JPH0918059A - Thermoelectric converter - Google Patents

Abstract

(57) [Summary] [Object] To provide a thermoelectric conversion device having a sufficiently high thermoelectric conversion capability and excellent in performance. The liquid heat transfer medium 2 is arranged so that the liquid heat transfer medium 21 collides with the surface of the base 4 supporting the N-type semiconductor layer and the P-type semiconductor layer opposite to the semiconductor layer supporting surface.
It is characterized in that supply means 6 and 7 for supplying 1 are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric conversion device such as an electronic cooling device or a thermoelectric generator, and more particularly to a thermoelectric conversion device using a liquid such as water or antifreeze as its heat transfer medium.

[0002]

21 and 22 are views for explaining a conventional thermoelectric conversion device. FIG. 21 is a plan view showing a part of the thermoelectric conversion device in section, and FIG. 22 is a view taken on line XX of FIG. FIG.

As shown in FIG. 21, a heat absorbing side insulating substrate 100 and a heat radiating side insulating substrate 1 made of ceramic such as alumina.
01, a thermoelectric conversion element group 102 composed of electrodes and P-type and N-type semiconductor layers is interposed.

[0004] On the outer surface of the heat absorbing side insulating substrate 100,
A heat absorbing member 103 provided with heat absorbing fins or the like is attached. On the outer surface of the heat radiation side insulating substrate 101,
The flow path forming member 104 opened toward the substrate 101 side
Is attached. Inside the flow path forming member 104, water 105, which is a heat transfer medium, is placed on the heat radiation side insulating substrate 10.
A flow path forming member 104 composed of a partition plate for flowing in a meandering manner from one end to the other end along the outer surface of
Is provided. A supply pipe 107 is mounted near one end of the flow path forming member 104, and a discharge pipe 108 is mounted near the other end.

A predetermined current is supplied to the thermoelectric conversion element group 102, and water 105 is caused to flow from the supply pipe 107 into the flow path forming member 104. The heat absorbed by the heat absorbing member 103 is transmitted to the heat radiating side insulating substrate 101 via the heat absorbing side insulating substrate 100 and the thermoelectric conversion element group 102, and the water 105 meanders along the outer surface of the heat radiating side insulating substrate 101. The heat of the substrate 101 is absorbed by flowing the water, and the water 105 is discharged from the discharge pipe 108 to the outside of the system, whereby the heat absorbing member 103 side is cooled.

As a related technique, for example, Japanese Patent Application Laid-Open No.
04361, JP-A-5-322366, JP-A-5-343750 and the like.

[0007]

However, this conventional thermoelectric converter has a problem that a sufficiently high thermoelectric conversion capability cannot be obtained yet.

The present inventors have made intensive studies on this problem and as a result, have found out that there is a problem in the flow of the heat transfer medium, particularly in the thermoelectric converter. That is, in the conventional thermoelectric conversion device, since the heat transfer medium simply flows in a meandering shape along the surface of the insulating substrate, the thermal conductance between the heat transfer medium and the insulating substrate is low, and therefore, sufficient thermoelectric conversion I found that I could not get the ability.

An object of the present invention is to solve the above disadvantages of the prior art and to provide a thermoelectric conversion device having a sufficiently high thermoelectric conversion capability and excellent performance.

[0010]

In order to achieve the above object, the present invention provides a semiconductor layer supporting surface of a substrate which supports an N-type semiconductor layer and a P-type semiconductor layer, for example, a metal plate having an electrically insulating thin film. The liquid heat transfer medium such as water or antifreeze is collided with the surface opposite to the liquid heat transfer medium, for example, a supply member such as a dispersion member is provided. Is.

[0011]

In the conventional thermoelectric conversion device, the liquid heat transfer medium is caused to flow along the surface of the base (substrate) to transfer heat between the base and the liquid heat transfer medium. On the other hand, according to the present invention, the liquid heat transfer medium is made to collide with the surface of the substrate, and the state in which the liquid heat transfer medium is in contact with the substrate is surely a turbulent flow. Therefore, the heat exchange capacity of the entire device is enhanced.

