JP6567337B2 - Thermoelectric conversion module and manufacturing method thereof - Google Patents

Description

  The present invention relates to a thermoelectric conversion module and a manufacturing method thereof.

  Conventionally, thermoelectric conversion modules for thermoelectric power generation are known. Such a thermoelectric conversion module generally includes a plurality of thermoelectric elements (n-type semiconductor element and p-type semiconductor element), a plurality of metal electrodes for electrically connecting the plurality of thermoelectric elements, a plurality of thermoelectric elements, and A pair of insulating substrates (for example, ceramic substrates) sandwiching a plurality of metal electrodes is used.

  A thermoelectric conversion module for thermoelectric power generation is generally used in a high-temperature environment (for example, about 600 ° C.). Therefore, bonding between a thermoelectric element and a metal electrode or bonding between a metal electrode and an insulating substrate is performed by brazing. It is done in However, thermoelectric elements and insulating substrates are generally made of a material that makes it difficult to wet the brazing, and direct brazing is difficult. The brazing is performed after providing the metal layer.

  In JP 2004-342879 A, a thermoelectric conversion member in which iron and nickel are metallized in a laminated state at both ends is prepared, and an electrode member made of nickel is prepared, and a space between the thermoelectric conversion member and the electrode member is prepared. It describes that an electrode member is joined to both ends of a thermoelectric conversion member by brazing in a 100% hydrogen atmosphere with a brazing material interposed.

JP 2004-342879 A

  The objective of this invention is providing the thermoelectric conversion module which can simplify a manufacturing process, and its manufacturing method.

  The thermoelectric conversion module according to the present invention is disposed so as to sandwich a plurality of thermoelectric elements, a plurality of electrodes for electrically connecting the plurality of thermoelectric elements, and the plurality of thermoelectric elements and the plurality of electrodes. And a plurality of electrodes are made of an active metal brazing.

  In this case, the plurality of electrodes may be made of active silver solder. Further, the active silver brazing may contain titanium.

  Further, in the above case, the plurality of thermoelectric elements are constituted by an n-type thermoelectric element and a p-type thermoelectric element, and the n-type thermoelectric element is constituted by one of iron silicide and cobalt silicide, The p-type thermoelectric element may be composed of either iron silicide or manganese silicide.

  In the above case, the insulating substrate may be made of either aluminum oxide or aluminum nitride.

  The method for manufacturing a thermoelectric conversion module according to the present invention includes a plurality of thermoelectric elements, a plurality of electrodes for electrically connecting the plurality of thermoelectric elements, and the plurality of thermoelectric elements and the plurality of electrodes sandwiched therebetween. A method of manufacturing a thermoelectric conversion module comprising a pair of insulating substrates arranged, an electrode pattern forming step of forming an electrode pattern with active metal brazing on a surface of the insulating substrate, and the plurality of thermoelectrics An assembly process for assembling an element and a pair of insulating substrates on which the electrode pattern is formed, and a brazing process for heating and brazing the thermoelectric conversion module assembled in the assembly process. And

  In this case, the electrode pattern may be formed of active silver solder. Further, the active silver brazing may contain titanium.

  Further, in the above case, the plurality of thermoelectric elements are constituted by an n-type thermoelectric element and a p-type thermoelectric element, and the n-type thermoelectric element is constituted by one of iron silicide and cobalt silicide, The p-type thermoelectric element may be composed of either iron silicide or manganese silicide.

  In the above case, the insulating substrate may be made of either aluminum oxide or aluminum nitride.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to simplify the manufacturing process of a thermoelectric conversion module.

It is a figure for demonstrating the structure of the thermoelectric conversion module by this invention. It is FIG. (1) for demonstrating the manufacturing method of the thermoelectric conversion module by this invention. It is FIG. (2) for demonstrating the manufacturing method of the thermoelectric conversion module by this invention.

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

  FIG. 1 is a diagram for explaining a configuration of a thermoelectric conversion module according to the present invention. The figure (a) shows a top view, the figure (b) shows a front view, and the figure (c) shows a right side view.

