JP2012204623A - Bonding structure of thermoelectric conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bonding structure of a thermoelectric conversion element having high durability.SOLUTION: Electrode plates 5 and 7 in a thermoelectric conversion module are respectively provided with: pairs of electrode-side bonding surfaces 5a and 5b, and 7a and 7b which are spaced apart from each other; and coupling parts 5c and 7c which couple the electrode-side bonding surfaces 5a and 5b, and 7a and 7b, respectively. Thermoelectric conversion elements 9 are each formed in a prismatic shape, and element-side bonding surfaces 9a and 9b are each formed in a rectangular shape. The electrode-side bonding surfaces 5a, 5b, 7a and 7b are similar to the element-side bonding surfaces 9a and 9b. Each of the electrode-side bonding surfaces 5a, 5b, 7a and 7b has an area smaller than that of each of the element-side bonding surfaces 9a and 9b. Each of the electrode-side bonding surfaces 5a and 5b is bonded to the element-side bonding surface 9a via solder 15, and each of the electrode-side bonding surfaces 7a and 7b is bonded to the element-side bonding surface 9b via solder 17. Consequently, solder 15 and 17 is formed thinner on all corners C and peripheral sides L of each of the thermoelectric conversion elements 9 when compared with that on other portions.

Description

  The present invention relates to a junction structure of thermoelectric conversion elements.

  Patent Document 1 discloses a conventional thermoelectric conversion module. As shown in FIG. 1, the thermoelectric conversion module includes a first insulating substrate 91 and a second insulating substrate 92 having inner surfaces 91a and 92a facing each other and outer surfaces 91b and 92b facing each other. The thermoelectric conversion module is electrically connected in series by a plurality of electrode plates 93 and 94 provided on the inner surfaces 91a and 92a of the first insulating substrate 91 and the second insulating substrate 92, respectively. And a plurality of thermoelectric conversion elements 95 that are thermally connected in parallel by the first insulating substrate 91 and the second insulating substrate 92.

  As shown in FIG. 2, the end faces of the thermoelectric conversion elements 95 are rectangular element-side joining faces 95a and 95b to which solders 96 and 97 are joined. On the other hand, the surfaces of the electrode plates 93 and 94 are electrode side joining surfaces 93a and 94a to which the solders 96 and 97 are joined. Thereby, the solders 96 and 97 exist between the element side bonding surfaces 95a and 95b of the thermoelectric conversion elements 95 and the electrode side bonding surfaces 93a and 94a of the electrode plates 93 and 94, respectively.

  In this thermoelectric conversion module, for example, due to the Peltier effect generated by each thermoelectric conversion element 95, heat absorption or heat dissipation is generated on the first insulating substrate 91 side, and the second insulating substrate 92 side is opposite to the first insulating substrate 91 side. It is possible to generate heat dissipation or heat absorption. For this reason, such a thermoelectric conversion module is employed in an air conditioner or the like as a cooling or heating means for a heat exchange medium or the like using heat transfer between the first insulating substrate 91 side and the second insulating substrate 92 side. It is being done. Moreover, this thermoelectric conversion module can also generate electric power based on a temperature difference by the Seebeck effect.

  Further, in such a thermoelectric conversion module, it is transmitted to the outer surfaces 91b and 92b of the first insulating substrate 91 and the second insulating substrate 92 by means of brazing or the like for the purpose of enhancing the effects of heat absorption and heat dissipation or heat reception. Thermal members 98, 99 may be provided. These heat transfer members 98 and 99 are formed of a metal having a high heat transfer property for the above purpose.

JP 2004-207428 A

  However, according to the confirmation of the inventors, in the thermoelectric conversion module as described above, there is a possibility that the thermoelectric conversion element 95 may be cracked at the corners C in the element side joint surfaces 95a and 95b during use. This defect is caused not only in the thermoelectric conversion module including the first insulating substrates 91 and 92 but also in the junction structure of the thermoelectric conversion element including the electrode plates 93 and 94 and the thermoelectric conversion element 95 joined by the solders 96 and 97. Arise. In the thermoelectric conversion module including the first and second insulating substrates 91 and 92, the insulating substrates 91 and 92 are thermally deformed in the direction of the solid line arrows shown in FIG. The tendency is strong.

  This invention is made | formed in view of the said conventional situation, Comprising: It is set as the problem which should be solved to provide the joining structure of the thermoelectric conversion element with high durability.

