JP2011091137A - Thermoelectric module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoelectric module capable of keeping a temperature difference between electrodes by reducing the amount of heat transfer between a substrate and a thermoelectric conversion material. <P>SOLUTION: The thermoelectric module 10 includes an insulating substrate 12, a thermoelectric conversion portion 14 having the thermoelectric conversion material formed on the substrate 12 in a thin film form, and a pair of electrodes 16a, 16b formed on the thermoelectric conversion portion 14. The distance between the electrodes is equal to or less than a half as large as the length of the thermoelectric conversion portion 14 in a direction wherein the electrodes 16a, 16b are arrayed. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a thermoelectric module using a thermoelectric conversion material.

  The Peltier effect is a phenomenon in which, when different metals are joined and a voltage is applied, heat is generated or absorbed. Heat generation and heat absorption are determined by the direction of current flow. Thermoelectric modules using the Peltier effect have been developed.

  A conventional thermoelectric module 50 shown in FIGS. 6A and 6B includes a substrate 12, a thermoelectric conversion unit 14 on the substrate 12, and a pair of electrodes 16 a and 16 b connected to both ends of the thermoelectric conversion unit 14. The substrate 12 is an insulating substrate. Examples of the thermoelectric conversion unit 14 include a thermoelectric conversion material in which a metal having a large Peltier effect or a thermoelectric semiconductor is formed into a thin film, and examples thereof include Bi—Te, Pb—Te, and Si—Ge materials. The electrodes 16a and 16b are a positive electrode and a negative electrode formed of metal.

  It is assumed that the thermoelectric conversion part 14 of the thermoelectric module 50 is a P-type semiconductor material. In this case, if the current I flows in the direction of the arrow, heat is absorbed at the junction between the electrode 16a and the thermoelectric conversion unit 14, and heat is generated at the junction between the electrode 16b and the thermoelectric conversion unit 14. By bringing the electrode 16a into direct or indirect contact with the location where cooling is desired, the contacted location is cooled. Such a thermoelectric module 50 can be used for local cooling of electronic equipment. If the thermoelectric converter 14 is an N-type semiconductor material, heat generation and heat absorption are reversed.

  However, when the distance between the electrode 16a and the electrode 16b is short, heat is transferred from the electrode 16b to the electrode 16a due to heat conduction of the thermoelectric converter 14 and the substrate 12. The electrode 16a and its vicinity are warmed, and local cooling cannot be performed.

  The following Patent Document 1 discloses a thermoelectric module in which a substrate is divided into two places. There is no heat transfer through the substrate. However, since the substrate is divided, a crack is likely to occur at the center of the thermoelectric conversion portion.

JP-A-6-188464

  An object of the present invention is to provide a thermoelectric module capable of reducing the amount of heat transferred between a substrate and a thermoelectric conversion unit and maintaining a temperature difference between electrodes.

  The thermoelectric module includes an insulating substrate, a thermoelectric conversion portion formed in a thin film state on the substrate, and a pair of electrodes formed on the thermoelectric conversion portion and arranged in one direction of the thermoelectric conversion portion. Prepare. Moreover, the distance between electrodes is 1/2 or less of the length of the one direction in a thermoelectric conversion part. The distance between the electrodes is set to ½ or less of the length of the thermoelectric conversion part to reduce the heat transfer between the electrodes.

  The thickness of the thermoelectric conversion part is 0.1 mm or less. The distance between the electrodes is 1 mm or less. Furthermore, the thermal conductivity of the thermoelectric converter is 1 W / mK or less. With the above configuration, the movement of heat between the electrodes is reduced.

  There is a thermoelectric conversion portion between the substrate and the electrode, and heat hardly moves through the substrate.

  According to the present invention, by adopting the above-described configuration, the joint between the electrode and the thermoelectric conversion material, that is, the portion that absorbs heat and generates heat, unlike the conventional configuration, the heat transfer becomes small. In the conventional configuration, the temperature difference between the electrodes could not be kept large. However, the temperature difference between the electrodes can be kept large by adopting the above-described configuration of the electrode spacing.

