JPH09148634A - Thermoelectric conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric conversion device which is elongated in service life by restraining a thermoelectric element from being disconnected due to thermal expansion. SOLUTION: A thermoelectric conversion device is equipped with opposed nearly plate-like heat exchangers 1 and 2, thermoelectric elements 4 each equipped with a pair of a P-type semiconductor 5 and an N-type semiconductor 6 and arranged in an array between the heat exchangers 1 and 2, and electrodes 10 which are linked to the thermoelectric elements 4 so as to make the P-type semiconductors 5 and the N-type semiconductors 6 alternately connected in series and mounted on the heat exchangers 1 and 2. Furthermore, cracking preventing holes 8 which restrain cracks from opening in the element 4 are provided to the thermoelectric element 4 vertical to a direction in which the elements 4 are linked together with the electrodes 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric converter for converting electricity into heat or heat into electricity.

[0002]

2. Description of the Related Art Conventionally, there is a thermoelectric converter that converts electricity into heat using the Peltier effect and heat into electricity using the Seebeck effect. As shown in FIG. 7, this thermoelectric conversion device is provided between a heat exchanger 1 and a heat exchanger 2 on the high temperature side and a heat exchanger 2 on the low temperature side which are arranged in a substantially flat plate shape so as to face each other. P-type semiconductors arranged side by side in a grid pattern 5
And thermoelectric element 4 having N-type semiconductor 6 and P of thermoelectric element 4
Type electrodes 5 and N type semiconductors 6 are connected so that they are alternately arranged in series and are attached to the heat exchangers 1 and 2.
And

The P-type semiconductor 5 and the N-type semiconductor 6 of the thermoelectric element 4 are substantially rectangular parallelepiped made of heavy metal formed by sintering or the like, and the P-type semiconductor 5 and the N-type semiconductor 6 and the electrode 10 are solder
It is joined at 7 mag. The electrode 7 is fixed to the high temperature side heat exchanger 1 or the low temperature side heat exchanger 2 made of aluminum with an adhesive or the like. Further, although not shown, the high temperature side heat exchanger 1 and the low temperature side heat exchanger 2 position each heat exchanger 1, 2 at a predetermined position by tightening with a screw or the like, and each heat exchanger 1 , 2 sandwich the thermoelectric element 4 and the electrode 10 between them. Then, by passing an electric current through the thermoelectric conversion device, heat is dissipated in the high temperature side heat exchanger 1 and heat is absorbed in the low temperature side heat exchanger 2.

[0004]

In the thermoelectric converter described above, the high-temperature side and low-temperature side heat exchangers are held at predetermined positions so that the thermoelectric element and the electrodes are sandwiched, and the high-temperature side and low-temperature side heat exchanges are performed. The thermal conductivity between the container, the thermoelectric element, and the electrode is improved. However, since each heat exchanger has a large thermal expansion because it is formed of aluminum or the like having good thermal conductivity, the clamping force between the thermoelectric element and the electrode becomes too large when each heat exchanger is positioned, Large thermal stress may be applied to the thermoelectric elements and electrodes. As a result, cracks may occur in the thermoelectric element or the like, leading to disconnection.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thermoelectric conversion device for suppressing the disconnection of a thermoelectric element due to thermal expansion and prolonging its life. is there.

[0006]

In order to solve the above-mentioned problems, the thermoelectric conversion device according to claim 1 is arranged in parallel between heat exchangers of substantially flat plate shape facing each other and between the heat exchangers. A thermoelectric element having at least one pair of P-type semiconductor and N-type semiconductor, and a heat exchanger, wherein the P-type semiconductor and the N-type semiconductor of the thermoelectric element are alternately connected in series so as to be arranged in series. In the thermoelectric conversion device, the thermoelectric element is provided with a hole-shaped crack suppressing portion for suppressing the progress of cracks.

Further, the thermoelectric converter according to claim 2 is
The crack suppressing portion according to claim 1 is arranged so as to extend in a direction orthogonal to the connecting direction in which the thermoelectric elements are connected by the electrodes.

The thermoelectric converter according to claim 3 is
The crack suppressing portion according to claim 2 is formed from adjacent solder by 1
It is arranged at a position separated by about 0 μm.

The thermoelectric converter according to claim 4 is
An elastic material is filled in the crack suppressing portion according to any one of claims 1 to 3.

The thermoelectric converter according to claim 5 is
The crack suppressor according to any one of claims 1 to 4 is provided with a notch-shaped expander extending in the direction of the adjacent electrode.

Further, the thermoelectric conversion device according to claim 6 is configured such that a plurality of crack suppressing portions according to claims 1 to 5 are provided.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. Members having the same basic functions as those described in the related art are designated by the same reference numerals. FIG. 3 is a cross-sectional view of the thermoelectric conversion device, and the thermoelectric conversion device has a high temperature side heat exchanger 1, a low temperature side heat exchanger 2, a thermoelectric element 4, and an electrode 10 as main constituent members.

