JP2020057730A - Thermoelectric converter - Google Patents

Abstract

To provide a thermoelectric conversion device capable of coping with the dimensional variation of each component and mitigating the influence of external force generated on a thermoelectric conversion module due to vibration during transportation.SOLUTION: A heat absorption side heat transfer portion 110 is constituted by a heat transfer block 111 and a heat transfer sheet 112, and the heat transfer sheet 112 is constituted by a deformable material. Further, when a case 130 is fixed to a heat dissipation fin 120, a heat transfer block 111 contacts the heat transfer sheet 112, the heat transfer sheet 112 is deformed, and the heat transfer sheet 112 is pressed against a thermoelectric conversion module 140. Since the thermoelectric conversion device 100 has such a configuration, even when there are variations in the dimensions of the case 130 and the thermoelectric conversion module 140 due to manufacturing, there is no unnecessary gap between the heat transfer block 111 and the heat transfer sheet 112, etc. Further, even when an external force is applied to the heat transfer block 111, the external force is not directly transmitted to the thermoelectric conversion module 140 but is absorbed by the heat transfer sheet 112.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a thermoelectric conversion device used as a cooling unit of a refrigerator or the like, for example.

  Conventionally, an electronic cooling system utilizing the Peltier effect has been known. In such an electronic cooling system, generally, a thermoelectric conversion module (Peltier module) in which a large number of thermoelectric elements are integrated to improve the heat absorption and radiation efficiency is used.

  FIG. 5 is a diagram for explaining the structure of the thermoelectric conversion module. As shown in the figure, the thermoelectric conversion module 500 includes a plurality of π-type thermoelectric elements 510 (one ends of an n-type semiconductor element 511 and a p-type semiconductor element 512 joined by a metal electrode 513) arranged in a plate shape. The plurality of π-type thermoelectric elements 510 are electrically connected in series and thermally in parallel by the metal electrode 520. In the example shown in the figure, when a direct current is passed in the direction of the arrow (the direction from the n-side to the p-side of the π-type thermoelectric element), heat is absorbed on the upper surface side (np junction side of the π-type thermoelectric element). The heat is dissipated on the bottom side. In general, an insulating substrate (for example, a ceramic substrate) 530 is bonded to the upper surface and the lower surface, respectively, to form a heat absorbing surface and a heat radiating surface. In addition, in the figure, the insulating substrate on the upper surface side is omitted.

  Such a thermoelectric conversion module has, for example, a top surface and a bottom surface sandwiched between a heat-absorbing-side heat transfer member (for example, a heat transfer block) and a heat-dissipation-side heat transfer member (for example, a radiation fin). (Side) is used in a state covered with a synthetic resin case, that is, in a unitized state.

  FIG. 6 is a cross-sectional view illustrating an example of a thermoelectric conversion unit (Peltier unit). As shown in the figure, the thermoelectric conversion unit 600 includes a heat transfer block 610, a radiation fin 620, and a case 630, and a thermoelectric conversion module 640 is sandwiched between the heat transfer block 610 and the radiation fin 620. Have been.

  In the thermoelectric conversion unit 600 shown in the figure, the case 630 is formed by insert molding so as to be integrated with the heat transfer block 610, but the dimensions of the case 630 have a certain variation. Further, the thickness of the thermoelectric conversion module 640 also has manufacturing variations. Therefore, when the components 610 to 640 of the thermoelectric conversion unit 600 are assembled, an unnecessary gap may be generated between the heat transfer block 610 (or the radiation fin 620) and the thermoelectric conversion module 640. In this case, for example, if the two are directly adhered with a heat conductive adhesive, the thickness of the adhesive layer that adheres the two becomes large, and the heat conductivity deteriorates.

  When the thermoelectric conversion unit 600 shown in the figure is used as a cooling unit of a refrigerator, for example, a heat transfer block 610 is screwed to the back of a refrigerator, which is an object to be cooled. 600 will be supported in a cantilever manner. Therefore, when vibration generated during transportation of the refrigerator or the like is transmitted to the thermoelectric conversion unit 600, an uneven force (uneven load) is applied to the thermoelectric conversion module 640 via the heat transfer block 610, and as a result, the thermoelectric conversion is performed. The module 640 may be destroyed.

  JP-A-2003-114080 discloses that a thermoelectric conversion element is sandwiched between a heat-absorbing heat conductor and a heat-dissipating heat conductor made of metal, and the heat-absorbing heat conductor is arranged inside a synthetic resin frame. A thermoelectric conversion device in which a frame is integrally insert-molded around the heat-absorbing-side heat conductor is disclosed.

