JP2011134940A - Thermoelectric conversion element, and thermoelectric conversion module and thermoelectric conversion device employing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoelectric conversion element that facilitates high volume production of thermoelectric conversion modules with high efficiency of thermoelectric conversion, and possibly operable in small-sized integration, and to provide a thermoelectric conversion module employing the same. <P>SOLUTION: The thermoelectric conversion element 10 includes a p-type semiconductor element 2a having a Seebeck effect, and filled in one inner portion through the partition 1a of an insulating supporter 1; an n-type semiconductor element 2b having the Seebeck effect, filled in another inner portion through the partition 1a, and directly electrically connected to the p-type semiconductor element 2a at one end 1c; and an electrode formed in the p-type semiconductor element 2a and the n-type semiconductor element 2b at an opening 1b. The thermoelectric conversion element 10 can be connected to another element by the electrode 6 mounted at another side of the insulating supporter 1 in the thermoelectic conversion element 10, and can be connected in series at the upper and lower surfaces of the p-type and the n-type semiconductor elements 2a, 2b without using an electrode plate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermoelectric conversion element using the Seebeck effect for converting heat into electricity, a thermoelectric conversion module and a thermoelectric conversion apparatus using the thermoelectric conversion element.

In order to reduce the environmental load, thermoelectric conversion technology that effectively uses heat energy such as exhaust heat by converting it into electrical energy has attracted attention. Conventionally, as a thermoelectric conversion element that performs thermoelectric conversion, a p-type semiconductor element and an n-type semiconductor element made of a material such as BiTe, PbTe, CoSb, or Mg ₂ Si are known.

  FIG. 9 is a front view showing the configuration of such a conventional thermoelectric conversion module, in which an electrode plate 106 is joined to both ends of a p-type semiconductor element 102a and an n-type semiconductor element 102b so as to be connected in series. It has a connection structure. The upper and lower surfaces of the electrode plate 106 have high thermal conductivity, and an electrically insulating upper surface plate 105a and lower surface plate 105b are attached. When the upper surface plate 105a and the lower surface plate 105b are brought into close contact with, for example, a high temperature portion of several hundred degrees Celsius and a low temperature portion of several tens of degrees Celsius, in the n-type semiconductor element 102b, the energy of conduction electrons increases on the high temperature side, In order to diffuse, a thermoelectromotive force is generated in a direction in which current flows from the low temperature portion to the high temperature portion. In the p-type semiconductor element 102a, similarly, the energy of holes on the high temperature side becomes high and diffuses to the low temperature side, so that a thermoelectromotive force is generated in the direction in which current flows from the high temperature portion to the low temperature portion. Since the p-type semiconductor element 102a and the n-type semiconductor element 102b are connected in series in the π-type by the electrode plate 106, electricity can be taken out from both ends of the thermoelectric module and used.

JP-A-1-214280

  However, in the conventional thermoelectric conversion module, the operation of aligning the p-type and n-type semiconductor elements 102a and 102b for thermoelectric conversion with a certain gap is complicated, and it is difficult to achieve mass production and cost reduction.

  In addition, the conventional thermoelectric conversion module is processed into the p-type semiconductor element 102a and the n-type semiconductor element 102b by cutting a sintered body of a large semiconductor material, but the p-type semiconductor element 102a and the n-type semiconductor element 102b are small. If it becomes, a crack and a chip | tip may arise in an end surface at the time of a cutting process. Therefore, it is difficult to reduce the size of the p-type semiconductor element 102a and the n-type semiconductor element 102b. Further, when the semiconductor elements 102a and 102b become small, it becomes difficult to align and join the upper and lower surface plates 105a and 105b.

  Therefore, it is difficult to manufacture a thermoelectric conversion module having a small and integrated structure used for thermoelectric conversion in a small area, and a high efficiency using a small heat source such as a semiconductor component on a circuit board of an electronic device as a heat source. It is difficult to realize as a thermoelectric conversion module.