It is a figure which shows the structure of the thermoelectric module of this invention, (a) is a side view, (b) is a top view. It is a figure which shows the other structure of the thermoelectric module of this invention, (a) is a side view, (b) is a top view. It is a graph which shows the relationship between the ratio of length in the simulation result 1, and the decreasing rate of temperature. It is a graph which shows the relationship between the thickness of the thermoelectric conversion part in the simulation result 2, and the decreasing rate of a temperature difference. It is a graph which shows the relationship between the electrode interval in the simulation result 3, and the decreasing rate of a temperature difference. It is a figure which shows the structure of the conventional thermoelectric module, (a) is a side view, (b) is a top view.

  The thermoelectric module of the present invention will be described with reference to the drawings.

  A thermoelectric module 10 shown in FIG. 1 includes an insulating substrate 12, a thermoelectric conversion portion 14 in which a thermoelectric conversion material is formed in a thin film on the substrate 12, and a pair of electrodes 16a formed on the thermoelectric conversion portion 14. 16b.

  Examples of the substrate 12 include a glass substrate, a ceramic substrate, and a resin substrate. The thermoelectric conversion part 14 can utilize the Peltier effect. Specifically, a thermoelectric semiconductor is formed into a thin film, and examples include Bi—Te, Pb—Te, or Si—Ge materials. Electrode 16a, 16b is a positive electrode and a negative electrode, and is formed with metals, such as copper and a copper alloy. The electrodes 16 a and 16 b are arranged in one direction of the thermoelectric conversion unit 14. In FIG. 1, the electrodes 16a and 16b are arranged in the x-axis direction, but may be arranged in the y-axis direction.

  Further, as shown in FIG. 2, a part of the electrodes 16 a and 16 b may be in contact with the substrate 12. If the distance between the portions of the electrodes 16 a and 16 b that are in contact with the substrate is sufficiently large, heat transfer is less likely to occur through the substrate 12.

  In addition, a power source is provided so that a current I flows between the electrodes, and the power source and the electrodes 16a and 16b are connected. The electrode 16a (or 16b) on the heat absorption side is directly or indirectly brought into contact with a location where local cooling is desired.

  Next, various calculation results regarding heat generation and heat absorption of the thermoelectric module 10 of the present invention will be described. The thermoelectric module 10 of FIG. 2 was used as a model for the calculation. The thermoelectric converter 14 has a thermal conductivity of 0.5 W / mK, the thickness of the substrate 12 is 0.05 mm, the thermal conductivity of the substrate 12 is 1.0 W / mK, the electrodes 16a and 16b are copper, and the thickness of the electrodes 16a and 16b. Is 0.01 mm, the x direction of the thermoelectric module 10 is 0.5 mm, and the y direction is 3 mm.

Simulation result 1
Table 1 shows the simulation results when the length ratio of the thermoelectric conversion material 14 is wt, the length of the electrode interval is wg, the length ratio is wt / wg, and the length ratio is changed. The maximum temperature is the maximum temperature of the electrode 16a (or 16b) that generates heat, and the minimum temperature is the minimum temperature of the electrode 16b (or 16a) that absorbs heat. The decrease rate indicates a change in temperature difference based on the case where the length ratio is 5. FIG. 3 is a graph showing the ratio of length and the rate of temperature decrease. When the electrode interval and the length of the thermoelectric converter 14 are the same, the configuration is the same as that of the conventional thermoelectric module 50.

  From Table 1, when the length ratio is smaller than 2, the temperature difference reduction rate (comparison with the temperature difference when the length ratio is 5) increases rapidly. Since the temperature difference between the exothermic electrode 16a (16b) and the endothermic electrode 16b (16a) is small, it can be seen that heat transfer occurs between the two electrodes. When the electrodes 16 a and 16 b are in contact with the substrate 12, heat is transferred through the substrate 12. On the other hand, when the length ratio is greater than 2, the temperature decrease rate decreases. It can be seen that the heat transfer between the electrodes is small. Therefore, it is preferable to form the electrodes 16a and 16b on the thermoelectric conversion portion 14, and the distance between the electrodes is particularly ½ or less of the length of the thermoelectric conversion portion 14 in the x-axis direction, particularly 1/5 to 1. It can be seen that / 2 is preferred.

