprises a heat exchange substrate 11,
The thermoelectric element 3 is manufactured by bonding a bonding material 5 such as solder on the electrode 3 fixed on the electrode 12 with an adhesive or the like. When a DC current is applied between the terminals 4 and 4, one of the heat exchange boards 11 becomes low in temperature and the other heat exchange board 12 becomes high in temperature. Dissipates heat.

The heat exchange substrates 11 and 12 made of an alumina ceramic material are thermally expanded at a high temperature and thermally contracted at a low temperature. Then, stress is applied to the thermoelectric element 2 due to the thermal expansion and thermal contraction. In a long-term use, the thermal expansion and thermal contraction are repeated, and the joint between the thermoelectric element 2 and the electrode 3 is formed. Cracks may occur. As a result, there has been a problem that the conduction of the thermoelectric element 2 is not established due to the crack, leading to a failure. As a countermeasure against this problem, the present inventors, as shown in FIG. Thermoelectric element 2 even if shrunk
Has proposed a structure in which no stress is applied by sliding.

[0005]

By the way, the thermoelectric element 2 having the above-mentioned spherical surface has only a surface in contact with the electrode 3 in a spherical shape and has directivity. Therefore, when installing on the heat exchange boards 11 and 12, it is necessary to perform the work while confirming the spherical shape, which requires time and labor for assembly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is not to apply stress to an electrical junction portion of a thermoelectric element even when a heat exchange substrate expands and contracts, and it is easy to assemble. A thermoelectric conversion device is provided.

[0007]

In order to achieve the above object, a thermoelectric conversion device according to a first aspect of the present invention has two substantially flat heat exchange substrates opposed to each other, and is arranged in pressure contact between the heat exchange substrates. A thermoelectric element formed of a pair of P-type and N-type semiconductors, and an electrode provided on the heat exchange substrate and connecting the P-type and N-type thermoelectric elements in series and joining them. In the thermoelectric device provided, the thermoelectric element is formed in a spherical shape. As a result, the thermoelectric element has no directionality.

According to a second aspect of the present invention, there is provided a thermoelectric conversion device, wherein the electrode according to the first aspect has a concave portion in contact with the thermoelectric element. Thereby, the thermoelectric element can be held at a predetermined position.

According to a third aspect of the present invention, in the thermoelectric conversion device, at least one of the heat exchange substrates is formed as a long groove extending from the center toward the outer edge. Thereby, at least one contact portion with the electrode of the thermoelectric element is held by the long groove extending from the center to the outer edge.

According to a fourth aspect of the present invention, in the thermoelectric conversion device, the long groove according to the third aspect is formed such that the outer peripheral side of the heat exchange substrate is longer than the central side. Thereby, the thermoelectric element provided on the outer edge side is held by the long groove longer than the thermoelectric element on the center side.

According to a fifth aspect of the present invention, there is provided a thermoelectric conversion device, wherein the long groove according to the third or fourth aspect can contact the thermoelectric element at one point on the bottom surface as viewed in the lateral direction of the long groove. Is formed. Thereby, the thermoelectric element is held at one point of the long groove.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the thermoelectric converter of the present invention will be described with reference to FIGS. 1 to 4, and a second embodiment will be described with reference to FIG.

[First Embodiment] FIG. 1 is an explanatory view showing an installation state of a thermoelectric element which is a main part of a Peltier element which is a thermoelectric converter according to a first embodiment. 2A and 2B are perspective views showing the electrode of the above, wherein FIG.
Indicates an upper electrode. 3A and 3B are plan views showing the electrode patterns of the above, wherein FIG. 3A shows a lower surface side heat exchange substrate, and FIG. 3B shows an upper surface side heat exchange substrate. FIG. 4 is a schematic configuration diagram of the above.

This thermoelectric conversion device is a Peltier element that converts electric energy into heat to absorb and radiate heat, and comprises two substantially flat heat exchange substrates 11 and 12 opposed to each other. A thermoelectric element 2 formed of a pair of P-type and N-type semiconductors which are pressed against and juxtaposed with each other, and P-type and N-type thermoelectric elements 2 provided on heat exchange substrates 11 and 12. And electrodes 31 and 32 connected and joined in series.

The heat exchange substrates 11 and 12 are provided with electrodes 3 to be described later.
1 and 32 and radiate heat from the thermoelectric element 2 to the outside, or absorb heat from the outside and
For example, it is formed in a substantially square shape by sintering or the like using a material having a good heat transfer coefficient such as alumina ceramic. As shown in FIG. 4, the heat exchange boards 11 and 12 are tightened at predetermined positions on the outer edge side by means of a spring 7 using a tightening means such as a bolt 6, so that the bolt 6 is inserted. Is formed in an appropriate fin shape so that heat can be efficiently exchanged with the surrounding air. As shown in FIG. 4, one end of an elastic body such as a spring 7 abuts on one of the heat exchange substrates 11 and is interposed between the heat exchange substrates 11 and 12, so that the heat exchange substrate
The bolt 6 is tightened with a predetermined tightening torque so as to be pressed with a predetermined pressing force. Then, one of the heat exchange substrates has a low temperature and the other has a high temperature. The low-temperature substrates absorb heat and the high-temperature substrates dissipate heat.

