JP2008085309A - Thermoelectric conversion module, its manufacturing method, and thermoelectric conversion material used for thermoelectric conversion module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoelectric conversion module having high long term reliability by suppressing the deterioration of thermal performance caused by the usage and breakage of the thermoelectric conversion module. <P>SOLUTION: A plurality of P-type and N-type thermoelectric conversion elements 5 (5a, 5b) are connected via a solder 9 and an electrode 2 to form a circuit of the thermoelectric conversion elements 5 (5a, 5b). For example, a Peltier module wherein one end side of the thermoelectric conversion elements 5 (5a, 5b) is made to be an endothermic side surface and the other end side is made to be a heat-dissipating side surface according to the direction of a current fed through the circuit is formed. The thermoelectric conversion elements 5 (5a, 5b) are formed by adding at least one of Ag and Cu to a thermoelectric conversion material which contains Bi and Te as main raw materials and at least one of Se and Sb is added thereto. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is used for, for example, optical communication parts, physics and chemistry equipment, portable coolers, process temperature management in semiconductor processes, etc. to cool and heat, or to generate electricity using the Seebeck effect, The present invention relates to a conversion module, a manufacturing method thereof, and a thermoelectric conversion material used for the thermoelectric conversion module.

  Peltier modules, which are thermoelectric conversion modules, are used in various fields such as the optical communication field (for example, see Patent Documents 1 and 2).

  FIG. 7A shows an example of a Peltier module by a schematic cross-sectional view, and FIG. 7B shows an exploded perspective view of the Peltier module by a schematic view. The Peltier module shown in these drawings is formed by arranging a plurality of thermoelectric conversion elements 5 (5a, 5b) between a plurality of substrates 6 and 7 which are vertically opposed to each other with a space therebetween. .

The substrates 6 and 7 are ceramic substrates such as alumina (Al ₂ O ₃ ) having electrical insulation. A plurality of conductive electrodes 2 are formed on the opposing surfaces of the substrates 6 and 7 in a state where the electrodes are spaced apart from each other and spaced from each other. A plurality of thermoelectric conversion elements 5 are fixed to the electrode 2 by solder 9 and connected in series via the solder 9 and the electrode 2 as a conductive material, and a circuit of the thermoelectric conversion element 5 is formed.

  The thermoelectric conversion element 5 (5a, 5b) is generally known as a Peltier element, and a P-type (p-type) thermoelectric conversion element 5a formed of a P-type semiconductor and an N-type semiconductor formed of N-type semiconductor. Type (n-type) thermoelectric conversion element 5b.

The P-type thermoelectric conversion element 5a and the N-type thermoelectric conversion element 5b are mainly composed of an intermetallic compound (Bi ₂ Te ₃ ) of bismuth (Bi) / tellurium (Te), for example, antimony (Sb), selenium. It is formed of a thermoelectric conversion material to which an element such as (Se) is added. The thermoelectric conversion element 5 is formed in a columnar shape or a prismatic shape, for example, and has a diameter of about 0.6 to 3 mm and a length of about 0.5 to 3 mm. The end surface of the thermoelectric conversion element 5 (5a, 5b) is provided with Ni plating (not shown) as a conductive material.

  P-type thermoelectric conversion elements 5a and N-type thermoelectric conversion elements 5b are alternately arranged and connected in series via the electrode 2 to form a PN element pair. In addition, a lead wire 28 is connected to the electrode 2 (2a) formed on the substrate 7 at the end of the connection circuit of the thermoelectric conversion element 5 by a solder 10, and the lead wire 28 is connected by an energizing means (not shown). When a current flows from the line 28 to the electrode 2a, a current flows through the P-type thermoelectric conversion element 5a and the N-type thermoelectric conversion element 5b.

  And a cooling and heating effect arises in the junction part (interface) of thermoelectric conversion element 5 (5a, 5b) and electrode 2. FIG. That is, a so-called Peltier effect is generated in which one end portion of the thermoelectric conversion element 5 (5a, 5b) is heated while the other end portion is cooled depending on the direction of the current flowing through the junction.

