JPH08107237A - Thermoelectric element and electronic apparatus using thermoelectric element - Google Patents

Abstract

PURPOSE: To provide a thermoelectric element wherein the thicknesses of an N-type semiconductor and a P-type semiconductor are determined by considering power generation capability and miniaturization, and an electronic apparatus using the thermoelectric element. CONSTITUTION: A first insulator 101 of aluminum having an oxide film is set as a heat absorption side. A second insulator 102 of aluminum having an oxide film is set as a heat radiation side. When temperature difference is applied in the manner in which the temperature of the heat absorption side is higher than that of the heat radiation side, heat is conducted from the first insulator 101 to the second insulator 102. In this case, electrons in N-type semiconductor 103 move toward the insulator 102 on the heat radiation side. Positive holes in P-type semiconductor 104 move toward the insulator 102 on the heat radiation side. Since the the N-type semiconductors 103 and the P-type semiconductors 104 are electrically connected in series through connection parts 105, the conduction of heat is converted into a current, and an electromotive force can be obtained from both output terminal parts 106.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric element for realizing an electronic device that does not use a battery as an energy source, and an electronic device using the thermoelectric element as an energy source.

[0002]

2. Description of the Related Art As an energy source for electronic equipment,
Batteries were mainly used. However, the user must always have a concern that the battery will run out during use, and if the battery runs out during use, the damage can be significant. Then, when the battery runs out, the battery is replaced, or when the user cannot do it, he is forced to ask another person. Moreover, used batteries cannot be disposed of in the same manner as general waste, because they cause environmental damage.

As an energy source replacing the battery, a thermoelectric element that generates an electromotive force based on the Seebeck effect has been recently researched. For example, FIG. 9 is a diagram showing a power generation principle of a thermoelectric generator. In the thermoelectric generator, a large number of p-type thermoelectric elements (901) and n-type thermoelectric elements (902) are connected in series, and an insulating plate (903), a heat radiating plate (904) and a heat absorbing plate (90) are connected.
5). The thermoelectric generator as above
For example, it is disclosed in Japanese Patent Application Laid-Open No. 54-123047.

On the other hand, electronic devices using thermoelectric elements have been recently researched. For example, FIG. 10 is a diagram showing a configuration of a thermoelectric wristwatch. The thermoelectric wristwatch has a movement (100
1), a thermoelectric generator (1002), an electric energy storage device, and a multi-part wristwatch casing (1003) including a metal bottom, a frame, and a metal top.
And. The thermoelectric wristwatch as described above is disclosed in, for example, Japanese Patent Laid-Open No. 55-20483. However, a thermoelectric element module considering power generation capacity and miniaturization has not yet been put into practical use.

[0005]

The power generation capacity of the thermoelectric element is proportional to the number of n-type semiconductors and p-type semiconductors, and the n-type semiconductors and p-type semiconductors are thicker. That is, in order to obtain high power generation capability, the number of n-type semiconductors and p-type semiconductors is increased and the thickness is increased, so that the entire thermoelectric element becomes large. However, when this thermoelectric element is mounted on an electronic device, it is ideal that the thermoelectric element is as small as possible, and there is a conflicting requirement between increasing the power generation capacity and downsizing the thermoelectric element.

Therefore, an object of the present invention is to provide a thermoelectric element in which the thicknesses of the n-type semiconductor and the p-type semiconductor are determined in consideration of power generation capability and miniaturization, and electronic equipment using the thermoelectric element. .

[0007]

In order to solve the above problems, the present invention provides a thermoelectric element having an n-type semiconductor and a p-type semiconductor.
Focusing not only on the number and thickness of the n-type semiconductors, but also on the thermal conductivity of the insulator. When aluminum with an oxide film is used for the insulator, the n-type semiconductor and p-type semiconductor are used.
The thickness of the type semiconductor is 0.1 to 3 mm, more preferably 0.
It was 2-1 mm.

[0008]

1 is a diagram showing the structure and power generation principle of the first thermoelectric element of the present invention. The first insulator 101 is on the heat absorption side, and the second insulator 102 is on the heat dissipation side. When the temperature difference on the heat absorption side is higher than that on the heat radiation side, heat is transferred from the first insulator 101 to the second insulator 102. At that time, in the n-type semiconductor 103, electrons move toward the heat radiating side insulator 102. In the p-type semiconductor 104, holes move in the direction of the insulator 102 on the heat dissipation side. Since the n-type semiconductor 103 and the p-type semiconductor 104 are electrically connected in series via the connection part 105, heat transfer is converted into a current, and the output terminal parts 10 at both ends are converted.
An electromotive force can be obtained from 6.

FIG. 2 is a diagram showing the structure and power generation principle of the second thermoelectric element of the present invention. The first insulator 201 is on the heat absorption side and the second insulator 202 is on the heat dissipation side. When the temperature difference on the heat absorption side is higher than that on the heat radiation side, heat is transferred from the first insulator 201 to the second insulator 202. At that time, the n-type semiconductor composite element 20
In 3, the electrons move toward the insulator 202 on the heat radiation side. In the p-type semiconductor composite element 204, holes move in the direction of the insulator 202 on the heat dissipation side. Since the n-type semiconductor composite element 203 and the p-type semiconductor composite element 204 are electrically connected in series via the connection part 205, heat transfer is converted into an electric current, and electromotive force is generated from the output terminal parts 206 at both ends. Can be obtained.