JP 2003-114080 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoelectric conversion device capable of coping with a dimensional variation of each component member and mitigating an influence on a thermoelectric conversion module of an external force generated by vibration or the like during transportation. It is in.

  The thermoelectric conversion device according to the present invention is a thermoelectric conversion device including a thermoelectric conversion module including a plurality of thermoelectric elements, and a heat transfer unit that contacts and transfers heat to the thermoelectric conversion module, wherein the heat transfer unit Comprises a first heat transfer member and a second heat transfer member, the second heat transfer member is disposed between the first heat transfer member and the thermoelectric conversion module, It is characterized by being made of a possible material.

  In this case, the second heat transfer member may be made of a porous material having a large number of pores. In this case, the pores may be filled with a heat conductive substance. Further, in this case, the heat conductive substance may be a heat conductive grease.

  In the above case, the porous material may be a porous metal. In this case, the porous metal may be a metal sponge.

  In the above case, the first heat transfer member is in contact with the second heat transfer member, and the second heat transfer member is in contact with the first heat transfer member. It may be deformed. In this case, the size of the bottom surface of the first heat transfer member (the surface facing the second heat transfer member) is equal to the size of the upper surface of the second heat transfer member (the surface facing the first heat transfer member). May be smaller than the size of. Further, the size of the bottom surface of the first heat transfer member may correspond to a region where the plurality of thermoelectric elements exist.

  In the above case, the second heat transfer member may have a sheet-like shape. Further, the heat transfer section may be in contact with a heat absorbing surface of the thermoelectric conversion module.

  Further, in the above case, a case may be further provided to cover the periphery of the thermoelectric conversion module, and the first heat transfer member may be fixed to the case. In this case, the thermoelectric conversion module may further include a heat-dissipation-side heat transfer unit (for example, a heat-dissipation fin) that contacts the heat-dissipation surface, and the case may be fixed to the heat-dissipation-side heat transfer unit.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to deal with the dispersion | variation in the dimension of each component. In addition, since the effect of external force applied to the heat transfer section can be prevented from directly affecting the thermoelectric conversion module, the thermoelectric conversion module can be prevented from being destroyed, and the reliability of the thermoelectric conversion device is improved. It is possible to do.

FIG. 2 is a front view for explaining the configuration of the thermoelectric conversion unit 100 according to the present invention. FIG. 2 is a plan view for explaining a configuration of a thermoelectric conversion unit 100 according to the present invention. It is AA sectional drawing of FIG. FIG. 4 is an enlarged sectional view illustrating a periphery of a thermoelectric conversion module 140 of FIG. 3. FIG. 4 is a diagram for explaining a structure of a thermoelectric conversion module 500. FIG. 4 is a cross-sectional view illustrating an example of a thermoelectric conversion unit 600.

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

  Hereinafter, a thermoelectric conversion unit (Peltier unit) as a thermoelectric conversion device according to the present invention will be described. The thermoelectric conversion unit according to the present invention is used for a cooling system, and is used, for example, as a cooling unit for a refrigerator or a freezer.

  1 to 4 are diagrams for explaining the configuration of a thermoelectric conversion unit (Peltier unit) according to the present invention. 1 shows a front view, FIG. 2 shows a plan view, FIG. 3 shows an AA cross-sectional view of FIG. 2, and FIG. 4 shows an enlarged cross-sectional view around the thermoelectric conversion module of FIG.

  As shown in FIG. 1, the thermoelectric conversion unit 100 according to the present invention includes a heat transfer unit 110, a radiating fin 120, and a case 130. Furthermore, as shown in FIG. 3, a thermoelectric conversion module 140 is sandwiched between the heat transfer section 110 and the radiation fins 120.

  The heat transfer unit 110 is a heat transfer member that contacts one surface of the thermoelectric conversion module 140 (a heat absorption surface in the present embodiment) to transfer heat. As shown in FIG. 3, in the present embodiment, the heat transfer unit 110 includes two members, that is, a heat transfer block 111 and a heat transfer sheet 112. The heat transfer block 111 and the heat transfer sheet 112 are used in a state where they are in contact with each other, and the heat transfer sheet 112 comes into contact with one surface (the heat absorbing surface in the present embodiment) of the thermoelectric conversion module 140, and The block 111 is fixed (for example, screwed) to the object to be cooled. The details of the heat transfer block 111 and the heat transfer sheet 112 will be described later.