The thermoelectric conversion element bonding structure of the present invention is a thermoelectric conversion element bonding structure including an electrode plate and a thermoelectric conversion element bonded to the electrode plate by soldering.
Of the joint surfaces between the thermoelectric conversion element and the solder, the element side joint surface on the thermoelectric conversion element side is rectangular,
In at least one corner of the element-side joint surface, the solder is formed thinner than the other parts (claim 1).

  The inventors have conducted intensive research on the above-described defects. In the above-described defects, as shown in FIG. 2, the corners C of the element-side joint surfaces 95a and 95b are thicker than the other parts. The present invention was completed by confirming that it is likely to occur.

  That is, in the thermoelectric conversion module as described above, each thermoelectric conversion element 95 is joined to each electrode plate 93, 94 by solder 96, 97. On the other hand, in the thermoelectric conversion module, for example, the first insulating substrate 91 on the heat dissipation side is exposed to a high temperature while the second insulating substrate 92 on the heat absorption side is exposed to a low temperature. It becomes. For this reason, in this thermoelectric conversion module, thermal stress is applied between the element side bonding surface 95 a and the solder 96 of each thermoelectric conversion element 95 and between the element side bonding surface 95 b and the solder 97. Here, when the corners C of the element-side joining surfaces 95a and 95b are thicker than the other parts, the solders 96 and 97 are difficult to deform. C cracks.

  On the other hand, in the junction structure of the thermoelectric conversion element of the present invention, the solder on the element side joint surface is thinner than the other parts, so that the solder is easily deformed, and the thermoelectric element is formed at the corner part on the element side joint surface. Cracks are less likely to occur in the conversion element.

  Therefore, the junction structure of the thermoelectric conversion element can exhibit excellent durability.

  In the present invention, the corner portion C means a predetermined range including the vertex P. Further, in the corner portion C of the thermoelectric conversion element 95, as shown in FIG. 13, it has been clarified by simulation that a certain level of stress that may cause damage to the thermoelectric conversion element 95 is applied within a predetermined range from the apex P. . Therefore, it is preferable not only to thin the solder only at the apex P of the corner C, but also to form the solder thinly on each of the pair of outer peripheries L forming the corner C. For example, assuming that the length of each outer periphery L is 100%, a triangle connecting the vertex P with each position separated from the vertex P of the corner C by a length of 5% or more along each outer periphery L It is preferable to form a thin solder for the inner region. Further, assuming that the length of each outer periphery L is 100%, each vertex separated from the vertex P of the corner C by a length of 10% or more along each outer periphery L is connected to the vertex P. It is more preferable to form a thin solder in the region within the triangle.

  Note that a thermoelectric conversion module can be obtained by providing at least a first insulating substrate and a second insulating substrate for the junction structure of thermoelectric conversion elements of the present invention. The thermoelectric conversion module may include a heat transfer member such as a fin on at least one of the first insulating substrate and the second insulating substrate.

  It is preferable that solder is formed thinner at all corners on the element-side bonding surface than at other portions. In this case, it is difficult to cause cracks at all corners of the thermoelectric conversion element, and excellent durability can be exhibited.

  Of the bonding surfaces of the electrode plate and the solder, the electrode-side bonding surface on the electrode plate side is preferably provided at a position excluding all corners of the element-side bonding surface. By arranging the electrode side joining surface of the electrode plate in this way, it is possible to easily reduce the solder at the corners of the element side joining surface. Such an electrode-side joining surface can be formed by etching the electrode plate or masking the electrode plate.

  Moreover, it is preferable that the electrode side joining surface is provided in the position except at least one outer periphery among the outer periphery located between each corner | angular part (Claim 4). In this case, cracks are less likely to occur not only at the element-side joint surface of the thermoelectric conversion element but also at the outer peripheral portion thereof.

  The outer periphery of the electrode-side bonding surface can be defined by the outer periphery of the electrode plate. (Claim 5) In this case, the electrode-side bonding surface can be obtained simultaneously by obtaining the electrode plate by etching.

  The electrode plate has a smaller area than the element-side bonding surface, and connects a pair of electrode-side bonding surfaces provided inside the outer periphery of the element-side bonding surface with each electrode-side bonding surface, and from the width of each electrode-side bonding surface Can also be configured with a connecting portion having a small width. According to this electrode plate, the p-type thermoelectric conversion element and the n-type thermoelectric conversion element can be suitably connected. This electrode plate can also be formed by etching or masking.

