Thermoelectric conversion element and manufacturing method for same
09859486 ยท 2018-01-02
Assignee
Inventors
Cpc classification
H10N10/00
ELECTRICITY
H10N15/00
ELECTRICITY
International classification
Abstract
A thermoelectric conversion element includes a thermoelectric conversion sheet possessing flexibility. The thermoelectric conversion sheet includes a magnetic layer, an electricity-generating layer that is formed on the magnetic layer so as to contact with the magnetic layer and that is formed of a material exhibiting spin orbit coupling, and a first electrode and a second electrode formed on the electricity-generating layer so as to contact with the electricity-generating layer. The first electrode and the second electrode extend in a longitudinal direction of the thermoelectric conversion sheet, and are separated from each other in a first direction perpendicular to the longitudinal direction.
Claims
1. A thermoelectric conversion element that comprises a flexible thermoelectric conversion sheet, wherein the thermoelectric conversion sheet comprises: a magnetic layer; an electricity-generating layer that is formed on the magnetic layer so as to contact the magnetic layer, and that is formed of a material exhibiting spin orbit coupling; and a first electrode and a second electrode formed on the electricity-generating layer so as to contact the electricity-generating layer; and the first electrode and the second electrode extend in a longitudinal direction of the thermoelectric conversion sheet, and are separated from each other in a first direction substantially perpendicular to the longitudinal direction, wherein a length of the electricity generating layer in the longitudinal direction is greater than a length of the electricity generating layer in the first direction, and wherein magnetization of the magnetic layer comprises a component in the longitudinal direction.
2. The thermoelectric conversion element according to claim 1, wherein the thermoelectric conversion sheet is configured such that electromotive force is generated in the first direction in the electricity-generating layer.
3. The thermoelectric conversion element according to claim 1, wherein the thermoelectric conversion sheet further comprises: an insulator formed so as to cover the electricity-generating layer, and to occupy a space between the first electrode and the second electrode.
4. The thermoelectric conversion element according to claim 1, wherein the thermoelectric conversion sheet is wound around a center axis substantially parallel with the first direction.
5. The thermoelectric conversion element according to claim 4, wherein the thermoelectric conversion sheet is wound around a heat source thereon, whose axial direction is the first direction.
6. The thermoelectric conversion element according to claim 1, wherein the electricity-generating layer has a meandering-shaped part located between the first electrode and the second electrode.
7. The thermoelectric conversion element according to claim 6, wherein the meandering-shaped part of the electricity-generating layer has a first efficiency electricity-generating part and a second efficiency electricity-generating part, and wherein electricity generating efficiency of the first efficiency electricity-generating part is higher than that of the second efficiency electricity-generating part.
8. The thermoelectric conversion element according to claim 6, wherein the meandering-shaped part of the electricity-generating layer includes one or more first efficiency electricity-generating parts and one or more second efficiency electricity-generating parts, the first efficiency electricity-generating parts and the second efficiency electricity-generating parts being arranged alternately in the meandering-shaped part, and the first efficiency being higher than the second efficiency.
9. The thermoelectric conversion element according to claim 8, wherein the meandering-shaped part of the electricity-generating layer is repeatedly formed in the thermoelectric conversion sheet.
10. The thermoelectric conversion element according to claim 1, wherein a material of the electricity-generating layer is Au, Pt, Pd, or Ir.
11. The thermoelectric conversion element according to claim 1, wherein a material of the electricity-generating layer is an oxide.
12. The thermoelectric conversion element according to claim 1, wherein a material of the magnetic layer is a ferromagnetic metal.
13. The thermoelectric conversion element according to claim 1, wherein the first electrode and the second electrode are formed from the same material as the electricity-generating layer.
14. The thermoelectric conversion element according to claim 1, wherein a first sheet resistance of the first electrode and a second sheet resistance of the second electrode is lower than a sheet resistance of the electricity-generating layer.