  The radiating fins 120 are heat transfer members (radiation side heat transfer portions) that transfer (dissipate) heat by contacting the other surface of the thermoelectric conversion module 140 (in the present embodiment, the heat radiating surface). It is made of a highly conductive metal (for example, aluminum). For example, a heat conductive grease (thermal grease), which is a semi-solid substance having excellent heat conductivity, is applied to a contact surface between the radiation fin 120 and the thermoelectric conversion module 140 in order to enhance heat conductivity. . The radiating fins 120 include a rectangular flat plate 121 and a number of fins 122 attached to the bottom surface thereof, and are forcibly air-cooled by, for example, a fan (not shown).

  The case 130 covers the periphery (sides) of the thermoelectric conversion module 140 sandwiched between the heat transfer section 110 (heat transfer sheet 112) and the radiating fins 120 (rectangular flat plate 121) to form a closed space. It is made of, for example, a synthetic resin (for example, polyphenylene sulfide) having low thermal conductivity, water resistance, and low gas permeability. The case 130 includes a side wall 131 extending along the side surface of the heat transfer block 111 so as to cover most of the side surface of the heat transfer block 111 and an upper surface of the heat radiation fin 120 so as to cover a part of the upper surface of the heat radiation fin 120. And a projecting portion 132 extending outwardly along the line, and is formed so as to have a substantially L-shaped cross section. The case 130 is formed by, for example, insert molding so as to be integrated with the heat transfer block 111, and the overhang portion 132 is fixed (screwed) to the radiation fin 120 (the rectangular flat plate 121).

  As shown in FIG. 2, a pair of tab terminals 133 for supplying a direct current to the thermoelectric conversion module 140 is provided on one side of the overhang 132 of the case 130. The tab terminals 133 and the (metal electrodes of) the thermoelectric conversion module 140 are connected by lead wires 134.

  As described above, the thermoelectric conversion module 140 is configured by a plurality of π-type thermoelectric elements arranged in a plate shape, and the plurality of π-type thermoelectric elements are electrically connected in series by a metal electrode. Are connected in parallel. In addition, as shown in FIG. 4, insulating substrates (for example, ceramic substrates) 143 and 144 are bonded to the metal electrodes 141 and 142 on the top surface and the bottom surface, respectively. That is, the plurality of semiconductor elements 145 joined by the metal electrodes 141 and 142 are sandwiched between the pair of insulating substrates 143 and 144. Note that, for simplicity, the lead wire 134 and the fin 122 of the heat radiation fin 120 are omitted in FIG.

  Next, details of the heat transfer block 111 and the heat transfer sheet 112 constituting the heat transfer section 110 will be described.

  The heat transfer block 111 is a heat transfer member that transfers heat by contacting the heat transfer sheet 112, and is made of, for example, a metal having high heat conductivity (for example, aluminum). The heat transfer block 111 has a substantially quadrangular prism shape, and a part thereof is exposed from the case 130 to the outside, and an object to be cooled (for example, a refrigerator compartment) is provided on (the exposed portion of) the heat transfer block 111. ) Is connected.

  As shown in FIG. 3, the bottom surface (the surface on the thermoelectric conversion module 140 side) of the heat transfer block 111 is formed to be slightly smaller than the heat dissipation surface of the thermoelectric conversion module 140. More specifically, as shown in FIG. 4, it is formed to have the same size as the range (region) where the semiconductor element 145 constituting the thermoelectric conversion module 140 exists. As described above, by making the size of the bottom surface of the heat transfer block 111 correspond to the size of the region where the semiconductor element 145 exists, the edge portion of the insulating substrate 143 that is not supported by the semiconductor element 145 becomes It can be prevented from being pushed by 111.

  The heat transfer sheet 112 is a heat transfer member that transfers heat by contacting the heat transfer block 111 and the thermoelectric conversion module 140, and is made of a highly heat-conductive and deformable material (for example, a porous metal). You. In the present embodiment, the heat transfer sheet 112 is formed of a metal sponge (for example, a nickel sponge), which is a kind of porous metal. The heat transfer sheet 112 has a thin plate-like (sheet-like) shape, and is arranged in the case 130 between the heat transfer block 111 and the thermoelectric conversion module 140. At the time of assembling, for example, the heat transfer sheet 112 is mounted on the thermoelectric conversion module 140 mounted on the radiation fins 120, and the heat transfer block 111 is further mounted thereon.