  In order to solve the above-described problem, a thermoelectric conversion element according to an embodiment of the present invention has a cylindrical insulating support having a partition in the inner axial direction except for one end and having an opening on the outer peripheral surface on the other end. A p-type semiconductor element having a Seebeck effect filled in one of the insulating supports through the partition, and filled in the other of the insulating support through the partition. An n-type semiconductor element having a Seebeck effect directly electrically connected, and an electrode provided in the p-type semiconductor element and the n-type semiconductor element in the opening.

In the p-type semiconductor element, different p-type semiconductor members may be connected to a high temperature side and a low temperature side.
In the n-type semiconductor element, different n-type semiconductor members may be connected to the high temperature side and the low temperature side.

  It is preferable that the thermal conductivity of the insulating support is smaller than the thermal conductivity of the p-type semiconductor element and the n-type semiconductor element.

  Moreover, it is preferable that a slit is provided in the circumferential direction of the insulating support.

  Furthermore, it is preferable that a slit is provided in the axial direction of the insulating support.

  Moreover, the thermoelectric conversion module according to an embodiment of the present invention is arranged such that the thermoelectric conversion element is in close contact so that the electrodes provided in the opening on the outer peripheral surface of the other end are connected in series, An upper surface plate and a lower surface plate are joined to one end surface and the other end surface of the thermoelectric conversion element, respectively.

  Moreover, the thermoelectric conversion apparatus which concerns on one Embodiment of this invention has connected the electrode plate provided in the outer-wall end of each said thermoelectric conversion module while overlapping the said thermoelectric conversion modules in multiple steps up and down.

  The thermoelectric conversion element according to one embodiment of the present invention can be installed in close contact with each thermoelectric conversion element by arranging the p-type semiconductor element and the n-type semiconductor element inside the cylindrical insulating support, Since assembly work becomes easy, mass production and cost reduction are easy.

  Further, by connecting the p-type semiconductor element and the n-type semiconductor element at one end in the cylindrical insulating support and attaching an electrode to each semiconductor element at the other end, the adjacent thermoelectric conversion elements are brought into close contact with each other. The electrodes can be conducted, and the electrodes on the upper and lower surface plates can be eliminated, and a substrate having high thermal conductivity can be directly mounted on the upper and lower surfaces. And the process of forming the upper and lower surface electrodes can be reduced.

  Further, when p-type semiconductor elements have different p-type semiconductor elements connected to the high-temperature side and the low-temperature side, or n-type semiconductor elements have different n-type semiconductor elements connected to the high-temperature side and the low-temperature side. In this case, a combination of semiconductor elements that are excellent in a low temperature region and a high temperature region can be combined to obtain a thermoelectric conversion device having high conversion efficiency.

  In addition, when the thermal conductivity of the insulating support is smaller than the thermal conductivity of the p-type semiconductor element and the n-type semiconductor element, the amount of heat passing through the cross section including the insulating support decreases, and the thermal resistance increases. The figure of merit Z of the thermoelectric conversion element increases.

  In addition, when slits are provided in the circumferential direction of the insulating support, distortion caused by the difference in thermal expansion between the semiconductor element and the insulating support can be released, and the thermoelectric conversion element is used for parts with a large temperature difference. can do. In particular, by providing the slits in the circumferential direction of the thermoelectric conversion element, it is possible to reduce distortion due to the difference in thermal expansion between the support 1 and the semiconductor element in the axial direction.

  In addition, even when a slit is provided in the axial direction of the insulating support, distortion caused by a difference in thermal expansion between the semiconductor element and the insulating support can be released, and the thermoelectric conversion element is a part having a large temperature difference. Can be used for In particular, by providing the slit in the axial direction of the thermoelectric conversion element, it is possible to reduce distortion due to a difference in thermal expansion in the circumferential direction between the insulating support and the semiconductor element.

