WO2021200264A1

WO2021200264A1 - Thermoelectric conversion module

Info

Publication number: WO2021200264A1
Application number: PCT/JP2021/011333
Authority: WO
Inventors: 佑太関; 邦久加藤; 豪志武藤
Original assignee: リンテック株式会社
Priority date: 2020-03-30
Filing date: 2021-03-19
Publication date: 2021-10-07

Abstract

Provided is a thermoelectric conversion module which exhibits a further improved heat-absorbing property with a simple configuration. The thermoelectric conversion module is provided with a first electrode, a p-type thermoelectric element layer and n-type thermoelectric element layer, and a second electrode disposed so as to face the first electrode. In the thermoelectric conversion module, a plurality of pairs of p‐n junctions, each of which is formed by joining the p-type thermoelectric element layer and the n-type thermoelectric element layer with the first electrode or the second electrode interposed therebetween, are electrically connected in series with the first electrode and the second electrode alternately disposed. The thermoelectric conversion module is provided to a circuit substrate comprising electronic elements. The second electrode is disposed on the circuit substrate and/or inside the circuit substrate.

Description

Thermoelectric conversion module

The present invention relates to a thermoelectric conversion module.

Conventionally, there is a thermoelectric conversion module that uses a thermoelectric conversion material having a thermoelectric effect such as the Seebeck effect and the Perche effect to convert between thermal energy and electrical energy.
As the thermoelectric conversion module, a configuration of a so-called π-type thermoelectric conversion element is known. In the π-type, for example, a pair of electrodes that are separated from each other are provided on the substrate, and the lower surface of the P-type thermoelectric element is provided on the one electrode and the lower surface of the N-type thermoelectric element is provided on the other electrode. The P-type thermoelectric element and the N-type thermoelectric element are provided apart from each other, and the upper surfaces of the P-type thermoelectric elements and the N-type thermoelectric elements are bonded to the electrodes of the opposing substrates (hereinafter, may be referred to as “PN junction”). Usually, from the viewpoint of thermoelectric performance, a plurality of pairs of PN-junctioned P-type thermoelectric elements and N-type thermoelectric elements are used, and are configured to be electrically connected in series and thermally connected in parallel.

In recent years, electronic devices such as computers, mirrorless cameras, and mobile terminals such as smartphones have been used as semiconductor elements such as CPUs (Central Processing Units) and CMOSs (Complementary Metal Axis Semiconductor Image Sensors) that operate and control them. While it has become commonplace for typical electronic devices to be mounted on a substrate at high density, the temperature of semiconductor devices themselves becomes high as semiconductor devices become smaller and have higher performance due to further miniaturization. Moreover, it has become a heating element that emits a large amount of heat. Under such circumstances, there is a demand for a cooling device that more efficiently absorbs and dissipates heat generated by a semiconductor element mounted on a circuit board.
As one of the corresponding methods, electronic cooling or the like using the thermoelectric conversion module is used.
Patent Document 1 describes a first semiconductor substrate having a photoelectric conversion unit, a heat conductive wiring provided in contact with the first semiconductor substrate, and a cooling element that controls the temperature of the photoelectric conversion unit via the heat conductive wiring. The provided imaging device is disclosed. For example, the above-mentioned CMOS is used as the first semiconductor substrate having a photoelectric conversion unit, and a light receiving region having a plurality of pixels constituting the CMOS and a peripheral region provided outside the light receiving tilt region and having a peripheral circuit are provided. In order to cool, a CMOS element is used as a cooling element, and a heat conductive wiring is interposed or the above region is directly cooled.
Patent Document 2 is a circuit board including at least one Perche heat pump device, wherein the Perche heat pump device includes at least one pair of thermoelectric semiconductor members that are thermally arranged in parallel and electrically arranged in series, and at least one pair. The semiconductor member of the above discloses a circuit board in which the semiconductor member is at least partially embedded in the circuit board. For example, in the thermoelectric semiconductor member, an electrode serving as a heat absorbing surface and an electrode serving as a heat radiating surface are arranged on the same plane. As described above, those having a so-called comb-shaped structure are described.

International Publication No. 2019/078291 Japanese Unexamined Patent Publication No. 2014-204123

However, from the viewpoint of dimensions, functional action, etc., a thermoelectric conversion module having a configuration for more efficient temperature control is desired in a circuit board or the like on which an electronic element or the like that requires a specific arrangement is mounted. There is.

In view of the above, it is an object of the present invention to provide a thermoelectric conversion module having a simple structure and further improved endothermic property.

