JP2006332188A - Thermoelectric power generation module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoelectric power generation module which can keep appropriate power generation performance for a long time even under severe application condition where a heat collector on the high-temerpature side becomes higher. <P>SOLUTION: When a heat collecting substrate 1 becomes higher in temperature while it is being used, an electrode plate 5 and the high-temperature ends of respective thermoelectric power generation elements N and P are got in contact with each other flexibly and appropriately by means of a melted low-melting-point metal layer 8A. As a result, appropriate thermal and electric conduction is realized between the heat collecting substrate 1 and the high-temperature ends of the respective thermoelectric power generation elements N and P, and the generation of thermal stress between the electrode plate 5 and the high-temperature ends of the respective thermoelectric power generation elements N and P can be prevented in advance. In addition, an insulator 9 blocks in advance the recondensation of vapor on the circumferential surface of the thermoelectric power generation elements N and P that is generated from melted low-melting-point metal layers 8A and 8B, thereby keeping appropriate insulation on the circumferential surface of the thermoelectric power generation elements N and P. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermoelectric power generation module (thermoelectric conversion module) that directly converts thermal energy into electrical energy.

  The thermoelectric power generation module generates two types of thermoelectric power generation elements (thermoelectric conversion elements) having different polarities that generate a thermoelectromotive force according to a temperature difference by the Seebeck effect, that is, an n-type thermoelectric power generation element and a p-type thermoelectric power generation element. Are installed between the heat collecting part and the low-temperature heat radiation part, and the ends of these thermoelectric power generation elements are alternately connected in series via electrodes, and heat energy is directly converted into electrical energy. Can be converted.

  By the way, in this type of thermoelectric power generation module, when the high temperature end portion of the thermoelectric power generation element and the electrode are joined by brazing or the like, the difference between the two thermal expansion causes a difference between the high temperature end portion of the thermoelectric power generation element and the electrode. For example, under a use condition in which the high temperature side is 500 ° C. or higher, a large thermal stress is generated between the high temperature end portion of the thermoelectric power generation element and the electrode, and the joint portion may be broken.

From such a technical background, a diffusion barrier layer is formed on the surface of the high temperature end of the thermoelectric power generation element in order to increase the bonding strength between the high temperature end of the thermoelectric power generation element and the electrode against the thermal stress generated between the electrodes. Has been proposed (see, for example, Patent Document 1).
JP-A-9-243201 (paragraph number 32, FIG. 1)

  By the way, in the thermoelectric power generation module as described in Patent Document 1, when the heat collecting portion on the high temperature side becomes further high temperature and a larger thermal stress is generated between the high temperature end portion of the thermoelectric power generating element and the electrode, Due to the large thermal stress, the joint between the high temperature end portion of the thermoelectric power generation element and the electrode may break down and break down.

  Then, this invention makes it a subject to provide the thermoelectric power generation module which can maintain favorable electric power generation performance over a long period of time also under the severe use conditions in which the high temperature side heat collecting part becomes still higher temperature.

  In the thermoelectric power generation module according to the present invention, a plurality of thermoelectric power generation elements having different polarities are arranged between the high temperature side heat collecting section and the low temperature side heat radiation section, and the high temperature ends and the low temperature ends of each thermoelectric generation element Are thermoelectric power generation modules in which thermoelectric power generation elements having different polarities are alternately connected in series by being connected via electrodes, and a low melting point metal layer is formed between the high temperature portion of each thermoelectric power generation element and the electrode. The thermoelectric power generation element is interposed and filled with an insulator.

  In the thermoelectric power generation module according to the present invention, when the heat collecting part becomes high in use, the low melting point metal layer between the high temperature end of each thermoelectric power generation element and the electrode is melted, and the melted low melting point metal layer is Thus, the electrode and the high temperature end portion of each thermoelectric generator are in good contact with flexibility. As a result, heat conduction and electrical conduction from the heat collecting part to the high temperature end of each thermoelectric power generation element can be performed well, and the thermal stress between the electrode and the high temperature end of each thermoelectric power generation element is improved. Occurrence is prevented in advance. In addition, since the insulator filled around each thermoelectric power generation element prevents vapor from being generated from the molten low melting point metal and recondensing on the peripheral surface of each thermoelectric power generation element, each thermoelectric power generation element The insulation of the peripheral surface is kept good.