The electrodes 31 and 32 are used to supply a DC current to the thermoelectric element 2 described later. For example, the electrodes 31 and 32 are made of a thin plate material such as a copper foil material and are arranged at predetermined intervals on the opposing surfaces of the heat exchange substrates 11 and 12. An adhesive having good elasticity and a good heat transfer coefficient, such as a silicon-based adhesive, formed in a pattern shape in which a pair of P-type and N-type semiconductor thermoelectric elements 2 are arranged and connected in series. Are bonded to opposing surfaces of the heat exchange substrates 11 and 12. The electrodes 31 and 32 are formed by etching or the like so that the thermoelectric element can be held at a predetermined position by pressing the heat exchange substrate with a spring as described above. The electrode 31 on the upper surface is formed in a long groove 31a, that is, an oval concave shape, and the long groove 31a is formed in the heat exchange substrate 11,
As shown in FIG. 3B, the groove 12 is formed as a long groove extending from the center to the outer edge in order to absorb a dimensional change in thermal contraction and thermal expansion from the center to the outer edge. Further, the length of the long groove 31a is made longer at the outer edge than at the center in order to effectively absorb the dimensional change which is larger at the outer edge of the heat exchange substrates 11 and 12. As shown in FIG. 1, the long groove and the thermoelectric element are formed with a width dimension w1 in which the long groove and the thermoelectric element contact each other at three points, that is, both edges of the groove and the bottom surface when viewed in the lateral direction of the long groove.
In addition, the electrode 31 at the start and end on the peripheral side includes:
Terminals 4 for connection to external wiring are fixed by soldering or the like.

The thermoelectric element 2 is, for example, a Bi-Te based semiconductor element, and is formed in a spherical shape having a predetermined size by, for example, sintering. The thermoelectric element 2 has a P-type between the heat exchange boards 11 and 12 so that one of the heat exchange boards 11 and 12 generates heat by passing a direct current and the other heatsink. And N-types are alternately arranged, and are alternately connected in series by the electrodes 31 and 32. The junction between the thermoelectric element 2 and the electrodes 31 and 32 is a point junction between the spherical surface side electrode 32 and the long groove side electrode 31 at three points. Therefore, in order to stably perform electric and thermal bonding, conductive grease or the like is applied to the bonding portion with the electrode 31 for both conductivity and heat transfer.

The above-described assembling of the thermoelectric conversion device is performed by firstly mounting the heat exchange substrate 12 having the lower circular spherical electrode 32.
The P-type and N-type thermoelectric elements 2 are arranged at predetermined positions on the electrodes so as to be connected and joined in series between the upper and lower heat exchange substrates 11 and 12. . Then
After placing the upper heat exchange board 11 on the upper surface of the thermoelectric element 2, the spring 7 is interposed in the through hole h and the bolt 6 is inserted, and tightened with a predetermined tightening torque. When a DC current is applied to the terminals (not shown), one of the heat exchange boards becomes low in temperature and the other heat exchange board becomes high in temperature. . The electrodes 31 and 32 and the thermoelectric element 2 are joined by being pressed with a predetermined pressing force by the spring 7 via the heat exchange substrates 11 and 12, so that the heat exchange substrates 11 and 12 are joined.
The thermoelectric element 2 formed in a spherical shape also rotates due to the thermal contraction and thermal expansion of, so that no stress is applied.

According to the above-described thermoelectric conversion device, the thermoelectric element 2 is formed in a spherical shape, and hence has no directionality, so that the thermoelectric element 2 can be easily disposed on the heat exchange substrate 12,
Thus, it is easy to assemble. Further, since the thermoelectric element 2 can be held at a predetermined position, assembly becomes easier. Further, at least one of the thermoelectric elements 2 has a long groove 31a.
, The dimensional change due to large thermal contraction and thermal expansion can be absorbed by the dimensional margin of the long groove 31a,
Thus, a long life is achieved. Further, since the thermoelectric elements disposed on the outer edge side are held by long grooves longer than the thermoelectric elements on the center side, the grooves are adjusted in accordance with the size of dimensional displacement due to thermal contraction and thermal expansion of the heat exchange substrates 11 and 12. By setting the length, the electrodes can be formed and more thermoelectric elements 2 can be arranged.

[Second Embodiment] FIG. 5 is an explanatory diagram showing the installation state of a thermoelectric device of a Peltier device, which is a thermoelectric converter of a second embodiment.

This Peltier element is different from the first embodiment only in the shape of the electrode 31, and the other components are the same as those in the first embodiment. Omitted.