As a result of diligent studies to solve the above problems, the present inventors have made a second electrode used for forming a PN junction pair composed of a P-type thermoelectric element layer and an N-type thermoelectric element layer constituting a thermoelectric conversion module. By extending and / or arranging inside the circuit board on the circuit board provided with the electronic element, the heat absorption generated on the surface of the second electrode is directly applied to the electronic element, and the electronic element is arranged in the circuit board. We have found that the electronic device can be efficiently cooled without limitation, and completed the present invention.
That is, the present invention provides the following (1) to (8).
(1) The P-type thermoelectric element layer and the N-type thermoelectric element layer including a first electrode, a P-type thermoelectric element layer, an N-type thermoelectric element layer, and a second electrode arranged to face the first electrode, and the P-type thermoelectric element layer and the above. There are a plurality of pairs of PN junctions in which the N-type thermoelectric element layer is PN-bonded with the first electrode or the second electrode interposed therebetween, and the first electrode and the second electrode are alternately electrically connected. A thermoelectric conversion module arranged in series on a circuit board provided with an electronic element, wherein the second electrode is arranged on the circuit board and / or inside the circuit board.
(2) The thermoelectric conversion module according to (1) above, further comprising a first substrate, wherein the first substrate has the first electrode.
(3) The thermoelectric conversion module according to (1) or (2) above, wherein the second electrode extends on the circuit board and is thermally connected to the electronic element.
(4) The thermoelectric conversion according to any one of (1) to (3) above, wherein the second electrode extends on the circuit board and inside the circuit board and is thermally connected to the electronic element. module.
(5) The circuit board has a through hole, and the second electrode is thermally connected to the electronic element from a surface of the circuit board opposite to the electronic element side via the through hole. The thermoelectric conversion module according to any one of (1) to (4) above.
(6) The thermoelectric conversion module according to any one of (1) to (5) above, wherein all of the second electrodes are arranged inside the through holes and thermally connected to the electronic element.
(7) The above-mentioned (1) to (6), wherein the entire thermoelectric conversion module is arranged inside the through hole, and the second electrode is thermally connected to the electronic element. Thermoelectric conversion module.
(8) Any of the above (1) to (7), wherein the second electrode further extends in the in-plane direction of the circuit board on the electronic element side and is thermally connected to the electronic element. The thermoelectric conversion module described in.

According to the present invention, it is possible to provide a thermoelectric conversion module having further improved endothermic properties with a simple configuration.

It is a perspective view which shows an example of the basic structure of the thermoelectric conversion module used in this invention. It is a top view for demonstrating the structure of the thermoelectric conversion module which concerns on 1st Embodiment of this invention. It is a transmission perspective view for demonstrating an example of the structure of the conventional thermoelectric conversion module. It is sectional drawing for demonstrating the structure of the thermoelectric conversion module which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the structure of the thermoelectric conversion module which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the structure of the thermoelectric conversion module which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the structure of the thermoelectric conversion module which concerns on 5th Embodiment of this invention. It is sectional drawing which shows the structure of the thermoelectric conversion module which concerns on 6th Embodiment of this invention.

[Thermoelectric conversion module]
The thermoelectric conversion module of the present invention includes a first electrode, a P-type thermoelectric element layer, an N-type thermoelectric element layer, and a second electrode arranged to face the first electrode, and the P-type. A plurality of pairs of PN junctions in which the thermoelectric element layer and the N-type thermoelectric element layer are PN-bonded with the first electrode or the second electrode interposed therebetween, and the first electrode and the second electrode are used. It is a thermoelectric conversion module arranged on a circuit board provided with electronic elements, which are alternately electrically connected in series, and is characterized in that the second electrode is arranged on the circuit board and / or inside the circuit board. do.
In the thermoelectric conversion module of the present invention, a second electrode used for forming a PN junction pair composed of a P-type thermoelectric element layer and an N-type thermoelectric element layer constituting the thermoelectric conversion module is extended on a circuit board provided with an electronic element. By arranging it in the circuit board and / or inside the circuit board, the heat absorption generated on the surface of the second electrode is directly applied to the electronic element, and the electronic element is efficiently cooled without limitation in the arrangement of the electronic element in the circuit board. can do.
In the thermoelectric conversion element, the positional relationship between the endothermic side and the heat radiating side is usually reversed depending on the direction of energization. Further, the polarity of the output is switched by switching the endothermic side and the heat radiating side. Therefore, the present invention is not limited as to which electrode is on the endothermic side or the heat radiating side. In this specification, for convenience, the second electrode side is described as the endothermic side, and the first electrode side is described as the heat dissipation side.

FIG. 1 is a perspective view showing an example of a basic configuration of a thermoelectric conversion module used in the present invention. The thermoelectric conversion module is configured as a so-called π-type thermoelectric conversion element, and faces, for example, the first electrode 1b, the P-type thermoelectric element layer 3 and the N-type thermoelectric element layer 4, and the first electrode 1b. A second electrode 2b, which is arranged in the same manner, is included in the configuration.
In the configuration of the thermoelectric conversion module of the present invention, it is preferable that the first substrate is further included, and the first substrate has the first electrode. By providing the first substrate on the side of the first electrode opposite to the P-type thermoelectric element layer and the N-type thermoelectric element layer, the heat dissipation distribution from the first electrode is made uniform and the heat dissipation is improved.
Further, in FIG. 1, a plurality of PN junction pairs in which the P-type thermoelectric element layer 3 and the N-type thermoelectric element layer 4 are PN-junctioned with the first electrode 1b or the second electrode 2b interposed therebetween are the first pair. The electrode 1 and the second electrode are alternately electrically connected in series and thermally connected in parallel. The number of PN junction pairs composed of the P-type thermoelectric element layer 3 and the N-type thermoelectric element layer 4 is not particularly limited, and is usually a plurality of pairs, which can be appropriately adjusted and used.

Hereinafter, the present invention will be specifically described with reference to the drawings.

(First Embodiment)
It is preferred that the second electrode extends over the circuit board and is thermally connected to the electronic device.
The second electrode constituting the thermoelectric conversion module arranged on the circuit board extends in the direction toward the electronic element separated on the circuit board and is thermally connected to efficiently cool the electronic element. can do.
More preferably, the second electrode is disposed over the entire surface of any of the upper and lower surfaces of the electronic device and is thermally connected.