  The shape of the electrode-side bonding surface can be similar to the shape of the element-side bonding surface. Such an electrode-side joining surface can be formed by etching the electrode plate.

  The electrode-side joining surface can be defined by a mask material that is provided on the surface of the electrode plate and to which solder does not adhere (claim 8). Furthermore, the electrode-side bonding surface is smaller than the element-side bonding surface in a state of being separated from each other with respect to one electrode plate, and is provided on the inner side from the outer periphery of the element-side bonding surface and is formed as a pair. (Claim 9). In addition, the shape of the electrode side bonding surface can be similar to the shape of the element side bonding surface.

  The junction structure of this thermoelectric conversion element can exhibit excellent durability.

It is CAE analysis sectional drawing in the conventional thermoelectric conversion module. It is an expanded sectional view which shows the joining structure in the conventional thermoelectric conversion module. 1 is a cross-sectional view showing a thermoelectric conversion module of Example 1. FIG. It is a back view which concerns on the thermoelectric conversion module of Example 1, and shows an electrode plate. It is a top view which shows the arrangement | positioning of an electrode plate and a thermoelectric conversion element in connection with the thermoelectric conversion module of Example 1. FIG. FIG. 6 is a cross-sectional view in the A-A ′ direction in FIG. 5 according to the thermoelectric conversion module of Example 1. It is a top view which shows the arrangement | positioning of an electrode plate and a thermoelectric conversion element in connection with the thermoelectric conversion module of Example 2. FIG. It is a top view which shows the arrangement | positioning of an electrode plate and a thermoelectric conversion element in connection with the thermoelectric conversion module of Example 3. FIG. It is a top view which shows the arrangement | positioning of an electrode plate and a thermoelectric conversion element in connection with the thermoelectric conversion module of Example 4. FIG. It is a top view which shows the arrangement | positioning of an electrode plate and a thermoelectric conversion element regarding the thermoelectric conversion module of Example 5. FIG. It is a top view which concerns on the thermoelectric conversion module of Example 6, and shows arrangement | positioning of an electrode plate and a thermoelectric conversion element. It is a back view which concerns on the thermoelectric conversion module of Example 7, and shows an electrode plate. It is a stress distribution figure of the thermoelectric conversion element in the junction structure of the conventional thermoelectric conversion element.

  Examples 1 to 7 embodying the present invention will be described below with reference to the drawings.

Example 1
As shown in FIG. 3, the thermoelectric conversion module of Example 1 includes first and second insulating substrates 1 and 3, electrode plates 5 and 7, a plurality of thermoelectric conversion elements 9, first and second corrugated fins 11, 13.

  The first and second insulating substrates 1 and 3 are each made of aluminum nitride formed into a square plate shape. A plurality of electrode plates 5 and 7 made of aluminum are joined to the inner surfaces 1a and 3a of the 1 and 2 insulating substrates 1 and 3 by brazing, respectively. Aluminum plates 6 and 8 are also joined to the outer surfaces 1b and 3b of the 1 and 2 insulating substrates 1 and 3 by brazing. Each thermoelectric conversion element 9 is joined to each electrode plate 5, 7 by solder 15, 17.

  The first and second corrugated fins 11 and 13 have the same configuration, and are obtained by processing an aluminum plate into a corrugated shape. The corrugated fins 11 and 13 are joined to the aluminum plates 6 and 8 by brazing, respectively, and the first and second insulating substrates 1 and 3 and the corrugated fins 11 and 13 are thermally joined to each other. ing. Instead of the corrugated fins 11 and 13, plate-like fins extending vertically from the insulating substrates 1 and 3 toward the outside may be employed.

  Hereinafter, the electrode plates 5 and 7, the thermoelectric conversion elements 9, and their joint structures will be described in detail.

  Each thermoelectric conversion element 9 is composed of a known p-type thermoelectric conversion element or n-type thermoelectric conversion element, and is obtained from a bismuth-tellurium-based alloy or the like. Each of these thermoelectric conversion elements 9 has a prismatic shape of the same shape. Each end face of each thermoelectric conversion element 9 is rectangular, and element side bonding surfaces 9a and 9b to which solders 15 and 17 are bonded are formed. .