Further, FIG. 3 is a block diagram showing the operating principle of an electronic device using the thermoelectric element of the present invention as an energy source. When a temperature difference is applied to the thermoelectric element 301 and an electromotive force is generated, electricity is stored in the power storage mechanism 302. The voltage of electricity stored in the power storage mechanism 302 is the driving mechanism 303.
When it reaches a size large enough to drive the
3 is driven, and the operation / display mechanism 304 starts working.

[0011]

EXAMPLE FIG. 4 is a diagram showing the structure and power generation principle of an example of the thermoelectric element of the present invention. The first insulator is made of, for example, aluminum 401 to which an oxide film 407 is attached, and has a heat absorbing side. The second insulator is made of, for example, aluminum 402 to which an oxide film 408 is attached, and serves as a heat radiation side. When a temperature difference of about 2 degrees is given such that the temperature on the heat absorption side is higher than that on the heat radiation side, heat is transferred from the first insulator to the second insulator. At that time, in the n-type semiconductor 403, for example, in the bismuth-tellurium system, the namaly-tellurium system, or the iron-silicide system, the electrons move toward the second insulator on the heat radiation side. In the p-type semiconductor 404, for example, in the bismuth-tellurium system, the namari-tellurium system, or the iron-silicide system, holes move toward the second insulator on the heat dissipation side. Since the n-type semiconductor 403 and the p-type semiconductor 404 are electrically connected in series via the connecting portion 405, for example, an electrode, heat transfer is converted into a current, and electromotive force can be obtained from the output terminal portion 406. The electromotive force obtained from the output terminal portion 406 charges the storage element 409.

FIG. 5 is a graph showing changes in the output voltage with respect to the thicknesses of the n-type semiconductor and the p-type semiconductor when aluminum having an oxide film attached to the first insulator and the second insulator is used. is there. At this time, the temperature difference applied to the thermoelectric element was 2 degrees, and the cross-sectional area of the semiconductor was 0.01 mm ² . The total number of semiconductors, including n-type and p-type, is 3000, 4000, 5
The cases of 000 and 6000 are shown. In order to substitute for the 1.5v battery, the variation in the output voltage due to the thickness error of the n-type semiconductor and the p-type semiconductor is reduced.
400 mm can be obtained at least 1.4 V
0 is required. In addition, defects during manufacturing and temperature difference of 2
Considering the case of slightly lower than the degree, about 5000 pieces are required. Here, the temperature difference is set to 2 degrees because, when the thermoelectric element of the present invention is mounted on an electronic wristwatch, the temperature difference obtained is about 2 degrees by an experiment.

The actual value of the operating voltage of a general IC is 0.7v.
However, when mounted on an electronic device, for example, an electronic wristwatch, there is a restriction on the appearance, so that it is desirable that the thicknesses of the n-type semiconductor and the p-type semiconductor are 0.1 mm or more and 3 mm or less as shown in FIG. More desirably, when the standard value of the operating voltage of a general IC is set to 1.2v and a larger voltage is to be obtained, n
It is preferable that the rate of increase of the output voltage with respect to the increase of the thicknesses of the n-type semiconductor and the p-type semiconductor is 10% or more in view of efficiency. It is desirable to set it to 2 mm or more and 1 mm or less. For example, the cross-sectional area of n-type semiconductor and p-type semiconductor is 0.01 mm
2, thickness is 1mm, the number is n-type and p-type total 4000, n
Assuming that the distance between the p-type semiconductor and the p-type semiconductor is about 0.2 mm, and the combined thickness of the heat-radiating and heat-absorbing electrodes and the insulating plate is 1 mm, the size of the thermoelectric element is about 14 mm x 1
It becomes 4 mm x 3 mm, and it is possible to obtain an electromotive force of about 1.4 V when a temperature difference of 2 degrees is given.

FIG. 6 is a block diagram showing the operating principle of an electronic wristwatch as an embodiment of an electronic device using the thermoelectric element of the present invention as a power source. When a temperature difference is applied to the thermoelectric element 601 and an electromotive force is generated, electricity is stored in the storage element 603 via the charge control circuit 602. Power storage element 603
The drive control circuit 604 is driven by the electricity stored in
The time is displayed on the display mechanism 605.