  Moreover, the thermoelectric conversion module according to an embodiment of the present invention arranges the plurality of thermoelectric conversion elements in close contact so that the electrodes provided on the opening on the outer peripheral surface of the other end are connected in series. Since the upper surface plate and the lower surface plate are respectively joined to the one end surface and the other end surface of the thermoelectric conversion element, the thermoelectric conversion element can be compact and have high thermoelectric conversion efficiency η.

  Furthermore, when the thermoelectric conversion modules are stacked in a plurality of stages, and when an electrode plate provided on the outer wall end of each thermoelectric conversion module is connected, a large thermoelectric conversion power can be taken out.

  As described above, according to the thermoelectric conversion element of the present invention, it is possible to realize a thermoelectric conversion element that can be used in a portion having a large temperature difference and has high conversion efficiency η. In the case of a thermoelectric conversion module, a thermoelectric conversion module that can be easily mass-produced with a small integrated structure can be easily manufactured.

(A) is a perspective view which shows an example of embodiment of the thermoelectric conversion element of this invention, (b) is a perspective view which shows an example of other embodiment. (A) is AA sectional drawing of Fig.1 (a) or FIG.1 (b). (A), (b) is sectional drawing which shows each example of embodiment in the BB cross section of Fig.1 (a), respectively. (C), (d) is sectional drawing which shows each example of embodiment in the BB cross section of FIG.1 (b), respectively. An example of embodiment of the thermoelectric conversion module of this invention is shown, (a) is sectional drawing in planar view, (b) is a side view, (c) is sectional drawing which shows CC cross section of (a). . The other example of embodiment of the thermoelectric conversion module of this invention is shown, (a) is sectional drawing in planar view, (b) is a side view, (c) is sectional drawing which shows CC cross section of (a) It is. It is sectional drawing which shows the other example of embodiment of the thermoelectric conversion module of this invention. The other example of embodiment of the thermoelectric conversion element of this invention is shown, (a) is a side view, (b) is a front view, (c) is sectional drawing which shows the AA cross section of (a). It is principal part sectional drawing which shows the example of the thermoelectric conversion module using the thermoelectric conversion element shown in FIG. It is a side view which shows the example of the thermoelectric conversion module using the conventional thermoelectric conversion element.

  Hereinafter, examples of embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an example of an embodiment of a thermoelectric conversion element of the present invention. (A) is a thermoelectric conversion element 10 using a rectangular cylindrical insulating support 1, and (b) is cylindrical. The example of embodiment of the thermoelectric conversion element 10 using the insulating support body 1 of this is shown. In FIG. 1A and FIG. 1B, a part of the outer peripheral wall surface of the insulating support 1 is removed to show the inside of the thermoelectric conversion element 10. FIG. 2 is a cross-sectional view showing the AA cross section of FIG. 1A or FIG.

  As shown in FIGS. 1 (a), 1 (b), and 2, the cylindrical insulating support 1 has an inner axial direction (except for one end (upper part in FIG. 1, left side in FIG. 2)). A partition wall 1a is provided in the vertical direction in FIG. 1 and in the horizontal direction in FIG. The insulating support 1 has openings at one end and the other end. Moreover, the opening 1b provided by notching the outer peripheral surface of the insulation support body 1 is provided in the outer peripheral surface which opposes via the partition 1a of the other end side, respectively. Through the opening 1b facing the partition wall 1a, one inside and the other inside through the partition wall 1a of the insulating support 1 communicate with the outside.

  One side of the insulating support 1 across the partition wall 1a is filled with a p-type semiconductor element 2a having a Seebeck effect. The other inside through the partition wall 1a is filled with an n-type semiconductor element 2b having a Seebeck effect. The p-type semiconductor element 2a and the n-type semiconductor element 2b are in contact with each other and electrically connected at a portion 1c where the partition wall 1a on one end side is absent. On the other end side, an electrode 6 is provided on the surface of the p-type semiconductor element 2a and the n-type semiconductor element 2b exposed by the opening 1b.