[0012]

EXAMPLES Before describing specific examples of the present invention, general knowledge of the present inventor regarding performance improvement of a thermoelectric conversion device using this heat transfer medium will be described.

Measures for improving the performance of a thermoelectric converter using a heat transfer medium include: [I] a reduction in the thermal resistance of the substrate; and [II].
Improvement of the flow of the heat transfer medium, and the like.

[0014] As an effective means for lowering the thermal resistance of the former substrate, a metal substrate having an insulating thin film such as an aluminum substrate formed with an alumite layer having a low thermal resistance is used instead of the conventional ceramic insulating substrate made of alumina or the like. There is a way to do that. Specifically, there is a method of forming an alumite film on the surface of an aluminum substrate by an anodizing method, or a method of spraying aluminum on the surface of an aluminum substrate and thereafter transforming it into an alumite layer.

However, if the heat-radiating-side substrate and the heat-absorbing-side substrate have similar thicknesses, the metal substrate has a much larger expansion and contraction ratio due to heat than the ceramic substrate. In the side electrode-P, N semiconductor layer-heat-absorbing electrode-heat-absorbing substrate system, the shear stress accompanying the thermal stress increases, causing a problem of reliability.

[0016] In order to solve this, one substrate (for example, the heat absorbing side substrate) is made thick as usual,
The other substrate (for example, the heat radiation side substrate) is made sufficiently thinner than the heat absorption side substrate, that is, by providing a difference in thickness between the heat radiation side substrate and the heat absorption side substrate, the heat radiation side substrate is The generation of thermal stress in the system can be reduced by following the thermal deformation.

However, as the substrate becomes thinner, P, N
When the occupation density of the semiconductor layer (the ratio of the sum of the cross-sectional areas of the P and N semiconductor layers to the total area of the substrate) is small, the thermal resistance may be increased.

.. Therefore, when the occupation density of the P and N semiconductor layers is small, the area of the electrode is relatively widened while the substrate remains thin, and the effective heat transfer area is maintained, thereby suppressing an increase in thermal resistance.

On the other hand, with regard to the flow of the heat transfer medium, when viewed as a whole system of the thermoelectric conversion device,
For example, there is a need to improve so that a high heat exchange capacity can be obtained with less input power required for moving the medium.

[0020] As a means for obtaining high heat exchange capacity, it is advisable to improve the structure to increase the effective heat transfer area.

[0021] Further, as another means of obtaining a high heat exchange capacity, it is conceivable to increase the heat transfer coefficient. For that purpose, when the input power for moving the medium is constant, the flow pressure loss in the flow path of the heat transfer medium is reduced. It is a good idea to lower the flow rate of the heat transfer medium, that is, increase the heat transfer amount. The present invention mainly relates to the technology in this section.

Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view of a thermoelectric conversion device used as an electronic cooling device, FIG. 2 is a sectional view of the thermoelectric conversion device, and FIG. 3 is FIG. 2A.
-A sectional view on the line, FIGS. 4 and 5 are plan views and sectional views of the cover member, FIG. 6 is a plan view of the dispersion member, and FIG. 7 is a sectional view on the line BB-B.

As shown in FIGS. 1 and 2, the thermoelectric conversion device comprises a heat absorbing member 1 in contact with the side to be cooled and a heat absorbing side substrate 2.
, A thermoelectric conversion element group 3 (see FIG. 2), and a heat radiation side substrate 4
(See FIG. 2), a support frame 5, a cover member 6, and a dispersion member 7 (see FIG. 2).

Although not shown, the heat absorbing member 1 has a large number of heat absorbing fins therein, and a fan can be provided if necessary.

The heat absorbing side substrate 2 and the heat radiating side substrate 4 are both made of a metal plate such as aluminum, and an electrically insulating thin film such as alumite is formed on the surface in contact with the thermoelectric conversion element group 3. In the case where an alumite insulating film is formed by an anodizing method, the sealing property with the thermoelectric conversion element group 3 is better if the insulating thin film is not sealed. The electrical insulating film can also be formed by thermal spraying or the like.

