KR19980064197A - Thermoelectric element and thermoelectric cooling device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric element using a thermoelectric semiconductor element and a cooling device thereof. Specifically, the present invention provides a technique for preventing the deterioration of the cooling efficiency and at the same time extending the life of the thermoelectric element. It is about.

In the present invention, since both the upper and lower metal electrodes of the thermoelectric semiconductor element are not fixed to the rigid substrate, the thermal stress applied to the thermoelectric semiconductor element is alleviated. As a result, the life of the thermoelectric element can be extended. It is possible.

In addition, by directly cooling the thermoelectric semiconductor elements, it is possible to minimize the decrease in the cooling efficiency and effectively bring out the performance of the thermoelectric semiconductor elements.

Description

Thermoelectric element and thermoelectric cooler

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric element using a thermoelectric semiconductor element and a cooling device thereof. Specifically, the present invention relates to preventing a decrease in cooling efficiency and extending the life of a thermoelectric element. The present invention relates to a technique for realizing a change.

BACKGROUND OF THE INVENTION A thermoelectric element using a thermoelectric semiconductor element composed of a compound such as bismuth tellurine, iron, silicon or cobalt and antimony is used for a cooling / heating device and the like.

These thermoelectric elements are conveniently used as cooling / heating sources that do not use liquids or gases, have no empty space, have no rotational friction, and do not require maintenance.

The thermoelectric elements are generally arranged in two layers of p- and n-type thermoelectric elements, and the thermoelectric elements are soldered and bonded to a metal electrode, and a π-type series circuit is formed. BACKGROUND ART A metal electrode sandwiched with a ceramic substrate having a metal film is widely used as a thermoelectric module.

7 illustrates a conventional thermoelectric module configuration. In FIG. 7, (a) is a front view and (b) is a perspective view. As shown in FIG. 7, the thermoelectric module alternately arranges the n-type thermoconductor element and the p-type thermoconductor element, and connects the n-type thermoconductor element and the p-type thermoconductor element to the metal electrode. The n-type thermoelectric semiconductor element and the p-type thermoelectric semiconductor element are alternately connected to the metal electrode in an upper side and a lower side, and finally all the elements are connected in series. The connection between the upper and lower metal electrodes and the thermoelectric semiconductor element is made by soldering. Each of the upper and lower metal electrodes is bonded to a ceramic substrate metalized with copper and aluminum to fix the whole. The thermoelectric element thus produced is usually called a thermoelectric module.

When a power source is connected to the electrode of such a thermoelectric module and a current flows from the n-type element to the p-type element, the endothermic effect causes heat absorption at the upper portion of the π-type and dissipation at the lower portion. At this time, if the connection direction of the electrodes is reversed, the direction of heat absorption and heat dissipation is changed. By using this phenomenon, thermoelectric elements are used in cooling / heating devices. Thermoelectric modules have a wide range of applications, from cooling to LSIs, computer CPUs, and lasers, to thermal refrigerators.

When using such a thermoelectric element as a cooling device, it is necessary to cool the heat radiation side. Therefore, conventionally, as a method of cooling a thermoelectric element, as shown in FIG. 8 (a), an air cooling fin is installed on a heat dissipating side of the thermoelectric element 31, and air is blown out of the fan 33 toward the heat dissipated 32. As shown in Fig. 8 (b) and a water cooling system 34, a water cooling jacket 34 is provided in the heat dissipation heat of the thermoelectric element 31, and the water cooling system allows the cooling water to pass through the water cooling jacket 34.

9 is a diagram illustrating a temperature state of a thermoelectric element. The parameters for evaluating the cooling capability of the thermoelectric element are the module ΔT and the system ΔT. The module ΔT is the difference ΔT1 between the temperature at the cooling end of the thermoelectric element, that is, the temperature Q2 of the upper ceramic substrate, and the temperature at the heat dissipating side of the thermoelectric element, that is, the temperature Q5 of the lower ceramic substrate. The system ΔT is the difference ΔT 2 between the temperature Q 3 of the cooling side portion of the thermoelectric element and the ambient temperature Q 6 ′ on the heat dissipation side. Here, the ambient temperature corresponds to the ambient temperature of the heat radiation fin 32 in FIG. 8 (a) and the water temperature in the water cooling jacket 34 in FIG. 8 (b).