  Due to the Peltier effect, one end side of the thermoelectric conversion element 5 (5a, 5b) forms a heat absorption side surface, and the other end side forms a heat dissipation side (heat generation side) surface. For example, in FIG. 7A, when the upper end portion of the thermoelectric conversion element 5 (5a, 5b) forms a heat absorption side surface, cooling of the member provided on the upper side of the substrate 6 (heat absorption) is performed. The lower end side of the thermoelectric conversion element 5 (5a, 5b) forms a heat radiating surface, and heat is radiated from the substrate 7 side. On the contrary, when the upper end portion of the thermoelectric conversion element 5 (5a, 5b) forms a heat radiation side surface by the Peltier effect, the member provided on the upper side of the substrate 6 is heated via the substrate 6.

  In addition to the above example, as a Peltier module, for example, as shown in the side view of FIG. 7C, a module in which no substrate is provided above and below the thermoelectric conversion elements 5 (5a, 5b) is proposed. ing. The Peltier module shown in this figure is formed by fitting P-type and N-type thermoelectric conversion elements 5 (5a, 5b) to an insulating substrate 30 in which a plurality of penetrating element fitting holes 3 are formed. The electrode 2 is disposed on one end side (upper side here) and the other end side (lower side here) of the thermoelectric conversion element 5 (5a, 5b) in the penetration direction to the element fitting hole 3, respectively. And thermoelectric conversion element 5 (5a, 5b) are joined by solder 9.

  The electrode 2 extends in the same direction as the end face of the corresponding P-type thermoelectric conversion element 5a and the end face of the N-type thermoelectric conversion element 5b, and is provided across the end faces of the thermoelectric conversion elements 5 (5a, 5b). The P-type and N-type thermoelectric conversion elements 5 (5a, 5b) are connected in series. The circuit of the thermoelectric conversion element 5 (5a, 5b) is connected to a power supply circuit or the like via lead terminals and lead wires (not shown), and this type of Peltier module is also shown in FIG. 7 (a). As with the Peltier module, heating and cooling operations are performed using the Peltier effect.

JP-A-9-181362 JP-A-10-178216

  By the way, the thermoelectric conversion module such as the Peltier module has an increase in internal resistance value due to changes in the use environment of the thermoelectric conversion module and the like. In some cases, it could lead to damage.

  The present invention has been made in order to solve the above-described conventional problems, and its purpose is to suppress deterioration of thermal characteristics and breakage of the thermoelectric conversion module due to use, and a thermoelectric conversion module with high long-term reliability and The manufacturing method and the thermoelectric conversion material used for a thermoelectric conversion module are provided.

  In order to achieve the above object, the present invention has the following configuration as means for solving the problems. That is, the thermoelectric conversion module according to the first aspect of the present invention forms a circuit of thermoelectric conversion elements by connecting a plurality of P-type and N-type thermoelectric conversion elements to each other through a conductive material, and according to the direction of the current flowing through the circuit. Then, power generation is performed using the function of forming one end side of the thermoelectric conversion element as a heat absorption side surface and the other end side as a heat dissipation side surface and the temperature difference between the one end side and the other end side of the thermoelectric conversion element. In the thermoelectric conversion module having at least one of the functions, the thermoelectric conversion element is made of Bi and Te as main raw materials, and at least one of Se and Sb is added to Ag (silver) and Cu (copper). ) Is added as a means for solving the problem.

  Further, the thermoelectric conversion module of the second invention forms a circuit of the thermoelectric conversion element by connecting a plurality of P-type and N-type thermoelectric conversion elements to each other through a conductive material, and according to the direction of the current flowing through the circuit. Then, power generation is performed using the function of forming one end side of the thermoelectric conversion element as a heat absorption side surface and the other end side as a heat dissipation side surface and the temperature difference between the one end side and the other end side of the thermoelectric conversion element. In the thermoelectric conversion module having at least one of the functions, the conductive material has at least one of solder and Ni plating, and at least one of Ag and Cu is added to at least one of the solder and Ni plating As a means to solve the problem.