Simulation result 2
Table 2 shows the simulation results when the thickness of the thermoelectric converter 14 is changed when the ratio of the two lengths (wt / wg) is 1 and 3. When the length ratio is 1, it is the conventional thermoelectric module 50, and when the length ratio is 3, it is the thermoelectric module 10 of the present application. Further, the reduction rate is a change in temperature difference between length ratios 1 and 3 in the same thickness of the thermoelectric conversion unit 14. FIG. 4 is a graph showing the relationship between the thickness of the thermoelectric converter 14 and the rate of decrease in temperature difference.

  From Table 2, when the thickness of the thermoelectric conversion part 14 is increased, heat is not easily transmitted from the electrodes 16a and 16b to the substrate 12 by the thermoelectric conversion part 14, and the change (decrease rate) in temperature difference between the present application and the conventional one is reduced. That is, there is no difference between the present application and the conventional one. If the thickness of the thermoelectric conversion part 14 is 0.1 mm or less, especially 0.01-0.1 mm if it is the structure of this invention, a temperature difference will become larger than the conventional structure, and the effect of the structure of this invention Is demonstrated.

Simulation result 3
Table 3 shows the simulation results when the electrode spacing is changed when the ratio of the two lengths (wt / wg) is 1 and 3. When the length ratio is 1, it is the conventional thermoelectric module 50, and when the length ratio is 3, it is the thermoelectric module 10 of the present application. Further, the decrease rate is a change in length ratio 1 and 3 temperature difference at the same electrode spacing. FIG. 5 is a graph showing the relationship between the electrode interval and the temperature difference reduction rate.

  From Table 3, if the distance between the electrodes becomes longer, it becomes difficult for heat to move between the electrodes, and the change (decrease rate) in the temperature difference between the present application and the conventional one becomes smaller. That is, it is not necessary to form the electrodes 16a and 16b on the thermoelectric converter 14 as shown in FIG. Therefore, the configuration of the present invention has an effect of forming the electrodes 16a and 16b on the thermoelectric conversion portion 14 by setting the electrode interval to 1 mm or less, particularly 0.1 to 1 mm.

  Furthermore, the configuration of the present invention is effective when the thermal conductivity of the substrate 12 is higher than the thermal conductivity of the thermoelectric conversion unit 14, but the thermal conductivity of the substrate 12 is higher than the thermal conductivity of the thermoelectric conversion unit 14. Even if it is low, the thermoelectric conversion unit 14 is interposed between the electrodes 16a and 16b and the substrate 12. Therefore, the heat transfer between the electrodes can be reduced.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

10: Thermoelectric module 12: Substrate 14: Thermoelectric converter 16a, 16b: Electrode

Claims (5)

An insulating substrate;
A thermoelectric conversion part in which a thermoelectric conversion material is formed in a thin film state on the substrate;
A pair of electrodes on the thermoelectric converter;
A thermoelectric module comprising:
The thermoelectric module in which the distance between the electrodes is ½ or less of the length in the direction in which the electrodes are arranged in the thermoelectric conversion material. The thermoelectric module according to claim 1, wherein the thermoelectric conversion part has a thickness of 0.1 mm or less. The thermoelectric module according to claim 1 or 2, wherein a distance between the electrodes is 1 mm or less. The thermoelectric module according to any one of claims 1 to 3, wherein the thermoelectric conversion material has a thermal conductivity of 1 W / mK or less. The thermoelectric module according to any one of claims 1 to 4, wherein the thermal conductivity of the substrate is higher than the thermal conductivity of the thermoelectric converter.

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