JP2018120908A - Electrothermal power module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrothermal power module capable of alleviating a thermal stress generated in a module on the whole.SOLUTION: An electrothermal power module 1 includes: a high-temperature side electrode part 12; a low-temperature side electrode part 22 opposing to, spaced from the high-temperature electrode part 12; and a plurality of electrothermal elements 30 with different polarities, arranged between the high-temperature side electrode part 12 and the low-temperature side electrode part 22. Between the low-temperature side electrode part 22 and the electrothermal elements 30, a heat transfer conductive layer 25 formed from grease or metal mesh member is provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermoelectric power generation module.

  Thermoelectric power generation is attracting attention as a clean energy resource because it can convert exhaust heat from automobiles and factories into electrical energy. A thermoelectric power generation module used for thermoelectric power generation has two types of thermoelectric elements (p-type thermoelectric element and n-type thermoelectric element) having different polarities arranged alternately between a high-temperature side electrode part and a low-temperature side electrode part. Electric energy is generated according to the temperature difference between the electrode part and the low temperature side electrode part.

  However, in the thermoelectric power generation module at the time of driving, since the high temperature part side provided with the high temperature side electrode part is thermally expanded more than the low temperature part side provided with the low temperature side electrode part, thermal stress is generated between them. For this reason, the problem that the electric power generation output of a thermoelectric power generation module falls or a thermoelectric element is damaged arises.

  Several proposals have been made to solve such problems. For example, Patent Document 1 below discloses a thermoelectric power generation module that hardly generates thermal stress. In the thermoelectric power generation module described in this document, the low-temperature side insulating substrate is connected to the heat radiating part via the non-constraining thermal contact layer, and thus is lubricated by the heat contact layer without being fixed to the heat radiating part. It is movable along the heat dissipation part. Thereby, the low temperature part side including the low temperature side insulating substrate is intended to alleviate the thermal stress without disturbing the thermal expansion of the high temperature part side.

JP 2016-28422 A

  However, in the thermoelectric power generation module described above, the high temperature side (or low temperature side) insulating substrate and the high temperature side (or low temperature side) electrode part, the high temperature side (or low temperature side) electrode part, and the thermoelectric element are joined together. There remains a problem that the thermal stress generated in this part cannot be relaxed.

  The present invention has been made to solve such technical problems, and an object of the present invention is to provide a thermoelectric power generation module that can alleviate the thermal stress generated in the module as a whole.

  A thermoelectric power generation module according to the present invention is disposed between a high temperature side electrode portion, a low temperature side electrode portion facing away from the high temperature side electrode portion, and the high temperature side electrode portion and the low temperature side electrode portion. A thermoelectric power generation module comprising a plurality of thermoelectric elements having different polarities, wherein a heat transfer conductive layer made of grease or a metal mesh member is provided between the low temperature side electrode portion and the thermoelectric element. It is a feature.

  In the thermoelectric power generation module according to the present invention, since the heat transfer conductive layer made of grease or a metal mesh member is provided between the low temperature side electrode part and the thermoelectric element, the thermoelectric element and the low temperature side electrode part are directly joined or fixed. It is possible to move relative to each other during thermal expansion. Therefore, when the high-temperature part side thermally expands, the low-temperature part side including the low-temperature side electrode part does not hinder the thermal expansion, so the overall thermal stress generated in the module can be relaxed, and the module durability Can be improved.

  According to the present invention, the thermal stress generated in the module as a whole can be relaxed.

It is a schematic sectional drawing which shows the thermoelectric power generation module which concerns on embodiment. It is a schematic sectional drawing which shows the thermoelectric power generation module of an Example. 6 is a schematic cross-sectional view showing a thermoelectric power generation module of Comparative Example 1. FIG. 6 is a schematic cross-sectional view showing a thermoelectric power generation module of Comparative Example 2. FIG. It is a graph which shows the result of an Example and a comparative example.

  Hereinafter, an embodiment of a thermoelectric power generation module according to the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a thermoelectric power generation module according to an embodiment. The thermoelectric power generation module 1 of the present embodiment is used for, for example, recovering the exhaust heat of an automobile and generating electric power. 10 and a plurality of thermoelectric elements 30 arranged between the low temperature part 20.

  The high temperature portion 10 includes a flat plate-like high temperature side insulating substrate 11, a high temperature side electrode portion 12 arranged in a predetermined pattern on the first main surface 11a facing the low temperature portion 20 side of the high temperature side insulating substrate 11, and a high temperature portion. It has the heat collection part 13 provided in the 2nd main surface 11b on the opposite side to the 1st main surface 11a of the side insulation board | substrate 11. As shown in FIG.

