JP2001230455A - Seebeck element and cooling device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost Seebeck element in which an efficient open- circuit voltage can be obtained even at a slight temperature difference, and to provide a cooling device which applies the Seebeck element of high efficiency. SOLUTION: In the Seebeck element, tannin is contained in an N-type element 5 on the side of a low-temperature. The N-type element 5 and a P-type element 3 are connected to each other in two points so as to constituted a circuit. When their two connected parts are held at mutually different temperatures, an open- circuit voltage which corresponds to the temperature difference between the different temperature is generated across terminals of the open circuit. The Seebeck element thus obtained can be used in various cooling devices such as a cooling device for a notebook-type personal computer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Seebeck element suitable for efficient power generation of large electric power due to a temperature difference and efficient cooling of a heating element, and a cooling device using the same.

[0002]

2. Description of the Related Art A circuit is formed by joining two conductors made of different conductive substances A and B as shown in FIG. 4 to form two junctions at different temperatures _TL and T, respectively.
Keeping the _{H (T L <T H)} , the phenomenon that the open-circuit voltage according to the temperature difference ΔT = T _H -T _L between the terminals of an open circuit occurs as the Seebeck effect. Further, a change in V _ab with respect to a change in the temperature at one junction of 1 ° C. is referred to as a Seebeck coefficient of substance B with respect to substance A.

[0003] By the way, as a combination of substances A and B capable of obtaining a large open-circuit voltage by such a Seebeck effect, conventionally, alumel-chromel (seebeck coefficient of 4) is used.
0), copper / constantan (Seebeck coefficient 41), chromel / constantan (Seebeck coefficient 62) and the like are known.
-8% Al-2% Mn, chromel 90% Ni-10%
Cr and constantan are, for example, 40% Ni-60% Cu, and both contain expensive nickel at a high concentration (% is% by weight; the same applies hereinafter).

[0004]

The value of the open circuit voltage Vab shown in FIG. 1 is a function of the temperature difference ΔT. Even at a low temperature near room temperature of 100 ° C. or less, if there is a temperature difference between the two junctions, the electric energy of Occurrence is possible. However, in order to efficiently generate electric power or efficiently cool a high-temperature joint (or efficiently heat a low-temperature joint) according to this principle, a large amount of the above-described alloy is required. The use of these alloys, which contain high concentrations of expensive nickel, was not economical and practical.

It is an object of the present invention to provide an inexpensive Seebeck element capable of obtaining an efficient open circuit voltage even with a slight temperature difference, and to provide a cooling device to which the high efficiency Seebeck element is applied.

[0006]

In order to solve the above-mentioned problems, a Seebeck element according to the present invention forms a circuit by joining an N-type element and a P-type element to each other at two points, and connects these two joints to each other. In a Seebeck element for maintaining an open circuit at a different temperature and generating an open voltage corresponding to the temperature difference between the different temperatures between the terminals of the open circuit, tannin is contained in the N-type element. Here, the P-type element refers to a conductor having a positive Seebeck coefficient, and the N-type element refers to a conductor having a negative Seebeck coefficient. Tannin was used for the first time in a Seebeck element in the present invention, and it is difficult to say that its action has been scientifically elucidated yet, but tests by the present inventor have revealed that the Seebeck element of the present invention is a conventional Seebeck element. It was confirmed that the element had a Seebeck coefficient several times that of the device.

Although tannin is included in an N-type element to increase the electromotive force, the tannin can be further included in a P-type element to further increase the electromotive force. However, no matter how much tannin is contained in the P-type element, the electromotive force cannot be increased unless tannin is contained in the N-type element.

[0008] The N-type element of the Seebeck element of the present invention can contain Si, Al or P, Fe, tannin, polyvinyl alcohol or the like as components. Further, the P-type element can include Si, Fe, tannin, and polyvinyl alcohol.