15. A thermoelectric conversion element that comprises a flexible thermoelectric conversion sheet, wherein the thermoelectric conversion sheet comprises: a magnetic layer; an electricity-generating layer that is formed on the magnetic layer so as to contact the magnetic layer, and that is formed of a material exhibiting spin orbit coupling; and a first electrode and a second electrode formed on the electricity-generating layer so as to contact the electricity-generating layer; and the first electrode and the second electrode extend in a longitudinal direction of the thermoelectric conversion sheet, and are separated from each other in a first direction substantially perpendicular to the longitudinal direction, wherein a material of the magnetic layer is iron garnet, wherein a length of the electricity generating layer in the longitudinal direction is greater than a length of the electricity generating layer in the first direction, and wherein magnetization of the magnetic layer comprises a component in the longitudinal direction.
16. A thermoelectric conversion element that comprises a flexible thermoelectric conversion sheet, wherein the thermoelectric conversion sheet comprises: a magnetic layer; an electricity-generating layer that is formed on the magnetic layer so as to contact the magnetic layer, and that is formed of a material exhibiting spin orbit coupling; and a first electrode and a second electrode formed on the electricity-generating layer so as to contact the electricity-generating layer; and the first electrode and the second electrode extend in a longitudinal direction of the thermoelectric conversion sheet, and are separated from each other in a first direction substantially perpendicular to the longitudinal direction, wherein a material of the magnetic layer is at least one of yttrium iron garnet (YIG, Y.sub.3Fe.sub.5O.sub.12), bismuth-doped YIG (Bi:YIG), lanthanum-doped YIG (LaY.sub.2Fe.sub.5O.sub.12), or yttrium gallium iron garnet (Y.sub.3Fe.sub.5-xGa.sub.xO.sub.12), wherein a length of the electricity generating layer in the longitudinal direction is greater than a length of the electricity generating layer in the first direction, and wherein magnetization of the magnetic layer comprises a component in the longitudinal direction.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
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DESCRIPTION OF EMBODIMENTS
(14) Embodiments of the present invention are described with reference to the accompanying drawings.
1. Configuration
(15)
(16) As illustrated in
(17) The thermoelectric conversion sheet 10 includes a substrate 20, a magnetic layer 30, an electricity-generating layer 40, a first electrode 51, and a second electrode 52. The magnetic layer 30 is formed on the substrate 20. The electricity-generating layer 40 is formed on the magnetic layer 30 so as to contact with the magnetic layer 30. Namely, the substrate 20, the magnetic layer 30, and the electricity-generating layer 40 are laminated in this order. This laminating direction is perpendicular to the above-described longitudinal direction (S direction), and is represented by T in the drawings. Since the thermoelectric conversion sheet 10 can be bent, the laminating direction (T direction) can be locally defined at each point of the thermoelectric conversion sheet 10 (refer to
(18) The magnetic layer 30 is formed by a material exhibiting the spin-Seebeck effect. A material of the magnetic layer 30 may be a ferromagnetic metal, or a magnetic insulator. As the ferromagnetic metal, NiFe, CoFe, CoFeB, and the like can be cited. As the magnetic insulator, yttrium iron garnet (YIG, Y.sub.3Fe.sub.5O.sub.12), YIG (Bi:YIG) to which bismuth (Bi) has been doped, YIG (LaY.sub.2Fe.sub.5O.sub.12) to which lanthanum (La) has been doped, yttrium gallium iron garnet (Y.sub.3Fe.sub.5-xGa.sub.xO.sub.12), and the like are cited. From the standpoint of suppressing thermal conduction due to electrons, it is desirable to use the magnetic insulator.
(19) The electricity-generating layer (electric conduction layer) 40 is formed by a material exhibiting the inverse spin-Hall effect (spin orbit coupling). More specifically, a material of the electricity-generating layer 40 includes a metal material of which spin orbit coupling is strong. For example, Au, Pt, Pd or Ir of which spin orbit coupling is relatively strong, other metal materials having the f-orbit, or alloy materials including them are used. Only by doping a material such as Au, Pt, Pd, or Ir by approximately 0.5 to 10% to a general metal film material such as Cu, the same effect can be obtained. Alternatively, the electricity-generating layer 40 may be an oxide such as ITO.