  The high temperature side insulating substrate 11 is electrically insulative and has thermal conductivity, and is formed of, for example, alumina, aluminum nitride, boron nitride, silicon carbide, or the like. The high temperature side insulating substrate 11 may be made of a resin material such as a fiber reinforced plastic such as polyimide resin, fluororesin, epoxy resin, or glass epoxy.

  The high temperature side electrode portion 12 is formed by performing metal plating on the first main surface 11 a of the high temperature side insulating substrate 11. Examples of the metal plating include gold plating, nickel plating, and tin plating. The high temperature side electrode portion 12 is electrically connected to the thermoelectric element 30 so as to conduct a pair of p-type thermoelectric element 30a and n-type thermoelectric element 30b (described later).

  The heat collecting unit 13 includes a flat plate-like heat diffusion plate 13a disposed on the second main surface 11b of the high temperature side insulating substrate 11, and a plurality of heat absorbing fins 13b arranged on the heat diffusion plate 13a at predetermined intervals. Have The heat absorption fins 13b have a rod shape having a rectangular cross section, and project upward from the heat diffusion plate 13a.

  The plurality of thermoelectric elements 30 includes a p-type thermoelectric element 30a and an n-type thermoelectric element 30b that are paired with each other. These thermoelectric elements 30 are formed of a thermoelectric material having a thermoelectric effect such as Peltier effect, Seebeck effect, or Thomson effect. That is, the p-type thermoelectric element 30a is formed of a p-type thermoelectric material, and the n-type thermoelectric element 30b is formed of an n-type thermoelectric material.

  Examples of thermoelectric materials include bismuth-tellurium compounds, silicide compounds, half-Heusler compounds, lead-tellurium compounds, silicon-germanium compounds, skutterudite compounds, and the like.

  The p-type thermoelectric element 30a and the n-type thermoelectric element 30b are each formed in a prismatic shape or a cylindrical shape, and are spaced apart at a predetermined interval. The upper end portions of the p-type thermoelectric element 30a and the n-type thermoelectric element 30b are joined to the above-described high temperature side electrode portion 12 by soldering or brazing.

  On the other hand, the low temperature part 20 includes a flat plate-like low temperature side insulating substrate 21 and low temperature side electrode parts 22 arranged in a predetermined pattern on the first main surface 21a facing the high temperature part 10 side of the low temperature side insulating substrate 21. The low-temperature side insulating substrate 21 has a heat dissipating part 23 provided on the second main surface 21b opposite to the first main surface 21a.

  Similar to the high temperature side insulating substrate 11, the low temperature side insulating substrate 21 is electrically insulating and thermally conductive, and is formed of alumina, aluminum nitride, boron nitride, silicon carbide, or the like. The low temperature side electrode portion 22 is formed by performing metal plating on the first main surface 21 a of the low temperature side insulating substrate 21. Examples of the metal plating include gold plating, nickel plating, and tin plating. The low temperature side electrode portion 22 is not joined to the lower end portion of the thermoelectric element 30 and is arranged at a predetermined distance.

  On the low temperature side electrode part 22, a heat transfer conductive layer 25 made of grease or a metal mesh member having high heat transfer and conductivity is provided. The heat transfer conductive layer 25 is formed to have the same area as the low temperature side electrode portion 22 so as to cover the low temperature side electrode portion 22. Further, the heat transfer conductive layer 25 is not joined to the lower end portion of the thermoelectric element 30 and is arranged at a predetermined distance.

  The heat dissipating part 23 is disposed on the second main surface 21 b of the low temperature side insulating substrate 21 via the heat transfer grease 24. The heat dissipating part 23 includes a flat plate-like heat diffusion plate 23a disposed in the heat transfer grease 24, and a plurality of cooling fins 23b arranged at predetermined intervals below the heat diffusion plate 23a. The cooling fins 23b have a rod shape having a rectangular cross section, and project downward from the heat diffusion plate 23a.

  In the thermoelectric power generation module 1 configured in this way, when a predetermined load F is applied to the high temperature part 10 and the low temperature part 20 so that the thermoelectric element 30 and the low temperature part 20 are relatively close to each other, the lower end of the thermoelectric element 30 The part comes into contact with the heat transfer conductive layer 25. Thereby, the thermoelectric element 30 and the low temperature side electrode part 22 are electrically connected via the heat transfer conductive layer 25.