As shown in FIG. 2, the heat absorption side substrate 2 and the heat radiation side substrate 4 have different plate thicknesses (in the case of this embodiment, the heat absorption side substrate 2 has a plate thickness of 5 mm, and the heat radiation side substrate 4 has a plate thickness of: 0.2 mm
Heat-absorption side substrate 2 >> Heat-radiation side substrate 4), the thinner substrate is able to better follow the thermal contraction (thermal expansion) of the thicker substrate, whereby the heat-absorption side substrate 2-thermoelectric conversion element The occurrence of thermal stress between the group 3 and the heat dissipation side substrate 4 is reduced.

The thermoelectric conversion element group 3 includes a heat-absorbing electrode, a heat-dissipating electrode, and a large number of P-type semiconductor layers and N-type semiconductor layers disposed between both electrodes, which are not shown but are well known. The P-type semiconductor layer and the N-type semiconductor layer are structurally and thermally arranged in parallel, but are electrically connected in series via the electrodes.

The support frame 5 is made of synthetic resin, supports the heat radiation side substrate 4, and has a base end attached to the heat absorption side substrate 2.

The cover member 6 is made of synthetic resin, and has a water supply pipe portion 8 and a drain pipe portion 9 extending vertically in the upper part.
Are integrally provided, and the water supply pipe portion 8 is arranged substantially at the center of the cover member 6, and the drainage pipe portion 9 is arranged near the peripheral edge of the cover member 6. A peripheral wall 10 that opens downward is provided in the lower half of the cover member 6, a space 11 is formed inside the peripheral wall 10, and the dispersion member 7 is installed therein.

The dispersion member 7 is also formed of a synthetic resin.
As shown in FIG. 6, a circular concave portion 12 is formed substantially at the center of the upper surface, and a wall portion 13 is provided so as to surround the concave portion. A collar portion 14 is provided at the outer peripheral portion of the dispersion member 7 and at a substantially intermediate position in the thickness direction thereof, and discharge holes 15 having a relatively large diameter are formed at four corners of the collar portion 14.

In addition, one supply hole 16a is formed in the central portion of the recess 12 and eight supply holes 16a are formed in the outer peripheral portion thereof and vertically penetrate at equal intervals.
16i is provided, and the supply hole 16a in the central portion is slightly larger in diameter than the other supply holes 16b to 16i.

As shown in FIG. 2, the dispersing member 7 is inserted into the space 11 of the cover member 6 and the wall 13 of the dispersing member 7 is
Of the dispersing member 7 on the inner surface of the cover member 6.
The dispersion member 7 is positioned and fixed in the cover member 6 by bonding the outer peripheral surface of the cover member 4 to the inner surface of the peripheral wall 10 of the cover member 6. A flat first space 17 is formed between the inner surface of the cover member 6 and the upper surface of the dispersion member 7, and a rectangular frame-shaped frame surrounded by the peripheral wall 10, the wall portion 13, and the flange portion 14 and communicating with the drain pipe 9. Drainage channels 18 are respectively formed.

By bonding the lower surface of the peripheral wall 10 of the cover member 6 to the heat radiation side substrate 4, a flat shape having a narrow gap of about 1 to 3 mm between the lower surface of the dispersion member 7 and the upper surface of the heat radiation side substrate 4. Second space 19 and four corner drainage holes 1 around it
A catchment channel 20 communicating with 5 is formed.

As shown in FIG. 2, water 21 as a heat transfer medium
When the water is supplied from the central water supply pipe portion 8, the water is spread all at once in the first space 17, and is jetted vigorously from the nine supply holes 16a to 16i toward the plane of the heat radiation side substrate 4. The water 21 that has collided with the heat dissipation side substrate 4 and has deprived the heat of the heat dissipation side substrate 4 diffuses in the second space 19 having a narrow gap, is collected by the water collecting passage 20 around the second space 19, and is drained from the drain hole 15 near the drain hole 15. Through drainage pipe section 9
From the system. The discharged water 21 is cooled by a radiator (not shown) or natural cooling, and is reused through a circulation system.