  The insulating support 1 is a cylindrical structure and is manufactured by molding a ceramic material having low thermal conductivity and high electrical insulation, such as zirconia ceramics, aluminum nitride ceramics, or silicon nitride ceramics. For example, in the case of using zirconia ceramics, it is formed by press-molding a heated powder using a resin binder into a predetermined shape and then firing it for about 1400 ° C./24 hours. The thickness of the insulating support 1 is preferably as thin as possible, and is a container of p-type and n-type semiconductor elements 2a and 2b of about 0.2 mm to 0.5 mm. Zirconia ceramics are suitable for use in the insulating support 1 of the thermoelectric conversion element 10 because the thermal conductivity is 3.0 W / m · K, which is a low thermal conductivity among ceramic materials.

  Then, two types of semiconductor materials (p-type semiconductor element 2a and n-type semiconductor element 2b) are filled into the insulating support 1 having the partition wall 1a separating the internal space. As the material of the semiconductor element for the thermoelectric conversion element 10, silicide-based, SiGe-based, oxide-based, and BiTe-based p-type and n-type semiconductor materials using Si material are used.

Silicide-based semiconductor materials are suitable in that they are abundant as resources and are harmless to the human body. As an example, for example, in the synthesis of Mg ₂ Si as an n-type semiconductor, Mg (magnesium) and Si (silicon) powders are heated and melted to about 1100 ° C. over time to produce an Mg—Si solution. . This molten material is injected into the insulating support 1, and then the temperature of the furnace is lowered to obtain the crystal by using a crystal growth method called Bridgman method that aligns the crystal orientation. Alternatively, the insulating support 1 can be filled with Mg—Si powder and heated in a baking furnace at about 800 ° C. for about 10 hours in a state where it is pressed at high pressure.

  Thereafter, Ni plating or Cu plating is performed on the surfaces of the p-type and n-type semiconductor elements 2 a and 2 b exposed at the upper and lower ends of the insulating support 1. Then, by a dicing saw, a plurality of slits 9a in the axial direction from the upper end to the lower end of the outer peripheral surface of the insulating support 1 or a plurality of circumferential slits 9b are formed in a part of the side surface. The depth of each slit 9 (the axial slit 9a and the circumferential slit 9b) is preferably formed by cutting to the thickness of the insulating support 1 or more. A smaller slit width is preferred. Thereby, the length of the joint portion between the insulating support 1 material and the semiconductor element 2 material can be divided and shortened, and due to the difference in thermal expansion between the semiconductor element 2 and the insulating support 1 in the axial direction or the circumferential direction. The amount of distortion that occurs can be kept small. For example, in the example of FIG. 1B, the joint length between the insulating support 1 and the semiconductor element 2 is about half of the axial length by the circumferential slit 9b, and in the circumferential direction by the axial slit 9a. It is divided into about 1/4.

  The slits 9b partially provided in the circumferential direction divide the thermoelectric conversion element 10 into two in the axial direction, thereby relaxing the strain stress due to the difference in thermal expansion occurring in the axial direction and preventing the occurrence of cracks. Similarly, the slits 9a partially provided in the axial direction relieve stress strain caused by the difference in thermal expansion in the circumferential direction, and prevent the occurrence of cracks. The slits are provided in two or four places in the axial direction and one or two places in the circumferential direction. Since the strain stress can be relaxed, the thermoelectric conversion element 10 can be used in a portion having a large temperature difference, and the amount of power generation can be increased.

  It is necessary to provide an electrode plate on the upper surface plate 5a by providing a partition wall 1a except for one end portion inside the insulating support 1, and electrically connecting the p-type semiconductor element 2a and the n-type semiconductor element 2b at one end portion. Absent. Moreover, the electrode 6 is provided on the side surface on the other end side of the p-type semiconductor element 2a and the n-type semiconductor element 2b, and it is not necessary to provide an electrode plate on the lower surface plate 5b. Accordingly, the semiconductor element 2 can be directly adhered and fixed to the upper and lower surface plates 5a and 5b by silver brazing or the like without using an electrode plate, and the conversion efficiency η of the thermoelectric conversion element 10 is improved.