(20) By lamination of these magnetic layer 30 and electricity-generating layer 40, the thermoelectric conversion sheet 10 comes to possess thermoelectric conversion function that uses the spin-Seebeck effect and the inverse spin-Hall effect. More specifically, the magnetic material 30 generates (drives) spin-current from temperature gradient by the spin-Seebeck effect. The electricity-generating layer 40 generates electromotive force from the spin-current by the inverse spin-Hall effect. The direction of the generated electromotive force is given by an outer product of the magnetization direction of the magnetic layer 30 and the temperature gradient direction.
(21) The first electrode 51 and the second electrode 52 are provided for efficiently bringing out electromotive force generated in the electricity-generating layer 40. More specifically, the first electrode 51 and the second electrode 52 are formed on the electricity-generating layer 40 so as to contact with the electricity-generating layer 40. Both the first electrode 51 and the second electrode 52 extend in the same direction as the longitudinal direction (S direction) of the thermoelectric conversion sheet 10. Further, the first electrode 51 and the second electrode 52 are separated from each other in a Y direction (first direction). The Y direction is the direction perpendicular to both of the longitudinal direction (S direction) and the laminating direction (T direction) of the thermoelectric conversion sheet 10.
(22) Sheet resistance of each of the first electrode 51 and the second electrode 52 is preferably lower than sheet resistance of the electricity-generating layer 40. Namely, the first electrode 51 and the second electrode 52 form low resistance regions. The first electrode 51 and the second electrode 52 may be formed of a material different from a material of the electricity-generating layer 40, or may be formed of the same material as a material of the electricity-generating layer 40.
(23) One example of the element configuration is as follows. A length of the thermoelectric conversion sheet 10 in the longitudinal direction is 300 mm, and its width in the Y direction is 30 mm. The electricity-generating layer 40 is a Pt film, its thickness is 10 nm, and its sheet resistance is approximately 50 square. In this case, a resistance value of the electricity-generating layer 40 in the Y direction is approximately 5. Meanwhile, each of the first electrode 51 and the second electrode 52 is a Cu film, its thickness is 1 m, and its width in the Y direction is 3 mm. In this case, an S-direction resistance value of each of the first electrode 51 and the second electrode 52 is approximately 1. Using such first electrode 51 and second electrode 52 enables electromotive force generated in the electricity-generating layer 40 to be efficiently brought out.
2. Use Method
(24) As described above, the thermoelectric conversion sheet 10 according to the present embodiment has flexibility, and can be bent. Actually, the thermoelectric conversion sheet 10 is preferably used in a state where the thermoelectric conversion sheet 10 is bent. More specifically, as illustrated in
(25) Furthermore, the thermoelectric conversion sheet 10 is configured such that electromotive force is generated in the Y direction (Y direction in the example of
(26) Electromotive force generated in the Y direction in the electricity-generating layer 40 can be brought out through the first electrode 51 and the second electrode 52 separated from each other in the Y direction. At this time, the first electrode 51 has an approximately uniform electric potential. The second electrode 52 has an approximately uniform electric potential, as well. As illustrated in
3. Advantageous Effect
(27) According to the present embodiment, the thermoelectric conversion sheet 10 having flexibility is used. Therefore, even when an area of the thermoelectric conversion sheet 10 is increased for making output high, folding the thermoelectric conversion sheet 10 can suppress increase in an area of the entire thermoelectric conversion element. In other words, it becomes possible to increase electric power generation amount, i.e., output electric power without increasing an area of the element.
(28) Furthermore, according to the present embodiment, electromotive force generated in the Y direction in the electricity-generating layer 40 is brought out through the first electrode 51 and the second electrode 52 separated from each other in the Y direction. These first electrode 51 and second electrode 52 extend in the S direction perpendicular to the Y direction. Thereby, an electric-current path between the first electrode 51 and the second electrode 52 becomes the shortest, and resistance loss (ohmic loss) in the electricity-generating layer 40 can be greatly reduced. This aspect, also, contributes to increase in electric power generation amount, i.e., output electric power.