FIG. 2 is a plan view showing the configuration of the thermoelectric conversion module according to the first embodiment of the present invention (however, it extends to the region of the surface of the first electrode, the first substrate, and the electronic element on the circuit board side). The second electrode to be used is not shown).

In the configuration of the thermoelectric conversion module according to the first embodiment of the present invention, the electronic element 6 is mounted on the circuit board 5, and at a position separated from the circuit board 5, directly above the second electrode 2b. A thermoelectric conversion module including the laminated P-type thermoelectric element layer 3 and N-type thermoelectric element layer 4 is arranged, and heat is provided with the electronic element 6 via an electrode portion extending from the second electrode 2b of the thermoelectric conversion module. Is connected.
Regarding the area of the first electrode 1b (not shown) and the area of the second electrode 2b facing each other, the area of the second electrode 2b is sufficiently larger than the area of the first electrode 1b. When the thermoelectric conversion module is energized so that the second electrode 2b serves as a heat absorbing surface, the heat absorbing property is increased, and the electronic element 6 separated on the circuit board 5 can be efficiently cooled.

FIG. 3 is a transmission perspective view (a part of the constituent portion is visualized) showing an example of the configuration of the conventional thermoelectric conversion module.
The conventional thermoelectric conversion module is configured as a π-type thermoelectric conversion element. For example, a first substrate 1a having a first electrode 1b, a P-type thermoelectric element layer 3 and an N-type thermoelectric element layer 4, and the above-mentioned first. It includes a second electrode 2b'arranged so as to face the electrode 1b of 1, and further includes a second substrate 2a'.
As a configuration of the thermoelectric conversion module on the circuit board 5, when the second substrate 2a'having the second electrode 2b'is used as a heat absorbing surface, the thermoelectric conversion module is arranged on the electronic element 6 mounted on the circuit board 5. It is thermally connected to the electronic element 6.

In the thermoelectric conversion module of the embodiment of the present invention, the surface of the first electrode 1b opposite to the P-type thermoelectric element layer 3 and the N-type thermoelectric element layer 4 side is the heat dissipation surface, and the other surface is the second surface. The surface of the electrode 2b opposite to the P-type thermoelectric element layer 3 and the N-type thermoelectric element layer 4 can be used as a heat absorbing surface, and the electronic element is thermally connected to the heat absorbing surface side. It is cooled.
The electronic element is not particularly limited, but usually includes an electronic component arranged on a mounting portion of a circuit board, and includes heat-generating electronic components such as a CPU, CMOS, a light emitting diode, a semiconductor laser, and a capacitor.
The arrangement of the electronic elements provided on the circuit board is not particularly limited, and may be one surface or the other surface of the circuit board. It may also be inside the circuit board. Further, they may be arranged in combination.
The number of electronic elements is not particularly limited, and a plurality or a combination of a plurality of the above electronic elements can be cooled. The area of the second electrode and the like are appropriately adjusted within a range in which the thermoelectric performance is not impaired.
Examples of the method for joining the electronic element 6 and the second electrode 2b include known methods such as bonding with an adhesive and soldering.

As the circuit board 5, an insulating substrate containing mainly components such as paper phenol, paper epoxy, glass composite, glass polyimide, fluorine, glass PPO, glass epoxy, polyimide, polyester, ceramics, epoxy, and bismaleimide triazine is usually used. Be done. Among these, from the viewpoint of thermoelectric performance, it is preferable to use ceramics having high thermal conductivity. Further, from the viewpoint of versatility, it is preferable to use paper phenol, paper epoxy, glass composite, glass polyimide, glass epoxy, epoxy and polyester.

According to the first embodiment, for example, when the second electrode 2b side is used as an endothermic surface and is thermally connected to the electronic element 6, the heat from the electronic element 6 is efficiently transferred from the second electrode 2b side. The heat is absorbed and the heat is dissipated from the first substrate 1a side having the first electrode 1b. Since the second electrode 2b is extended, the area of the second electrode 2b is larger than the area of the first electrode 1b, and heat is efficiently and quickly absorbed from the second electrode 2b. The thermoelectric conversion module having such a configuration can efficiently absorb the heat generated by the electronic element.

(Second Embodiment)
In the configuration of the thermoelectric conversion module of the present invention, it is preferable that the second electrode extends on the circuit board and inside the circuit board and is thermally connected to the electronic element.
The second electrodes constituting the thermoelectric conversion module arranged on the circuit board are arranged so as to extend on the circuit board and inside the circuit board on the electronic element side separated on the circuit board, and are thermally connected to each other. , The electronic element can be cooled efficiently.

FIG. 4 is a cross-sectional view showing the configuration of the thermoelectric conversion module according to the second embodiment of the present invention.
In the configuration of the thermoelectric conversion module according to the second embodiment of the present invention, the component 8 mounted on another substrate that hinders the thermal connection with the electronic element 6 is arranged on the circuit board 5. The second electrode 2b is thermally connected to the electronic element 6 by extending and arranging the second electrode 2b up to the height of the upper surface of the component 8 including the inside of the substrate 5. The thermoelectric conversion module includes a P-type thermoelectric element layer 3 and an N-type thermoelectric element layer 4, a first electrode 1b, and a first substrate 1a on the second electrode 2b.

