JPH043475A - electronic components - Google Patents

Abstract

PURPOSE:To reduce thermal conductivity as the performance index of a semiconductor substance is left as it is by forming the inside of the semiconductor substance of a porous body in an electronic part for electronic cooling and heating utilizing a heat-generation heat- absorption phenomenon or for thermoelectric generation using electromotive force. CONSTITUTION:The insides of semiconductor substances are formed of a porous body or sections among the semiconductor substances are filled with insulating inorganic porous bodies or powder. Even when there are pores in the semiconductor substances, a Seebeck coefficient is approximately the same as that of a semiconductor substance having no pore because of not only the small contribution of the reduction of mobility of carriers by distortion, a grain boundary, etc., in the substances but also the insulating pores. Volume percentage of 5.0% or more in the semiconductor substance is favorable in the pores at that time. On the contrary, electric conductivity and thermal conductivity lower with the increase of porosity, but the ratio is approximately the same as a semiconductor substance having no porosity approximately up to the wide range of the porosity. When the clearances of P-type semiconductor 1 and N-type semiconductor substances 3 are filled with an insulating inorganic porous substance or powder and the sections of the clearances are deaerated until the sections are brought to a vacuum state, the convection of air by temperature difference generated in the clearance sections is prevented, thus reducing thermal conductivity as an element component. The vacuum state of lmmHg or less is favorable at that time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to electronic components such as electronic cooling, heating elements, and thermoelectric power generation elements, and particularly to electronic components composed of thermoelectric substances and elements with low thermal conductivity. It is related to.

(Conventional technology) In recent years, regulations on the use of fluorocarbons due to global environmental issues, demand for local cooling of electronic equipment, demand for compact cooling devices such as dehumidification, demand for small-scale waste heat utilization1, etc., Peltier effect, Seebeck, etc. There is a great demand for electronic parts such as electronic cooling and heating elements and thermoelectric power generation elements that utilize this effect.

Among these, for electronic cooling elements used near room temperature, a B1-Te system single crystal or polycrystalline solidified body is used as the semiconductor material, and p-type and n-type materials are alternately bonded with metal copper plates, etc. The structure was such that the meter for each substance was a void. Furthermore, polycrystalline sintered bodies of Fe, Si, etc. have not been used as thermoelectric power generation elements, and have a structure in which p-type and n-type materials are directly joined at high temperatures.

(Problem to be Solved by the Invention) In electronic cooling elements, it is known that the amount of heat absorbed on the cooling side per unit of power consumption of the element is defined by the figure of merit 2 of the semiconductor material, and this Z is Using the Seebeck coefficient S, electrical conductivity σ and thermal conductivity k, z == s
It is expressed as 2xσ/.

For this reason, semiconductor materials are required to have high electrical conductivity and low thermal conductivity since they have a high Seebeck coefficient. Furthermore, in the operation method in which the device is operated intermittently after reaching the cooling temperature, the device must have as good insulation as possible except when voltage is applied, so even if the figure of merit is the same, the thermal conductivity is small. Desired.

In an element for thermoelectric power generation, in order to maintain a temperature difference between a high temperature side and a low temperature side, it is preferable that the thermal conductivity of the element is small.

On the other hand, in the case of B1Te-based single crystals, there are methods that reduce the contribution of lattice vibration to thermal conduction by solid solutioning sb, Se, etc., and methods that control the grain size without growing single crystals from the molten state. A method of reducing thermal conductivity as a crystal solidified body is known.

The present invention solves the above-mentioned demands and provides an electronic component for electronic cooling, heating, and thermoelectric power generation that has low thermal conductivity as a semiconductor material or element configuration.

(Means for Solving the Problems) The present invention uses a semiconductor material as a porous body. Alternatively, the spaces between the semiconductor materials may be filled with an insulating inorganic porous material or powder, the interior may be evacuated to a vacuum state, or any of these methods may be combined.

(Function) Even if pores exist in a semiconductor material, the contribution of reducing carrier mobility due to strain in the material, grain boundaries, etc. is small, and since pores are insulating, the Seebeck coefficient is almost the same as that without pores. It's no different from anything else. On the other hand, electrical conductivity and thermal conductivity are
Although it decreases as the porosity increases, the ratio is almost the same as that of no porosity over a wide range of porosity, so the thermal conductivity can be lowered while the figure of merit of the semiconductor material remains the same.