  Further, since it can be fixed tightly, more thermoelectric conversion elements 10 can be arranged in the same area as the conventional thermoelectric module, and the output voltage can be increased. Alternatively, the supplied power can be increased.

As the semiconductor element 2 filled in the insulating support 1, a silicide-based semiconductor element 2 (for example, p-type is MnSi _1.73 or the like, n-type is Mg ₂ Si or the like) has a use temperature range of 300 ° C. The dimensionless figure of merit ZT is about 1 to 1.5, which is as wide as ˜600 ° C., and is a semiconductor material for thermoelectric conversion that may further improve ZT in the future. The dimensionless figure of merit ZT indicates the performance of the thermoelectric conversion element,
ZT = α ² · T / (ρ · κ)
Where Z: figure of merit α ² · T / (ρ · κ)
α: Seebeck coefficient
T: Absolute temperature (° K)
κ: Thermal conductivity
ρ: Expressed by electrical resistivity, the larger the value, the greater the conversion efficiency η.

In the case of a combination using zirconia ceramics for the insulating support 1 and silicide-based Mg ₂ Si for the n-type semiconductor element material 2b, the thermal expansion coefficient is close, and damage due to strain due to temperature fluctuations, cracks, and the like hardly occur. The thermal conductivity is 3.0 W / m · K for zirconia ceramics and 8.0 W / m · K for Mg ₂ Si, which is smaller for zirconia ceramics. Therefore, when the insulating support 1 made of a cylindrical structure made of zirconia ceramic and the n-type semiconductor element 2b are combined, the structure including the insulating support 1 is more heated than the case of using only the n-type semiconductor element 2b material. Since the conductivity is reduced, the value of the dimensionless figure of merit ZT is improved, and the conversion efficiency η is improved. Therefore, it is preferable that the thermal conductivity of the material of the insulating support 1 is smaller than that of the semiconductor element material 2 for thermoelectric conversion because the conversion efficiency η is improved due to an increase in thermal resistance. Moreover, by covering the periphery of the semiconductor element 2 with the insulating support 1, the thermoelectric conversion elements 10 can be installed in close contact with each other.

  3A and 3B are cross-sectional views showing a BB cross section of the thermoelectric conversion element 10 shown in FIG. 1 or FIG. 2, wherein FIG. 3A is a cross-sectional view when the insulating support 1 is a rectangular cylinder, and FIG. In the cross-sectional view when the partition wall 1a inside the cylindrical insulating support 1 is formed in a diagonal direction, when the electrode 6 is provided on the side adjacent to the partition wall 1a, (c) is a cylinder FIG. 6D is a cross-sectional view of the cylindrical insulating support 1 in the case where the inner partition wall 1a of the cylindrical insulating support 1 in FIG. It is a case where it is provided in a 90 degree direction on both sides. Moreover, the electrode 6 is provided on the outer peripheral surface of the insulating support 1, and the adjacent thermoelectric conversion elements 10 can be connected to each other. The electrode 6 is formed by depositing Ni or Cu on the surface of the semiconductor element 2 by PVD or CVD and brazing a Cu plate or Ni plate thereon. Alternatively, the electrode 6 may be formed by applying a thick film plating of Cu (copper), Ag (silver), Ni (nickel), Al (aluminum) or the like on the surface of the semiconductor element 2 to a thickness of about 50 μm to 100 μm.

  FIG. 4 shows an example of an embodiment of the thermoelectric conversion module 11 using the thermoelectric conversion element 10 shown in FIG. 3, FIG. 4 (a) is a sectional view in plan view, and FIG. A side view and FIG.4 (c) show CC sectional drawing of Fig.4 (a). FIG. 4A shows the DD cross section of FIG. 4C, and shows ten thermoelectric conversion elements 10 shown in FIG. 3A and FIG. 3B. A total of 16 thermoelectric conversion elements 10 are combined into a thermoelectric conversion module 11. In addition, the arrow in a figure shows the direction through which an electric current flows.