FIG. 7 is a view showing the external appearance of an embodiment of the electronic wrist watch of the present invention. Heat dissipation plate 701 to facilitate heat dissipation
Is exposed on the surface. The heat dissipation plate 701 is made of, for example, aluminum with an oxide film attached for insulation.
FIG. 8 is a sectional view showing the structure of the embodiment of the electronic wrist watch of the present invention. The insulating plate 801 is a heat absorbing side for touching an arm that is generally higher in temperature than the air temperature, and the insulating plate 802 is a heat radiating side for being in the atmosphere. The insulating plates 801 and 802 are made of, for example, aluminum with an oxide film. For example, if the wearer's body temperature is 36 degrees Celsius and the temperature is 20 degrees Celsius and the entire electronic wristwatch is close to the arm temperature,
The temperature difference between the insulating plate 801 and the insulating plate 802 is 2
It is around. When a temperature difference occurs, heat is transferred from the insulating plate 801 through the n-type and p-type semiconductors 803 to the insulating plate 802 and radiated into the atmosphere. At this time, electromotive force is generated by the Seebeck effect, and the electricity is stored in the electricity storage element 804, for example, a lithium secondary battery, a carbon-lithium secondary battery, or a vanadium-lithium secondary battery. The stored electricity drives a movement 805 which is composed of a train wheel and a motor and performs a hand movement operation.

[0016]

As described above, according to the present invention,
By setting the thickness of the n-type and p-type semiconductor of the thermoelectric element using aluminum with an oxide film attached to the insulator to 0.1 to 3 mm, more preferably 0.2 to 1 mm, the required electromotive force can be obtained. As the thermoelectric element for obtaining the thermoelectric element, it is possible to obtain a thermoelectric element having high power generation efficiency and a small size. Furthermore, by using this thermoelectric element in an electronic device, the electronic device can be downsized.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure and a power generation principle of a first thermoelectric element of the present invention.

FIG. 2 is a diagram showing a structure and a power generation principle of a second thermoelectric element of the present invention.

FIG. 3 is a block diagram showing an operation principle of an electronic device using the thermoelectric element of the present invention as an energy source.

FIG. 4 is a diagram showing a structure and a power generation principle of an embodiment of the thermoelectric element of the present invention.

FIG. 5 is a diagram showing a relationship between a semiconductor thickness and an output voltage according to a difference in the number of semiconductors of the thermoelectric element of the present invention.

FIG. 6 is a block diagram showing an operation principle of an electronic wristwatch as an embodiment of an electronic device using the thermoelectric element of the present invention as a power source.

FIG. 7 is a diagram showing an appearance of an electronic wrist watch according to an embodiment of the present invention.

FIG. 8 is a sectional view showing the structure of an electronic wrist watch according to an embodiment of the present invention.

FIG. 9 is a diagram showing a structure of a conventional thermoelectric element and a power generation principle.

FIG. 10 is a cross-sectional view showing the structure of a conventional electronic wristwatch using a thermoelectric element as a power source.

[Explanation of symbols]

 Reference Signs List 101 first insulator 102 second insulator 103 n-type semiconductor 104 p-type semiconductor 105 connecting portion 106 output terminal portion 203 n-type semiconductor composite element 204 p-type semiconductor composite element 301, 601 thermoelectric element 302 storage mechanism 409, 603 , 804 Storage element 303 Drive mechanism 304 Operation, display mechanism 401, 402 Aluminum 407, 408 Oxide film 602 Charge control circuit 604 Drive control circuit 605 Display mechanism 701, 801 Heat sink 802 Insulating plate 803 N-type and p-type semiconductor 805 Movement

Claims (6)

[Claims] 1. A plurality of n-type semiconductors (103) and a plurality of p-types.
Type semiconductors (104) and a plurality of connection parts (105) and output terminal parts (10) for alternately connecting them in series electrically.
6) and a first insulator (101) made of aluminum with an oxide film for fixing every other connecting portion (105), and one not connected by the first insulator A second insulator (102) made of aluminum having an oxide film for fixing every other connection portion (105), and a first insulator (101) and a second insulator (102). A plurality of n-type semiconductors (103) and a plurality of p fixed between
The thickness of each type semiconductor (104) is 0.1 mm to 3 mm
A thermoelectric element characterized in that 2. A plurality of n-type semiconductor composite elements (203) composed of a plurality of n-type semiconductors, and a plurality of p-type semiconductor composite elements (204) composed of a plurality of p-type semiconductors. Of the n-type semiconductor composite element (203) and the plurality of p-type semiconductor composite elements (204) are alternately connected so as to be electrically connected in series. The first insulator (201) made of aluminum with an oxide film for fixing every other connecting portion (205) and every other first insulator (201) not connected by the first insulator (201). A second insulator (202) made of aluminum with an oxide film for fixing the connection part (205)
And a first insulator (201) and a second insulator (2
02) a plurality of n-type semiconductor composite elements (203) and a plurality of p-type semiconductor composite elements (204)
A thermoelectric element having a thickness of 0.1 mm to 3 mm. 3. The thermoelectric element according to claim 1, wherein a plurality of n-type semiconductors (103) and a plurality of p-type semiconductors (10).
A thermoelectric element characterized in that each thickness of 4) is 0.2 mm to 1 mm. 4. The thermoelectric element according to claim 2, wherein each of the plurality of n-type semiconductor composite elements (203) and the plurality of p-type semiconductor composite elements (204) has a thickness of 0.2 mm to 1.
mm is a thermoelectric element. 5. An electronic device which requires an energy source, wherein the thermoelectric element according to any one of claims 1 to 4 is used as the energy source. 6. An electronic timepiece which requires an energy source, wherein the thermoelectric element according to any one of claims 1 to 4 is used as the energy source.