FIG. 8 is a view showing a second embodiment. In this embodiment, a discharge pipe portion 9 is provided on the peripheral wall 10 of the cover member 6, and water 21 collected by a water collecting channel 20 (see FIG. 2) is discharged. Drained directly from part 9.

FIG. 9 is a view showing a third embodiment. In this embodiment, a large number of pipes 22 are integrally provided on the lower surface of the dispersion member 7.
The hole of the pipe body 22 serves as the supply hole 16, and the gap between the pipe bodies 22 serves as the water collecting passage 20.

FIG. 10 is a diagram showing a fourth embodiment. In this example, a guide portion 23 for guiding the flow of the water 21 is provided on the lower surface of the dispersion member 7 near the supply hole 16, and the guide portion 2 is provided.
The shape of 3 may be curved or straight, and the dispersion member 7
Extends toward the surrounding water collecting channel 20 side from the central portion side.

FIG. 11 is a view showing a fifth embodiment. In this example, a plurality of slit-shaped supply holes 16 extending from the central portion side of the dispersion member 7 toward the surrounding water collecting channel 20 side are provided. .

FIG. 12 is a diagram showing a sixth embodiment. In this example, four slit-shaped supply holes 16 extend substantially parallel to the water collecting passage 20.

FIG. 13 is a diagram showing a seventh embodiment. In this example, a plurality of protrusions 24 are provided on the lower surface of the dispersion member 7, and one or a plurality of supply holes 16 are bored in the protrusions 24. Thus, the water collecting passage 20 is formed between the protruding portions 24.

FIG. 14 is a diagram showing an eighth embodiment. In this example, the plurality of supply holes 16 as described above are not formed, and an upper member having a water supply pipe portion 8 that vertically hangs in the central portion. The dispersion member 7 is configured by a combination of 25 and the lower member 26 having the drain pipe portion 9.

A flat second space 19 having a narrow gap is formed between the upper member 25 and the heat radiating substrate 4.
5 and the inner circumference of the lower member 26
Are formed.

FIG. 15 is a view showing a ninth embodiment. In this embodiment, a water supply pipe section 8 extends from the side surface of the dispersion member 7 toward the lower surface of the central portion. Is discharged from the upper surface of the central part.

FIG. 16 is a view showing a tenth embodiment. In each of the above-mentioned embodiments, the supply hole 16 or the water supply pipe portion 8 is arranged substantially perpendicular to the surface of the heat dissipation board 4, but in this embodiment, The supply hole 16 or the water supply pipe portion 8 is provided so as to be inclined with respect to the surface of the heat dissipation substrate 4, and the inclination makes the flow direction of the water 21 constant, and the water 21 flows smoothly to contribute to the reduction of pressure loss.

FIGS. 17 and 18 show the eleventh embodiment. In this embodiment, the mounting area 27 of the thermoelectric conversion element group 3 with respect to the heat radiating substrate 4 is divided into four sides with reference to the center of the heat radiating substrate 4. A bent portion 28 having a mountain-shaped cross section is formed between the attachment regions 27. The bent portion 28 may be continuous in a rib shape as shown in the figure or may be intermittent. The bent portion 28 may project toward the thermoelectric conversion element group 3 side, or may 3 may protrude toward the opposite side. In the present embodiment, the bent portion 28 is formed in a cross shape.
Can be formed in large numbers.

FIG. 19 is a view showing a twelfth embodiment. In this embodiment, for example, a wire mesh, an expanded metal, a punching metal or the like is provided on the surface of the heat radiation side substrate 4 opposite to the surface on which the thermoelectric conversion element group 3 is mounted. A thin porous heat conductor 29 having a large aperture ratio is attached by spot welding or the like.