  In the thermoelectric power generation module according to the present invention, when the insulator is composed of an aggregate of hollow particles bonded to each other, the insulator exhibits flexibility based on the elasticity of each hollow particle, and the heat of the thermoelectric power generation element. It is preferable because it absorbs expansion and prevents its destruction.

  In addition, when the insulator is composed of an aggregate of hollow glass beads bonded to each other with a glass-based adhesive, the insulator exhibits flexibility and high heat resistance based on the elasticity of the hollow glass beads, and thermoelectric power generation This is preferable because the thermal expansion of the element is surely absorbed and its destruction is reliably prevented.

  In the thermoelectric power generation module according to the present invention, since the electrode and the high-temperature end of each thermoelectric power generation element are in good contact with each other through the low melting point metal layer melted in use, each thermoelectric power generation element from the heat collecting section Thus, heat conduction and electrical conduction to the high temperature end portion of the thermoelectric generator are performed well, and generation of thermal stress between the electrode and the high temperature end portion of each thermoelectric power generation element is prevented. In addition, the insulator filled around each thermoelectric power generation element prevents the generation of vapor from the molten low melting point metal and recondensation on the peripheral surface of each thermoelectric power generation element. The insulation of the peripheral surface is kept good. Therefore, according to the thermoelectric power generation module of the present invention, good power generation performance can be maintained over a long period of time even under severe use conditions where the heat collecting part is further heated.

  In the thermoelectric power generation module of the present invention, when the insulator is composed of an aggregate of hollow particles bonded to each other, the insulator exhibits flexibility based on the elasticity of each hollow particle, and the thermal expansion of the thermoelectric power generation element Therefore, it is possible to prevent destruction of the thermoelectric power generation element and maintain better power generation performance.

  In addition, when the insulator is composed of an assembly of hollow glass beads bonded to each other with a glass-based adhesive, the insulator exhibits flexibility and high heat resistance based on the elasticity of the hollow glass beads, and thermoelectric power generation Since the thermal expansion of the element is reliably absorbed, it is possible to reliably prevent destruction of the thermoelectric power generation element and maintain even better power generation performance.

  Hereinafter, embodiments of a thermoelectric power generation module according to the present invention will be described with reference to the drawings. In the drawings to be referred to, FIG. 1 is a perspective view showing a schematic structure of a thermoelectric power generation module according to an embodiment, and FIG. 2 is a partial vertical cross-sectional view showing a cross-sectional structure of the thermoelectric power generation module shown in FIG.

  As shown in FIG. 1, a thermoelectric power generation module according to an embodiment includes a heat collecting substrate 1 made of insulating ceramics that constitutes a high temperature side heat collecting portion and a heat radiating substrate made of insulating ceramics that constitutes a low temperature side heat radiating portion. 2, a plurality of n-type thermoelectric power generation elements N and p-type thermoelectric power generation elements P are arranged, and these n-type thermoelectric power generation elements N and p-type thermoelectric power generation elements P are disposed between the + terminal 3 and the − terminal 4. And have a basic structure that is alternately connected in series via the electrode plates 5 and 6.

  Here, as shown in FIG. 2, the n-type thermoelectric power generation element N generates a thermoelectromotive force due to the Seebeck effect. At this time, the high-temperature end portion on the heat collecting substrate 1 side becomes a positive pole, and The low temperature end becomes the negative pole. On the other hand, the p-type thermoelectric generator P generates a thermoelectromotive force due to the Seebeck effect. At this time, the high temperature end on the heat collecting substrate 1 side becomes a negative pole, and the low temperature end on the heat dissipation substrate 2 side becomes a positive pole. Become.