As can be seen from FIG. 9, the portion of the thermoelectric element having the lowest temperature (temperature Q1) is the stage on the cooling side of the thermoelectric semiconductor element, from which the temperature rises as it passes through the metal electrode and the ceramic substrate, thereby cooling load. At part (iii), the temperature is Q3.

The highest temperature (temperature Q4) is the end of the heat dissipation side of the thermoelectric semiconductor element, and the temperature decreases as it passes through the metal electrode and the ceramic substrate, resulting in the ambient temperature Q6 'on the heat dissipation side. In particular, since ceramics have a low thermal conductivity, the cooling efficiency is greatly reduced by interposing a ceramic substrate.

In this case, an aluminum substrate whose surface is oxidized in place of the ceramic substrate is used, and a water cooling jacket equipped with a spray nozzle is used to efficiently cool the aluminum substrate on the heat dissipation side. A Lecce cooling system has been proposed (Nikkei Mechanical, Sept. 16, 1996, 48--56). According to this Pulse cooling apparatus, the cooling efficiency equivalent to the normal cooling system using a flon gas can be implement | achieved.

However, since both the Pyrche cooling device and the cooling device shown in FIG. 8 are indirectly cooling the thermoelectric element through the lower substrate, the performance of the thermoelectric element cannot be maximized.

In addition, since the thermoelectric element shown in FIG. 7 is a steel structure in which upper and lower sides are fixed with a ceramic substrate, a large thermal stress is applied to the thermoelectric semiconductor element during operation, thereby shortening the life of the thermoelectric semiconductor element.

In view of the above situation, the present invention aims to minimize the reduction in cooling efficiency and to maximize the performance of the thermoelectric semiconductor element by directly cooling the thermoelectric semiconductor element and the metal electrode on the heat dissipation side. In addition, an object of the present invention is to realize that the life of the thermoelectric semiconductor element is extended by alleviating the thermal stress applied to the thermoelectric semiconductor element.

Figure 1 shows an example of the configuration of the thermoelectric element to which the present invention is applied and its operation,

Figure 2 shows the cooling method of the thermoelectric device to which the present invention is applied,

Figure 3 shows the temperature state of the thermoelectric element to which the present invention is applied,

Figure 4 shows a specific example of the thermoelectric device to which the present invention is applied,

FIG. 5 shows a specific example of a liquid-cooled thermoelectric cooling unit using the thermoelectric element shown in FIG. 4,

6 shows another example of a liquid-cooled thermoelectric cooling unit,

7 shows a configuration of a conventional thermoelectric element,

8 shows a cooling method of a conventional thermoelectric device,

9 shows a temperature state of a conventional thermoelectric element.

* Description of the symbols for the main parts of the drawings *

1-thermoelectric element 2- trimmer

3A-p type thermoelectric semiconductor element 3B-n type thermoelectric semiconductor element

4- copper electrode 5-T-shaped coin pole

6-Air Cooling Jacket 9-Liquid Cooling Jacket

10-Bass Plate 11-Aluminum Endothermic Block

The thermoelectric elements according to the present invention are the same number of p-type thermoconductor elements and n-type thermoconductors fixed to the trimming plate 2 while penetrating through the trimming plate 2 and the trimming plate 2 having electrical insulation properties. An element, a first metal electrode connected to the heat absorbing side of the p-type thermoconductor element and the n-type thermoconductor element, and a second metal electrode connected to the heat dissipation side of the p-type thermoconductor element and the n-type thermoconductor element. It is characterized in that the configuration.

The thermoelectric cooling device according to the present invention is characterized by comprising a cooling container for housing the heat dissipation side from the trimming plate 2 and the structural requirements of the thermoelectric element according to the present invention.

Since both the first metal electrode and the second metal electrode are not fixed to the ceramic substrate by the thermoelectric element according to the present invention, the thermal stress applied to the thermoelectric semiconductor element is alleviated. In addition, according to the thermoelectric cooling device according to the present invention, a portion of the p-type thermoconductor element and the n-type thermoelectric semiconductor element protruding toward the heat dissipation side from the trimming plate and the second metal connected to the end thereof from the trimming plate. Since the electrode is directly cooled in the cooling vessel, it is possible to minimize the decrease in cooling efficiency.