  As shown in FIG. 4, the electrode plates 5 and 7 have a pair of electrode-side bonding surfaces 5a, 5b, 7a and 7b which are separated from each other by etching, and the electrode-side bonding surfaces 5a, 5b, 7a and 7b. Connecting portions 5c and 7c for connecting the two are formed. The outer peripheries of these electrode-side joining surfaces 5a, 5b, 7a, and 7b are defined by the outer peripheries of the electrode plates 5 and 7, respectively. Further, each electrode-side joining surface 5a, 5b, 7a, 7b is rectangular, and a vertex P 'is formed. Each of these electrode side bonding surfaces 5a, 5b, 7a, 7b is similar to each of the above element side bonding surfaces 9a, 9b, and is formed to have a smaller area than each of the element side bonding surfaces 9a, 9b (FIG. 5). reference). Moreover, as shown in FIG. 4, each connection part 5c, 7c is narrower than each electrode side joining surface 5a, 5b, 7a, 7b.

  As shown in FIG. 5, when viewed from the top side from the first insulating substrate 1 side, each thermoelectric conversion element 9 is connected to the electrode plate 5 in the width direction midpoint α of each electrode side bonding surface 5 a and each element side bonding. The middle point β in the width direction of the surface 9a is arranged on the virtual horizontal line HL. Thereby, the outer periphery L ′ of the electrode-side bonding surfaces 5a and 5b is positioned inside each outer periphery L of each element-side bonding surface 9a, and the electrode-side bonding surfaces 5a and 5b are formed on the respective element-side bonding surfaces 9a. It will be provided inside each outer periphery L. In each of the electrode side bonding surfaces 5a and 5b, an element side bonding surface 9a of a p-type electric conversion element and an element side bonding surface 9a of an n-type electric conversion element are arranged. And each electrode side joining surface 5a, 5b and each element joining surface 9a of a p-type electrical conversion element and an n-type electrical conversion element are joined by the solder 15, respectively. As shown in FIG. 6, the electrode plate 7 side is similarly joined by solder 17. In FIG. 5, illustration of the solder 15 is omitted. The same applies to FIGS. 7 to 11 described later.

  As a result, the p-type thermoelectric conversion elements and the n-type thermoelectric conversion elements are arranged in a grid pattern with respect to the electrode plates 5 and 7, and are electrically connected in series by the electrode plates 5 and 7, respectively. The conversion element 9 is thermally connected in parallel by the first insulating substrate 1 and the second insulating substrate 3. Further, solder 15 is formed between the element side bonding surface 9a of each thermoelectric conversion element 9 and the electrode side bonding surfaces 5a and 5b of the electrode plate 5, and the element side bonding surface of each thermoelectric conversion element 9 is also formed. A solder 17 is formed between 9b and the electrode-side joining surfaces 7a and 7b of the electrode plate 7.

  According to the bonding structure as described above, the length of each outer periphery L ′ of each electrode-side bonding surface 5a, 5b, 7a, 7b in a cross-sectional view is greater than the length of each outer periphery L of the element-side bonding surfaces 9a, 9b. Is also shortened. For this reason, in the solder 15 formed between the electrode side bonding surfaces 5a and 5b and each element side bonding surface 9a, the electrode from the corner portion C of each thermoelectric conversion element 9 with the electrode side bonding surfaces 5a and 5b side as a vertex. A fillet F directed to each vertex P ′ of the side joining surfaces 5a and 5b is formed. Similarly, in the solder 17 formed between the electrode-side bonding surfaces 7a and 7b and the element-side bonding surfaces 9b, the electrodes from the corners C of the thermoelectric conversion elements 9 with the electrode-side bonding surfaces 7a and 7b side as apexes. A fillet F directed to each vertex P ′ of the side joining surfaces 7a and 7b is formed. Therefore, according to this bonding structure, the thickness T1 of the solder 15 and 17 at the corner C of each element-side bonding surface 9a and 9b of each thermoelectric conversion element 9 is equal to each element-side bonding surface in the conventional structure shown in FIG. It becomes thinner than the thickness T2 of the solders 96 and 97 at the corners C of 95a and 95b.

