JP2014011469A - Thermoelectric cooling module and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoelectric cooling module and a manufacturing method of the thermoelectric cooling module.SOLUTION: A thermoelectric cooling module includes: first and second substrates in which metal electrodes are formed, the first and second substrates facing each other; and multiple thermoelectric elements formed between the first substrate and the second substrate. The first and second substrates include aluminum layers and alumina (AlO) layers formed at parts of facing surfaces of the aluminum layers. Providing the thermoelectric cooling module reduces joint resistance thereby improving the efficiency of the thermoelectric cooling module and reducing the costs.

Description

  The present invention relates to a thermoelectric cooling module and a method for manufacturing the same, and more specifically, by forming a porous alumina by anodizing an aluminum layer, the thermoelectric cooling module can improve the efficiency of the thermoelectric cooling module by reducing the junction resistance. It relates to a cooling module.

  A thermoelectric element is a generic term for elements that use phenomena that correlate heat and electricity, such as the Seebeck effect, Peltier effect, and Thomson effect. A P-type thermoelectric material and an N-type thermoelectric material are joined between metal electrodes. By doing so, a PN junction pair is formed. When a temperature difference is provided between such a PN junction pair, electric power is generated by the Seebeck effect, whereby the thermoelectric element functions as a power generator. Also, the thermoelectric element can be used as a temperature control device due to the Peltier effect in which one of the PN junction pairs is cooled and the other generates heat.

  Here, as shown in FIG. 1, when the DC voltage is applied externally, the Peltier effect causes the holes of the P-type thermoelectric material and the electrons of the N-type thermoelectric material to move, thereby generating heat and heat absorption at both ends of the material. It is a phenomenon that causes As shown in FIG. 2, the Seebeck effect refers to a phenomenon in which, when heat is supplied from an external heat source, electrons and holes move while a material flows while generating power.

  Active cooling using such thermoelectric materials improves the thermal stability of the device, is free of vibration and noise, and uses no separate condenser and refrigerant, so it is recognized as a small volume and environmentally friendly method. ing. Applications of active cooling using such thermoelectric materials include refrigerant-free refrigerators, air conditioners, various micro-cooling systems, etc. Especially when thermoelectric elements are mounted on various memory elements, compared to conventional cooling methods. Thus, the device performance can be improved because the device can be maintained at a uniform and stable temperature while reducing the volume.

  Hereinafter, a configuration of a thermoelectric module according to the prior art will be described with reference to the accompanying drawings.

FIG. 3 is a longitudinal sectional view showing a configuration of a thermoelectric module according to the prior art.
As shown in the drawing, a first substrate (lower substrate) 11 and a second substrate (upper substrate) 12 which are insulating substrates are provided on the upper and lower surfaces of the thermoelectric module. The first substrate 11 and the second substrate 12 serve to release or absorb heat, and are maintained in a state of being spaced apart from each other at a certain distance.

  A P-type thermoelectric element 41 and an N-type thermoelectric element 42 are provided between the first substrate 11 and the second substrate 12. The P-type thermoelectric element 41 and the N-type thermoelectric element 42 are elements formed so that the thermoelectric material has a certain shape and size, and are alternately arranged between the first substrate 11 and the second substrate 12. Placed in.

  A metal electrode 20 is provided between the P-type thermoelectric element 41 and the N-type thermoelectric element 42 and the first substrate 11 and the second substrate 12. The metal electrode 20 is configured to electrically connect the P-type thermoelectric element 41 and the N-type thermoelectric element 42.

  A diffusion preventing film 30 may be further included between the metal electrode 20 and the P-type thermoelectric element 41 and the N-type thermoelectric element 42 to prevent metal diffusion.

  In such a conventional thermoelectric module, as disclosed in Patent Document 1, heat radiating from the thermoelectric module is radiated to the outside, and heat sinks are attached to both side surfaces of the thermoelectric element to absorb the external heat. It is done.

  As described above, the conventional thermoelectric module as a heat radiating element for electronic products, etc., dissipates heat from the heat generating part by joining the heat radiating plate to the heat generating part. Due to the convection phenomenon, a thermal equilibria state is reached, and there is a problem that it cannot properly serve as a heat dissipation element.

Korean Registered Patent No. 10-0766612

  The present invention has been made in order to solve the above-described problems, and by forming the first and second substrates having an integrated structure in which porous alumina and aluminum are in contact with each other by anodization of aluminum, It is an object of the present invention to provide a thermoelectric cooling module that can improve the efficiency of the thermoelectric cooling module by reducing the junction resistance, and that can also realize a cost reduction effect, and a manufacturing method thereof.