Since the Seebeck element of the present invention has a Seebeck coefficient several times that of the prior art, a cooling device using this Seebeck element is practically possible. For example, heat generating elements such as a CPU and a hard disk in a notebook personal computer need to be efficiently cooled because the surrounding space is narrow. If an element that can easily convert heat into electric energy is used, heat energy that tends to be trapped inside the notebook PC can be converted to electric energy and then easily released to a metal housing or the like that is advantageous for heat dissipation. Can be.

[0010]

Embodiments of the present invention will be described below. FIG. 1 shows a CPU cooling device for a notebook computer using a Seebeck element according to the present invention. In the figure, 1 is a motherboard substrate, 2 is a CPU, 3 is a P-type element,
Reference numeral 4 denotes a plate-like Teflon spacer having a heat insulating function, reference numeral 5 denotes an N-type element, and reference numeral 6 denotes a plate-type heat pipe in which water as a heat transfer medium is sealed and whose inner surface is processed into a fine rough surface. However, this plate type heat pipe 6 is for further enhancing the cooling effect of the Seebeck element of the present invention,
It is not necessarily essential to the present invention. Therefore,
Instead of the plate-type heat pipe 6, for example, a radiator plate simply made of aluminum may be used.

The P-type element 3 is formed into a plate-like square having substantially the same shape as that of the CPU 2 and is bonded to the CPU 2 without gaps through a suitable bonding material such as silicon grease in order to improve heat conductivity. . The lower surface of one end of the Teflon spacer 4 is joined onto the P-type element 3. A plate-shaped rectangular N-type element 5 is joined to the other end face of the Teflon spacer 4. A common heat pipe 6 is joined to the upper surfaces of the Teflon spacer 4 and the N-type element 5, and the P-type element 3 and the N-type element 5 are electrically coupled on one side surface by an electrode 7 made of copper wire. The elements 3 and 5 are electrically coupled on the opposite side surfaces to the common conductor, for example, a not-shown metal housing or the like, which has sufficient heat dissipation of a notebook computer, through electrodes 8 and 9 made of another copper wire. ing. The P-type element 3, the N-type element 5, and the heat pipe 6 are joined to each other without any gap via a suitable bonding material such as silicon grease.

As shown in FIG. 2, the P-type element 3 and the N-type element 5 are conductive substances containing Si, Fe, and the like as components.
After being pressed into a predetermined metal mold, it is sintered by a suitable heating means such as high-frequency induction heating. The P-type element 3 and the N-type element 5 are desirably made ultra-thin so as to be advantageous for mounting on a notebook personal computer, and have a thickness of 1.5 mm in the present invention. In the components shown in FIG. 2, only tannin has no compounding example in the conventional Seebeck device, and is the first compounded compound in the present invention. Note that FIG. 2 is merely an example of the combination, and is not an absolute one. In short, it is sufficient to add tannin to the components of the conventional general Seebeck element, and the compounding amount may be increased or decreased as necessary, and it is not limited to the compounding amount shown in FIG. Of course.

The present inventor conducted a function test of the Seebeck element of the present invention using a pseudo-cooling device having an electric heater of the same shape and size (with a built-in nichrome wire) instead of the CPU 2 of FIG. However, the heat pipe 6 was omitted to measure the cooling effect only by the Seebeck element. The function test was performed by sealing the pseudo cooling device in a desiccator in order to eliminate the influence of the convection of the surrounding air. FIG. 3 shows a schematic result of the function test. First, the electric heater was energized in a state where nothing was mounted on the electric heater, and about 96
Temperature measurement was performed when the temperature of the electric heater became stable after a lapse of minutes. The power supply unit is “PAN1” manufactured by KIKUSUI.
6-10A "at 9.95 V and 0.36 A (3.
At 58 W). For measurement of temperature, voltage and current, “DR130” manufactured by Yokogawa Electric was used. About 9
After 6 minutes, the temperature was 112.3 ° C.