4. Various Examples
4-1. First Example
(29) Description is made about a concrete example of a using method of the thermoelectric conversion sheet 10 (a manufacturing method for the thermoelectric conversion element) according to the present embodiment. First, the thermoelectric conversion sheet 10 illustrated in
(30) After the winding on it, as illustrated in
(31)
(32) The magnetization direction of the magnetic layer 30 (electricity-generating part) is the S direction in this example, but is not limited to this. It suffices that an electric potential difference is generated between the first electrode 51 and the second electrode 52. For this purpose, the magnetization of the magnetic layer 30 has only to include a component of the S direction.
4-2. Second Example
(33) Description is made about another concrete example of a using method of the thermoelectric conversion sheet 10 (a manufacturing method for the thermoelectric conversion element) according to the present embodiment. First, the thermoelectric conversion sheet 10 illustrated in
(34) After the magnetization-direction initializing process, as illustrated in
(35) In this example, as illustrated in
(36) The magnetization direction of the magnetic layer 30 is the S direction in this example, but is not limited to this. It suffices that an electric potential difference is generated between the first electrode 51 and the second electrode 52. For this purpose, the magnetization of the magnetic layer 30 has only to include a component of the S direction.
(37) When the magnetization-direction initializing process is performed before the thermoelectric conversion sheet 10 is wound around the heat source 80 thereon as described above, a uniform external magnetic field HE may be applied. Therefore, a simple manufacturing apparatus (an apparatus for the magnetization-direction initializing process) can be used. However, a method of the magnetization-direction initializing process is not limited to this. The magnetization-direction initializing process by methods as illustrated in
(38) Concretely, as illustrated in
4-3. Third Example
(39) If a space remains between the first electrode 51 and the second electrode 52 when the thermoelectric conversion sheet 10 is wound, thermal conduction slows down in the space, and electricity-generating efficiency is reduced. For this reason, the thermoelectric conversion sheet 10 may be formed such that a space does not remain between the first electrode 51 and the second electrode 52.
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(41) By such an insulator 90, when the thermoelectric conversion sheet 10 is wound, a space is prevented from being generated, and electricity-generating efficiency is improved.
4-4. Fourth Example
(42) A formation pattern of the electricity-generating layer 40 is not limited to the above-described examples. As long as an electric potential difference is generated between the first electrode 51 and the second electrode 52, any formation pattern of the electricity-generating layer 40 is possible.
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(44) In view of it, an electricity-generating efficiency distribution in the electricity-generating layer 40 is preferably adjusted such that the mutual cancellation of the electromotive force is suppressed as much as possible. Concretely, the electricity-generating layer 40 is formed so as to include a high-efficiency electricity-generating part 41 of which electricity-generating efficiency is high, and a low-efficiency electricity-generating part 42 of which electricity-generating efficiency is low. The high-efficiency electricity-generating part 41 and the low-efficiency electricity-generating part 42 are formed of materials having different electricity-generating efficiency, for example.
(45) In the high-efficiency electricity-generating part 41 and the low-efficiency electricity-generating part 42, electromotive force E1 and E2 in the Y direction is generated respectively. The electromotive force E1 is larger than the electromotive force E2 (E1>E2). Accordingly, the high-efficiency electricity-generating part 41 and the low-efficiency electricity-generating part 42 are arranged alternately so that the mutual cancellation of the electromotive force can be suppressed even in the meandering-shaped electricity-generating layer 40. In the example of
(46) A pattern as illustrated in
(47) A formation pattern of the electricity-generating layer 40 is not limited to a meandering shape, and may be appropriately designed in accordance with desired characteristics. Appropriately adjusting a formation pattern of the electricity-generating layer 40 can control internal resistance between the first electrode 51 and the second electrode 52 without changing a width (a Y-direction width of the thermoelectric conversion sheet 10) between the first electrode 51 and the second electrode 52. Thereby, it becomes possible to obtain desired characteristics.