The high temperature side heat exchanger 1 includes a thermoelectric element 4 which will be described later.
It radiates the heat generated at one end to the outside, and is formed of a material having good heat conduction such as aluminum in a substantially flat plate shape having an outer surface 1a and an inner surface 1b. This outer surface 1a is
Contact with gases or solids that want to transfer heat.

The low temperature side heat exchanger 2 includes a thermoelectric element 4 which will be described later.
It absorbs heat from the outside as the other end of it cools, and like the high temperature side heat exchanger 1, it has an outer surface 2a and an inner surface 2b.
Is formed of a material having good heat conduction such as aluminum in a substantially flat plate shape. The outer surface 2a also comes into contact with a gas, a solid, or the like that wants to absorb heat. The low-temperature side heat exchanger 2 and the high-temperature side heat exchanger 1 have inner surfaces 2b, 1b facing each other substantially parallel to each other, and have a predetermined interval for accommodating and sandwiching a thermoelectric element 4 and an electrode 10 described later. It is fixed with screws and so on.

The thermoelectric element 4 converts electricity into heat and has a plurality of P-type semiconductors 5,5 ... And N-type semiconductors 6,6. The P-type semiconductors 5 and the N-type semiconductors 6 are made of heavy metal and are formed in a substantially rectangular parallelepiped shape. The P-type semiconductors 5 and the N-type semiconductors 6 are arranged side by side in a grid pattern so that the P-type semiconductors 5 and the N-type semiconductors 6 are alternately arranged. The end faces of the semiconductor 5 and the N-type semiconductor 6 are electrodes 10 to be described later.
It is joined to the solder via solder 7. Therefore, the P-type semiconductors 5 and the N-type semiconductors 6 are alternately arranged in series with the electrodes 10 interposed therebetween. Note that this series does not necessarily have to be all in series, and may have a structure having a plurality of series. The P-type semiconductor 5 and the N-type semiconductor 6 are
Where current flows from the P-type semiconductor 5 to the N-type semiconductor 6, one end thereof generates heat, and where current flows from the N-type semiconductor 6 to the P-type semiconductor 5, the other end thereof. Is cooled.

Each of the thermoelectric elements 4 has, for example, four crack suppressing portions 8,8 ... Crack suppression part 8,8…
Is for suppressing the development of cracks 9 generated in each thermoelectric element 4, and is a through hole shape extending in a direction orthogonal to the connecting direction connecting the thermoelectric element 4 with an electrode 10 described later. Is formed. Specifically, this crack suppression part
8 and 8 are located at a position about 10 μm away from the contact surface with the adjacent solder 7, and have a diameter of about 5 μm.
It is formed at the four corners of 4.

The electrode 10 is composed of the P-type semiconductor 5 and N of the thermoelectric element 4.
It is connected to the mold semiconductor 6 and is attached to the heat exchangers 1 and 2, and is composed of first electrodes 11, 11 ... And second electrodes 12, 12. The first electrodes 11,11 ... And the second electrodes 12,1
2 ... is formed of a conductive material such as copper into a substantially flat plate shape,
The first electrodes 11 and 11 are attached to the inner surface 1b of the high temperature side heat exchanger 1, and the second electrodes 12 and 12 are attached to the inner surface 2b of the low temperature side heat exchanger 2 via an adhesive or grease. To be done.

In this device, one of the ends of the P-type semiconductor 5 and the N-type semiconductor 6 generates heat and the other end thereof is cooled by passing a current. Therefore, the heat generated at one end is transmitted to the high temperature side heat exchanger 1 through the first electrode 11 and is radiated from the outer surface 1a, and the low temperature side heat exchanger 2
Heat is absorbed from the outer surface 2a of the
Heat is transferred to the other end of the type semiconductor 5 and the N-type semiconductor 6.

Further, the high temperature side heat exchanger 1 expands due to the high temperature, and even if the expansion causes a thermal stress to the thermoelectric element 4 and a crack 9 occurs in a long-term use, the crack suppressing portion. The cracks 9 stay at 8, 8 ... And their progress is suppressed, so that the thermoelectric element 4 does not break, and the disconnection of the circuit is suppressed.

Next, a second embodiment of the present invention will be described with reference to FIG. This is obtained by filling the crack suppressing portion 8 of the first embodiment with an elastic material 8a.

The elastic material 8a has elasticity such as rubber, and by deforming, the stress at the tip of the crack 9 can be reduced and the development of the crack 9 can be suppressed.

Next, a third embodiment of the present invention will be described with reference to FIG. In this case, the shape of the crack suppressing portion 8 is slightly different from that of the first embodiment.

