JP2000012916A - Thermo-element and power-generating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assembly precision through better assembly characteristics and to provide a thermo-element, wherein a sufficient power-generation amount is assured without increasing the size. SOLUTION: This thermo-element 10 in which a P-type thermo-element 31 and an N-type thermo-element 32 are pinched and jointed between a pair of substrates 11 and 21 wherein electrodes 12 and 22 are provided on facing surfaces respectively, while the P-type thermo-element 31 and the N-type thermo- element 32 are alternately connected in series. Here, at least one of the pair of substrates 1 and 21 is formed of a transparent material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoelectric element capable of performing power generation by a temperature difference or cooling and heat generation by passing an electric current, and a thermoelectric device having the same.

[0002]

2. Description of the Related Art A thermoelectric element is manufactured by joining a P-type thermoelectric material and an N-type thermoelectric material via a conductive electrode such as a metal to form a PN junction pair. This thermoelectric element generates an electromotive force based on the Seebeck effect by giving a temperature difference between a pair of PN junctions, and thus has a use as a power generation device utilizing the temperature difference. Conversely, there is a use as a cooling device, a heating device, or the like utilizing the Peltier effect in which a current flows through the element to cool one of the joints and generate heat at the other joint.

[0003] Such a thermoelectric element is used as a thermoelectric module in which a plurality of elements are connected in series in order to improve its performance. The structure of this thermoelectric module is such that a P-type thermoelectric element and an N-type thermoelectric element each having a rectangular parallelepiped shape having a side of several hundreds μm to several mm are sandwiched between two electrically insulating substrates such as alumina and aluminum nitride. The type thermoelectric element and the N type thermoelectric element are joined on this substrate by electrodes made of a conductive material such as metal,
This joining connects the thermoelectric elements in series.

[0004] As a method of manufacturing such a thermoelectric module in which a plurality of P-type thermoelectric elements and N-type thermoelectric elements are arranged in series, generally, a P-type thermoelectric material and an N-type thermoelectric material are each heated at a temperature. After cutting into a plate having the thickness necessary to keep the difference, to join with electrodes such as metal formed on the substrate, subjected to a surface treatment such as nickel plating on both surfaces so that soldering can be performed, afterwards,
This thermoelectric material is cut into chips of a desired size, and solder for bonding is printed in advance as a wiring pattern.
There is a method of arranging and using a jig or the like on a sheet of an electrically insulating substrate such as alumina and holding them, then soldering them by heating and joining them.

Further, in order to reduce the size, a resin-molded thermoelectric element in which thermoelectric elements are integrated while being molded during cutting is also known. Further, there is known a thermoelectric element in which smaller N-type and P-type thermoelectric material elements are integrated using a thick film method. Even in the case of such a small thermoelectric element, it is necessary to perform surface treatment on the end face of each thermoelectric element, and then join the joining substrates having electrodes formed on one face to both faces.

[0006]

However, in the above-described method of manufacturing the conventional thermoelectric module, particularly when the size of the P-type thermoelectric element or the N-type thermoelectric element is reduced or the arrangement interval thereof is reduced, It becomes difficult to align the bonding surface subjected to the surface treatment such as nickel plating with the electrode formed on the bonding substrate. And
If a misalignment occurs between the P-type thermoelectric element or N-type thermoelectric element bonding surface and the proper electrode, the bonding surface of each thermoelectric element comes into contact with another electrode adjacent to the proper electrode, There is a problem that a short circuit occurs.

[0007] In the case of temperature difference power generation by a general thermoelectric module, when the temperature difference is small, a sufficient amount of power cannot be obtained, and power generation may be insufficient. In this case, it is conceivable to combine thermoelectric power generation with photovoltaic power generation used as a solar cell, but there is a problem that the element becomes large. The present invention is intended to solve such a problem, and aims at improving the assembling accuracy by improving the assembling property, and a thermoelectric element capable of securing a sufficient power generation amount without increasing the size. The task is to provide.