  Therefore, in the arrangement example shown in FIG. 2, for example, in the arrangement example shown in FIG. The end and the high temperature end serving as the negative pole of the p-type thermoelectric generator P disposed on the right side thereof are connected via the electrode plate 5 on the heat collecting substrate 1 side. A low-temperature end portion serving as a pole and a low-temperature end portion serving as a negative pole of the n-type thermoelectric generator N arranged on the right side thereof are connected via an electrode plate 6 on the heat dissipation substrate 2 side. A plurality of n-type thermoelectric generators N and p-type thermoelectric generators P are alternately connected in series by sequentially repeating the same connection state.

  Here, in the thermoelectric power generation module of the present embodiment, the diffusion prevention layer 7 is attached to the high temperature end portion of each n-type thermoelectric power generation element N and the high temperature end portion of each p-type thermoelectric power generation element P. Further, low melting point metal layers 8A and 8B are formed on both sides of each electrode plate 5. An insulator 9 is filled around each n-type thermoelectric generator N and p-type thermoelectric generator P between the heat collecting substrate 1 and the heat dissipation substrate 2.

  The diffusion prevention layer 7 is a layer formed by depositing a high melting point metal such as molybdenum (Mo) to a thickness of, for example, about 10 μm by an appropriate means such as plating, vapor deposition, or thermal spraying. The molten low melting point metal layers 8A and 8B Of the low melting point metal is prevented from diffusing into the high temperature end portions of the n-type thermoelectric generator N and the p-type thermoelectric generator P.

  The low melting point metal layers 8A and 8B are formed by spraying a low melting point metal such as tin (Sn), lead (Pb), and zinc (Zn) to a thickness of about 0.5 mm, for example. Here, for example, the low melting point metal layer 8 containing tin (Sn) as a component is surely melted when a high temperature of 250 ° C. or higher is reached in the use state of the thermoelectric power generation module.

  The insulator 9 is composed of an aggregate of hollow particles bonded to each other, for example, an aggregate of hollow glass beads in which a large number of hollow glass beads having a particle size of about 3 to 30 μm are bonded to each other with a silicate glass-based adhesive. ing. The insulator 9 has flexibility based on the elasticity of each hollow glass bead and has high heat resistance of 500 ° C. or higher.

  FIG. 3 shows an example of a manufacturing process of the thermoelectric power generation module having the cross-sectional structure shown in FIG. First, in the step shown in FIG. 3A, the diffusion prevention layer 7 is deposited on the high temperature end portions of the n-type thermoelectric elements N and the p-type thermoelectric elements P, respectively.

  In the step shown in FIG. 3 (b), each n-type thermoelectric power generation element N and each p-type thermoelectric power generation element P are arranged at a predetermined position in a mold (not shown), and the insulator 9 is filled in the space around them. . After the insulator 9 is solidified, both sides of the block-like insulator 9 integrated with each n-type thermoelectric power generation element N and each p-type thermoelectric power generation element P are connected to each n-type thermoelectric power generation element N and each p-type thermoelectric power supply. Polishing so as to be flush with both end faces of the power generation element P.

  In the step shown in FIG. 3 (c), one surface of the block-like insulator 9 whose both surfaces are polished, that is, the high-temperature end portions of the n-type thermoelectric elements N and the p-type thermoelectric elements P are deposited. A low melting point metal layer 8A, an electrode material layer 5A such as molybdenum (Mo), and a low melting point metal layer 8B are sequentially laminated on one surface where the diffusion prevention layer 7 is exposed.

  In the step shown in FIG. 3D, the other surface of the block-shaped insulator 9, that is, the end surface on the low temperature end portion side of each n-type thermoelectric element N and each p-type thermoelectric element P is exposed. An electrode material layer 6A such as molybdenum (Mo) is formed on the other surface by thermal spraying.

  In the step shown in FIG. 3E, separation grooves are formed at a depth from the low melting point metal layer 8B to the low melting point metal layer 8A, and the electrode material layers 5A are separated from each other to form the respective electrode plates 5. In addition, separation grooves are formed in the electrode material layer 6A to form the electrode plates 6 separated from each other.