Examples of the component 8 mounted on another substrate include a passive element and an active element.
When wiring for connecting the component 8 or the like or other wiring is provided on the board, it is arranged on the board so as not to cause a short circuit with the electronic element. In order to arrange the electronic element so as not to cause a short circuit, a method of using a multilayer substrate, or an method of arranging an insulating resin or the like on an electrode and providing wiring on the electrode can be mentioned.

According to the second embodiment, for example, when the second electrode 2b side is used as an endothermic surface and is thermally connected to the electronic element 6, the heat from the electronic element 6 is efficiently transferred from the second electrode 2b side. The heat is absorbed and the heat is dissipated from the first substrate 1a side having the first electrode 1b. By arranging the second electrode extending to the height of the upper surface of the component 8 mounted on another substrate that hinders the thermal connection, the area of the second electrode 2b becomes that of the first electrode 1b. Since it is larger than the area, heat is efficiently and quickly absorbed from the second electrode 2b. The thermoelectric conversion module having such a configuration can efficiently absorb the heat generated by the electronic element.

(Third Embodiment)
In the configuration of the thermoelectric conversion module of the present invention, the circuit board has a through hole, and the second electrode thermally enters the electronic element through the through hole from the surface opposite to the electronic element side of the circuit board. It is preferable to be connected.
Further, it is preferable that all of the second electrodes are arranged inside the through hole and are thermally connected to the electronic element.
By providing a through hole in the circuit board and thermally connecting the second electrode constituting the thermoelectric conversion module to, for example, an electronic element mounted on the circuit board via the through hole from the lower surface side of the circuit board. , The electronic element can be cooled efficiently.
With the above configuration, for example, the surface area of the circuit board on the electronic element side can be reduced, and the mounting density can be increased.

FIG. 5 is a cross-sectional view showing the configuration of the thermoelectric conversion module according to the third embodiment of the present invention.
In the configuration of the thermoelectric conversion module according to the third embodiment of the present invention, the first substrate 11a having the first electrode 11b, the P-type thermoelectric element layer 13 and the N-type thermoelectric element layer 14, and the first The second electrode 12b of the thermoelectric conversion module includes the second electrode 12b arranged to face the electrode 11b, and the second electrode 12b of the thermoelectric conversion module is arranged on both sides of the circuit board 15 by the through hole 17 and is separated from the second electrode 12b. Is insulated by the circuit board 15. The electronic element 16 is thermally directly connected to the second electrode 12b side.
All of the second electrodes constituting the thermoelectric conversion module are arranged inside the through hole from the lower surface side of the circuit board, and are thermally directly connected to the electronic elements mounted on the circuit board to obtain electrons. The element can be cooled efficiently.

The circuit board 15 has through holes 17. The shape and length of the through hole 17 are appropriately adjusted according to the size of the second electrode of the thermoelectric conversion module to be used.
The through holes 17 can be formed by a known method. For example, it can be formed by drilling or plating. The through holes may be filled with a metal material or the like.

As the substrate material used for the circuit board 15, the same substrate material as that used for the circuit board 5 described above can be used.

According to the third embodiment, the heat from the electronic element 16 is generated by directly arranging the second electrode 12b side arranged in the through hole 17 of the circuit board 15 as the endothermic surface on the electronic element 16. , Heat is absorbed from the endothermic surface on the side of the second electrode 12b, and heat is dissipated from the first substrate 11a. The thermoelectric conversion module having such a configuration can efficiently absorb the heat generated by the electronic element 16.

(Fourth Embodiment)
In the configuration of the thermoelectric conversion module of the present invention, it is preferable that the entire thermoelectric conversion module is arranged inside the through hole and the second electrode is thermally connected to the electronic element.
With the above configuration, for example, the mounting density on the electronic element side of the circuit board can be increased, and the thickness of the entire circuit board can be reduced.

FIG. 6 is a cross-sectional view showing the configuration of the thermoelectric conversion module according to the fourth embodiment of the present invention.
The thermoelectric conversion module according to the fourth embodiment of the present invention has a first electrode 11b, a P-type thermoelectric element layer 13 and an N-type thermoelectric element layer 14, and a first electrode 11b arranged to face the first electrode 11b. The entire thermoelectric conversion module including the electrode 12b of 2 is arranged inside the through hole 17 of the circuit board 15. Further, it is insulated by the circuit board 15 between the first electrodes 11b that are separated from each other and between the second electrodes 12b that are separated from each other. The electronic element 16 is thermally directly connected to the second electrode 12b side.
The entire thermoelectric conversion module is arranged inside the through hole from the lower surface side of the circuit board, and the electronic element can be efficiently cooled by directly connecting to the electronic element mounted on the circuit board. ..

According to the fourth embodiment, the entire thermoelectric conversion module is arranged in the through hole 17 of the circuit board 15, and the electronic element 16 is arranged directly on the electronic element 16 with the second electrode 12b side as the endothermic surface. Is absorbed from the endothermic surface on the side of the second electrode 12b and dissipated from the first electrode 11b. The thermoelectric conversion module having such a configuration can efficiently absorb the heat generated by the electronic element 16. Further, since all of the thermoelectric conversion modules are arranged inside the through holes 17 of the circuit board 15, the thickness of the entire circuit board can be further reduced.

(Fifth Embodiment)
In the configuration of the thermoelectric conversion module of the present invention, it is preferable that the second electrode further extends in the in-plane direction on the electronic element side of the circuit board and is thermally connected to the electronic element.