[0008]

A first aspect of the present invention to solve the above-mentioned problem is to sandwich and join a P-type thermoelectric element and an N-type thermoelectric element by a pair of substrates provided with electrodes on one surface facing each other. In the thermoelectric element in which the P-type thermoelectric elements and the N-type thermoelectric elements are alternately connected in series, at least one of the pair of substrates is made of a transparent material.

Therefore, when a substrate having an electrode provided on the bonding surface is bonded to the end surfaces of the P-type thermoelectric element and the N-type thermoelectric element, the substrate is made of a transparent material. In addition, the positional relationship between the end face of the N-type thermoelectric element and the electrode can be adjusted, and the assembling accuracy can be improved. A second aspect of the present invention is the thermoelectric element according to the first aspect, wherein the transparent material is sapphire glass.

By using sapphire glass having a high thermal conductivity as the material of the substrate, the assembling accuracy can be improved, while a sufficient power generation amount can be secured. According to a third aspect of the present invention, a P-type thermoelectric element and an N-type thermoelectric element are sandwiched and joined by a pair of substrates, each of which is provided with an electrode on one of the opposing surfaces. In the thermoelectric element connected in series, one of the pair of substrates is a piezoelectric substrate made of a piezoelectric material, and a counter electrode is provided on a surface of the piezoelectric substrate opposite to the electrode to form a piezoelectric element. A thermoelectric element characterized in that it is configured.

Therefore, even when mechanical stress occurs in the thermoelectric element, power is generated by the piezoelectric element. Further, by integrally attaching the piezoelectric element to the thermoelectric element, auxiliary power can be obtained without increasing the size, and a sufficient power generation amount can be secured. A fourth aspect of the present invention is the thermoelectric element according to the third aspect, wherein the piezoelectric substrate is made of a transparent material.

Therefore, when a piezoelectric substrate having electrodes provided on one side is joined to the P-type thermoelectric element and the N-type thermoelectric element, the P-type thermoelectric element is visually or image-recognized because the piezoelectric substrate is a transparent material. Good alignment between the electrode and the bonding surface of the element and the N-type thermoelectric element can be performed. According to a fifth aspect of the present invention, there is provided a power generator including the thermoelectric element according to the third or fourth aspect, and a secondary battery for charging electricity.

Therefore, the electricity generated by the thermoelectric element and the piezoelectric element can be stored in the secondary battery and used as needed.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 schematically shows a thermoelectric element according to the first embodiment of the present invention, FIG. 2 shows a plan view of the thermoelectric element constituting the thermoelectric element of the present embodiment, and FIG. 3 shows a first substrate constituting the thermoelectric element of the present embodiment. 4 and a plan view of the second substrate constituting the thermoelectric element of the present embodiment are shown in FIG.

As shown in FIG. 1, a thermoelectric element 10 according to the present embodiment has a plurality of P-type thermoelectric elements 31 and a plurality of N-type thermoelectric elements 32 joined and held between a first substrate 11 and a second substrate 21. . Here, a plurality of electrodes 12 are provided on the upper surface of the first substrate 11, and a plurality of electrodes 22 are provided on the surface of the second substrate 21. A P-type thermoelectric element 31 is provided between the opposed electrodes 12 and 22 of each substrate.
The P-type thermoelectric element 31 and the N-type thermoelectric element 32 are alternately wired in series by sandwiching the electrode and the element by soldering or the like. I have. In this embodiment, the first substrate 11 and the second substrate 21 are formed of sapphire glass as a transparent material.

Hereinafter, a method for manufacturing the thermoelectric element 10 of the present embodiment will be described. Although illustration is omitted in FIG. 1,
As shown in FIG. 2, the periphery of each P-type thermoelectric element 31 and N-type thermoelectric element 32 is molded with a thermoelectric element fixing resin 33, and the P-type thermoelectric elements 3
This constitutes a thermoelectric element fixing substrate 34 in which only the end faces of the 1 and N-type thermoelectric elements 32 are exposed. As for the P-type thermoelectric element 31 and the N-type thermoelectric element 32 of the thermoelectric element fixing board 34, the same kind of elements are arranged in a column in the figure,
In the rows, elements of different types are arranged alternately. Note that nickel layers are formed on the end faces of the P-type thermoelectric element 31 and the N-type thermoelectric element 32 by electroless plating.

