JP2862998B2 - Electronic cooling panel - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic cooling panel, and more particularly to an electronic cooling panel having a low minimum temperature of a cooling surface under a use condition of a small heat radiation efficiency on a heat radiation side.

[Related Art] In recent years, there has been a great demand for restrictions on the use of chlorofluorocarbons due to global environmental problems, a demand for small cooling devices such as local cooling and dehumidification of electronic devices, and a demand for electronic components for electronic cooling utilizing the Peltier effect. Here, the Peltier effect refers to an effect that, when a current flows through a junction between two metals, heat is generated or absorbed at the junction. For example, when a current flows in a certain direction to generate heat, if the direction of the current is reversed, the heat is absorbed this time.

Among these, as electronic components for electronic cooling used near room temperature, a Bi-Te-based single crystal or polycrystalline solidified material is used as a thermoelectric semiconductor material, and p-type and n-type semiconductor materials are alternately formed by a metal plate or the like. Joined in series, the junction surface from n-type to p-type is arranged on one side from the electrically positive side, and used as a cooling surface, and the junction surface from p-type to n-type is arranged on the other surface. It is known that a heat radiation surface is used and a gap is provided between each substance.

Theoretically, Bi-Te materials have a temperature of 60 ° C between the high and low temperatures.
Although it is possible to take a temperature difference of the order, if the heat radiation amount on the high temperature side is small in the above configuration, the temperature on the high temperature side rises,
There is a problem that the lowest temperature on the low temperature side rises. The thermal resistance between the outside air conventional heat radiating plate, 0.0002~0.005W / cm ² · deg about the natural cooling, a forced air cooling 0.0004
It is about 0.002 W / cm ² · deg, and the temperature rise on the heat radiation side of the semiconductor element was a serious problem.

On the other hand, in the conventional electronic cooling electronic component, at the element stage in which p-type and n-type elements are alternately arranged in a plane and electrically connected in series, a space is provided between the p-type and n-type elements. A cross-sectional area of up to 3 times, a metal radiator plate having a cross-sectional area of about 10 times is joined to this, and this radiator plate has a fin having an area of 5 to 7 times the cross-sectional area. Means have been taken such that the heat radiation area is increased to about 100 to 200 times the cross-sectional area of the semiconductor element, and this is forcibly air-cooled by a fan or water-cooled on the heat radiation surface.

[Problems to be Solved by the Invention] However, in the above-described conventional technology, there is a problem that forced air cooling or water cooling means using a fan is required, and the apparatus cost is increased.

The present invention solves the above-mentioned problems of the prior art, and does not require forced air cooling or water cooling means using a fan, and an electronic cooling panel capable of cooling a cooling surface to a low temperature even under use conditions in which the heat radiation efficiency on the heat radiation side is small. The purpose is to provide.

[Means for Solving the Problems] In order to achieve the above object, the electronic cooling panel of the present invention electrically connects a p-type and an n-type semiconductor element in series to each other at a junction interface when a direct current is applied. In an electronic cooling panel utilizing an exothermic endothermic reaction, the semiconductor element part is hollow,
Alternatively, it is characterized by comprising a carrier particle having a porous shape, a thermoelectric semiconductor layer formed on the surface thereof and in an electrically conductive state, and a void other than the inside of the carrier.

In the above configuration, it is preferable that the thermoelectric semiconductor material layers are sintered together, and the semiconductor layer in an electrically conductive state is continuous rather than just in a contact state.

[Operation] According to the configuration of the present invention, the heat conductivity of the semiconductor element is reduced, and even if the temperature of the heat radiation side increases, the amount of heat conduction to the cooling side decreases, and the cooling side temperature can be reduced. it can.

Further, according to the preferred configuration of the present invention in which the thermoelectric semiconductor material layers are sintered together and the semiconductor layers are continuous, more excellent natural cooling can be achieved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

Example 1 A Bi-Te-based material was studied as a thermoelectric semiconductor material. p
(Bi, Sb) ₂ Te ₃ was selected as the type material, and Bi ₂ (Te, Se) ₃ was selected as the n-type material.

As the carrier particles, glass balloons (hollow glass particles) having an average particle size of 8 μm and a film thickness of 0.5 μm were used. Although this balloon has a hollow structure, there is no airtightness between the inside and the outside, and the glass itself is a porous body.

Semiconductor material, using a polycrystalline solidified material of each material as a starting material, using an organic solvent in a ball mill after crushing, pulverized in a medium stirring mill using zirconia balls of 0.2 mmφ as a medium, an average particle size of 0.08 μm Powder. After drying, the powder and the viscous solvent were mixed to form a slurry, and a glass balloon was immersed and dried. The number of times of the treatment of dipping and drying in the slurry was changed to prepare a sample in which the thickness of the thermoelectric semiconductor layer was changed. The particles after the treatment and drying were molded and heat-treated in argon at 500 ° C. for 2 hours. FIG. 1 is an enlarged view of a cross section of the obtained semiconductor element.

In FIG. 1, 11 is a glass balloon and 12 is a thermoelectric semiconductor. And 12 thermoelectric semiconductor layers are formed on the surface of 11 glass balloons. The prepared semiconductor element was cut into 1 cm cube for both p-type and n-type, coated with insulating resin on the side, immersed in slurry, and dried. The elements were alternately arranged, the resin was cured and joined, and the respective elements were electrically connected in series on the upper and lower surfaces with a Ni plate. Further, as a reference sample, a dense polycrystalline solidified body was used for both the p-type and the n-type, and those joined in the same shape were also prepared.