FIG. 7 is a cross-sectional view showing the configuration of the thermoelectric conversion module according to the fifth embodiment of the present invention.
The thermoelectric conversion module according to the fifth embodiment of the present invention includes a first substrate 11a having a first electrode 11b, a P-type thermoelectric element layer 13 and an N-type thermoelectric element layer 14, and the first electrode 11b. The second electrode 12b is arranged so as to face each other, the entire second electrode 12b is arranged inside the through hole 17 of the circuit board 15, and the second electrode 12b is on the upper surface side of the circuit board 15. It extends to and is arranged as a continuous layer. Further, it is insulated by the circuit board 15 between the second electrodes 12b that are separated from each other. The electronic element 16 is thermally directly connected to the second electrode 12b side.
The area of the second electrode 12b, which is arranged inside the through hole 17 of the circuit board 15 and has a continuous layer on the upper surface side of the circuit board 15, can be expanded to the upper surface side of the circuit board 15. ..

According to the fifth embodiment, the electronic element 16 is included in all the through holes 17 of the circuit board 15, and the second electrode 12b side extending in the in-plane direction on the upper surface side of the circuit board is used as an endothermic surface. The heat from the electronic element 16 is absorbed from the endothermic surface on the side of the second electrode 12b and dissipated from the first substrate 11a. The thermoelectric conversion module having such a configuration can absorb heat generated by the electronic element 16 more efficiently.

(Sixth Embodiment)
FIG. 8 is a cross-sectional view showing the configuration of the thermoelectric conversion module according to the sixth embodiment of the present invention. The configuration of the thermoelectric conversion module according to the sixth embodiment is that a plurality of electronic elements 16 are arranged on the surface of the second electrode 12b extending in the in-plane direction on the upper surface side of the circuit board 15.
According to the sixth embodiment, a plurality of electronic elements 16 can be arranged by appropriately adjusting the surface area of the second electrode 12b extending in the in-plane direction on the upper surface side of the circuit board 15, and one thermoelectric conversion can be performed. The module can absorb the heat generated by a plurality of electronic elements more efficiently.

<Thermoelectric element layer>
The P-type thermoelectric element layer and the N-type thermoelectric element layer used in the present invention are not particularly limited, but consist of a thermoelectric semiconductor material, a heat-resistant resin, and a thermoelectric semiconductor composition containing an ionic liquid and / or an inorganic ionic compound. Is preferable.

(Thermoelectric semiconductor material)
The thermoelectric semiconductor material used for the thermoelectric element layer is preferably pulverized to a predetermined size by, for example, a fine pulverizer or the like and used as thermoelectric semiconductor particles (hereinafter, the thermoelectric semiconductor material may be referred to as "thermoelectric semiconductor particles"). .).
The particle size of the thermoelectric semiconductor particles is preferably 10 nm to 100 μm, more preferably 20 nm to 50 μm, and even more preferably 30 nm to 30 μm.
The average particle size of the thermoelectric semiconductor fine particles was obtained by measuring with a laser diffraction type particle size analyzer (Mastersizer 3000 manufactured by Malvern), and was used as the median value of the particle size distribution.

In the thermoelectric element layer used in the present invention, the thermoelectric semiconductor material constituting the P-type thermoelectric element layer and the N-type thermoelectric element layer is any material that can generate a thermoelectric force by imparting a temperature difference. The present invention is not particularly limited, and for example, a bismuth-tellu thermoelectric semiconductor material such as P-type bismasterlide and N-type bismasterlide; a telluride thermoelectric semiconductor material such as GeTe and PbTe; an antimony-tellu thermoelectric semiconductor material; ZnSb, Zn ₃ Sb. _{Zinc-antimon thermoelectric semiconductor materials such as 2,} Zn ₄ Sb ₃ ; silicon-germanium thermoelectric semiconductor materials such as SiGe; bismus selenide thermoelectric semiconductor materials such as _{Bi 2} Se ₃ _{; β-FeSi 2} , CrSi _{2, MnSi} _{VDD-based thermoelectric semiconductor materials such as 1.73} and Mg ₂ Si; oxide-based thermoelectric semiconductor materials; Whistler materials such as FeVAL, FeVALSi, and FeVTiAl, and sulfide-based thermoelectric semiconductor materials such as _{TiS 2 are used.}

Among these, the thermoelectric semiconductor material used in the present invention is preferably a bismuth-tellurium-based thermoelectric semiconductor material such as P-type bismuthellide or N-type bismuthellide.
As the P-type bismuth telluride, one having a hole as a carrier and a positive Seebeck coefficient, for example, _{represented by Bi X} Te ₃ Sb _2-X is preferably used. In this case, X is preferably 0 <X ≦ 0.8, more preferably 0.4 ≦ X ≦ 0.6. When X is larger than 0 and 0.8 or less, the Seebeck coefficient and the electric conductivity become large, and the characteristics as a P-type thermoelectric conversion material are maintained, which is preferable.
Further, as the N-type bismuth telluride, one having an electron carrier and a negative Seebeck coefficient, for example, _{represented by Bi 2} Te _3-Y Se _Y is preferably used. In this case, Y is preferably 0 ≦ Y ≦ 3 (when Y = 0: Bi ₂ Te ₃ ), and more preferably 0.1 <Y ≦ 2.7. When Y is 0 or more and 3 or less, the Seebeck coefficient and the electric conductivity become large, and the characteristics as an N-type thermoelectric conversion material are maintained, which is preferable.