On the other hand, as shown in FIG. 3, a plurality of electrodes 12 are arranged in a grid on the upper surface of a first substrate 11 having a thickness of about 0.3 mm and having electrical insulation. Each electrode 12
Is made of nickel, and solder bumps are provided on its surface by printing or the like. Here, each electrode 12 is composed of P-type thermoelectric elements 31 alternately arranged in rows as shown in FIG.
And the N-type thermoelectric element 32 is provided so as to be connected to adjacent end faces.

As shown in FIG. 4, a plurality of electrodes 22 are also provided on the upper surface of the second substrate 21 having a thickness of about 0.3 mm having electrical insulation. Here, the electrode 22 is
Although it is the same as the electrode 12, the arrangement of the electrode 22 is provided so as to connect adjacent P-type thermoelectric elements 31 and N-type thermoelectric elements 32 that are not connected by the electrode 12. Therefore, a wiring 23 is provided to connect the left end of each row in the figure and the right end of the next row, whereby all the P-type thermoelectric elements 31 and the N-type thermoelectric elements are connected via the electrodes 12 and 22. 32 can be connected alternately in series. Both ends of these series connections are taken out of the electrodes 22A and 22B. Here, these substrates 11 and 21 have high thermal conductivity, and it is necessary to transmit heat to each thermoelectric material as much as possible without loss. In general, the ease of conducting heat is represented by the equation of easy conducting of heat = heat conductivity × (cross sectional area of flowing heat / length of flowing heat).

Here, the thermal conductivity of the Bi-Te-based thermoelectric material is about 1 W / (m · κ), and the thermal conductivity of copper or nickel is 4
It is about 00 to 100 W / (m · κ). In order to reduce the loss of the substrate, it is desirable that the thermal conductivity of the substrates 11 and 12 be at least 10 times that of the thermoelectric material. The sapphire glass used in this embodiment has a thermal conductivity of about 40 W / (m · κ), which is sufficient in terms of thermal conductivity.

The substrates 11 and 21 are joined to the thermoelectric element fixed substrate 34. That is, first, for example, the substrate 11 is placed on one surface of the thermoelectric element fixed substrate 34, and the electrodes 12 and the end faces of the P-type thermoelectric elements 31 and the N-type thermoelectric elements 32 are aligned and adhered. By heating, the electrode 12 and the P-type thermoelectric element 31 and N
The end face of the mold thermoelectric element 32 is soldered. At this time, since the substrate 11 is transparent, each electrode 12 and the end faces of each of the P-type thermoelectric elements 31 and the N-type thermoelectric elements 32 can be reliably aligned while recognizing them with images.
At least the electrode 12 can be prevented from contacting the adjacent end face that should not be in contact. Next, the bonding of the substrate 21 can be performed in the same manner, and similarly, the alignment of each electrode 22 with the end faces of the P-type thermoelectric element 31 and the N-type thermoelectric element 32 can be performed by image processing.

In this manner, the P-type thermoelectric element 31 and the N-type thermoelectric element 32 are sandwiched between the substrates 11 and 21 on which the electrodes 12 and 22 are formed, and are joined to each other. N-type thermoelectric element 3
Thus, the thermoelectric element 10 in which the two are alternately wired in series is configured. With such a configuration, the first substrate 11 and the second substrate 21 can be easily joined to the P-type thermoelectric element 31 and the N-type thermoelectric element 32, and
The joining accuracy is improved and the defect rate is significantly reduced. In addition, a fine thermoelectric element can be manufactured, and can be used as a thermoelectric element for a small low-power device or as a cooling element, and versatility is improved. In the above-described embodiment, both the substrates 11 and 21 are transparent substrates. However, either one of them may be used. In addition to a sapphire glass, a transparent substrate having good thermal conductivity may be used. Can be used.