The thermoelectric cooling module of the present invention provided to solve the above-described problem is formed between a first substrate and a second substrate on which metal electrodes are formed and opposed to each other, and the first substrate and the second substrate. The first substrate and the second substrate each include a plurality of thermoelectric elements. The first substrate and the second substrate include an aluminum layer and an alumina (Al ₂ O ₃ ) layer formed on part of the surfaces of the aluminum layer facing each other.

  According to the present invention, the junction resistance is reduced by integrally forming an aluminum layer as a heat sink and an alumina layer formed by an anodization method and used as a joined body of a thermoelectric material. Thus, the efficiency of the thermoelectric cooling module is improved and the cost is reduced.

It is the schematic which shows the thermoelectric cooling by the Peltier effect. It is the schematic which shows the thermoelectric power generation by a Seebeck effect. It is sectional drawing which shows the internal structure of the thermoelectric module by the form of a prior art. 1 is a cross-sectional view of a thermoelectric cooling module according to a preferred embodiment of the present invention. It is a perspective view of the board | substrate which formed the porous alumina by anodizing aluminum by this invention. It is sectional drawing of the board | substrate which formed the porous alumina by anodizing aluminum by this invention. 3 shows an actual image of the upper part of an alumina layer anodized on an aluminum layer. The actual image of the cross section of the alumina layer anodized to the aluminum layer is shown. 1 is a top view of a substrate on which metal electrodes and thermoelectric elements are formed according to a preferred embodiment of the present invention. 3 is a flowchart illustrating a method of manufacturing a thermoelectric cooling module according to a preferred embodiment of the present invention. FIG. 5 is a manufacturing process diagram illustrating a method of manufacturing a thermoelectric cooling module according to a preferred embodiment of the present invention. FIG. 5 is a manufacturing process diagram illustrating a method of manufacturing a thermoelectric cooling module according to a preferred embodiment of the present invention. FIG. 5 is a manufacturing process diagram illustrating a method of manufacturing a thermoelectric cooling module according to a preferred embodiment of the present invention. FIG. 5 is a manufacturing process diagram illustrating a method of manufacturing a thermoelectric cooling module according to a preferred embodiment of the present invention.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these. Throughout the specification, the same components are denoted by the same reference numerals.

  The present invention provides a thermoelectric cooling module that is provided with an integrated substrate having an anodized alumina layer formed on an aluminum layer, thereby improving efficiency by reducing junction resistance and reducing costs. Is the gist.

  FIG. 4 is a cross-sectional view of a thermoelectric cooling module according to a preferred embodiment of the present invention, and FIGS. 5 and 6 are a perspective view and a cross-sectional view of a substrate on which porous alumina is formed by anodizing aluminum according to the present invention. 7 and 8 show actual images of the top and cross-section of the substrate, and FIG. 9 is a top view of the substrate on which the metal electrode and the thermoelectric element are formed according to the preferred embodiment of the present invention. is there.

  Referring to the drawing, the thermoelectric cooling module 100 of the present invention is formed between the first and second substrates 110 and 120 facing each other on which the metal electrode 130 is formed, and the first and second substrates 110 and 120. A plurality of thermoelectric elements 141 and 142 are included.

In particular, the first and second substrates 110 and 120 include aluminum layers 111 and 121 and porous alumina (Al ₂ O ₃ ) layers 112 and 122 formed by anodization, as shown in FIG. The alumina layers 112 and 122 are formed on a part of the aluminum layers 111 and 121 facing each other. The first and second substrates 110 and 120 have an integrated structure of aluminum and alumina, and the aluminum layers 111 and 121 function as a heat sink to dissipate heat from the heat generating portion to the outside of the system. The porous alumina layers 112 and 122 are insulating layers and are used as a joined body of the thermoelectric elements 141 and 142.

  In the conventional thermoelectric cooling module, a heat sink made of different materials is joined to the heat generating part. However, the present invention realizes an integrated structure such as aluminum-alumina by anodization of aluminum, thereby reducing the contact resistance and reducing the thermoelectricity. Not only can the efficiency of the cooling module be improved, but also a cost reduction effect can be achieved.

  At this time, the alumina layers 112 and 122 formed on the first and second substrates 110 and 120 are opposed to each other and correspond to each other. Therefore, the alumina layers 112 and 122 in the first and second substrates 110 and 120 preferably have the same area and the same shape and thickness, but they do not necessarily have to coincide with each other.

  The first and second substrates 110 and 120 formed of the aluminum layers 111 and 121 and the alumina layers 112 and 122 can be formed in a circular shape as shown in FIGS. 5 and 9, but are not limited thereto. However, it is of course possible to form an oval or a polygon such as a rectangle.

  The thickness (d) of the alumina layers 112 and 122 is preferably 30 to 200 μm. When the thickness is less than 30 μm, electrical conductivity exists and cannot function as an insulator.