  Furthermore, the manufacturing method of the thermoelectric conversion module of the third invention is such that Ag and Cu contained in the conductive material are contained in the thermoelectric conversion element by aging the thermoelectric conversion module of the second invention at a set temperature for a set time. It is characterized by diffusing.

  Further, the thermoelectric conversion material of the fourth invention is a thermoelectric conversion material forming the thermoelectric conversion element of the thermoelectric conversion module of the first or second invention, wherein Bi and Te are main raw materials, and Se and Sb It is characterized in that at least one of Ag and Cu is added to the thermoelectric conversion material obtained by adding at least one.

  In the thermoelectric conversion module of the present invention, the thermoelectric conversion element is formed by adding at least one of Ag and Cu to a thermoelectric conversion material obtained by adding at least one of Se and Sb using Bi and Te as main raw materials. In addition, by adding Ag or Cu, the electrical conductivity of the thermoelectric conversion element can be increased and the electrical resistance value can be reduced, so that the increase in the internal resistance value of the thermoelectric conversion module can be suppressed, and the thermal characteristics. Degradation and damage to the thermoelectric conversion module can be suppressed.

  In the present invention, the conductive material for connecting the corresponding thermoelectric conversion elements has at least one of solder and Ni plating, and at least one of Ag and Cu is added to at least one of the solder and Ni plating. In one, with the use of the thermoelectric conversion module, whenever one end side or the other end side of the thermoelectric conversion element is heated, Ag or Cu contained in the conductive material is diffused in the thermoelectric conversion element (the thermoelectric conversion element is So that the electric conductivity of the thermoelectric conversion element can be increased, the electric resistance value can be reduced, and the increase in the internal resistance value of the thermoelectric conversion module can be suppressed, Deterioration of thermal characteristics and breakage of thermoelectric conversion module can be suppressed.

  Moreover, according to the manufacturing method of the thermoelectric conversion module of the present invention, the thermoelectric conversion module in which at least one of Ag and Cu is contained in the conductive material is included in the conductive material by aging for a set time at a set temperature. By diffusing Ag and Cu into the thermoelectric conversion element, the effect of improving the electrical conductivity of the thermoelectric conversion element by Ag and Cu can be further increased, and the electric resistance value can be further reduced. An increase in resistance value can be further effectively suppressed, and deterioration of thermal characteristics and breakage of the thermoelectric conversion module can be suppressed.

  Further, the thermoelectric conversion material forming the thermoelectric conversion element of the thermoelectric conversion module of the present invention is a thermoelectric conversion material comprising Bi and Te as main raw materials and at least one of Se and Sb, and at least one of Ag and Cu. As described above, the electrical conductivity of the thermoelectric conversion element can be increased, and the deterioration of the thermal characteristics of the thermoelectric conversion module and the breakage of the thermoelectric conversion module can be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the present embodiment, the same reference numerals are assigned to the same name portions as those in the conventional example, and the duplicate description is omitted or simplified.

  FIG. 1 is a schematic sectional view showing a first embodiment of a thermoelectric conversion module according to the present invention. The thermoelectric conversion module of the present embodiment is configured in substantially the same manner as the thermoelectric conversion module of the conventional example shown in FIGS. 7A and 7B, and this embodiment is different from the conventional example. Is that it is formed by adding at least one additive 1 of Ag and Cu to the thermoelectric conversion material for forming the thermoelectric conversion element 5 (5a, 5b). In addition, in FIG. 1, the state in which the additive 1 is added to the thermoelectric conversion element 5 (5a, 5b) is shown typically.