FIG. 5 schematically shows a thermoelectric element according to a second embodiment of the present invention, and FIG. 6 shows a circuit of a power generating apparatus to which the thermoelectric element of the present embodiment is applied. Note that members having the same functions as those described in the above-described embodiment are denoted by the same reference numerals, and redundant description will be omitted. As shown in FIG. 5, the thermoelectric element of the present embodiment is the same as the thermoelectric element 10 of the first embodiment described above.
The function of the piezoelectric element 50 is added to FIG.

That is, in this embodiment, the piezoelectric substrate 41 made of a piezoelectric material is used instead of the first substrate 11 of the above-described embodiment.
Is used. A plurality of electrodes 12 are provided on the upper surface of the piezoelectric substrate 41.
Are provided in the same manner, while a plurality of electrodes 22 are also provided on the surface of the second substrate 21. The P-type thermoelectric element 31 and the N
The point that the P-type thermoelectric element 31 and the N-type thermoelectric element 32 are alternately wired in series by sandwiching the mold thermoelectric element 32 and joining the joining surfaces by soldering is different from the above-described embodiment. The same is true. Therefore,
Thus, the thermoelectric element 10A is formed, and the piezoelectric substrate 41 is formed.
When a temperature difference occurs between the first substrate and the second substrate 21, power is generated.

On the opposite side of the piezoelectric substrate 41 from the electrode 12, a counter electrode 51 and a vibration plate 52 are sequentially joined to form a piezoelectric element 50. Therefore, when distortion occurs in the piezoelectric substrate 41, power is generated. Further, in the present embodiment, the vibration plate 52 has a function of transmitting distortion (vibration) from the outside to the piezoelectric substrate 41, and gives favorable distortion to the piezoelectric substrate 41.

In this embodiment, the first substrate 11 is made of PZT (trade name: PbZrO3-Pb) as a piezoelectric material.
The second substrate 21 is formed of sapphire glass as a transparent material. Also,
The vibration plate 52 may be made of a material that easily transmits vibration to the piezoelectric substrate 41 and has high thermal conductivity and easily transmits heat to the piezoelectric substrate 41, for example, a copper alloy such as brass.

The thermoelectric element configured as described above can extract electric power based on the original function of the thermoelectric element between the electrode 22A and the electrode 22B of the thermoelectric element 10A.
Electric power by the piezoelectric element 50 can be taken out between the second electrode 2 and the counter electrode 51. However, actually, the voltage is not directly taken out from the electrode 12, but is taken out from the electrode 22A. With these configurations, as shown in FIG. 6, by connecting the electrodes 22A and 22B of the thermoelectric element 10A to the secondary battery 62 via the charge control circuit 61, the generated electricity is stored in the secondary battery 62. The electrode 12 and the counter electrode 51 of the piezoelectric element 50 are connected to a secondary battery 62 via a rectifier 63 and a charge control circuit 61, so that the power generated by the piezoelectric element 50 simultaneously
Can be stored.

As a result, the electric power generated by the temperature difference in the thermoelectric element 10A and the electric power generated by the distortion of the diaphragm 52 by the piezoelectric element 50 are added in the charge control circuit 61, and the energy can be effectively used. Also, the piezoelectric substrate 51
Also, since the electrode 12 is shared by both elements, there is an advantage that the element does not increase in size. Also in this case, since the second substrate 21 is formed of a transparent material,
This has the effect of facilitating assembly and improving assembly accuracy. Further, by forming the piezoelectric substrate 41 from a transparent material such as quartz or PLZT, the assembling becomes easier and the assembling accuracy is similarly improved.