  In the first and second substrates 110 and 120, the area of the alumina layers 112 and 122 is preferably 5 to 50% of the area of the aluminum layers 111 and 121. This is because when the area of the alumina layers 112, 122 exceeds 50% of the area of the aluminum layers 111, 121, the heat of the heat generating part is diffused to the cooling part, and the temperature of the cooling part rises to serve as a heat dissipation element. This is because the thermoelectric elements 141 and 142 are difficult to connect when the ratio is 5% or less.

  The metal electrode 130 is formed on the alumina layers 112 and 122 in the first and second substrates 110 and 120, and a plurality of P-type thermoelectric elements 141 and N-type thermoelectric elements 142 are separated from each other via the metal electrode 130. Are electrically connected. The metal electrode 130 is at least one metal selected from the group including Cu, Au, Ag, Ni, Al, Cr, Ru, Re, Pb, Sn, In, and Zn, or an alloy including these metals. The P-type and N-type thermoelectric elements 141 and 142 can be formed by appropriately doping a material generally used in the technical field, for example, a thermoelectric material such as a BiTe-based material or a PbTe-based material. it can.

  Although not shown, a buffer layer (not shown) for improving the adhesive force between the metal electrode 130 and the P-type and N-type thermoelectric elements 141 and 142 and a diffusion prevention film for preventing metal diffusion. (Not shown) may further be included, and the diffusion barrier film is preferably nickel.

FIG. 10 is a flowchart illustrating a method of manufacturing a thermoelectric cooling module according to a preferred embodiment of the present invention. Referring to the drawing, first, a first substrate 110 and a second substrate 120 are formed (S10). Specifically, by using a mask on the prepared aluminum test piece and forming the porous alumina layers 112 and 122 by an anodic oxidation method (S11) (S12), an aluminum-alumina integrated structure is obtained. One substrate and second substrates 110 and 120 are manufactured. The anodic oxidation of aluminum is performed by applying a voltage of 195 V at 1 wt% H ₃ PO ₄ (phosphoric acid) at 1 ° C. for 10 hours or more. At this time, the area where the alumina layers 112 and 122 are formed is The area of the aluminum layers 111 and 121 is preferably 5 to 50%, and the thickness of the alumina layers 112 and 122 is preferably 30 to 200 μm, as described above. In the first and second substrates 110 and 120, the alumina layers 112 and 122 are preferably formed to have the same area, shape, and thickness.

  Thereafter, a metal electrode 130 is formed on the alumina layers 112 and 122 of the first substrate 110 and the second substrate 120 (S20). The metal electrode 130 is formed of Cu, Au, Ag, Ni, Al, Cr, Ru, It can be formed of at least one metal selected from the group including Re, Pb, Sn, In, and Zn, or an alloy including these metals.

  Next, a thermoelectric material such as a BiTe material or a PbTe material is appropriately doped on the metal electrode 130 of the first substrate 110 to form a pair of P-type and N-type thermoelectric elements 141 and 142 (S30).

  At this time, although not shown, a buffer layer for improving adhesion between the metal electrode 130 and the P-type and N-type thermoelectric elements 141 and 142 and a diffusion preventing film for preventing metal diffusion are provided. A forming step may be further included.

  Thereafter, the upper substrate on which the metal electrode 130 is formed so that the P-type and N-type thermoelectric elements 141 and 142 formed on the metal electrode 130 in the first substrate 110 as the lower substrate are electrically connected, That is, the thermoelectric cooling module is manufactured by bonding the second substrate 120 (S40).

  11 to 14 are manufacturing process diagrams illustrating a method of manufacturing a thermoelectric cooling module according to a preferred embodiment of the present invention.

Referring to the figure, the first substrate 110 and the second substrate 120 facing each other are made of alumina layers 112 and 122 formed by anodic oxidation on a part of the aluminum layers 111 and 121. The anodic oxidation of the aluminum can be performed by applying a voltage of 195 V at 1 ° C. for 10 hours or more at 1 wt% H ₃ PO ₄ (phosphoric acid). The first substrate 110 and the second substrate 120 are circular as shown in FIGS. 5 and 9, and may have an elliptical shape or a polygonal structure such as a quadrangle. In the following description, FIG. Description will be made on the assumption that the shape is circular as shown in FIG.

  At this time, the thickness of the alumina layers 112 and 122 is desirably 30 to 200 μm, and the area of the alumina layers 112 and 122 is desirably 5 to 50% of the area of the aluminum layers 111 and 121. As shown in FIG. 11, the thickness, shape, and area of the alumina layers 112 and 122 in the first and second substrates 110 and 120 are desirably the same, but they do not necessarily need to match each other.