By filling the gaps between p-type and n-type semiconductor materials with an insulating inorganic porous material or powder, and then evacuating the area to a vacuum, air convection due to the temperature difference that occurs in the gaps is prevented, and the element configuration can be improved. It is possible to reduce the thermal conductivity of the body.

(Example) Five examples of the present invention will be explained with reference to FIGS. 1 to 5, respectively.

First, a first example will be described.

The B1-Te system was studied as a semiconductor material, and samples were prepared in which (Bi, 5b)2Te3 was selected as the n-type material and B12('re, 5e)a was selected as the n-type material. First, raw materials for polycrystalline solidified bodies of each substance are coarsely crushed, and then crushed in a ball mill using ethanol as a solvent and zirconia balls of 2 mm diameter as a crushing medium. The dried powder was put into a platinum tube, sealed after degassing, and heated at a temperature of 500℃ and a pressure of 10kg/cd to 1000℃.
HIP treatment was performed at kg/cd.

The prepared sample was taken out from the platinum tube and
It was cut into 3 mm x 20 mm, and the bulk density was measured at room temperature to determine the porosity. Furthermore, a temperature difference of about 5° C. was applied to both ends of the element at room temperature, and the electromotive force and temperature at both ends were measured to determine the Seebeck coefficient. Furthermore, the entire device was held at room temperature, and the resistance value was measured by the four-probe method to determine the electrical conductivity. Also,
The element was suspended at both ends with a conductive wire of 0.07 Iφ in vacuum at room temperature, and the element figure of merit 2 was determined by the Rivermer method, and the thermal conductivity was determined from the electrical conductivity and Seebeck coefficient.

Table 1 shows the porosity, electrical conductivity, thermal conductivity, Seebeck coefficient, and figure of merit of the samples of the p-type material and the table 2 of the n-type material, respectively.

Next, a cooling panel shown in FIG. 1 was prototyped using the above sample. The cooling panel was made by cutting the above p-type and n-type materials into 1.5m cubes, making a total of 225 p-type and n-type cooling elements 1 and 2 with a gap of 2.0m, 15 in each direction and in each direction. Each element 1 is arranged alternately and electrically in series.
and 2 are tied together with a Ni plate 3, with a thickness of 1 m on the top and bottom surfaces, 55!
I attached alumina plate 4 from l1lX55 Sono.

Thermal conductivity between the upper and lower surfaces of the above cooling panel was measured, and the thermal conductivity per unit area of the panel was determined.

Table 3 shows the relationship between element porosity and thermal conductivity.

The umbrella part is a comparative example outside the scope of claims. No. , Comparative example outside the scope of claims The stamp is a comparative example outside the scope of the present invention. A polycrystalline solidified body was used as the semiconductor.

As is clear from Tables 1, 2, and 3, semiconductor materials with pores have lower thermal conductivity as a material, and Cooling Elements 1 and 2 manufactured using the semiconductor materials have lower thermal conductivity. Its thermal conductivity also decreases.

In particular, when the porosity is in the range of 5.0% or more, the decrease in the figure of merit is small even though the thermal conductivity is greatly decreased.

Next, a second example will be described.

FIG. 2 is a side sectional view of a cooling panel showing this embodiment. The difference from the first embodiment shown in FIG.
Polycrystalline solids containing no pores and porosity 3, which are listed as comparative examples in Tables 1 and 2, are used as type semiconductor materials.
P-type and n-type cooling elements 1 and 2 using 0% samples
The bulk specific gravity is 0.04g/a+ in the gap between the two.
? The glass fiber insulation material or perlite powder 5 with an average particle size of 15 μm was filled and the surrounding area was solidified with an inorganic adhesive 6. Since the rest is the same as the first embodiment, the same components are given the same reference numerals and their explanations will be omitted.

Table 4 shows the thermal conductivity per unit area of the panel (W/a+f
-deg).

Table 4 As is clear from Table 4, P-type and n-type cooling elements 1
In the case of a cooling panel in which the gap between 2 and 2 is filled with glass fiber or pearlite powder, heat conduction due to air convection in the gap is suppressed, so the thermal conductivity of the panel decreases. Moreover, the thermal conductivity of panels using cooling elements 1 and 2 containing pores in the semiconductor is further reduced.

Next, a third example will be described.

FIG. 3 is a side sectional view of a cooling panel showing this embodiment. The difference between this embodiment and the second embodiment shown in FIG. The entire cooling panel is heated in vacuum to form a low-melting glass sealing part 7 on the outer periphery of the panel, and then cooled to create a vacuum state of about 0.001 mHg between the P-type and N-type cooling elements 1 and 2. This is the point.