After thinly applying insulating grease to the low-temperature side surface of the prepared sample, a copper plate having a thickness of 0.3 mm was joined, and a thermocouple was bonded to this surface to measure the temperature. On the high-temperature side, the following three heat radiation conditions were set, and the heat-radiating plate was thinly coated with insulating grease as in the low-temperature side, then placed, and a thermocouple was bonded to measure the temperature. The conditions for heat dissipation are as follows.

A 10cm square (area 100cm ² ) copper plate with a thickness of 0.5mm with a radiating surface oxidized (radiation plate surface area equal to the cross-sectional area of the semiconductor element, natural cooling) 10cm square (area 100cm ² ) and a thickness of 0.5 mm on copper plate thickness
A fin made of 0.3 mm deep 7 mm copper plate fins at 7 mm pitch and oxidizing the heat radiation surface (heat sink surface area three times the cross-sectional area of the semiconductor element, natural cooling) 20 cm square (area 400 cm ² ) 0.5 mm thick copper plate 0.3 thickness
A copper plate fin with a depth of 10 mm and a fin made up at a pitch of 5 mm and oxidizing the heat radiation surface (heat radiation surface area of 20 times the cross-sectional area of the semiconductor element, natural cooling). The conditions for minimizing the temperature of the copper plate on the low temperature side were determined. All measurements were performed at an outside temperature of 300K.

Table 1 shows that the volume fraction a (%) of the thermoelectric semiconductor material, the volume fraction b (%) of the pores, the apparent resistivity c (Ωcm) of the thermoelectric semiconductor material under the above three heat radiation conditions, and (a, b, c are all values) The average value of the p-type and n-type elements), the lowest temperature at low temperature d (K), the radiation fin temperature e (K) when the lowest temperature reaches the low temperature, and the current amount f (A) at the time when the lowest temperature reaches the low temperature. Show.

As is evident from Table 1, the semiconductor element portion composed of the carrier particles having a hollow shape and the thermoelectric semiconductor material layer formed on the surface thereof as in the present embodiment is the one using a dense thermoelectric semiconductor. In comparison, the lowest temperature on the low temperature side can be lowered.

Example 2 As a thermoelectric semiconductor substance, (Bi, Sb) ₂ Te ₃ similar to the example was examined for the p-type, and SrTiO _{3 -X,} which was calcined in titanium sponge and strongly reduced, was examined as the n-type substance. As the carrier particles, a porous granular powder of an alumina foamed balloon having an average particle diameter of 1 mm (porosity of 95%, average pore diameter of 4 μm) was used. As a semiconductor material, a polycrystalline solidified or sintered body of each material was used as a starting material. This was crushed and then pulverized in a ball mill using an organic solvent and a medium stirring mill using zirconia balls having a diameter of 0.2 mm as a medium to obtain a powder having an average particle diameter of 0.08 μm. After drying, the powder and the viscous solvent were mixed to form a high-concentration slurry, and the alumina-based balloon was immersed and dried. At this time, the slurry concentration was selected so that the thermoelectric semiconductor mainly adhered to the balloon surface. The number of times of immersion in the slurry and drying was changed to prepare a sample in which the thickness of the thermoelectric semiconductor layer was changed. The particles after the treatment and drying were molded and heat-treated at 500 ° C. for 2 hours in argon. FIG. 2 shows an enlarged view of a cross section of the prepared semiconductor device. In FIG. 2, 13 is an alumina balloon, and 14 is a thermoelectric semiconductor layer. And
Fourteen thermoelectric semiconductor layers are formed on the surface of thirteen alumina balloons.

The prepared semiconductor device was joined in the same manner as in Example 1, and the same cooling surface and heat radiation surface were formed, and the same measurement was performed.

Table 2 shows the volume fraction a of the thermoelectric semiconductor material, the volume fraction b of the pores, and the apparent resistivity c (Ωcm) of the thermoelectric semiconductor material under each heat radiation condition.
(All of a, b, and c are average values of p-type and n-type elements), low-temperature minimum temperature d (° C), radiation fin temperature e (° C) when low-temperature minimum temperature is reached, low-temperature minimum temperature attainment Current value f
(A) is shown.

As is evident from Table 2, as in the present example, the semiconductor element portion composed of the carrier particles having a porous body and the thermoelectric semiconductor material layer formed on the surface thereof is compared with the one using the dense thermoelectric semiconductor. , The lowest temperature on the low temperature side can be low,
In particular, the effect is exhibited under the condition that the heat dissipation surface area per semiconductor device cross-sectional area is small as in the three conditions shown in the embodiment and the heat dissipation efficiency is smaller than that of a general electronic cooling element such as natural cooling.

[Effects of the Invention] As described above, according to the electronic cooling panel of the present invention, when electronic cooling is performed, the lowest attainable temperature on the low temperature side can be reduced under the condition of low heat radiation efficiency. Further, it has an advantage that it can be easily formed into a large area and can be manufactured at low cost, and is industrially useful.

[Brief description of the drawings]

1 and 2 are enlarged schematic sectional views of a semiconductor element portion of an electronic cooling panel according to an embodiment of the present invention. 11: glass balloon, 12: thermoelectric semiconductor material, 13: alumina balloon, 14: thermoelectric semiconductor layer.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-50-86286 (JP, A) JP-A-59-152256 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 35/32 H01L 35/16

Claims (2)

(57) [Claims] 1. An electronic cooling panel in which a p-type and an n-type semiconductor elements are electrically connected in series and an exothermic endothermic reaction occurs at a bonding interface when a DC current is applied, wherein the semiconductor element portion is hollow or Carrier particles having a porous shape,
An electronic cooling panel comprising a thermoelectric semiconductor layer formed on a surface thereof and in an electrically conductive state, and a void other than inside the carrier. 2. The electronic cooling panel according to claim 1, wherein the thermoelectric semiconductor material layers are sintered together, and the semiconductor layers are continuous.