(48) In the above, the embodiment of the present invention is described with reference to the accompanying drawings. However, the present invention is not limited to the above-described embodiment, and can be appropriately modified by a person skilled in the art within a range that does not depart from the essence of the invention.
(49) A part or all of the above-described embodiment can be described as in the following supplemental notes, but is not limited to the following.
(50) (Supplemental Note 1)
(51) A thermoelectric conversion element that includes a thermoelectric conversion sheet possessing flexibility, wherein the thermoelectric conversion sheet includes: a magnetic layer; an electricity-generating layer that is formed on the magnetic layer so as to contact with the magnetic layer, and that is formed of a material exhibiting spin orbit coupling; and a first electrode and a second electrode formed on the electricity-generating layer so as to contact with the electricity-generating layer; and the first electrode and the second electrode extend in a longitudinal direction of the thermoelectric conversion sheet, and are separated from each other in a first direction perpendicular to the longitudinal direction.
(52) (Supplemental Note 2)
(53) The thermoelectric conversion element according to the supplemental note 1, wherein the thermoelectric conversion sheet is configured such that electromotive force is generated in the first direction in the electricity-generating layer.
(54) (Supplemental Note 3)
(55) The thermoelectric conversion element according to the supplemental note 2, wherein magnetization of the magnetic layer includes a component in the longitudinal direction.
(56) (Supplemental Note 4)
(57) The thermoelectric conversion element according to any one of the supplemental notes 1 to 3, wherein the thermoelectric conversion sheet further includes: an insulator formed so as to cover the electricity-generating layer, and to occupy a space between the first electrode and the second electrode.
(58) (Supplemental Note 5)
(59) The thermoelectric conversion element according to any one of the supplemental notes 1 to 4, wherein the thermoelectric conversion sheet is wound around a center axis parallel with the first direction.
(60) (Supplemental Note 6)
(61) The thermoelectric conversion element according to claim 5, wherein the thermoelectric conversion sheet is wound around a heat source thereon, whose axial direction is the first direction.
(62) (Supplemental Note 7)
(63) A manufacturing method for a thermoelectric conversion element, including:
(64) (A) a step of providing a thermoelectric conversion sheet possessing flexibility, wherein the thermoelectric conversion sheet includes: a magnetic layer; an electricity-generating layer that is formed on the magnetic layer so as to contact with the magnetic layer, and that is formed of a material exhibiting spin orbit coupling; and a first electrode and a second electrode formed on the electricity-generating layer so as to contact with the electricity-generating layer, and the first electrode and the second electrode extend in a longitudinal direction of the thermoelectric conversion sheet, and are separated from each other in a first direction perpendicular to the longitudinal direction; and
(65) (B) a step of winding the thermoelectric conversion sheet around a center axis parallel with the first direction.
(66) (Supplemental Note 8)
(67) The manufacturing method for the thermoelectric conversion element according to the supplemental note 7, wherein the thermoelectric conversion sheet is configured such that electromotive force is generated in the first direction in the electricity-generating layer.
(68) (Supplemental Note 9)
(69) The manufacturing method for the thermoelectric conversion element according to the supplemental note 7 or 8, wherein the step of winding the thermoelectric conversion sheet includes: a step of winding the thermoelectric conversion sheet around a support body thereon, whose axial direction is the first direction; and a step of, after the step of winding the thermoelectric conversion sheet thereon, performing magnetization entirely such that magnetization of the magnetic layer includes a component in the longitudinal direction.
(70) (Supplemental Note 10)
(71) The manufacturing method for the thermoelectric conversion element according to the supplemental note 7 or 8, wherein the step of winding the thermoelectric conversion sheet includes: a step of performing magnetization entirely such that magnetization of the magnetic layer includes a component in the longitudinal direction; and a step of, after the step of performing the magnetization, winding the thermoelectric conversion sheet around a heat source thereon, an axial direction of the heat source being the first direction.
(72) The present application claims the benefit of priority based upon Japanese Patent Application No. 2012-160242 filed on Jul. 19, 2012, the disclosure of which is incorporated herein in its entirety by reference.