  Moreover, as shown in FIG. 4, each electrode side joining surface 5a, 5b, 7a, 7b is a rectangle, Furthermore, each electrode side joining surface 5a, 5b, 7a, 7b, ie, each electrode plate 5, 7 is These are formed smaller than the element-side bonding surfaces 9a and 9b (see FIG. 5). For this reason, all the apexes P ′ of each electrode side bonding surface 5a, 5b, 7a, 7b and each electrode side bonding surface 5a, 5b, 7a, 7b are all corners of each element side bonding surface 9a, 9b. It will be arranged at a position excluding C and each of the four outer perimeters L. For this reason, in this joining structure, all of the corner portions C and all of the outer periphery L, which are a predetermined range including each vertex P of each element side joining surface 9a, 9b, are compared with the other portions with the solder 15 , 17 are formed thinly.

  For this reason, in this joining structure, even when thermal stress is applied between the element-side joining surface 9a of each thermoelectric conversion element 9 and the solder 15 or between the element-side joining surface 9b and the solder 17, The solders 15 and 17 at all the corners C and the outer periphery L of the thermoelectric conversion element 9 are easily deformed, and the thermoelectric conversion element 9 is hardly cracked at the corners C at the element-side joining surfaces 9a and 9b.

  Therefore, this joining structure can exhibit excellent durability, and the thermoelectric conversion module of Example 1 having this joining structure has high durability.

  In particular, the outer peripheries of the electrode-side joining surfaces 5a, 5b, 7a, 7b and the connecting portions 5c, 7c are defined by the outer peripheries of the electrode plates 5, 7. For this reason, by obtaining the electrode plates 5 and 7 by etching, it is possible to obtain the electrode-side bonding surfaces 5a, 5b, 7a and 7b and the connecting portions 5c and 7c at the same time.

  Each electrode plate 5, 7 has a smaller area than the element side bonding surfaces 9a, 9b, and a pair of electrode side bonding surfaces 5a, 5b, 7a provided inside the outer periphery L of the element side bonding surfaces 9a, 9b. 7b and each electrode side joint surface 5a, 5b, 7a, 7b, and it is comprised from the connection part 5c, 7c with a width | variety smaller than the width | variety of each electrode side joint surface. For this reason, in this thermoelectric conversion module, the p-type thermoelectric conversion element and the n-type thermoelectric conversion element are suitably connected by the electrode plates 5 and 7.

(Example 2)
As shown in FIG. 7, each electrode plate 50 provided on the inner surface 1 a of the first insulating substrate 1 of the thermoelectric conversion module of Example 2 has the electrode-side bonding surfaces 50 a and 50 b and the connecting portion 50 c by etching. It is equally formed in the width direction. That is, when viewed from the top from the first insulating substrate 1 side, each electrode plate 50 has a rectangular shape due to the outer peripheral shape of the electrode-side joining surfaces 50a and 50b and the connecting portion 50c. Further, the apexes and the outer periphery of each electrode plate 50 are the apexes P ′ and the outer periphery L ′ of the electrode-side joining surfaces 50a and 50b, respectively.

  The length in the width direction of each electrode plate 50 is formed so as to be smaller than the width direction of the element-side bonding surface 9 a of each thermoelectric conversion element 9. When viewed from the top from the first insulating substrate 1 side, each thermoelectric conversion element 9 is in contact with each electrode plate 50 in the width direction midpoint α of each electrode plate 50 and the element side joint surface of each thermoelectric conversion element 9. It is arranged so that the midpoint β in the 9a width direction is positioned on the virtual horizontal line HL. That is, the electrode-side bonding surfaces 50a and 50b are arranged at positions excluding all the corners C and the outer periphery L of the thermoelectric conversion element 9. Each element-side bonding surface 9 a and the electrode-side bonding surfaces 50 a and 50 b are bonded by solder 15. The same applies to each electrode plate provided on the inner side 3 a of the second insulating substrate 3. As described above, when the thermoelectric conversion element 9 is likely to be displaced due to the surface tension of the solder 15 when joining with the solder 15, the position of each thermoelectric conversion element 9 with respect to the electrode plates 5 and 7 is determined. It is preferable to use a positioning jig for preventing the displacement. In FIG. 7, the illustration of the connecting portion of the electrode plate on the second insulating substrate 3 side is omitted. The same applies to FIGS. 8 to 11 described later. Other configurations are the same as those of the thermoelectric conversion module according to the first embodiment. The same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  As described above, since the electrode plate 50 has a simple rectangular shape, the electrode plate 50 can be easily formed as compared with the electrode plates 5 and 7 in the thermoelectric conversion module of the first embodiment. It has become.