  Thereafter, a metal electrode 130 is formed on the alumina layers 112 and 122 in the first and second substrates 110 and 120, and the first and second thermoelectric elements 141 and 142 are connected to each other to form the first pair. It is formed on the metal electrode 130 formed on the substrate 110. FIG. 13 shows only a pair of P-type and N-type thermoelectric elements. As described above, since the first substrate 110 is assumed to be circular, the top view of FIG. Is the same as FIG. Therefore, as shown in FIG. 9, a pair of P-type and N-type thermoelectric elements 141 and 142 can be arranged in front and back, and can also be arranged in a row. There is no limit. At this time, in order to prevent diffusion of the metal, a step of forming a diffusion prevention film between the metal electrode 130 and the P-type and N-type thermoelectric elements 141 and 142 may be further included.

  Next, the plurality of P-type and N-type thermoelectric elements 141 and 142 are bonded to the second substrate 120 such that one ends of the P-type and N-type thermoelectric elements 141 and 142 are electrically connected via the metal electrode 130.

  As described above, the present invention realizes the aluminum-alumina monolithic substrates 110 and 120 by anodizing aluminum, thereby improving the efficiency of the thermoelectric cooling module by reducing the contact resistance and reducing the cost. Can be achieved.

[Experimental Example 1] Electrical Conductivity by Alumina Thickness Electrical Conductivity by 10 nm Thickness Alumina Layer Formed by Natural Oxidation of Aluminum and 20 μm and 30 μm Thickness Alumina Layers Formed by Anodizing Aluminum A comparison experiment of (= thickness / {resistance × area}) [S / m] was performed, and the results shown in Table 1 below were obtained. Here, the diameter of the aluminum sheet is 4 cm, the thickness is 1 cm, and the area of the anodized alumina is 12.56 cm ² (diameter 2 cm).

When an alumina layer having a thickness of 10 nm is formed on an aluminum sheet by natural oxidation, the measured resistance is 10 ⁻⁴ Ω, the electrical conductivity is 7.96 × 10 ⁴ [S / m], and anodization is performed. When an alumina layer having a thickness of 20 μm was formed, the measured resistance value was 1.7 × 10 ⁻² Ω, and the electrical conductivity was 4.69 × 10 ² [S / m]. However, when an alumina layer having a thickness of 30 μm is formed by anodization, the actually measured resistance value is overload, and the electrical conductivity is 0, that is, the alumina layer means an insulator. Thus, it can be seen that when the thickness of the alumina layer formed by anodic oxidation is 30 μm or less, the alumina layer cannot serve as an insulator.

[Experimental example 2] Temperature change with time depending on the area ratio of the aluminum layer and the alumina layer The temperature change of the cooling part according to time by the sample of the thermoelectric cooling module attached to the LED was comparatively observed, and the result of Table 2 was obtained . Here, sample A is the case where the area of alumina is 100% of the area of aluminum, and sample B is the case where the area of alumina is 50% of the area of aluminum, and the power is the same 0.37 W (1.0 V). X 0.37 A) was applied.

As can be seen from Table 2 above, the temperature difference in the cooling region between sample B in which the area of alumina is 50% of the area of aluminum over time and sample A in which the area of alumina is 100% of the area of aluminum is This is because when alumina is formed in the entire area of aluminum as in sample A, the temperature of the cooling part rises while the heat of the heat generation part is diffused to the cooling part. Therefore, the alumina layer is not formed to be the same as the area of the aluminum layer, and it is desirable that the alumina is formed only in a part, preferably within a range of 5 to 50% of the area of the aluminum layer.

11, 110 First substrate 12, 120 Second substrate 20, 130 Metal electrode 30 Diffusion prevention film 41, 141 P-type thermoelectric element 42, 142 N-type thermoelectric element 111, 121 Aluminum layer 112, 122 Alumina layer

Claims (6)

A first substrate and a second substrate formed with metal electrodes and facing each other;
A plurality of thermoelectric elements formed between the first substrate and the second substrate;
The first substrate and the second substrate are:
An aluminum layer;
A thermoelectric cooling module comprising: an alumina (Al ₂ O ₃ ) layer formed on a part of the mutually facing surfaces of the aluminum layer.   The thermoelectric cooling module according to claim 1, wherein the alumina layer has a thickness of 30 to 200 μm. The area of the alumina layer is
The thermoelectric cooling module according to claim 1 or 2, which is 5 to 50% of an area of the aluminum.   The thermoelectric cooling module according to any one of claims 1 to 3, wherein areas of the alumina layers formed on the first substrate and the second substrate are the same. The metal electrode is
It consists of at least 1 type of metal selected from the group containing Cu, Au, Ag, Ni, Al, Cr, Ru, Re, Pb, Sn, In, and Zn, or an alloy containing these metals. The thermoelectric cooling module according to claim 4.   The thermoelectric cooling module according to any one of claims 1 to 5, further comprising a diffusion prevention film formed between the metal electrode and the thermoelectric element.