  According to the thermoelectric power generation module 1 of the present embodiment, since the heat transfer conductive layer 25 made of grease or a metal mesh member is provided between the low temperature side electrode portion 22 and the thermoelectric element 30, the thermoelectric element 30 and the low temperature side electrode portion are provided. 22 is in a state where it is not directly joined or fixed, and both can move relatively during thermal expansion. Therefore, when the high temperature portion 10 side thermally expands, the low temperature portion 20 side including the low temperature side electrode portion 22 does not hinder the thermal expansion, so that the overall thermal stress generated in the module can be relaxed, The module durability can be improved.

  Further, when the heat transfer conductive layer 25 is made of a metal mesh member, the effect of preventing the occurrence of sticking due to mutual element diffusion between the thermoelectric element 30 and the low temperature side electrode portion 22 is further exhibited.

  Examples of the present invention will be described below. The present invention is not limited to the following examples.

<Example>
In the present embodiment, using the thermoelectric power generation module 1 (see FIG. 2) in which the heat transfer grease 24 is omitted, heat is produced under the conditions that the temperature on the high temperature part 10 side is 500 ° C. and the temperature on the low temperature part 20 side is 100 ° C. The initial thermal stresses were calculated using the high-temperature and outer high-temperature side electrode part 12 and the thermoelectric element 30 having high generated stress when applied as the thermal stress calculation part. The software used for the calculation was ABAQUS6-14, and a Cu mesh member was used for the heat transfer conductive layer 25, and Cu plating was used for the high temperature side electrode portion 12 and the low temperature side electrode portion 22, respectively.

<Comparative Example 1>
FIG. 3 is a schematic cross-sectional view showing the thermoelectric power generation module of Comparative Example 1. The thermoelectric power generation module 2 of the comparative example 1 is different from the embodiment in that the heat transfer conductive layer 25 is not provided, and the low temperature side electrode portion 22 is joined to the lower end portion of the thermoelectric element 30, but the other structure. Was similar to the example. And the initial thermal stress of the thermal-stress calculation part was computed with respect to this thermoelectric power generation module 2 on the conditions similar to an Example.

<Comparative example 2>
FIG. 4 is a schematic cross-sectional view showing the thermoelectric power generation module of Comparative Example 2. In the thermoelectric power generation module 3 of Comparative Example 2, the heat transfer conductive layer 25 is not provided, and the low temperature side electrode portion 22 is directly joined to the lower end portion of the thermoelectric element 30 and is separated from the low temperature side insulating substrate 21 by a predetermined distance. This is different from the example in that the carbon sheet layer 27 is provided on the first main surface 21a of the low-temperature side insulating substrate 21, and the other structures are the same as those in the example. And the initial thermal stress of the thermal-stress calculation part was computed with respect to this thermoelectric power generation module 3 on the conditions similar to an Example.

  FIG. 5 is a graph showing the results of Examples and Comparative Examples. As can be seen from FIG. 5, when the stress ratio of Comparative Example 1 is 100%, the stress ratio of the high-temperature side electrode portion 12 of Comparative Example 2 is 4% and the stress ratio of the thermoelectric element 30 is Comparative Example 1. Each decreased by 5% (in other words, thermal stress was relaxed). On the other hand, it was found that in Example, the stress ratio of the high temperature side electrode portion 12 was 2%, and the stress ratio of the thermoelectric element 30 was 6% (both were both side joining ratios). From this result, it was confirmed that according to the thermoelectric power generation module 1 of the present invention, the thermal stress generated in the module can be alleviated as a whole.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various designs can be made without departing from the spirit of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 1 Thermoelectric power generation module 10 High temperature part 11 High temperature side insulating substrate 12 High temperature side electrode part 13 Heat collecting part 13a Thermal diffusion plate 13b Heat absorption fin 20 Low temperature part 21 Low temperature side insulating substrate 22 Low temperature side electrode part 23 Heat radiation part 23a Thermal diffusion plate 23b Cooling Fin 24 Heat transfer grease 25 Heat transfer conductive layer

Claims (1)

A high temperature side electrode portion, a low temperature side electrode portion facing away from the high temperature side electrode portion, and a plurality of thermoelectric elements having different polarities disposed between the high temperature side electrode portion and the low temperature side electrode portion. A thermoelectric generation module comprising:
A thermoelectric power generation module, wherein a heat transfer conductive layer made of grease or a metal mesh member is provided between the low temperature side electrode portion and the thermoelectric element.

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