  Also in the junction structure in this thermoelectric conversion module, the solder 15 formed between the electrode side joining surfaces 50a and 50b and each element side joining surface 9a has each thermoelectric as the apex at the electrode side joining surfaces 50a and 50b. A fillet F is formed from each corner C of the conversion element 9 to each vertex P ′ of the electrode-side joining surfaces 5 a and 5 b and the outer periphery of the electrode plate 50. For this reason, the thickness of the solder 15 of the corner | angular part C of the thermoelectric conversion element 9 becomes thin similarly to the joining structure in Example 1. FIG. The same applies to the second insulating substrate 3 side. Other functions and effects are the same as those of the first embodiment.

(Example 3)
As shown in FIG. 8, each electrode plate 51 provided on the inner surface 1a of the first insulating substrate 1 of the thermoelectric conversion module of Example 3 is etched so that the electrode-side bonding surfaces 51a and 51b are in the top view. It is formed in a substantially cross shape whose length in the direction is equal to the outer periphery L of the element side joint surface 9 a of each thermoelectric conversion element 9. The connecting portion 51c is formed to be narrower than the electrode-side bonding surfaces 51a and 51b.

  In addition, each electrode plate 51 and each thermoelectric conversion element 9 are arranged on each electrode side so that the apex P ′ of each electrode side bonding surface 51a, 51b is provided at a position excluding all corners C of each thermoelectric conversion element 9. The outer periphery L ′ of the bonding surfaces 51 a and 51 b and the outer periphery L of the element-side bonding surface 9 a are arranged in a aligned state and are bonded by the solder 15. The same applies to each electrode plate provided on the inner side 3 a of the second insulating substrate 3. Other configurations are the same as those of the thermoelectric conversion module of the first embodiment.

  As described above, since the length in the width direction of each electrode-side bonding surface 51a, 51b is equal to the element-side bonding surface 9a, positioning of each electrode plate 51 and each thermoelectric conversion element 9 is facilitated. As for the solder 15 formed between the electrode-side bonding surfaces 51a and 51b and each element-side bonding surface 9a, the corner portion C of the thermoelectric conversion element 9 is thin as in the bonding structure in the first embodiment. The same applies to the second insulating substrate 3 side. The other effects are the same as those of the first embodiment except for the thickness T1 of the solder 15 in the outer periphery L of the element-side bonding surface 9a.

Example 4
As shown in FIG. 9, each electrode plate 52 provided on the inner surface 1 a of the first insulating substrate 1 of the thermoelectric conversion module of Example 4 is etched, so that the electrode-side bonding surfaces 52 a and 52 b have a width as viewed from above. It is formed in a substantially octagonal shape whose direction is equal to the element-side bonding surface 9 a of each thermoelectric conversion element 9. The connecting portion 52c is formed to be narrower than the electrode-side bonding surfaces 52a and 52b.

  Further, each electrode plate 52 and each thermoelectric conversion are provided so that each short side S of each electrode side bonding surface 52a, 52b is provided at a position excluding all corners C of the element side bonding surface 9a of each thermoelectric conversion element 9. The element 9 is arranged in a state where the outer periphery L ′, which is the long side of each electrode-side bonding surface 52 a, 52 b, and the outer periphery L of the element-side bonding surface 9 a are aligned, and are joined by solder 15. The same applies to each electrode plate provided on the inner side 3 a of the second insulating substrate 3. Other configurations are the same as those of the thermoelectric conversion module of the first embodiment.

  As described above, since the electrode-side joining surfaces 52a and 52b have a substantially octagonal shape, the electrode plate 52 can also be easily formed. Further, similarly to the electrode plate 51 in the thermoelectric conversion module of Example 3, the positioning of each electrode plate 51 and each thermoelectric conversion element 9 is also easy in the configuration of the electrode plate 52. And in the solder 15 formed between the electrode side joining surfaces 52a and 52b and each element side joining surface 9a, each electrode C from each corner C of the element side joining surface 9a with the electrode side joining surfaces 52a and 52b as a vertex A fillet F (see FIG. 6) is formed toward each short side S of the electrode-side joining surfaces 52a and 52b. For this reason, also in this joining structure, the solder 15 of the corner | angular part C of each element side joining surface 9a becomes thin. The same applies to the second insulating substrate 3 side. In addition, the other effects are the same as those of the first embodiment except for the thickness T1 of the solder 15 in the outer periphery L of the element-side bonding surface 9a.