The blending amount of the thermoelectric semiconductor particles in the thermoelectric semiconductor composition is preferably 30 to 99% by mass. It is more preferably 50 to 96% by mass, and even more preferably 70 to 95% by mass. When the blending amount of the thermoelectric semiconductor particles is within the above range, the Seebeck coefficient (absolute value of the Perche coefficient) is large, the decrease in the electric conductivity is suppressed, and only the thermal conductivity is decreased, so that high thermoelectric performance is exhibited. At the same time, a film having sufficient film strength and flexibility can be obtained, which is preferable.

Further, it is preferable that the thermoelectric semiconductor particles are annealed (hereinafter, may be referred to as "annealing treatment A"). By performing the annealing treatment A, the crystallinity of the thermoelectric semiconductor particles is improved, and the surface oxide film of the thermoelectric semiconductor particles is removed, so that the Seebeck coefficient (absolute value of the Perche coefficient) of the thermoelectric conversion material is increased. , The thermoelectric performance index can be further improved.

(Heat resistant resin)
The heat-resistant resin used in the present invention acts as a binder between thermoelectric semiconductor particles and enhances the flexibility of the thermoelectric element layer. The heat-resistant resin is not particularly limited, but when a thin film made of a thermoelectric semiconductor composition is subjected to crystal growth of thermoelectric semiconductor particles by annealing or the like, various factors such as mechanical strength and thermal conductivity as a resin are obtained. Use a heat-resistant resin that maintains its physical properties without being impaired.
Examples of the heat-resistant resin include polyamide resins, polyamideimide resins, polyimide resins, polyetherimide resins, polybenzoxazole resins, polybenzoimidazole resins, epoxy resins, and copolymers having a chemical structure of these resins. Can be mentioned. The heat-resistant resin may be used alone or in combination of two or more. Among these, polyamide resins, polyamide-imide resins, polyimide resins, and epoxy resins are preferable and have excellent flexibility because they have higher heat resistance and do not adversely affect the crystal growth of thermoelectric semiconductor particles in the thin film. Therefore, polyamide resin, polyamide-imide resin, and polyimide resin are more preferable. When a polyimide film is used as the above-mentioned support, the polyimide resin is more preferable as the heat-resistant resin from the viewpoint of adhesion to the polyimide film and the like. In the present invention, the polyimide resin is a general term for polyimide and its precursor.

The heat-resistant resin preferably has a decomposition temperature of 300 ° C. or higher. When the decomposition temperature is within the above range, the flexibility of the thermoelectric element layer can be maintained without losing the function as a binder even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

The blending amount of the heat-resistant resin in the thermoelectric semiconductor composition is preferably 0.1 to 40% by mass, more preferably 0.5 to 20% by mass, and further preferably 1 to 20% by mass. When the blending amount of the heat-resistant resin is within the above range, a film having both high thermoelectric performance and film strength can be obtained.

(Ionic liquid)
The ionic liquid that can be contained in the thermoelectric semiconductor composition is a molten salt formed by combining a cation and an anion, and refers to a salt that can exist as a liquid in any temperature range of −50 ° C. or higher and lower than 400 ° C. In other words, the ionic liquid is an ionic compound having a melting point in the range of −50 ° C. or higher and lower than 400 ° C. The melting point of the ionic liquid is preferably −25 ° C. or higher and 200 ° C. or lower, and more preferably 0 ° C. or higher and 150 ° C. or lower. Ionic liquids have features such as extremely low vapor pressure, non-volatility, excellent thermostability and electrochemical stability, low viscosity, and high ionic conductivity. Therefore, as a conductive auxiliary agent, it is possible to effectively suppress a decrease in electrical conductivity between thermoelectric semiconductor materials. Further, since the ionic liquid exhibits high polarity based on the aprotic ionic structure and has excellent compatibility with the heat-resistant resin, the electric conductivity of the thermoelectric conversion material can be made uniform.

As the ionic liquid, known or commercially available ones can be used. For example, nitrogen-containing cyclic cation compounds such as pyridinium, pyrimidinium, pyrazolium, pyrrolidinium, piperidinium, imidazolium and their derivatives; tetraalkylammonium-based amine-based cations and their derivatives; phosphonium, trialkylsulfonium, tetraalkylphosphonium and the like. phosphine cations and derivatives thereof; and a cationic component such as lithium cations and derivatives ^{^{^{_{^{thereof, Cl -, Br -, I}}}}} -, AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF 6 -, ClO 4 -, _{^{_{^{NO 3 -, CH 3 COO -}}}} , CF 3 COO -, CH 3 SO 3 -, CF 3 SO 3 -, (FSO 2) 2 N -, (CF 3 SO 2) 2 N -, (CF 3 SO 2) _{^{_{^{_{3 C -, AsF 6 -,}}}}} SbF 6 -, NbF 6 -, TaF 6 -, F (HF) n -, (CN) 2 n -, C 4 F 9 SO 3 -, (C 2 F 5 SO 2) Examples thereof include those composed of anionic components such as ₂ N ⁻ , C ₃ F ₇ ^{COO −} , and (CF ₃ SO ₂ ) (CF ₃ CO) N ^−.