The rest is the same as the second embodiment, so the same components are given the same reference numerals and their explanations will be omitted.

Table 5 shows the thermal conductivity per unit area of the panel (w/cn
-deg).

Table 5 As is clear from Table 5, p-type and n-type cooling elements 1
In the case of 2 and 2 in which the gap is in a vacuum state, heat conduction due to air convection in the gap is suppressed, resulting in a decrease in the thermal conductivity of the panel. Further, when used as a cooling panel, since no dew condensation occurs at the cooling element joint portion, corrosion and deterioration of the joint portion can be prevented.

Next, the fourth. Explanation of the fifth embodiment - Figures 4 and 5 are side sectional views showing the cooling channel of this embodiment, and the differences from the second embodiment shown in Figure 2 are as follows.
In Fig. 4, the entire panel is heated in vacuum to form a low melting point glass sealing part 7 on the outer periphery of the panel, and then cooled to create a vacuum state of about 0.01 mmHg between the cooling elements 1 and 2. In FIG. 5, after forming the resin sealing part 8 by molding the peripheral part with resin to a thickness of about 1 mm, the resin sealing part 8 is
The interior was evacuated from one end to a vacuum state of approximately 1 mmHg.

Since the rest is the same as the second embodiment, the same components are given the same reference numerals and their explanations will be omitted.

Table 6 shows the thermal conductivity per unit area of the panel (W/ff
l-deg).

As is clear from Table 6, p-type and n-type cooling elements 1
A cooling panel in which the gap between 2 and 2 is filled with insulating glass fiber or perlite powder and is further evacuated will reduce the thermal conductivity of the panel because heat conduction due to air convection in the gap is suppressed. Further, when used as a cooling panel, since no dew condensation occurs at the joint between the cooling elements 1 and 2, corrosion and deterioration of the joint can be prevented. especially.

As shown in sample number 63, when the gap is filled with insulating glass fiber or pearlite powder and a vacuum is created, 1+wn[(
A high reduction in thermal conductivity can be achieved with a vacuum degree as low as 1.5 g.
The structure and manufacturing process are easy, and the dew condensation prevention effect is sufficient.

(Effects of the Invention) As explained above, according to the present invention, when used in electronic components such as electronic cooling/heating elements and thermoelectric generation elements, low thermal conductivity can be obtained without reducing the figure of merit. , it is possible to prevent loss due to heat conduction during operation without applying voltage.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an electronic cooling panel according to a first embodiment of the present invention, and FIGS. Third. FIG. 7 is a side sectional view of an electronic cooling panel showing fourth and fifth embodiments. Fig. 1 1... P-type cooling element, 2... N-type cooling element, 3...
-Ni plate, 4...Alumina plate, 5...Glass fiber or pearlite powder, 7...Low melting point glass sealing part, 8...Resin sealing part. Patent Applicant Matsushita Electric Industrial Co., Ltd. District 2 Agent Koji Hoshino Perlite Powder Book Figure 3 District 5 Figure 4 Figure 8 Child Meeting No. 851 Dimension Procedure Amendment (Self-Regulation May 20, 1991)

Claims (7)

[Claims] (1) Electronic components for electronic cooling and heating that utilize heat generation and endothermic phenomena at the bonding interface when p-type and n-type semiconductor elements are electrically bonded in series and DC current is applied, and temperature differences at the bonding interface. An electronic component for thermoelectric power generation using electromotive force, characterized in that the semiconductor element is a porous body. (2) The electronic component according to claim (1), wherein the semiconductor element has a porosity of 5.0% or more. (3) Multiple p-type and n-type semiconductor elements are arranged in a planar manner and electrically connected in series, and electronic components for electronic cooling and heating utilize heat generation and endothermic phenomena at the bonding interface when direct current is passed. An electronic component characterized in that a gap between a semiconductor element is filled with an insulating inorganic porous material or powder. (4) The electronic component according to claim (3), wherein the semiconductor element is a porous body. (5) P-type and n-type semiconductor materials are arranged in a planar manner and electrically connected in series, and electrons for electronic cooling and heating utilize the exothermic and endothermic phenomenon at the bonding interface when a direct current is applied. An electronic component characterized by having a gap between semiconductor elements in a vacuum state. (6) The electronic component according to claim (5), wherein the gap between the semiconductor elements is further evacuated to a vacuum state of 1 mmHg or less. (7) The electronic component according to claim (5), wherein the gap between the semiconductor elements is further evacuated to a vacuum state of 1 mmHg or less.