  For example, heat conductive grease (thermal grease), which is a semi-solid substance having excellent heat conductivity, is applied to the upper and lower surfaces of the heat transfer sheet 112 in order to increase the heat conductivity. In the present embodiment, the heat conductive grease is spread on the upper and lower surfaces of the heat transfer sheet 112 by, for example, using a spatula before assembling. By spreading the heat conductive grease on the surface of the heat transfer sheet 112 using a spatula or the like, the heat conductive grease is pushed from the surface of the heat transfer sheet 112 to the inside, and the metal forming the heat transfer sheet 112 The heat conductive grease is filled in the pores of the sponge, and the heat conductivity of the heat transfer sheet 112 itself is also improved. A sufficient amount of thermal conductive grease is applied so that as many pores as possible are filled with thermal conductive grease.

  The top and bottom surfaces of the heat transfer sheet 112 have the same size as the heat absorbing surface (insulating substrate 143) of the thermoelectric conversion module 140. Therefore, when the heat transfer sheet 112 is placed on the heat absorption surface (insulating substrate 143) of the thermoelectric conversion module 140, the entire region of the heat absorption surface (upper surface of the insulating substrate 143) of the thermoelectric conversion module 140 is covered by the heat transfer sheet 112. Will be covered. The thickness (length in the vertical direction in FIG. 4) of the heat transfer sheet 112 is set to a size such that the heat transfer block 111 contacts the heat transfer sheet 112 when the respective components of the thermoelectric conversion unit 100 are assembled. You. That is, the thickness of the heat transfer sheet 112 is larger than the size of the gap between the heat transfer block 111 and the thermoelectric conversion module 140 formed when the respective components of the thermoelectric conversion unit 100 are assembled. The dimensions of the components are determined. For example, the size of the gap between the heat transfer block 111 and the thermoelectric conversion module 140 formed when assembling the components of the thermoelectric conversion unit 100 is 0.7 to 0. When the thickness is 8 mm, the thickness of the heat transfer sheet 112 is set to a dimension larger than 0.8 mm (for example, 1 mm).

  In the thermoelectric conversion unit 100, since the heat transfer block 111 is fixed to the case 130, when the thickness of the heat transfer sheet 112 is made equal to or more than a certain value, when the case 130 is fixed to the radiation fins 120, the heat transfer block 111 is fixed. 111 comes into contact with the heat transfer sheet 112 placed on the thermoelectric conversion module 140, and as a result, the heat transfer sheet 112 is deformed and the heat transfer sheet 112 is pressed against the thermoelectric conversion module 140. Become. Therefore, even if the dimensions of the case 130 and the thermoelectric conversion module 140 have manufacturing variations, if the thickness of the heat transfer sheet 112 is set to an appropriate value, the heat transfer block 111 and the heat transfer sheet 112 There is no gap between them, and it is possible to absorb the dimensional variation of each component.

  As described above, in the thermoelectric conversion unit 100, the deformable (compressible) heat transfer sheet 112 is appropriately deformed, thereby absorbing the dimensional variation of each component. For example, when the size of the gap between the heat transfer block 111 and the thermoelectric conversion module 140 is 0.7 mm at the minimum and 0.8 mm at the maximum due to manufacturing variations of each component, the thickness of the gap is 1 mm. When the heat transfer sheet 112 is used, the heat transfer sheet 112 is deformed to a thickness of 70 to 80% of the original thickness (0.7 to 0.8 mm) according to the actual gap size. By doing so, variations in the dimensions of each component are absorbed.

  Further, even when an external force is applied to the heat transfer block 111 due to vibration during transportation or the like, the external force is not directly transmitted to the thermoelectric conversion module 140, but is absorbed by the deformable heat transfer sheet 112. It is possible to reduce the influence of the external force on the conversion module 140. That is, it is possible to prevent the thermoelectric conversion module 140 from being destroyed due to vibration during transportation, and to improve the reliability of the thermoelectric conversion unit 100.