Furthermore, in the present invention, the second metal electrode is configured such that the area of the connection end with the p-type thermoconductor element and the n-type thermoconductor element has a shape larger than that of the other end, thereby leaving a space in the cooling vessel. It is possible to smooth the flow of gases and liquids.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail, referring drawings. 1 (a) is a front view of a thermoelectric device to which the present invention is applied. One of the features of the thermoelectric element 1 is a structure in which the p-type thermoconductor element 3A and the n-type thermoconductor element 3B are fixed to the trimming plate 2. On the upper side of the p-type thermoconductor element 3A and the n-type thermoconductor element 3B, a plate-shaped coin electrode 4 is formed, and on the lower side, a T-shaped coin electrode (hereinafter referred to as a T-shaped coin electrode) 5 is formed. Each is fixed by low temperature soldering such as a bismuth-tin alloy. It is also one of the features to form a T-shaped coin pole on the lower side of the thermoelectric semiconductor element. It is also characterized by not having a ceramic substrate above the coin 4 and below the T-shaped coin 5. As such, the structure in which the metal electrode is exposed without fixing the metal electrode to the substrate is referred to as a skeleton structure. In this embodiment, since the upper and lower metal electrodes are exposed, they have both Skelton structures.

The trimming plate 2 is composed of, for example, an electrically insulating plate of about 0.2 to 0.5 mm, for example, a glass epoxy plate or an aluminum plate subjected to anodization. The p-type and n-type thermoelectric semiconductor elements 3A and 3B are each formed of a semiconductor unit bottom such as bismuth-telunique having a length of about 1.5 to 2 mm and a cross section of about 1.5 to 2 mm ² . And it is fixed to the bottom of the trimming plate 2 so that the length of 0.2 ~ 0.3mm protrudes. Since a method for manufacturing a thermoelectric element having a structure in which a thermoelectric semiconductor element is fixed to a single trimmer is described in detail, Japanese Patent Application Laid-Open No. Hei 7-276751 (Patent Publication Hei 8-228027) will be described herein. I will not.

FIG. 1 (b) is an enlarged front view of the T-shaped coin pole 5 of FIG. (A), FIG. 1 (c) is the same enlarged side view, and FIG. 1 (d) is an enlarged bottom view. The seven T-shaped coin poles 5 shown in FIG. 1 all have the same shape and size, but two of the two ends are attached in a side view as shown in FIG. 1 (c), and the other five are shown in FIG. 1 (b). ) Is attached in the direction of the front view. Although described later in more detail, such a T-shaped coin pole 5 is disposed in water or the like, and is preferably plated with nickel or tin.

FIG. 1E is an enlarged view of a portion enclosed by O in order to explain the operation of the thermoelectric device of FIG. 1A. As shown in this figure, when the thermoelectric element of FIG. 1 (a) is used, the portion of the p-type and n-type thermoelectric semiconductor elements 3A and 3B, which is located below the trimming plate 2, and the T-shaped electrode 5 are formed of air or the like. Heat is removed by directly adhering to a liquid such as gas or water. The longer the vertical length of the T-shaped coin pole 5 is, the higher the heat exchange efficiency is, but the weight and cost are increased, so the thickness is about 5 mm in this embodiment.

2 is a view showing a cooling method of a thermoelectric device to which the present invention is applied. (A) of FIG. 2 is an air cooling system, (b) is a liquid cooling system. Here, parts corresponding to those in FIG. 1 are given the same numbers as in FIG. 1.

The air cooling system shown in FIG. 2 (a) is configured to attach an air cooling jacket 6 to the lower side of the thermoelectric element and to send wind from the fan 7 from the lower side of the air cooling jacket 6.