  The thermoelectric conversion element 10 of the type shown in FIG. 3A has an electrode 6 provided in parallel to the opposing outer wall surface of the insulating support 1, and is used in a portion where current flows linearly. In the thermoelectric conversion element 10 of the type shown in FIG. 3B, electrodes 6 are provided on adjacent outer wall surfaces, and the electrodes 6 are arranged in a perpendicular direction in plan view. Therefore, it can be used in a place where the direction of current flow is changed by 90 degrees. And the electrode 6 of the adjacent thermoelectric conversion elements 10 is connected, respectively, and the terminal 12 is connected to the electrode 6 of the terminal thermoelectric conversion element 10, and the thermoelectric conversion module 11 is comprised.

  By bringing the upper surface plate 5a into contact with the heat source as the high temperature side and bringing the lower surface plate 5b side into contact with the cooling surface as the low temperature side, the holes that have obtained energy from the high temperature side move to the low temperature side in the p-type semiconductor element 2a. Current flows from the high temperature side to the low temperature side. In the n-type semiconductor element 2b, electrons move from the high temperature side to the low temperature side, and a current flows from the low temperature side to the high temperature side. As a whole, current flows in the direction indicated by the arrow, and the thermoelectric conversion module 11 operates. In FIG. 4A, the right terminal 12 of the thermoelectric conversion module 11 is connected to the electrode 6 of the n-type semiconductor element 2b and operates as a − (minus) terminal, and the left terminal 12 is the p-type semiconductor element 2a. It is connected to the electrode 6 and operates as a + (plus) terminal.

  FIG. 5 shows an example of an embodiment in which the cylindrical insulating support 1 shown in FIGS. 3C and 3D is used, and FIG. 5A shows a thermoelectric conversion module. It is sectional drawing which shows the DD cross section of FIG.5 (b) which planarly viewed 11. 5 (b) is a side view of FIG. 5 (a), and FIG. 5 (c) is a cross-sectional view showing a CC cross section of FIG. 5 (a). Here, an example is shown in which a total of 16 thermoelectric conversion elements 10 shown in FIGS. 3C and 3D are used. The thermoelectric conversion element 10 of the type shown in FIG. 3C has an electrode 6 provided at a position facing the outer wall surface by 180 degrees, and is used in a portion where current flows linearly. The thermoelectric conversion element 10 of the type shown in FIG. 3D is provided with an electrode 6 at a 90-degree position on the outer wall surface, and is used in a place where the current flowing direction is changed to a right angle.

FIG. 6 shows an example of an embodiment in which the thermoelectric conversion element 10 is segmented vertically and stacked. When there is a relatively large temperature difference between the high temperature side and the low temperature side, the thermoelectric conversion module 11 having the same area can be used to increase the output. In this case, on the high temperature side, a stick dite-based or silicide-based p-type semiconductor element 2aa, for example, CoSb ₃ (temperature range: 350 ° C. to 650 ° C.), MnSi _1.73 (temperature range: 250 ° C. to 600 ° C.). ), FeSi ₂ (addition of a minute amount of Mn or Al) (temperature range: 300 ° C. to 700 ° C.), CrSi ₂ (temperature range: 300 ° C. to 700 ° C.), etc. are used for the n-type semiconductor element 2ba, for example, FeSi ₂ (a slight amount of Co or Ni added), Mg ₂ Si (temperature range: 150 ° C. to 550 ° C.), Mg ₂ Ge (temperature range: 150 ° C. to 500 ° C.), or the like can be used. On the low temperature side, BiTe-based p-type semiconductor element 2ab, for example, Bi ₂ Te ₃ (temperature range: 30 ° C. to 300 ° C.), CsBi ₄ Te ₆ (temperature range: 30 ° C. to 300 ° C.), etc., and n-type The thermoelectric conversion module 11 is made of a material such as Yb _0.2 Co ₄ Sb ₁₂ (temperature range: 30 ° C. to 400 ° C.), Bi ₈₈ Sb ₁₂ (temperature range: 30 ° C. to 300 ° C.) or the like for the semiconductor element 2bb. Can be configured.