  As shown in the figure, the thermoelectric conversion module 100 according to the present invention includes a plurality of thermoelectric elements 110 (111, 112) and a plurality of electrodes 120 (121, 122) for electrically connecting the plurality of thermoelectric elements 110. And a pair of insulating substrates 131 and 132 arranged to sandwich the plurality of thermoelectric elements 110 and the plurality of electrodes 120.

  The thermoelectric conversion module 100 shown in the figure is a thermoelectric conversion module for thermoelectric generation that generates an electromotive force due to the Seebeck effect when a temperature difference is given between a pair of insulating substrates 131 and 132.

  The plurality of thermoelectric elements 110 includes a plurality of n-type thermoelectric elements (n-type semiconductor elements) 111 and a plurality of p-type thermoelectric elements (p-type semiconductor elements) 112, and a pair of adjacent n-type thermoelectric elements. 111 and the one end of the p-type thermoelectric element 112 are electrically connected by an electrode 121 on one side (left side in FIG. 3C), thereby forming a plurality of π-type thermoelectric elements. The plurality of π-type thermoelectric elements arranged in a plate shape are electrically connected in series and thermally in parallel by the electrode 122 on the other side (the right side in FIG. 5C).

In the present embodiment, the n-type thermoelectric element 111 is composed of iron silicide (FeSi ₂ ) or cobalt silicide (CoSi). On the other hand, the p-type thermoelectric element 112 is composed of iron silicide (FeSi ₂ ) or manganese silicide (MnSi _1.73 ).

  The plurality of electrodes 120 electrically connect the plurality of thermoelectric elements 110 in series and are made of active metal brazing. In the present embodiment, a silver brazing containing titanium (active silver brazing) is used as the active metal brazing constituting the plurality of electrodes 120. As the active silver solder containing titanium, for example, active silver solder TB-608T or TB-629T manufactured by Tokyo Blaze Co., Ltd. (Setagaya-ku, Tokyo) can be used. TB-608T contains 70% silver (Ag), 28% copper (Cu), and 2% titanium (Ti) as its components. TB-629T contains 60% silver (Ag), 24% copper (Cu), 2% titanium (Ti), and 14% indium (In) as its components.

The pair of insulating substrates 131 and 132 are arranged so as to sandwich the plurality of thermoelectric elements 110 and the plurality of electrodes 120, and constitute a high temperature surface (heating surface) and a low temperature surface (heat radiation surface) of the thermoelectric conversion module. . In the present embodiment, the insulating substrates 131 and 132 are made of ceramics, more specifically, aluminum oxide (Al ₂ O ₃ ) or aluminum nitride (AlN).

  Next, the manufacturing method of the thermoelectric conversion module which has the above structures is demonstrated.

  2 and 3 are views for explaining a method of manufacturing a thermoelectric conversion module according to the present invention. 2 (a) and 3 (a) show plan views, and FIG. 2 (b) and FIG. 3 (b) show front views.

  First, a pair of insulating substrates 131 and 132 constituting a high temperature surface and a low temperature surface of the thermoelectric conversion module 100 are prepared. As shown in FIG. 2, the surfaces of the insulating substrates 131 and 132 (the thermoelectric element when assembled) The pattern 220 for the electrode 120 is formed with active silver brazing on the surface facing the electrode 110 (electrode pattern forming step). The electrode pattern 220 is formed, for example, by applying paste-like active silver brazing to the electrode formation locations on the surfaces of the insulating substrates 131 and 132 by screen printing.

  Next, as shown in FIG. 3, a plurality of thermoelectric elements 110 are placed at predetermined positions on one insulating substrate 132 on which the electrode pattern 220 is formed, and further, as shown in FIG. The other insulating substrate 131 on which the electrode pattern 220 is formed is placed, and the thermoelectric conversion module 100 is assembled (assembly process).

Next, atmosphere brazing is performed on the assembled thermoelectric conversion module (brazing step). In the present embodiment, the atmosphere in the furnace is argon (Ar) or vacuum (about 10 ⁻¹ to 10 ⁻³ Pa). In addition, a pressure jig is attached to the assembled thermoelectric conversion module, and atmosphere brazing is performed in a state where a pressure of about 500 kPa is applied.