(Example 5)
As shown in FIG. 10, each electrode plate 53 provided on the inner surface 1a of the first insulating substrate 1 of the thermoelectric conversion module of the fifth embodiment is configured by deforming the electrode plate 52 in the thermoelectric conversion module of the fourth embodiment. Yes. Each electrode plate 53 is formed in an approximately octagonal shape by etching so that the electrode-side bonding surfaces 53a and 53b are larger in the width direction than the element-side bonding surface 9a of each thermoelectric conversion element 9 when viewed from above. . The connecting portion 53c is formed to be narrower than the electrode-side bonding surfaces 53a and 53b. The same applies to each electrode plate provided on the inner side 3 a of the second insulating substrate 3. Other configurations are the same as those of the thermoelectric conversion modules of the first and fourth embodiments.

  Each electrode plate 53 and each thermoelectric conversion element 9 are arranged in a state in which the outer periphery L ′ which is the long side of each electrode-side bonding surface 53a, 53b is outside the outer periphery L of the element-side bonding surface 9a. Joined by solder 15. According to the configuration of the electrode plate 53, the positioning of each electrode plate 53 and each thermoelectric conversion element 9 is easier than the electrode plate 52 described above. Other functions and effects are the same as those of the thermoelectric conversion modules of the first and fourth embodiments.

(Example 6)
As shown in FIG. 11, each electrode plate 54 provided on the inner surface 1 a of the first insulating substrate 1 of the thermoelectric conversion module of Example 6 is etched so that the electrode-side bonding surfaces 54 a and 54 b have a width as viewed from above. The direction is made equal to the outer periphery L of the element-side joint surface 9 a of each thermoelectric conversion element 9, and each corner portion is formed in a substantially rectangular shape with rounded arcs R. The connecting portion 54c is formed to be narrower than the electrode-side bonding surfaces 54a and 54b.

  In addition, each electrode plate 54 and each thermoelectric conversion element are provided such that each arc R on each electrode-side bonding surface 54a, 54b is provided at a position excluding all corners C of the element-side bonding surface 9a of each thermoelectric conversion element 9. 9 are arranged in a state where the outer periphery L ′, which is the long side of each electrode-side bonding surface 54 a, 54 b, and the outer periphery L of the element-side bonding surface 9 a are aligned, and are joined by solder 15. The same applies to each electrode plate provided on the inner side 3 a of the second insulating substrate 3. Other configurations are the same as those of the thermoelectric conversion module of the first embodiment.

  In the configuration of the electrode plate 54, the positioning of each electrode plate 54 and each thermoelectric conversion element 9 is easy. In the solder 15 formed between the electrode-side bonding surfaces 54a and 54b and each element-side bonding surface 9a, each of the corners C of the element-side bonding surface 9a starts from each corner C of the electrode-side bonding surfaces 54a and 54b. A fillet F (see FIG. 6) is formed toward each arc R of the electrode-side joining surfaces 54a and 54b. For this reason, also in this joining structure, the solder 15 of the corner | angular part C of the thermoelectric conversion element 9 becomes thin. The same applies to the second insulating substrate 3 side. The other effects are the same as those of the first embodiment except for the thickness T1 of the solder 15 in the outer periphery L of the element-side bonding surface 9a.

(Example 7)
As shown in FIG. 12, a known mask material 19 to which solder 15, 17 does not adhere is partially applied to each electrode plate 55 provided on the inner surface 1 a of the first insulating substrate 1 of the thermoelectric conversion module of Example 2. Has been. Each of the electrode-side bonding surfaces 55 a and 55 b is a portion exposed by the mask material 19 in a rectangular shape while being partitioned by the mask material 19. Each electrode side joining surface 55a, 55b is similar to the element side joining surface 9a of each thermoelectric conversion element 9, and apex P 'and each outer periphery L' are formed. Further, each electrode-side bonding surface 55a, 55b has a smaller area than the element-side bonding surface 9a, and is provided inside the outer periphery L of the element-side bonding surface 9a when the solder 15 is bonded. Yes. Similarly, each electrode plate provided on the inner side 3 a of the second insulating substrate 3 is partially coated with a mask material 19. Other configurations are the same as those of the thermoelectric conversion module of the first embodiment.