It is configured to blow into the fan 7 from the lower side of the air cooling jacket 6. The bottom of the air cooling jacket 6 was provided with a hole lamp (not shown) to allow the wind sent from the fan 7 to pass through. The air cooling jacket 6 is made of aluminum subjected to anodization. In addition, the air cooling jacket 6 is provided with a ventilation / supporting member 6C for receiving a T-shaped coin 5 from below and supplying the wind from the fan 7 to the T-shaped coin 5. This ventilation / support member 6C is made of plastic with feet or mesh. Air outlets 6A are installed on both sides of the air cooling jacket 6. Then, the upper end of the air cooling jacket 6 is bonded to the trimming plate 2 by an adhesive seal 8. In this configuration, the wind sent from the fan 7 passes through the bottom of the air cooling jacket 6 and the ventilation / support member 6C to strike the T-shaped coin pole 5.

Then, it passes through both sides of the T-shaped electrode 5 and flows through the inside of the air cooling jacket 6 to exit the air cooling jacket 6 from the wind outlet 6A. In the T-shaped coin pole 5, the space exists on both sides of the narrow portion of the T-shape so that the wind flows smoothly. In the liquid cooling method shown in Fig. 2B, a liquid cooling jacket 9 is attached to the lower side of the thermoelectronic element.

The liquid cooling jacket 9 is made of aluminum subjected to anodization. In addition, a liquid inlet 9A is provided at the lower center of the liquid cooling jacket 9, and a liquid outlet 9B is provided at both upper sides. Then, the upper end of the liquid cooling jacket 9 is bonded to the trimming plate 2 using the adhesive seal 8. The inner bottom of the liquid cooling jacket 9 is in contact with the lower end of the T-shaped coin pole 5. In this configuration, when a coolant consisting of water or an organic solvent such as ethylene glycol is sent from the liquid inlet 9A to the interior of the liquid cooling jacket 9, the sent cooling liquid flows through both sides of the T-shaped coin pole 5 and flows inside the liquid cooling jacket 9 Exit liquid coolant 9 from liquid outlet 9B. At this time, the coolant is poured from the lower side, whereby the coolant can be diffused better than from the side.

In addition, since the space exists on both sides of the narrow portion of the T in the T-shaped coin pole 5, the flow of the cooling liquid is smooth. In FIG. 2 (b), the T-shaped coin 5 has a rectangular shape of a narrow portion of the T-shape. However, when the angle of the rectangular parallelepiped is rounded or circumferential instead of the rectangular parallelepiped, the flow of the coolant becomes smoother. The same is true in FIG. The shape of the electrode on the heat dissipation side may be a form other than a T-shape as long as the area of the connection end with the thermoelectric element is larger than the area of the other end. Shape ( The vertical line portion of the ruler may be fixed to the thermoelectric semiconductor element), an L shape, or the like.

The shape of the electrode on the heat absorbing side may also be configured to be suitable for the cooling load.

2 (a) and 2 (b), the cooling load is made of a material having high thermal conductivity and electrically insulating property, for example, aluminum which has been subjected to anodization because the cooling load is in direct contact with the coin electrode 4. Further, a resin moisture barrier is placed around the cooling load and fixed with an adhesive seal.

3 is a diagram showing a temperature state of the thermoelectric element in the present embodiment.

In FIG. 3, module (DELTA) T is the difference (DELTA) T1 'between the temperature P2 of the lower side of a cooling side, and the temperature P5 of T-shaped coin electrode 5. As shown in FIG. The system ΔT is the difference ΔT 2 ′ between the upper temperature P 3 on the cooling side and the ambient temperature P 6 on the heat dissipation side. Here, the cooling side corresponds to the cooling load of FIG. In addition, the ambient temperature corresponds to the temperature of the air in the air cooling jacket 6 in Fig. 2 (a) and the temperature of the liquid in the liquid cooling jacket 9 in Fig. 2 (b).

As described above, the ceramic substrate having a low thermal conductivity does not exist on the cooling side of the present embodiment, and the cooling load is in direct contact with the coin electrode 4. In addition, there is no ceramic substrate having a low thermal conductivity on the heat dissipation side, and the T-shaped coin pole 5 is in direct contact with the cooling air or liquid. Therefore, when compared with FIG. 9, it is (DELTA) T1 '(DELTA) T1 and (DELTA) T2' (DELTA) T2. In other words, even if a module or a cooling device of a conventional thermoelectric element is used, the cooling efficiency is increased.