  The thermoelectric conversion element 5 (5a, 5b) is manufactured by using a known single crystal manufacturing method or a known sintered material manufacturing method for a thermoelectric conversion material. In this embodiment example, Bi and Te are used as main raw materials, and when adding at least one of Se and Sb to this main component, a small amount of Ag or Cu is added to form a thermoelectric conversion material, and then a single crystal is manufactured. The thermoelectric conversion element 5 (5a, 5b) is manufactured by heating by an appropriate method such as a method or a sintered material manufacturing method.

  The present embodiment is configured as described above, and the thermoelectric conversion element 5 is obtained by adding at least one additive 1 of Ag and Cu to the thermoelectric conversion material forming the thermoelectric conversion element 5 (5a, 5b). Since the electrical conductivity of (5a, 5b) can be increased and the electrical resistance value can be reduced, the increase in the internal resistance value of the thermoelectric conversion module can be suppressed, and the deterioration of the thermal characteristics and the damage of the thermoelectric conversion module can be prevented. Can be suppressed.

  FIG. 2 is a schematic sectional view showing a second embodiment of the thermoelectric conversion module according to the present invention. The thermoelectric conversion module of the second embodiment is configured in substantially the same manner as the conventional thermoelectric conversion module shown in FIGS. 7A and 7B, and the second embodiment is different from the conventional example. What is important is that the solder 9 is formed by adding at least one additive 1 of Ag and Cu.

  The solder 9 is mainly made of Sn (tin). In the second embodiment, an appropriate amount of the additive 1 of 0.1 wt% or more is added to the solder 9 with respect to the solder 9. FIG. 2 schematically shows a state in which the additive 1 is added to the thermoelectric conversion element 5 (5a, 5b).

  In addition, the thermoelectric conversion module of the second embodiment is manufactured by aging the set material for a set time to diffuse the additive 1 contained in the conductive material into the thermoelectric conversion element.

  As shown in FIG. 3, Ni plating 11 is provided on the end face of the thermoelectric conversion element 5 (5a, 5b). When the aging is performed, the additive 1 added to the solder 9 is As indicated by the arrows, the Ni plating 11 enters the gap of the thermoelectric conversion material of the thermoelectric conversion element 5 (5a, 5b) from the valley. 3 exaggerates the unevenness of the Ni plating 11 and the solder 9 so that the valleys of the Ni plating 11 can be easily understood.

  In addition, each time one end or the other end of the thermoelectric conversion element 5 (5a, 5b) is heated with the use of the thermoelectric conversion module, the additive 1 is transferred from the valley of the Ni plating 11 to the thermoelectric conversion element 5 (5a, 5b). ) Enters the gap between the thermoelectric conversion materials. Therefore, the thermoelectric conversion module of the second embodiment can increase the electrical conductivity of the thermoelectric conversion element 5 (5a, 5b) compared to before use by using the thermoelectric conversion module. Therefore, it is possible to suppress an increase in the internal resistance value of the thermoelectric conversion module, and it is possible to suppress deterioration of thermal characteristics and breakage of the thermoelectric conversion module.

  The present inventor conducted the following experiment in order to confirm the effect of the aging. That is, when the thermoelectric conversion module is formed by adding at least one of Ag and Cu to the solder 9 of Sn, and without adding either Ag or Cu to the solder 9, Sb is added instead and the thermoelectric conversion module is formed. When the conversion module was formed (comparative example), aging treatment was performed at 150 ° C. for 1000 hours, and the relationship between the aging treatment time and the internal resistance value was examined.

  This examination was performed on samples having respective compositions shown in Table 1. That is, samples A1 to A3 in which only 0.7% by weight of Cu was added to Sn of solder 9 (Sn 99.3%), and samples B1 to B3 in which only 3.5% by weight of Ag was added to Sn (Sn 96.5%) Thermoelectric conversion modules were prepared using samples C1 to C3 in which 0.5 wt% of Ag and 3.0 wt% of Cu were added to Sn (Sn96.5%), and the aging test was performed. In addition, as a comparative example of the second embodiment, the same aging test was performed when the thermoelectric conversion module was formed using samples D1 to D3 in which 5% of Sb was added to Sn of the solder 9. The compositions of the samples D1 to D3 are those of the solder 9 that is generally used conventionally.