  Ni plating is applied between different upper and lower semiconductor element 2 materials, and the upper and lower semiconductor elements 2 are joined to each other via the Ni plating. Ni plating strengthens bonding by brazing or the like, and prevents characteristic deterioration due to mutual diffusion of the semiconductor element 2 materials in the boundary region between the upper and lower semiconductor element 2 materials.

  Thus, it can comprise easily as the thermoelectric conversion module 11 by combining the thermoelectric conversion element 10 of this invention according to the objective and a use. By laminating and using thermoelectric conversion materials suitable for each temperature range in the low temperature range and high temperature range, operation in each optimum temperature range can be achieved, so that the conversion efficiency η can be improved and the thermoelectric output can be improved. it can. For example, a thermoelectric conversion efficiency η of about 10% can be improved to about 15%.

  FIG. 7 shows an example of another embodiment of the thermoelectric conversion element 10 of the present invention. FIG. 7 (a) is a left side view, FIG. 7 (b) is a front view, and FIG. 7 (c) is FIG. The AA cross section of) is shown. In the present embodiment, the p-type semiconductor element 2aa filled in the insulating support 1 of the thermoelectric conversion element 10 shown in FIGS. 1A and 1B is changed into a p-type semiconductor element 2aa having different characteristics depending on the operating temperature. The n-type semiconductor element 2ab is connected, and the n-type semiconductor element 2b is configured by connecting the n-type semiconductor element 2ba and the n-type semiconductor element 2bb having different characteristics depending on the operating temperature.

For example, a p-type semiconductor element 2aa made of a silicide-based material such as MnSi _1.73 , FeSi ₂ (addition of a minute amount of Mn or Al), CrSi ₂ or the like having high characteristics in a high and medium temperature range, and Bi ₂ Te having high characteristics in a low temperature range. A BiTe-based material such as ₃ or a p-type semiconductor element 2ab such as CsBi ₄ Te ₆ is connected. Examples of the material of the n-type semiconductor element 2b include silicide-based materials such as FeSi ₂ (additional Co or Ni added) and Mg ₂ Si on the high temperature side, and Bi ₂ Te ₃ and CsBi ₄ Te ₆ on the low temperature side. BiTe-based materials can be used.

  In such a thermoelectric conversion element 10, a silicide-based semiconductor material is first put in the insulating support 1 and then pressurized at 30 MPa to 60 MPa, and simultaneously heated at about 800 ° C. to 1000 ° C. for several hours and fired, and then BiTe. The semiconductor support material is filled in the insulating support 1 and pressurized at 150 MPa to 200 MPa, and simultaneously heated to about 400 ° C. to 500 ° C. and fired. In order to prevent mutual diffusion of semiconductor materials having different characteristics, Ni plating or the like may be applied to the boundary surface.

  By placing such a thermoelectric conversion element 10 in close contact between the high temperature portion and the low temperature portion, the p-type semiconductor material 2a and the n-type semiconductor material 2b are used in comparison with those using one kind of material. The temperature range is expanded and thermoelectric conversion can be performed with higher efficiency. For example, when only the BiTe system in the above example is used, the operating temperature range of about 30 ° C. to 300 ° C. expands to about 30 ° C. to 600 ° C. when configured in combination with a silicide-based material. Further, by using each semiconductor material in an appropriate temperature range, it is possible to improve the conversion efficiency η, thereby increasing the generated power. By thus forming a p-type semiconductor element 2a and an n-type semiconductor element 2b by combining a plurality of semiconductor materials, it is possible to realize the thermoelectric conversion element 10 that can cover a wide use temperature range from a low temperature range to a high temperature range.