4 is a specific example of a thermoelectric device to which the present invention is applied. In FIG. 4, (a) is a top view, (b) is a right side view, (c) is a front view, (d) is a bottom view. In Fig. 4, parts corresponding to those in Fig. 1 are labeled with the same numbers as in Fig. 1.

In this thermoelectric element, 128 (= 16x8) sheets of coins 4 were attached on the upper side of the trimming plate 2 having a size of 48mm x 48mm, and 127 T-shaped coins 5 were provided on the bottom.

Then, a pair of both ends of the front side of the upper four poles was formed in an L shape, and a terminal for applying a direct current power supply was attached thereto.

FIG. 5 is a specific example of the liquid-cooled thermoelectric cooling unit using the thermoelectric element shown in FIG. 4. In FIG. 5, (a). Is a plan view, (b) is A-A 'cross section figure in (a), (c) is B-B' cross section figure in (a), and (d) is bottom view. In this case, the same reference numerals are given to the thermoelectric elements.

The liquid-cooled thermoelectric cooling unit has a spherical base plate 10 on the lower side, a spherical aluminum endothermic block 11 on the upper side, a thermoelectric element in the center between them, the base plate 10 and the aluminum endothermic block 11. It is fixed by tightening with bolt 12 made of resin with heat insulation in eight places around. In addition, although the spring washer is used together like FIG. 5 in resin bolt 12, this may be omitted. In addition, the contact surface between the coin electrode 4 and the aluminum endothermic block 11 and the T-shaped coin electrode 5 and the base plate 10 are bonded with a silicon grease or a gel-like insulator.

The base plate 10 and the aluminum heat absorbing block 11 were formed of aluminum anodized to contact with the T-shaped coin electrode 5 and the coin electrode 4, respectively. The liquid liquid port 10A was provided in the center of the lower side of the base plate 10, and the liquid outlet 10B was provided in the two places which oppose the stage of a thermoelectric element below the base plate 10. As shown in FIG.

In the center part of the upper side of the base plate 10, the groove part with a flat bottom for inserting the lower part from the trimming plate 2 of a thermoelectric element was formed. The lower end of the T-shaped coin pole 5 is supported by the bottom of this groove portion. However, in the portion facing the liquid inlet 10A, a groove portion 10D narrower than the width of the T-shaped coin pole 5 (the length in the lateral direction seen from the front) is formed, supporting the T-shaped coin pole 5, and the cooling liquid It was made to flow in the transverse direction of FIG.

In the same way, the groove portion 10E was also formed in the portion facing the two liquid outlets 10B.

In the base plate 10, the groove part for flowing the adhesive agent 15 was formed in the outer side of the groove part. The adhesive 15 is flowed into this mixing part, and the trimming plate 2 of a thermoelectric element is put on it, and it adheres.

The groove part for fitting the rubber ring 13 and the heat insulating material 14 was formed in the outer side of the groove part which flowed in the adhesive agent. In the aluminum heat absorbing block 11, grooves for inserting the rubber ring 13 and the heat insulating material 14 were also formed in the portion facing the grooves. Thus, a rubber ring is inserted into each of the groove portions facing up and down, and a heat insulating material 14 is inserted therebetween.

And the heat insulating material 14 uses what ceramic or plastic was formed previously suitable for the groove part size.

In a real system, a pump, a radiator and a fan are connected to this liquid-cooled thermoelectric cooling unit.

In the liquid-cooled thermoelectric cooling unit configured as described above, the coolant supplied from the liquid inlet 10A into the groove of the base plate 10 flows along the groove 10D in the transverse direction of FIG. 5 (d) and at the same time between the T-shaped coin 5. It passes in the longitudinal direction of Fig. 5 (d).

Then, it passes through the groove portion 10E and comes out from two liquid outlets 10B.

In addition, the liquid-cooled thermoelectric cooling unit surrounds the outer side of the thermoelectric element with a heat insulating material 14 and fixes the base plate 10 to the aluminum heat absorbing block 11 by fixing the resin bolt 12 having high thermal insulation between the base plate 10 and the aluminum heat absorbing block 11. Prevention of heat backflow and moistureproofing of thermoelectric elements are realized.