  Further, as described above, in the assembled state, the heat transfer block 111 and the heat transfer sheet 112 come into contact with each other, but the size of the bottom surface (the surface facing the heat transfer sheet 112) of the heat transfer block 111 is large. Is smaller than the size of the upper surface of heat transfer sheet 112 (the surface facing heat transfer block 111). When heat transfer block 111 is pressed against heat transfer sheet 112, the pressed portion is deformed. As shown in FIG. 4, a part (bottom part) of the heat transfer block 111 is fitted into a dent (recess) formed in the heat transfer sheet 112. As a result, the movement of the heat transfer block 111 in the horizontal direction (the left-right direction in FIG. 4) is restricted, and the heat transfer block 111 is shifted in the horizontal direction due to vibration or the like, and uneven force is applied to the thermoelectric conversion module 140. (Uneven load) can be prevented from being applied.

  As described above, in the present embodiment, the heat-absorbing-side heat transfer section 110 includes the heat transfer block 111 that is in contact with the heat transfer sheet 112, and the heat transfer sheet 112 that is appropriately deformed by being in contact with the heat transfer block 111. This prevents unnecessary gaps from being generated between the heat transfer block 111 and the heat transfer sheet 112 even if the dimensions of the case 130, the thermoelectric conversion module 140, and the like vary. It is possible to do. Further, even when an external force is applied to the heat transfer block 111, the external force is not directly transmitted to the thermoelectric conversion module 140, but is absorbed by the heat transfer sheet 112, so that the thermoelectric conversion module 140 is broken by vibration or the like. Can be prevented.

  Although the embodiment of the present invention has been described above, it is needless to say that the embodiment of the present invention is not limited to the above. For example, in the above-described embodiment, the heat transfer sheet 112 is made of a metal sponge which is a kind of porous metal. However, other materials having high heat conductivity and which can be deformed, such as carbon sponge, It is also conceivable to construct the heat conduction sheet from graphite.

REFERENCE SIGNS LIST 100 thermoelectric conversion unit 110 heat transfer section 111 heat transfer block 112 heat transfer sheet 120 radiating fin 121 rectangular flat plate 122 fin 130 case 131 side wall 132 overhang 133 tab terminal 134 lead wire 140 thermoelectric conversion module 141 low temperature side electrode 142 high temperature Side electrode 143 Low-temperature side insulating substrate 144 High-temperature side insulating substrate 145 Semiconductor element 500 Thermoelectric conversion module 510 π-type thermoelectric element 511 n-type semiconductor element 512 p-type semiconductor element 513,520 Metal electrode 530 Insulating substrate 600 Thermoelectric conversion unit 610 Heat transfer block 620 Heat radiation fin 630 Case 640 Thermoelectric conversion module

Claims (13)

A thermoelectric conversion module including a plurality of thermoelectric elements,
A thermoelectric conversion device including a heat transfer unit that contacts the thermoelectric conversion module and transmits heat.
The heat transfer section includes a first heat transfer member and a second heat transfer member,
The thermoelectric conversion device, wherein the second heat transfer member is disposed between the first heat transfer member and the thermoelectric conversion module, and is made of a deformable material. The thermoelectric conversion device according to claim 1, wherein the second heat transfer member is made of a porous material having a large number of pores. The thermoelectric conversion device according to claim 2, wherein the pores are filled with a heat conductive substance. The thermoelectric conversion device according to claim 3, wherein the heat conductive substance is a heat conductive grease. The thermoelectric conversion device according to claim 2, wherein the porous material is a porous metal. The thermoelectric conversion device according to claim 5, wherein the porous metal is a metal sponge. The first heat transfer member is in contact with the second heat transfer member,
The thermoelectric conversion device according to any one of claims 1 to 6, wherein the second heat transfer member is deformed by the contact of the first heat transfer member.   The thermoelectric conversion device according to claim 7, wherein the size of the bottom surface of the first heat transfer member is smaller than the size of the top surface of the second heat transfer member. The thermoelectric conversion device according to claim 7, wherein a size of a bottom surface of the first heat transfer member corresponds to a region where the plurality of thermoelectric elements exist. The thermoelectric conversion device according to any one of claims 1 to 9, wherein the second heat transfer member has a sheet-like shape. The thermoelectric conversion device according to any one of claims 1 to 10, wherein the heat transfer unit contacts a heat absorbing surface of the thermoelectric conversion module. Further comprising a case covering the periphery of the thermoelectric conversion module,
The thermoelectric conversion device according to claim 1, wherein the first heat transfer member is fixed to the case. A heat-dissipation-side heat transfer unit that contacts a heat-dissipation surface of the thermoelectric conversion module,
The thermoelectric conversion device according to claim 12, wherein the case is fixed to the heat-radiating-side heat transfer unit.

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