Among the above ionic liquids, the cation component of the ionic liquid is a pyridinium cation and its derivatives from the viewpoints of high temperature stability, compatibility with thermoelectric semiconductor materials and resins, and suppression of decrease in electrical conductivity between thermoelectric semiconductor material gaps. , It is preferable to contain at least one selected from the imidazolium cation and its derivatives.

As the ionic liquid containing the pyridinium cation and its derivative as the cation component, 1-butyl-4-methylpyridinium bromide, 1-butylpyridinium bromide, and 1-butyl-4-methylpyridinium hexafluorophosphate are preferable.

Further, as an ionic liquid containing an imidazolium cation and a derivative thereof, the cation component is [1-butyl-3- (2-hydroxyethyl) imidazolium bromide], [1-butyl-3- (2-hydroxyethyl) imidazole]. Rium tetrafluoroborate] is preferable.

Further, the above-mentioned ionic liquid preferably has a decomposition temperature of 300 ° C. or higher. As long as the decomposition temperature is within the above range, the effect as a conductive auxiliary agent can be maintained even when the thin film made of the thermoelectric semiconductor composition is annealed, as will be described later.

The blending amount of the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 20% by mass. When the blending amount of the ionic liquid is within the above range, the decrease in electrical conductivity is effectively suppressed, and a film having high thermoelectric performance can be obtained.

(Inorganic ionic compound)
The inorganic ionic compound that can be contained in the thermoelectric semiconductor composition is a compound composed of at least cations and anions. Since the inorganic ionic compound exists as a solid in a wide temperature range of 400 to 900 ° C. and has characteristics such as high ionic conductivity, it can be used as a conductivity auxiliary agent to reduce the electrical conductivity between thermoelectric semiconductor materials. Can be suppressed.

The blending amount of the inorganic ionic compound in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 10% by mass. When the blending amount of the inorganic ionic compound is within the above range, the decrease in electrical conductivity can be effectively suppressed, and as a result, a film having improved thermoelectric performance can be obtained.
When the inorganic ionic compound and the ionic liquid are used in combination, the total content of the inorganic ionic compound and the ionic liquid in the thermoelectric semiconductor composition is preferably 0.01 to 50% by mass, more preferably. Is 0.5 to 30% by mass, more preferably 1.0 to 10% by mass.

The thermoelectric element layer made of the thermoelectric semiconductor composition can be formed, for example, by applying the thermoelectric semiconductor composition on a substrate and drying it. By forming in this way, a large number of thermoelectric conversion element layers can be easily obtained at low cost.
As a method of applying a thermoelectric semiconductor composition to obtain a thermoelectric element layer, a screen printing method, a flexographic printing method, a gravure printing method, a spin coating method, a dip coating method, a die coating method, a spray coating method, a bar coating method, and a doctor blade Known methods such as a method can be mentioned and are not particularly limited. When the coating film is formed into a pattern, a screen printing method, a slot die coating method, or the like, which enables easy pattern formation using a screen plate having a desired pattern, is preferably used.
Then, the obtained coating film is dried to form a thermoelectric element layer.

The thickness of the thermoelectric element layer is not particularly limited, and is preferably 100 nm to 1000 μm, more preferably 300 nm to 600 μm, and further preferably 5 to 400 μm from the viewpoint of thermoelectric performance and film strength.

It is preferable that the P-type thermoelectric element layer and the N-type thermoelectric element layer as a thin film made of the thermoelectric semiconductor composition are further subjected to an annealing treatment (hereinafter, may be referred to as "annealing treatment B"). By performing the annealing treatment B, the thermoelectric performance can be stabilized, and the thermoelectric semiconductor particles in the thin film can be crystal-grown, so that the thermoelectric performance can be further improved. The annealing treatment B is not particularly limited, but is usually carried out under an inert gas atmosphere such as nitrogen or argon, a reducing gas atmosphere, or a vacuum condition in which the gas flow rate is controlled, and the resin and the ionic compound to be used are used. Although it depends on the heat-resistant temperature and the like, it is carried out at 100 to 500 ° C. for several minutes to several tens of hours.

<Board>
The first substrate used for the thermoelectric conversion module of the present invention is not particularly limited, and is independently a paper phenol substrate, a paper epoxy substrate, a glass composite substrate, a glass epoxy substrate, a glass polyimide substrate, a fluorine substrate, and a glass PPO substrate. , Glass, ceramics, plastic film and the like can be used. Among these, a plastic film is preferable from the viewpoint of having flexibility and having a degree of freedom for installation of a heat source on the surface. Further, from the viewpoint of high heat resistance and low generation of outgas, polyimide film, polyamide film, polyetherimide film, polyaramid film, polyamideimide film, polysulfon film, glass composite substrate, glass epoxy substrate, and glass polyimide substrate are available. Preferably, from the viewpoint of high versatility, a polyimide film, a paper phenol substrate, a paper epoxy substrate, a glass composite substrate, a glass epoxy substrate, and a glass polyimide substrate are particularly preferable.

The thickness of the first substrate is preferably 1 to 1000 μm, more preferably 10 to 500 μm, and even more preferably 20 to 100 μm from the viewpoint of heat resistance and flexibility.

<Electrode>
In the thermoelectric conversion module of the present invention, the metal materials used for the first electrode and the second electrode are not particularly limited, but are independently copper, gold, nickel, aluminum, rhodium, platinum, chromium, palladium, and stainless steel, respectively. Alloys containing steel, molybdenum or any of these metals are preferred. Further, not only a single layer but also a plurality of layers may be combined to form a multi-layer structure.
The thickness of the layers of the first electrode and the second electrode are independently, preferably 10 nm to 200 μm, more preferably 30 nm to 150 μm, and further preferably 50 nm to 120 μm. When the thickness of the layers of the first electrode and the second electrode is within the above range, the electrical conductivity is high and the resistance is low, and sufficient strength as an electrode can be obtained.