  In the step shown in FIG. 3 (f), the insulator 9 is filled in each separation groove formed in the step shown in FIG. 3 (e) and solidified, and then the one surface of the block-like insulator 9 is formed. The heat collecting substrate 1 is bonded, and the heat dissipation substrate 2 is bonded to the other surface.

  In the thermoelectric power generation module having the cross-sectional structure shown in FIG. 2 manufactured by the above steps, the low melting point metal layer 8A containing, for example, tin (Sn) as a component when the heat collecting substrate 1 reaches a high temperature of, for example, 250 ° C. or higher in use. 8B surely melts. The heat collecting substrate 1 and each electrode plate 5 are in good contact with each other through the melted low melting point metal layer 8B, and each electrode plate 5 and each n-type thermoelectric generator through the melted low melting point metal layer 8A. The diffusion prevention layer 7 deposited on the high temperature end portion of the N and p-type thermoelectric generators P makes good contact with flexibility.

  As a result, in the thermoelectric power generation module of the present embodiment, heat conduction and electrical conduction from the heat collecting substrate 1 to the high temperature end portions of the n-type thermoelectric power generation elements N and the p-type thermoelectric power generation elements P are favorably performed. Become. Moreover, since the melted low melting point metal layer 8A absorbs the difference in thermal expansion between the electrode plates 5 and the high-temperature ends of the n-type thermoelectric elements N and p-type thermoelectric elements P, In the meantime, the generation of thermal stress is prevented.

  Further, since the insulator 9 prevents vapor from being generated from the melted low melting point metal layers 8A and 8B and re-condensing around each n-type thermoelectric generator N and each p-type thermoelectric generator P, each n The insulation around the thermoelectric generator N and the p-type thermoelectric generator P is kept good. The insulator 9 seals the low melting point metal layers 8A and 8B, thereby preventing the low melting point metal layers 8A and 8B from being oxidized.

  Since this insulator 9 is composed of an aggregate of hollow glass beads in which a large number of hollow glass beads having a particle size of, for example, about 3 to 30 μm are bonded to each other with a silicate glass adhesive, the elasticity of each hollow glass bead The thermal expansion of each n-type thermoelectric power generation element N and each p-type thermoelectric power generation element P is reliably absorbed and the destruction thereof is reliably prevented.

  Therefore, according to the thermoelectric power generation module of the present embodiment, good power generation performance can be maintained over a long period even under severe use conditions in which the heat collecting substrate 1 is further heated.

  The thermoelectric power generation module according to the present invention is not limited to the above-described embodiment. For example, the low melting point metal layers 8A and 8B shown in FIG. 2 are formed by impregnating a low melting point metal such as tin (Sn), lead (Pb), or zinc (Zn) into an appropriate metal mesh such as a copper mesh. May be.

It is a perspective view which shows schematic structure of the thermoelectric power generation module which concerns on one Embodiment of this invention. It is a fragmentary longitudinal cross-section which shows the cross-section of the thermoelectric power generation module shown in FIG. It is a fragmentary longitudinal cross-section which shows the manufacturing process of the thermoelectric power generation module shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat collection board | substrate 2 Heat dissipation board 3 + terminal 4-terminal 5 Electrode board 5A Electrode material layer 6 Electrode board 6A Electrode material layer 7 Diffusion prevention layer 8A Low melting metal layer 8B Low melting metal layer 9 Insulator

Claims (3)

  A plurality of thermoelectric power generation elements having different polarities are arranged between the heat collecting section on the high temperature side and the heat radiation section on the low temperature side, and the high temperature ends and the low temperature ends of each thermoelectric generation element are connected via electrodes. Thermoelectric power generation modules in which thermoelectric power generation elements having different polarities are alternately connected in series, and a low melting point metal layer is interposed between the high temperature end of each thermoelectric power generation element, and each thermoelectric power generation element The thermoelectric power generation module is characterized by being filled with an insulator around.   The thermoelectric generator module according to claim 1, wherein the insulator is composed of an aggregate of hollow particles bonded to each other. The thermoelectric generator module according to claim 1, wherein the insulator is configured by an aggregate of hollow glass beads bonded to each other with a glass-based adhesive.

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