  When heating for brazing, for example, the temperature is increased at 200 to 400 ° C./h, and the active silver brazing is about 800 to 850 ° C. in the case of TB-608T, and 720 to 620 in the case of TB-629T. Hold at about 780 ° C. for about 5 minutes, then allow to cool naturally.

  Through the steps as described above, the thermoelectric conversion module 100 as shown in FIG. 1 is manufactured.

  As described above, in the thermoelectric conversion module 100 according to the present invention, the electrode 120 is made of active metal brazing, and the active metal brazing as a constituent material of the electrode 120 also functions as a bonding material. It is not necessary to separately provide a brazing metal layer for the element 110 and the insulating substrates 131 and 132, and the manufacturing process can be simplified.

  That is, the electrode pattern 220 is formed by active metal brazing on the surface of the pair of insulating substrates 131 and 132, and the thermoelectric element 110 is sandwiched between the pair of insulating substrates 131 and 132 on which the electrode pattern 220 is formed. The thermoelectric conversion module 100 can be produced simply by brazing.

  Next, examples of the present invention will be described.

First, iron silicide (n-type FeSi ₂ thermoelectric element) and cobalt silicide (n-type CoSi thermoelectric element) were prepared as n-type thermoelectric elements as described below. In addition, as a p-type thermoelectric element, one made of iron silicide (p-type FeSi ₂ thermoelectric element) and one made of manganese silicide (p-type MnSi _1.73 thermoelectric element) were produced.

<< n-type FeSi ₂ thermoelectric element >>
A predetermined amount of Fe, Si, Co was weighed so as to be Fe _0.96 Si ₂ Co _0.04, and for those weighed, 0.5 mass% of Cu was further added, and these raw materials were mixed, The ingot was manufactured by loading in a copper hearth that was cooled in water in an arc furnace and arc melting in a reduced pressure Ar atmosphere.

  The prepared ingot is coarsely pulverized using a mortar, then finely pulverized to a particle size of 30 μm or less in the air, and PVA (polyvinyl alcohol), which is a binder agent, is 1% by mass with respect to the pulverized powder. Was added and granulated to a particle size of about 180 to 355 μm. The granulated powder was cold pressed at a pressure of 300 MPa in the atmosphere to obtain a molded body.

  Then, the obtained molded body was sintered at 1173 ° C. for 5 hours, then subjected to β-treatment at 800 ° C. for 25 hours, and the obtained sintered body was processed into an element shape to obtain a thermoelectric element.

<< p-type FeSi ₂ thermoelectric element >>
A predetermined amount of Fe, Si, and Mn was weighed so as to be Fe _0.92 Si ₂ Mn _0.08, and 0.5% by mass of Cu was further added to the weighed material, and these raw materials were mixed. Thereafter, a thermoelectric element was obtained by the same treatment as that of the n-type FeSi ₂ thermoelectric element described above.

<< p-type MnSi _1.73 thermoelectric element >>
A predetermined amount of Mn and Si are weighed so as to be MnSi _1.73, and after mixing these raw materials, an ingot is manufactured by the same processing as in the case of the n-type FeSi ₂ thermoelectric element described above. The powder was appropriately pulverized, and the obtained powder was cold pressed to obtain a molded body.

  And the obtained molded object was sintered at 1130 degreeC for 5 hours, the obtained sintered compact was processed into the shape of an element, and the thermoelectric element was obtained.

<< n-type CoSi thermoelectric element >>
A predetermined amount of Co, Si, and Ni is weighed to become Co _0.97 Si ₂ Ni _0.03, and after mixing these raw materials, an ingot is manufactured by the same process as in the case of the n-type FeSi ₂ thermoelectric element described above. Then, the produced ingot was appropriately pulverized, and the obtained powder was cold pressed to obtain a molded body.

  And the obtained molded object was sintered at 1300 degreeC for 5 hours, the obtained sintered compact was processed into the shape of an element, and the thermoelectric element was obtained.