Reference numeral 8b denotes a propagator, which determines the propagating direction of the crack 9, and is formed in a notch shape extending in the direction of the electrode where the adjacent electrode 10 is located.

In this case, the crack 9 is a crack suppressing portion.
Even if it passes through 8, it progresses in the direction of the electrode by the spreader 8b, so the crack 9 stays in the part of the solder 7 where the thermoelectric element 4 and the electrode 10 are joined, so that further progress is suppressed and the fracture of the thermoelectric element 4 is suppressed. Suppressed.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In this case, a plurality of crack suppressing portions 8 are provided at one end of the thermoelectric element 4 with different diameters. In this case, since the cracks 9 are easily retained in the crack suppressing portion 8, the breakage of the thermoelectric element 4 is further suppressed.

Although the thermoelectric converter of the present invention has been described as one that converts electricity into heat by utilizing the Peltier effect, it can also be used to convert heat into electricity by utilizing the Seebeck effect. . Further, the position and the size of the crack suppressing portion are not limited to those in the present embodiment, and can be appropriately designed. Further, the crack suppressing portion is not limited to the one that penetrates the thermoelectric element and extends in the direction orthogonal to the connecting direction, and it is also possible to extend the hole that does not penetrate or a direction that does not orthogonally intersect the connecting direction. Is.

[0027]

In the thermoelectric conversion device according to the first aspect of the present invention, even if a crack generated in the thermoelectric element progresses to the crack suppressing portion, it stays in the crack suppressing portion. Therefore, the life is extended and the reliability is improved.

Further, the thermoelectric conversion device according to claim 2 is
In addition to the effect of the first aspect, since the crack suppressing portion is extended in the direction orthogonal to the connecting direction, it is easy to guide the crack and the reliability is further improved.

The thermoelectric converter according to claim 3 is
In addition to the effect of the second aspect, since the crack suppressing portion is arranged at the position where the crack easily propagates, the reliability is further improved.

The thermoelectric converter according to claim 4 is
In addition to the effect of any one of claims 1 to 3, since the stress at the crack tip portion due to thermal expansion can be relaxed by the elastic deformation of the elastic material, it is easy to suppress the development of the crack.

The thermoelectric converter according to claim 5 is
In addition to the effect according to any one of claims 1 to 4, even if the crack passes through the crack suppressing portion, the crack propagates toward the electrode by the spreader, so that the crack stays at the solder portion where the thermoelectric element and the electrode are joined. , Further progress is suppressed, and as a result, it is difficult for the wire to break.

Further, in the thermoelectric conversion device according to the sixth aspect, in addition to the effect according to any one of the first to fifth aspects, the cracks are more surely stagnated by the plurality of crack suppressing portions, so that the reliability is further improved. To do.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a thermoelectric conversion device showing a first embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a thermoelectric element of the thermoelectric conversion device.

FIG. 3 is a sectional view of the thermoelectric conversion device.

FIG. 4 is an enlarged sectional view of a thermoelectric element showing a second embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a thermoelectric element showing a third embodiment of the present invention.

FIG. 6 is an enlarged sectional view of a thermoelectric element showing a fourth embodiment of the present invention.

FIG. 7 is a cross-sectional view of a thermoelectric conversion device showing a conventional embodiment of the present invention.

[Explanation of symbols]

 1 High temperature side heat exchanger 2 Low temperature side heat exchanger 4 Thermoelectric element 5 P-type semiconductor 6 N-type semiconductor 7 Solder 8 Crack suppressor 8a Elastic material 8b Expander 9 Crack 10 Electrode 11 First electrode 12 Second electrode

Claims (6)

[Claims] 1. A substantially flat plate-shaped heat exchanger facing each other, a thermoelectric element having at least one pair of P-type semiconductor and N-type semiconductor arranged in parallel between the heat exchangers, and P of the thermoelectric element. In the thermoelectric conversion device, the thermoelectric element is provided with electrodes that are connected to each other via solder so that the N-type semiconductors and the N-type semiconductors are alternately arranged in series and are attached to the heat exchanger. And a hole-like crack suppressing portion for suppressing the progress of the thermoelectric conversion device. 2. The thermoelectric conversion device according to claim 1, wherein the crack suppressing portion is arranged so as to extend in a direction orthogonal to a connecting direction for connecting the thermoelectric elements with electrodes. 3. The thermoelectric conversion device according to claim 2, wherein the crack suppressing portion is arranged at a position separated by about 10 μm from the adjacent solder. 4. The thermoelectric conversion device according to claim 1, wherein the crack suppressing portion is filled with an elastic material. 5. The thermoelectric conversion device according to claim 1, wherein the crack suppressing portion is provided with a notch-shaped expander extending in the direction of the adjacent electrode. 6. The thermoelectric conversion device according to claim 1, wherein a plurality of the crack suppressing portions are provided.