As in the eleventh embodiment and the twelfth embodiment, the bent portion 28 is formed on the heat-radiating substrate 4 or the porous heat conductor 29 is attached to the heat-radiating substrate 4 so that the vicinity of the surface of the heat-radiating substrate 4 can be reduced. The flow of the water 21 becomes turbulent, and the heat absorption efficiency of the water 21 with respect to the heat radiation side substrate 4 increases.

The bent portion 28 and the porous heat conductor 29 do not extend to the sealing portion around the heat radiating substrate 4.

Although water is used as the heat transfer medium in the above embodiments, the present invention is not limited to this, and other liquids such as antifreeze liquid may be used in addition to water.

Although a metal substrate is used in the above embodiment, the present invention is not limited to this, and a ceramic such as alumina or aluminum nitride may be used.

In the above embodiment, the case where the heat transfer medium is brought into contact with the heat radiation side substrate has been described, but it is also possible to bring the heat transfer medium into contact with the heat absorption side substrate based on the above-mentioned embodiment.

Although the case of the electronic cooling device has been described in the above embodiment, the present invention is also applicable to a thermoelectric generator.

[0053]

FIG. 20 shows the thermal conductance characteristics. The horizontal axis of FIG. 20 represents the flow rate of water (pressure loss ΔP × flow velocity Gw) flowing in the thermoelectric conversion device with a fixed amount of power supplied to the water supply pump, and the vertical axis represents heat. Each conductance is taken. The curve marked with Δ in the figure is the thermoelectric conversion device of the embodiment of the present invention shown in FIG.
The curve marked with ◯ is the thermoelectric converter of the embodiment of the present invention shown in FIG. 14, the curve marked with ◆ is the thermoelectric converter of the embodiment of the present invention shown in FIG. 15, and the curves marked with ◯ are the conventional ones shown in FIGS. It is a characteristic of the thermoelectric conversion device.

In the conventional thermoelectric conversion device, as shown in FIG. 22, the flow path of the water 105 from the supply pipe 107 to the discharge pipe 108 is narrow, and moreover, it meanders a plurality of times and has a long distance.
The pressure loss of the water 105 is large. Further, since the water 105 flows in a laminar flow state in parallel with the surface of the heat radiation side insulating substrate 101, the heat transfer from the heat radiation side insulating substrate 101 to the water 105 is not so good. As shown, the thermal conductance is small.

On the other hand, in each of the embodiments of the present invention,
Water 21 is supplied so as to collide with the heat transfer surface of the heat radiation side substrate 4 to remove heat from the heat radiation side substrate 4, and the flow path length of the water 21 is larger than that of the conventional one. Since it is short and has a small pressure loss, it has a large thermal conductance and excellent characteristics.

As described above, in the present invention, the liquid heat transfer medium is made to collide with the surface of the substrate, and since the state in which the liquid heat transfer medium is in contact with the substrate is surely a turbulent flow, heat transfer is performed. Is efficiently performed, and as a result, the heat exchange capacity of the entire apparatus is enhanced and the performance is excellent.

When a metal substrate having an electrically insulating thin film is used as the substrate as in the above-mentioned embodiment, the heat resistance is extremely smaller than that of the substrate made of alumina or the like, so that the heat exchange capacity can be further enhanced.

Further, as in the above-mentioned embodiment, a space facing substantially the entire surface of the base is formed on the side of the supply means facing the base, and the liquid heat transfer medium that collides with the surface of the base is diffused in this space. By doing so, the liquid heat transfer medium diffuses quickly over a wide area in the vicinity of the surface of the substrate, so that the pressure loss is reduced and the heat exchange capacity is further enhanced.

Furthermore, as in the above-described embodiment, the flat first space from the upstream side to the downstream side, the plurality of supply holes, and the substantially entire surface of the substrate are provided on the heat transfer medium collision path of the supply means. The liquid heat transfer medium that has flowed into the first space is jetted toward the surface of the base body in a dispersed state from the supply holes and collides with the base surface. If the liquid heat transfer medium is configured to be diffused in the second space, the distance of the heat transfer medium to the substrate can be made shorter than that of the conventional one, and the pressure loss can be suppressed. It has advantages such as increased ability.