  Next, the thermoelectric element produced as described above is prepared by joining a pair of nickel electrodes (joint) via active silver brazing (TB-608T or TB-629T) to both ends of the thermoelectric element, After measuring the resistance, the joined body was cut longitudinally with a diamond saw, and the joined surface was observed with an optical microscope. As a result, no break was observed between the active silver solder and each thermoelectric element. Furthermore, when a force was applied to the joined body in the direction of separating the pair of nickel electrodes, it was confirmed that the fracture inside each thermoelectric element occurred first from the joined surface.

Also, a total of four types of thermoelectric conversion modules were manufactured by combining an n-type FeSi ₂ thermoelectric element, a p-type FeSi ₂ thermoelectric element or a p-type MnSi _1.73 thermoelectric element, and an insulating substrate made of alumina or aluminum nitride. .

  TB-608T or TB-629T was used as the active silver brazing, and atmosphere brazing was performed in an argon atmosphere. In the case of TB-608T, the furnace temperature was raised to 820 ° C. at 200 ° C./h, held at 820 ° C. for 5 minutes, and then naturally cooled. On the other hand, in the case of TB-629T, the furnace temperature was raised to 750 ° C. at 200 ° C./h, held at 750 ° C. for 5 minutes, and then naturally cooled.

  And when the high temperature surface of each produced thermoelectric conversion module was heated and operated to about 600 ° C., even if it was operated for about 200 hours, there was no change in the bonding state and there was no change in the internal resistance.

DESCRIPTION OF SYMBOLS 100 Thermoelectric conversion module 110 Thermoelectric element 111 N-type thermoelectric element 112 P-type thermoelectric element 120, 121, 122 Electrode 131, 132 Insulating substrate 220 Pattern for electrode

Claims (10)

A plurality of thermoelectric elements;
A plurality of electrodes for electrically connecting the plurality of thermoelectric elements;
A pair of insulating substrates disposed so as to sandwich the plurality of thermoelectric elements and the plurality of electrodes,
The thermoelectric conversion module, wherein the plurality of electrodes are made of active metal brazing. The thermoelectric conversion module according to claim 1, wherein the plurality of electrodes are made of activated silver solder. The thermoelectric conversion module according to claim 2, wherein the active silver brazing contains titanium. The plurality of thermoelectric elements includes an n-type thermoelectric element and a p-type thermoelectric element,
The n-type thermoelectric element is composed of either iron silicide or cobalt silicide,
The thermoelectric conversion module according to any one of claims 1 to 3, wherein the p-type thermoelectric element is composed of iron silicide or manganese silicide.   The thermoelectric conversion module according to any one of claims 1 to 4, wherein the insulating substrate is made of any one of aluminum oxide and aluminum nitride. A thermoelectric device comprising: a plurality of thermoelectric elements; a plurality of electrodes for electrically connecting the plurality of thermoelectric elements; and a pair of insulating substrates disposed so as to sandwich the plurality of thermoelectric elements and the plurality of electrodes. A method for manufacturing a conversion module, comprising:
An electrode pattern forming step of forming an electrode pattern with active metal brazing on the surface of the insulating substrate;
An assembly step of assembling the plurality of thermoelectric elements and a pair of insulating substrates on which the electrode pattern is formed;
A method of manufacturing a thermoelectric conversion module, comprising: a brazing step of heating and brazing the thermoelectric conversion module assembled in the assembly step. The method for manufacturing a thermoelectric conversion module according to claim 6, wherein the pattern for the electrode is formed of active silver brazing. The method for manufacturing a thermoelectric conversion module according to claim 7, wherein the active silver solder contains titanium. The plurality of thermoelectric elements includes an n-type thermoelectric element and a p-type thermoelectric element,
The n-type thermoelectric element is composed of either iron silicide or cobalt silicide,
The method for manufacturing a thermoelectric conversion module according to any one of claims 6 to 8, wherein the p-type thermoelectric element is composed of either iron silicide or manganese silicide.   The method for manufacturing a thermoelectric conversion module according to any one of claims 6 to 9, wherein the insulating substrate is made of any one of aluminum oxide and aluminum nitride.

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