Next, immediately after the temperature measurement, the Seebeck element having the P-type element 3 and the N-type element 5 was attached to the electric heater in the same state as in FIG. 1 (however, the heat pipe 6 was omitted).
The measurement was continued until the temperature of the electric heater was stabilized while measuring the temperature and the electromotive voltage (opening between the electrodes 8 and 9). The temperature measurement site of the electric heater is the left end of the electrode 7 in FIG.
The temperature of this portion can be regarded as substantially the same as the temperature of the electric heater because the P-type element 3 is 1.5 mm thick and extremely thin. The junction (low-temperature junction) of the left end of the electrode 9 with the N-type element 5 is sufficiently away from the electric heater and can be regarded as 20 ° C., which is the same as room temperature, so that the temperature measurement of this low-temperature junction is omitted. did. Immediately after attaching the Seebeck element, the temperature of the electric heater was 87.6 ° C., and the electromotive voltage was 0.44.
Although the voltage was 8 V, the temperature was stabilized after about 75 minutes had elapsed, the temperature at this time was 90 ° C., and the electromotive voltage was 0.03.
7V. From these results, the Seebeck coefficient of the N-type element 5 with respect to the P-type element 3 of the Seebeck element of the present invention is:
From the following equation, it is calculated as (0.448−0.037) / (90−87.6) = 0.171 = 171 μV / K.

The value of 171 μV / K is an epoch-making value, which is slightly more than four times the Seebeck coefficient (about 40 μV / K) of the conventional expensive nickel-containing alumel-chromel. Incidentally, since tannin is extremely cheap and easily and stably available as compared with nickel, the Seebeck element of the present invention is astonishingly four times more powerful in performance than expensive elements such as conventional alumel and chromel. Because it is inexpensive while having excellent performance,
It becomes practical to apply it as a cooling device suitable for efficient cooling of a heating element in a narrow space such as the inside of a notebook personal computer, or as an efficient power generating element of high power.

That is, as a specific application of the Seebeck element of the present invention, a DC generator is possible, and from the power generation characteristics, a geothermal generator, an ocean temperature difference generator, a waste heat generator, a solar heat generator, Generators utilizing waste heat from nuclear power,
It is suitable for use as a commercial power source, a private power source, a remote location power source, and an emergency power source, such as a generator using fission heat directly and a garbage generator.

[0017]

As described above, the present invention is a high-efficiency Seebeck element in which the N-type element contains tannin to greatly increase the Seebeck coefficient as compared with the conventional one, so that air having a slight temperature difference can be obtained. , Natural energy such as water, seawater, and geothermal energy can be efficiently converted to electric energy. Moreover, the Seebeck element of the present invention has a very simple structure without any mechanical driving part, and can be manufactured at low cost because it does not require nickel in material.
Although the thermoelectric conversion efficiency is not always high enough, it pioneered the possibility of using permanent natural energy as a means of producing industrial and household power in earnest, and from the perspective of preserving the global environment. Very useful.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a notebook computer CPU cooling device using a Seebeck element according to the present invention.

FIG. 2 is a component table of an N-type element and a P-type element.

FIG. 3 is a view showing test results of a cooling device using a Seebeck element according to the present invention.

FIG. 4 is a conceptual diagram showing a basic structure of a Seebeck element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Mother board 2 ... CPU 3 ... P-type element 4 ... Teflon spacer 5 ... N-type element 6 ... Plate type heat pipe 7, 8, 9 ... Electrode

Claims (6)

[Claims] An N-type element and a P-type element are joined to each other at two points to form a circuit, these two junctions are maintained at different temperatures, and the different circuit is connected between terminals of the open circuit. A Seebeck element for generating an open-circuit voltage according to a temperature difference, wherein the N-type element contains tannin. 2. The Seebeck element according to claim 1, wherein both the N-type element and the P-type element contain tannin. 3. The Seebeck element according to claim 1, wherein the N-type element contains Si, Al or P, Fe, tannin, or polyvinyl alcohol. 4. The Seebeck element according to claim 2, wherein the P-type element contains Si, Fe, tannin, and polyvinyl alcohol. 5. A cooling device using the Seebeck element according to claim 1. 6. A cooling device for a notebook personal computer, wherein the Seebeck element according to claim 1 is attached to a heating element such as a CPU or a hard disk inside the notebook personal computer.