The electrode 31 of the heat exchange substrate 11
In order to maintain a stable press-contact state even when a dimensional change in the twist direction occurs due to thermal shrinkage and thermal expansion due to internal stress strain or the like at the time of molding of No. 12, the long groove 31a of the first embodiment is used. The thermoelectric element 2 is formed so as to have a width dimension at which the thermoelectric element 2 comes into contact at one point of the bottom surface as viewed in the direction of the lateral side of the long groove 31a. Specifically, the electrode 31 has a long groove 31a having a width W larger than the width W1 shown in FIG.
2 are formed. Therefore, the electrode 31 and the thermoelectric element 2 are apparently in contact at one point and are pressed and joined. As a result, the joint between the electrode 31 and the thermoelectric element 2
In the heat contraction and thermal expansion of the heat exchange substrates 11 and 12,
Since the thermoelectric element 2 formed in a spherical shape rotates with a margin in the width direction of the long groove 31a, the dimensional change in the twist direction can be absorbed, and even if there is a dimensional change in the twist direction, excessive stress is applied to the thermoelectric element 2. Will not be added.

According to the thermoelectric conversion device described above, since the thermoelectric element 2 is held at one point of the long groove 31a, the dimensional change in the twist direction of the heat exchange substrates 11, 12 due to thermal contraction and thermal expansion can be absorbed. Thus, a longer life is achieved.

In the thermoelectric converter described above, it is assumed that the electrode has a concave shape and one of the electrodes has a long groove, and the outer edge of the heat exchange substrate is formed to have a longer length than that of the center. Although the present invention has been described, the present invention is not limited to itself, and it is possible to simply hold a non-concave member in a pressed state, or the concave portion may not be a long groove.

[0025]

According to the first aspect of the present invention, since the thermoelectric element has no directionality, it is easy to dispose the thermoelectric element on the heat exchange board, and therefore, it is easy to assemble.

In addition, the thermoelectric conversion device according to the second aspect has the effect of the first aspect, and the thermoelectric element can be held at a predetermined position, so that the assembly becomes easier.

According to the third aspect of the present invention, in addition to the effects of the second aspect, at least one of the thermoelectric elements is held in the recess of the long groove. Changes can be absorbed, and a long life is achieved.

In the thermoelectric converter according to the fourth aspect, in addition to the effect of the third aspect, the thermoelectric element disposed on the outer edge side is held by a long groove longer than the thermoelectric element on the center side. By setting the length of the groove in accordance with the size of the dimensional displacement due to the thermal contraction and thermal expansion of the heat exchange substrate, the electrodes can be formed and more thermoelectric elements can be arranged.

In the thermoelectric conversion device according to the fifth aspect, in addition to the effect of the third or fourth aspect, the thermoelectric element is held at one point of the long groove, so that the heat exchange substrate in the heat shrinkage and the thermal expansion is removed. The dimensional change in the twist direction can be absorbed, and
Longer life is achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an installation state of a thermoelectric element which is a main part of a Peltier element which is a thermoelectric conversion device according to a first embodiment of the present invention.

FIGS. 2A and 2B are perspective views showing the same electrode, wherein FIG. 2A shows a lower electrode and FIG. 2B shows an upper electrode.

FIGS. 3A and 3B are plan views showing the electrode patterns of the above, wherein FIG. 3A shows a lower surface side heat exchange substrate and FIG. 3B shows an upper surface side heat exchange substrate.

FIG. 4 is a schematic configuration diagram of the above.

FIG. 5 is an explanatory diagram showing an installation state of a thermoelectric device of a Peltier device, which is a thermoelectric conversion device according to a second embodiment.

FIG. 6 is a configuration diagram of a conventional example.

FIG. 7 is an explanatory view showing an installation state of a conventional thermoelectric element.

FIG. 8 is an explanatory diagram showing an installation state of another conventional thermoelectric element.

[Explanation of symbols]

 11, 12 heat exchange substrate 2 thermoelectric element 31, 32 electrode 31a long groove

Claims (5)

[Claims] 1. A thermoelectric element formed of a pair of substantially flat heat-exchange substrates facing each other, a pair of P-type and N-type semiconductors arranged in pressure contact with each other between the heat-exchange substrates, and A thermoelectric conversion device comprising an electrode provided on a heat exchange substrate and connecting and joining P-type and N-type thermoelectric elements in series, wherein the thermoelectric element is formed in a spherical shape. Thermoelectric conversion device. 2. The thermoelectric conversion device according to claim 1, wherein a contact portion of the electrode with the thermoelectric element is formed in a concave shape. 3. The thermoelectric conversion device according to claim 2, wherein at least one of the heat exchange substrates is formed as a long groove extending from a center toward an outer edge of the contact portion. 4. The thermoelectric conversion device according to claim 3, wherein the long groove is formed so that the one on the outer edge side of the heat exchange substrate is longer than the one on the center side. 5. The long groove according to claim 3 or 4, wherein the long groove is formed to have a width dimension capable of contacting the thermoelectric element at one point of a bottom surface as viewed from the side in the lateral direction of the long groove. Thermoelectric converter.