[Brief description of the drawings]

FIG. 1 is a perspective view of a thermoelectric converter according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the thermoelectric converter.

FIG. 3 is a sectional view taken along the line AA of FIG. 2;

FIG. 4 is a plan view of a cover member used for the thermoelectric conversion device.

FIG. 5 is a sectional view of the cover member.

FIG. 6 is a plan view of a dispersion member used in the thermoelectric conversion device.

FIG. 7 is a cross-sectional view taken along the line BB of FIG. 6;

FIG. 8 is a sectional view of a cover member according to a second embodiment of the present invention.

FIG. 9 is a bottom view in which a part of a thermoelectric conversion device according to a third embodiment of the present invention is shown in section.

FIG. 10 is a bottom view in which a part of a thermoelectric converter according to a fourth embodiment of the present invention is shown in cross section.

FIG. 11 is a bottom view in which a part of a thermoelectric converter according to a fifth embodiment of the present invention is sectioned.

FIG. 12 is a bottom view of a part of a thermoelectric conversion device according to a sixth embodiment of the present invention in section.

FIG. 13 is a bottom view showing a cross section of a part of a thermoelectric conversion device according to a seventh embodiment of the present invention.

FIG. 14 is a sectional view of a thermoelectric converter according to an eighth embodiment of the present invention.

FIG. 15 is a sectional view of a thermoelectric converter according to a ninth embodiment of the present invention.

FIG. 16 is a partially enlarged sectional view of a supply hole (water supply pipe portion) of the thermoelectric conversion device according to the tenth embodiment of the present invention.

FIG. 17 is a plan view of a heat radiation side substrate used in a thermoelectric conversion device according to an eleventh embodiment of the present invention.

FIG. 18 is a partially enlarged cross-sectional view of the heat dissipation side substrate.

FIG. 19 is a sectional view of a heat radiation side substrate used in a thermoelectric converter according to a twelfth embodiment of the present invention.

FIG. 20 is a thermal conductance characteristic diagram of each thermoelectric conversion device.

FIG. 21 is a vertical cross-sectional view of a conventional thermoelectric conversion device.

FIG. 22 is a sectional view taken along line XX-X in FIG.

[Explanation of symbols]

 1 Heat Absorption Member 2 Heat Absorption Side Substrate 3 Thermoelectric Conversion Element Group 4 Radiation Side Substrate 5 Support Frame 6 Cover Member 7 Dispersion Member 8 Water Supply Pipe Section 9 Drainage Pipe Section 10 Circumferential Wall 11 Space 12 Recessed Section 13 Wall Section 14 Collar Section 15 Discharge Hole 16 Supply hole 17 First space 18 Drainage channel 19 Second space 20 Water collection channel 21 Water 22 Tubular body 23 Guide portion 24 Projection portion 25 Upper member 26 Lower member 27 Mounting area 28 Bent portion 29 Porous body

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuya Sato 3-36-83 Kashiwagi-cho, Noboribetsu-shi, Hokkaido

Claims (4)

[Claims] 1. A supply for supplying the liquid heat transfer medium so that the liquid heat transfer medium collides with a surface of a substrate supporting the N-type semiconductor layer and the P-type semiconductor layer opposite to the semiconductor layer supporting surface. A thermoelectric conversion device comprising means. 2. The thermoelectric conversion device according to claim 1, wherein the base is a metal base having an electrically insulating thin film. 3. The substrate according to claim 1, wherein a space is formed on a side of the supply means facing the substrate, and the space faces substantially the entire surface of the substrate, and the liquid heat transfer medium colliding with the surface of the substrate is formed in this space. A thermoelectric conversion device characterized by being diffused. 4. The first space having a flat shape from the upstream side to the downstream side, a plurality of supply holes, and substantially the entire surface of the base on the heat transfer medium collision path of the supply means. The liquid heat transfer medium flowing into the first space is jetted toward the surface of the base body in a dispersed state from the supply holes and collides with the base body surface. The thermoelectric conversion device, wherein the liquid heat transfer medium is diffused in the second space.