In this liquid-cooled thermoelectric cooling unit, the number of the liquid outlets 10B is two but may be four or six.

6 is another example of a liquid-cooled thermoelectric cooling unit. Here, parts corresponding to those in FIG. 5 are assigned the same numbers as in FIG. 5. In the embodiment of FIG. 6, only the portion enclosed by ○ is different from the embodiment of FIG. 5, and thus, a view corresponding to the cross-sectional view taken along line BB ′ of FIG. 5 is shown.

Fig. 6A is fixed from both sides of the base plate 10 side and the aluminum endotherm 11 side by the metal bolt 16. Figs. And since the metal bolt 16 is low insulator, the heat insulating material 14 larger than FIG. 5 was used, and the heat insulating material 14, the base board 10, and the aluminum heat absorption block 11 were fixed with the metal bolt 16. FIG.

6 (b) is fixed with an adhesive 17 instead of the metal bolt 16 fixed from the side of the aluminum heat absorbing block 11 in FIG. 6 (a).

In the above description, a thermoelectric device having a structure in which a thermoelectric semiconductor element is embedded in a single trimmer plate and fixed is manufactured by the method described in Japanese Patent Application Laid-Open No. 8-2228027, but the glass epoxy or anodized aluminum plate is spherical. Punch a hole, insert a regular thermoelectric element in a cube into the hole, and fix it with a heat-curable resin such as polyimide resin. A thermoelectric element is embedded in a single trimmer to manufacture a thermoelectric element having a fixed structure. Also good.

As described in detail above, according to the present invention, since both the upper and lower metal electrodes of the thermoelectric semiconductor element are not fixed to the rigid substrate, the thermal stress applied to the thermoelectric semiconductor element is alleviated. As a result, it is possible to extend the life of the thermoelectric semiconductor element.

In addition, by directly cooling the thermoelectric semiconductor elements, it is possible to minimize the decrease in the cooling efficiency and effectively bring out the performance of the thermoelectric semiconductor elements.

Claims (10)

The same number of p-type thermoconductor elements and n-type thermoconductor elements and the p-type thermoconductor elements and n-type thermoconductors fixed in the trimming plate 2 while penetrating through the trimming plate 2 and the trimming plate 2 having electrical insulation properties. A thermoelectric element comprising a first metal electrode connected to a heat absorbing side of an element, and a second metal electrode connected to a heat dissipating side of said p-type thermoconductor element and an n-type thermoconductor element. The thermoelectric device of claim 1, wherein an area of a connection end of the second metal electrode with the p-type thermoelectric device and the n-type thermoelectric device is larger than that of the other end. The same number of p-type thermoconductor elements and n-type thermoconductor elements that are fixed to the trimmer plate 2 while penetrating through the trimmer plate 2 and the trimmer plate 2 having electrical insulation, and the p-type thermoelectric element and n-type A cooling vessel accommodating the heat dissipation side from the trimmer plate 2 and the first metal electrode connected to the heat absorbing side of the semiconductor element, the second metal electrode connected to the heat dissipation side of the p-type thermoelectric element, and the n-type thermoconductor element. Thermoelectric cooling device characterized in that it comprises a. The method of claim 3, wherein the second metal electrode is characterized in that the area of the connection end with the p-type thermoconductor element, n-type thermoconductor element and n-type thermoconductor element is larger than the area of the other end. Thermoelectric cooling system. The thermoelectric cooling apparatus according to claim 3, wherein the cooling vessel is cooled by gas. The thermoelectric cooling apparatus according to claim 3, wherein the cooling vessel is cooled by a liquid. 7. The thermoelectric cooling apparatus according to claim 6, wherein the liquid is introduced into the cooling vessel from a direction perpendicular to the trimming plate 2. The thermoelectric cooling apparatus according to claim 3, wherein the cooling container is made of metal having an insulating layer formed on a surface thereof. 4. The thermoelectric cooling apparatus according to claim 3, wherein a metal cooling load having an insulating layer formed on a surface thereof is provided on the first metal electrode. The thermoelectric cooling device according to claim 9, wherein a moisture proof border is arranged around a side surface of the cooling load.