The formation of the first electrode and the second electrode is performed using the metal material described above. As a method of forming the first electrode and the second electrode, after providing an electrode having no pattern formed on the substrate, a known physical treatment or chemical treatment mainly composed of a photolithography method, or a method thereof. A method of processing into a predetermined pattern shape by using the above in combination, or a method of directly forming an electrode pattern by a screen printing method, an inkjet method, or the like can be mentioned.
As a method for forming an electrode in which a pattern is not formed, PVD (Physical Vapor Deposition Method) such as vacuum deposition method, sputtering method, ion plating method, or CVD (Chemical Vapor Deposition) such as thermal CVD, atomic layer deposition (ALD), etc. Dry process such as vapor deposition method), various coating methods such as dip coating method, spin coating method, spray coating method, gravure coating method, die coating method, doctor blade method, wet process such as electrodeposition method, silver salt method , Electrolytic plating method, electroless plating method, lamination of metal foil and the like, and are appropriately selected according to the material of the electrode.
From the viewpoint of thermoelectric performance, high conductivity and high thermal conductivity are required, so it is preferable to use an electrode formed by a plating method or a vacuum film forming method.

A laminating agent is used to bond the P-type thermoelectric element layer and the N-type thermoelectric element layer to the electrodes.
Examples of the bonding agent include a conductive paste and the like. Examples of the conductive paste include copper paste, silver paste, nickel paste and the like, and when a binder is used, epoxy resin, acrylic resin, urethane resin and the like can be mentioned.
Examples of the method of applying the bonding agent on the electrodes of the substrate include known methods such as a screen printing method and a dispensing method.

Further, a solder material can be used for bonding with the electrode. The solder material may be appropriately selected, and Sn, Sn / Pb alloy, Sn / Ag alloy, Sn / Cu alloy, Sn / Sb alloy, Sn / In alloy, Sn / Zn alloy, Sn / In / Bi alloy, etc. Known materials such as Sn / In / Bi / Zn alloys and Sn / Bi / Pb / Cd alloys can be mentioned.
Examples of the method of applying the solder material onto the electrodes of the substrate include known methods such as a screen printing method and a dispensing method.

Although the embodiment of the thermoelectric conversion module of the present invention has been described above, the present invention is not limited to the above embodiment and can be further modified in various ways.

According to the configuration of the thermoelectric conversion module of the present invention, the second electrode constituting the thermoelectric conversion module is arranged on the circuit board and / or inside the circuit board in the electronic element mounted on the circuit board. A thermoelectric conversion module having further improved heat absorption can be obtained.

The thermoelectric conversion module of the present invention has a simple configuration in which a second electrode constituting the thermoelectric conversion module is arranged on the circuit board and / or inside the circuit board on an electronic element mounted on the circuit board.
Therefore, it is conceivable to apply it mainly to an electronic element mounted on a circuit board used in the above-mentioned field of electronic equipment as a cooling application.

1a: First substrate 1b: First electrode 2b: Second electrode 2a': Second substrate 2b': Second electrode 3: P-type thermoelectric element layer 4: N-type thermoelectric element layer 5: Circuit substrate 6: Electronic element 8: Component 11a: First substrate 11b: First electrode 12b: Second electrode 13: P-type thermoelectric element layer 14: N-type thermoelectric element layer 15: Circuit substrate 16: Electronic element 17: Through hole

Claims

It includes a first electrode, a P-type thermoelectric element layer, an N-type thermoelectric element layer, and a second electrode arranged so as to face the first electrode.
A plurality of pairs of PN junctions in which the P-type thermoelectric element layer and the N-type thermoelectric element layer are PN-bonded with the first electrode or the second electrode interposed therebetween, the first electrode and the second electrode. A thermoelectric conversion module arranged on a circuit board provided with an electronic element, which is electrically connected in series with electrodes alternately, wherein the second electrode is arranged on the circuit board and / or inside the circuit board. Thermoelectric conversion module.
The thermoelectric conversion module according to claim 1, further comprising a first substrate, wherein the first substrate has the first electrode.
The thermoelectric conversion module according to claim 1 or 2, wherein the second electrode extends on the circuit board and is thermally connected to the electronic element.
The thermoelectric conversion module according to any one of claims 1 to 3, wherein the second electrode extends on the circuit board and inside the circuit board and is thermally connected to the electronic element.
The circuit board has a through hole, and the second electrode is thermally connected to the electronic element from a surface of the circuit board opposite to the electronic element side via the through hole. The thermoelectric conversion module according to any one of claims 1 to 4.
The thermoelectric conversion module according to any one of claims 1 to 5, wherein all of the second electrodes are arranged inside the through hole and thermally connected to the electronic element.
The thermoelectric conversion module according to any one of claims 1 to 6, wherein all of the thermoelectric conversion modules are arranged inside the through holes, and the second electrode is thermally connected to the electronic element. ..
The thermoelectric according to any one of claims 1 to 7, wherein the second electrode further extends in the in-plane direction of the circuit board on the electronic element side and is thermally connected to the electronic element. Conversion module.