  FIG. 8 is a configuration example of the thermoelectric conversion module 11 when the thermoelectric conversion element 10 shown in FIG. 7 is used. When the lower side of the paper is the low temperature side and the upper side is the high temperature side, the upper side is the p-type semiconductor element 2aa and n-type semiconductor element 2ba for the medium-high temperature region, and the lower side is the p-type semiconductor element 2ab and n-type semiconductor for the medium-low temperature region Element 2bb. The heat of the n-type semiconductor elements 2ba and 2bb flows to the high temperature side by the heat conducted from the heat source on the high temperature side through the upper surface plate 5a and the bonding layer (plating layer 3 and solder layer 4). Then, current flows to the p-type semiconductor element 2aa via the junction between the n-type semiconductor element 2ba and the p-type semiconductor element 2aa on one end side. In the p-type semiconductor element 2aa and the p-type semiconductor element 2ab, the excited holes move to the low temperature side, and a current flows to the low temperature side. Then, it flows to the adjacent thermoelectric conversion element 10 through the electrode 6 installed on the side surface of the insulating support 1. In this way, a wide range of operating temperature ranges from low temperature to high temperature without using a cascade structure in which individual thermoelectric conversion modules manufactured using different semiconductor element 2 materials for low temperature and high temperature are stacked. The highly efficient thermoelectric conversion module 11 that can be covered can be easily realized, and the heat transfer conversion module 11 that is small and easy to integrate can be obtained.

  The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the present invention.

  In the above description, the terms “upper, lower, left and right” are merely used to describe the positional relationship on the drawing, and do not mean the positional relationship during actual use.

DESCRIPTION OF SYMBOLS 1: Insulation support 1a: Partition 1b: Opening 1c: One end part 2: Semiconductor element 2a: P-type semiconductor element 2b: N-type semiconductor element 3: Plating layer 4: Solder layer 5a: Upper surface plate 5b: Lower surface plate 9: Slit 9a: Axial slit 9b: Circumferential slit Thermoelectric conversion element 11. Thermoelectric conversion module

Claims (8)

A partition wall is provided in the inner axial direction except for one end, and a cylindrical insulating support having an opening on the outer peripheral surface on the other end side, and one inside of the insulating support is filled through the partition. A p-type semiconductor element having a Seebeck effect, an n-type semiconductor element having a Seebeck effect that is filled in the other through the partition and is directly electrically connected to the p-type semiconductor element at the one end, and the opening A thermoelectric conversion element comprising: an electrode provided on the p-type semiconductor element and the n-type semiconductor element in a portion. The thermoelectric conversion element according to claim 1, wherein the p-type semiconductor element is formed by connecting different p-type semiconductor members on a high temperature side and a low temperature side. The thermoelectric conversion element according to claim 1 or 2, wherein the n-type semiconductor element is formed by connecting different n-type semiconductor members on a high temperature side and a low temperature side. The thermoelectric conversion element according to any one of claims 1 to 3, wherein the insulating support has a thermal conductivity smaller than that of the p-type semiconductor element and the n-type semiconductor element. The thermoelectric conversion element according to claim 1, wherein a slit is provided in a circumferential direction of the insulating support. The thermoelectric conversion element according to any one of claims 1 to 5, wherein a slit is provided in an axial direction of the insulating support. The thermoelectric conversion element according to any one of claims 1 to 6, wherein the thermoelectric conversion elements are arranged in close contact so that electrodes provided on an opening on the outer peripheral surface of the other end are connected in series. A thermoelectric conversion module, wherein an upper surface plate and a lower surface plate are respectively joined to one end surface and the other end surface of the element. The thermoelectric conversion device according to claim 7, wherein the thermoelectric conversion modules are stacked in a plurality of upper and lower stages, and an electrode plate provided on an outer wall end of each thermoelectric conversion module is connected.

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