The electrodes 12, 22 of the substrates 41, 21
And each P-type thermoelectric element 31 and N-type thermoelectric element 3
There are a large number of junctions with 2 and it is necessary to ensure that all junctions are made. Generally, the connection is measured by measuring the electric resistance. If there is an incomplete connection, the electric resistance is initially normal, but may be broken thereafter. In order to solve this problem, in the present embodiment, a vibration plate 52 is provided on the piezoelectric substrate 41 via the counter electrode 51, and then an alternating voltage is applied to both surfaces of the piezoelectric substrate 41 to vibrate, thereby reducing defective products. Screening can be performed by accelerating the deterioration. Therefore, it is possible to prevent the occurrence of a subsequent defect beforehand.

As another example of use, it is possible to emit sound by vibration obtained by applying an alternating voltage to both surfaces of the piezoelectric substrate 41. This can be used, for example, as an alarm buzzer, and the generator with an alarm sounding function can be made small and inexpensive.

[0030]

As described above in detail in the embodiment, according to the thermoelectric element of the present invention, since the substrate is made of a transparent material, the P-type thermoelectric element and the N-type thermoelectric element can be visually or image-processed. The alignment between the bonding surface and the electrode can be reliably performed, and the assembling accuracy can be improved.

Further, by assembling the piezoelectric element using one electrode of the thermoelectric element and the substrate, power generation by temperature difference and power generation by vibration can be performed at the same time. The amount of power generation can be secured.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a thermoelectric element according to a first embodiment of the present invention.

FIG. 2 is a plan view of a thermoelectric element constituting the thermoelectric element of the present embodiment.

FIG. 3 is a plan view of a first substrate constituting the thermoelectric element of the present embodiment.

FIG. 4 is a plan view of a second substrate constituting the thermoelectric element of the present embodiment.

FIG. 5 is a schematic diagram of a thermoelectric element according to a second embodiment of the present invention.

FIG. 6 is a circuit diagram of a power generation device to which the thermoelectric element of the second embodiment is applied.

[Explanation of symbols]

 10, 10A Thermoelectric element 11 First substrate 12 Electrode 21 Second substrate 22 Electrode 23 Wiring 31 P-type thermoelectric element 32 N-type thermoelectric element 33 Fixing jig plate 41 Piezoelectric substrate 50 Piezoelectric element 51 Counter electrode 52 Vibration plate 61 Rectifier 62 Charge control circuit 63 Secondary battery

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasushi Nakabayashi 1-8-8 Nakase, Mihama-ku, Chiba-shi, Chiba Seiko Instruments Inc.

Claims (6)

[Claims] 1. A pair of substrates sandwiching a P-type thermoelectric element and an N-type thermoelectric element, and electrodes provided on the substrate for connecting the P-type thermoelectric element and the N-type thermoelectric element alternately in series. And at least one of the pair of substrates is made of a transparent material. 2. The thermoelectric element according to claim 1, wherein said transparent material is sapphire glass. 3. A pair of substrates sandwiching a P-type thermoelectric element and an N-type thermoelectric element, and electrodes provided on the substrate for connecting the P-type thermoelectric element and the N-type thermoelectric element alternately in series. A thermoelectric element comprising: a substrate of one of the pair of substrates being a piezoelectric substrate made of a piezoelectric material, and a counter electrode provided on a surface of the piezoelectric substrate opposite to a surface on which the electrodes are formed. A thermoelectric element comprising a piezoelectric element. 4. The thermoelectric element according to claim 3, wherein said piezoelectric substrate is made of a transparent material. 5. A piezoelectric substrate made of a piezoelectric material, a substrate which faces the piezoelectric substrate and sandwiches a P-type thermoelectric element and an N-type thermoelectric element, and the P-type thermoelectric element and the N-type thermoelectric element are alternately arranged. A thermoelectric element having the piezoelectric substrate and an electrode formed on the substrate for connecting in series, a counter electrode formed on a surface of the piezoelectric substrate opposite to the surface on which the electrode is formed, And a secondary battery for charging the generated electricity. 6. The power generator according to claim 5, wherein the piezoelectric substrate is made of a transparent material.