  The aging test result is shown in FIG. In FIG. 4, □ indicates the results using the samples A1 to A2, ● indicates the results using the samples B1 to B3, ○ indicates the results using the samples C1 to C3, and x indicates the results. The results using samples D1 to D3 are shown.

  As is clear from FIG. 4, in the case where the samples D1 to D3 of the comparative example were used (comparative example), the internal resistance value increased as the aging time increased, but at least one of Ag and Cu was used. In the case of using the added samples A1 to C3 (second embodiment example), it was found that any increase in the internal resistance value due to aging can be suppressed. In particular, when samples B1 to B3 to which only Ag was added and samples C1 to C3 to which both Ag and Cu were added were used, the internal resistance value decreased in all samples as the aging time increased. .

  That is, from this experiment, it was confirmed that the thermoelectric conversion module of the second embodiment example can suppress an increase in internal resistance value, and can suppress deterioration of thermal characteristics and breakage of the thermoelectric conversion module.

  In addition, the present inventor further conducted the following experiment in order to confirm the effect of the aging. That is, a thermoelectric conversion module using a sample obtained by adding at least one of Ag and Cu to Sn solder 9 and a thermoelectric conversion module using a solder sample (comparative example) made of Sn 100% at 150 ° C., respectively. Measure the values before and after the aging treatment for the endothermic surface temperature and the endothermic amount (maximum endothermic amount) when a predetermined constant current is applied for 1000 hours, and the rate of change for each. Asked about. The results are shown in Table 2 and Table 3, respectively. The results of Table 2 are shown as a graph in FIG. 5A, and the results of Table 3 are shown as a graph in FIG. 5B.

  As shown in Table 2, the endothermic surface temperature was examined three by three for the thermoelectric conversion module using the sample to which at least one of Ag and Cu was added, and the thermoelectric using the sample E of the comparative example was used. Two conversion modules were examined. As shown in Table 3, the endothermic amount was examined for each composition in two.

  From these results, when the thermoelectric conversion module is formed by adding at least one of Ag and Cu, compared to the case where the thermoelectric conversion module is formed without adding both Ag and Cu, the change in the endothermic surface temperature. The rate of change and the rate of change of the endothermic amount were both high, and the performance improvement was remarkable. The rate of change of the endothermic surface temperature is particularly large when both of Ag and Cu are added to form a thermoelectric conversion module, and the rate of change of the endothermic amount is the samples A1, A2, and Ag, to which only Cu is added. The thermoelectric conversion module using the samples C1 and C2 to which both of Cu were added had a large change rate of 10 times or more compared to the thermoelectric conversion module using the samples E1 and E2 without the addition of Ag and Cu.

  These results are considered to be the effect of Ag and Cu contained in the solder 9 entering the thermoelectric conversion element 5 (5a, 5b) by aging, and the performance improvement effect of the second embodiment was confirmed. It was done.

  In addition, this invention is not limited to the said embodiment, It can take various aspects. For example, in the first embodiment, a small amount of Ag or Cu is added to the thermoelectric conversion material for forming the thermoelectric conversion element 5 (5a, 5b). Although the indicated addition amounts of Ag and Cu were added, the addition amounts of Ag and Cu are not particularly limited, and are appropriately set. For example, when a small amount of Ag or Cu is added to the thermoelectric conversion material forming the thermoelectric conversion element 5 (5a, 5b), the addition amount is based on correlation data between the addition amount of Ag or Cu, the electrical resistance value, and the Peltier effect. It is good to decide.

  Further, when the additive 11 is added to the thermoelectric conversion material of the thermoelectric conversion element 5 (5a, 5b) as in the first embodiment, Au is added instead of or together with Ag and Cu. However, the same effect can be obtained. Furthermore, you may add the other material which raises electrical conductivity with respect to the material which has Bi and Te and Se and Sb which form the thermoelectric conversion element 5 (5a, 5b).