  As described above, even when the electrode-side bonding surfaces 55a and 55b are formed by partially covering the electrode plate 55 with the mask material 19, the electrode-side bonding surfaces 55a and 55b and the element-side bonding surfaces 9a are interposed between the electrode-side bonding surfaces 55a and 55b. In the solder 15 to be formed, a fillet F is formed from each corner C of the thermoelectric conversion element 9 to each vertex P ′ of the electrode-side joining surfaces 55a and 55b with the electrode-side joining surfaces 55a and 55b as the vertices. (See FIG. 6). For this reason, also in this junction structure, the solder 15 of the corner | angular part C and the outer periphery L of the thermoelectric conversion element 9 becomes thin. The same applies to the second insulating substrate 3 side. Other functions and effects are the same as those of the first embodiment.

  In the above, the present invention has been described with reference to the first to seventh embodiments. However, the present invention is not limited to the first to seventh embodiments, and can be appropriately modified and applied without departing from the spirit of the present invention. Needless to say.

  For example, the thermoelectric conversion modules of Examples 1 to 7 can be configured as a so-called skeleton type thermoelectric conversion module without providing the first and second insulating substrates 1 and 3.

  In addition, the electrode-side bonding surfaces 55a and 55b in the seventh embodiment can be formed into a substantially cross shape, a substantially octagonal shape, or a substantially rounded rectangular shape like the electrode-side bonding surfaces 51a and 51b in the third embodiment.

  The present invention can be used for a thermoelectric conversion module.

5, 7, 50-54 ... Electrode plate 15, 17 ... Solder 9 ... Thermoelectric conversion element 9a, 9b ... Element side joint surface C ... Corner 5a, 5b, 7a, 7b, 50a-54a, 50b-54b ... Electrode side Bonding surface L, L '... Outer periphery 5c, 7c, 50c-54c ... Connection part 19 ... Mask material

Claims (10)

In the junction structure of a thermoelectric conversion element comprising an electrode plate and a thermoelectric conversion element bonded to the electrode plate by solder,
Of the joint surfaces between the thermoelectric conversion element and the solder, the element side joint surface on the thermoelectric conversion element side is rectangular,
The junction structure of a thermoelectric conversion element, wherein the solder is formed thinner at least at one corner of the element-side joining surface than at other parts.   2. The thermoelectric conversion element bonding structure according to claim 1, wherein the solder is formed thinner at all the corners on the element side bonding surface than at other portions.   3. The thermoelectric device according to claim 2, wherein an electrode-side bonding surface on the electrode plate side among the bonding surfaces of the electrode plate and the solder is provided at a position excluding all the corner portions of the element-side bonding surface. The junction structure of the conversion element.   The thermoelectric conversion element bonding structure according to claim 3, wherein the electrode-side bonding surface is provided at a position excluding at least one of the outer peripheries located between the corners.   The thermoelectric conversion element bonding structure according to claim 3 or 4, wherein an outer periphery of the electrode-side bonding surface is defined by the outer periphery of the electrode plate.   The electrode plate has a smaller area than the element side bonding surface, and connects the pair of electrode side bonding surfaces provided inside the outer periphery of the element side bonding surface and the electrode side bonding surfaces, The thermoelectric conversion element bonding structure according to claim 5, wherein the thermoelectric conversion element bonding structure includes a connecting portion having a width smaller than a width of the electrode-side bonding surface.   The thermoelectric conversion element bonding structure according to claim 6, wherein a shape of the electrode-side bonding surface is similar to a shape of the element-side bonding surface.   5. The thermoelectric conversion element bonding structure according to claim 3, wherein the electrode-side bonding surface is provided on a surface of the electrode plate and is partitioned by a mask material to which the solder does not adhere.   The electrode-side bonding surface is smaller than the element-side bonding surface in a state of being separated from each other with respect to one electrode plate, is provided on the inner side of the outer periphery of the element-side bonding surface, and is formed as a pair The thermoelectric conversion element junction structure according to claim 8, wherein the thermoelectric conversion element is bonded.   The thermoelectric conversion element bonding structure according to claim 9, wherein a shape of the electrode-side bonding surface is similar to a shape of the element-side bonding surface.

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