  Further, the additive 11 is added to the thermoelectric conversion material of the thermoelectric conversion element 5 (5a, 5b) as in the first embodiment, and Ag or the like is added to the solder 9 as in the second embodiment. Cu may be added. Further, at least one of Cu and Ag may be added to the Ni plating 11.

  Furthermore, although each said embodiment was made into the type of thermoelectric conversion module which has the board | substrates 6 and 7 on the upper and lower sides, this invention is applied to the type of thermoelectric conversion module as shown in FIG.7 (c), for example. Alternatively, it may be applied to a thermoelectric conversion module of the type as shown in FIG. 6, and may be applied to various types of thermoelectric conversion modules. The size and shape are also set as appropriate.

  In the thermoelectric conversion module of the type shown in FIG. 6, P-type and N-type thermoelectric conversion elements 5 (5a, 5b) are alternately arranged via Ni plating 11 formed on the end face of the thermoelectric conversion elements 5 (5a, 5b). The fins 15 are interposed between the thermoelectric conversion elements 5 (5a, 5b) and used for applications such as air conditioning.

  Furthermore, although the above description described the Peltier module as a thermoelectric conversion module, the thermoelectric conversion module of the present invention can also be applied as a power generation module that generates power using the Seebeck effect.

1 is a cross-sectional view schematically showing a first embodiment of a thermoelectric conversion module according to the present invention. It is sectional drawing which shows typically the example of 2nd Embodiment of the thermoelectric conversion module which concerns on this invention. It is explanatory drawing which shows typically the state of the joint surface of the solder of the thermoelectric conversion module of a 2nd embodiment, and a thermoelectric conversion element, and an additive material diffusion form. It is a graph which shows the example of a change condition of the internal resistance value by the aging of a thermoelectric conversion module. It is a graph which shows the example of a thermal characteristic change by the aging of a thermoelectric conversion module. It is explanatory drawing which shows typically the other embodiment example of the thermoelectric conversion module of this invention. It is explanatory drawing which shows typically the representative example of a thermoelectric conversion module.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Additive material 2 Electrode 5,5a, 5b Thermoelectric conversion element 6,7 Board | substrate 9 Solder 11 Ni plating 30 Insulating board

Claims (4)

  A plurality of P-type and N-type thermoelectric conversion elements are connected to each other through a conductive material to form a circuit of the thermoelectric conversion element, and one end side of the thermoelectric conversion element is connected to the heat absorption side according to the direction of current flowing through the circuit. In a thermoelectric conversion module provided with at least one of a function of forming a surface and forming the other end side as a heat dissipation side surface and a function of generating power using a temperature difference between one end side and the other end side of the thermoelectric conversion element The thermoelectric conversion element is formed by adding at least one of Ag and Cu to a thermoelectric conversion material comprising Bi and Te as main raw materials and adding at least one of Se and Sb. .   A plurality of P-type and N-type thermoelectric conversion elements are connected to each other through a conductive material to form a circuit of the thermoelectric conversion element, and one end side of the thermoelectric conversion element is connected to the heat absorption side according to the direction of current flowing through the circuit. In a thermoelectric conversion module provided with at least one of a function of forming a surface and forming the other end side as a heat dissipation side surface and a function of generating power using a temperature difference between one end side and the other end side of the thermoelectric conversion element The thermoelectric conversion module, wherein the conductive material includes at least one of solder and Ni plating, and at least one of Ag and Cu is added to at least one of the solder and Ni plating.   A method for producing a thermoelectric conversion module, comprising: aging the thermoelectric conversion module according to claim 2 at a set temperature for a set time to diffuse Ag and Cu contained in the conductive material into the thermoelectric conversion element.   A thermoelectric conversion material for forming a thermoelectric conversion element of the thermoelectric conversion module according to claim 1 or 2, wherein Bi and Te are main raw materials, and at least one of Se and Sb is added. A thermoelectric conversion material characterized by adding at least one of Ag and Cu.

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