A sealing method for a thermoelectric cooler

Abstract

The present invention relates to the field of thermoelectric cooler material packaging. In order to solve the problem that when the thermoelectric cooler is working, extra heat leakage will cause the overall temperature difference of the thermoelectric cooler to decrease, the present invention proposes a sealing method for the thermoelectric cooler: the protected thermoelectric cooler is first immersed in a sealing solution, then taken out and immersed in a sedimentation solvent, and the process is repeated several times. Finally, the protection of the thermoelectric cooler is removed after heating and drying. The method can effectively reduce the extra heat leakage of the thermoelectric cooler and improve the energy utilization rate.

Description

Technical Field

[0001] The invention relates to the field of thermoelectric cooler material packaging, and in particular to a method for sealing a thermoelectric cooler. Background Art

[0002] At present, thermoelectric cooling technology is very mature. Among them, the working environment of thermoelectric coolers is relatively demanding. Thermoelectric coolers can only work in an environment with very good airtightness to prevent water and oxygen from oxidizing and corroding the thermoelectric cooler. The traditional process is to encapsulate a layer of glue on the outermost layer of the upper and lower substrates of the thermoelectric cooler to ensure the airtightness of the internal working of the thermoelectric cooler. However, when the thermoelectric cooler is working, in addition to the heat flow from the hot end to the cold end along the thermoelectric arm, it will also be conducted from the outermost packaging material. This additional heat leakage will cause the overall temperature difference of the thermoelectric cooler to decrease. Especially for miniature products, the temperature difference itself is not much different, and this additional heat transfer will greatly reduce the overall effect. Summary of the invention

[0003] In order to solve the problem that additional heat leakage during operation of the thermoelectric cooler will cause the overall temperature difference of the thermoelectric cooler to decrease, the present invention proposes a sealing method for the thermoelectric cooler, which can effectively reduce the additional heat leakage of the thermoelectric cooler and improve energy utilization.

[0004] The present invention is achieved through the following technical scheme: a sealing method for a thermoelectric cooler, the sealing method comprises the following steps: first immersing the protected thermoelectric cooler in a sealing solution, then taking it out and immersing it in a sedimentation solvent again, repeating this process several times, and finally heating and drying it to remove the protection of the thermoelectric cooler.

[0005] The protection method of the thermoelectric cooler is: the upper and lower substrates of the thermoelectric cooler are protected by adhesive tape. The adhesive tape can be removed by wiping or soaking. The protective tape is generally acrylic tape, vulcanized rubber tape, silicone rubber tape, etc.

[0006] The sealing solution includes organic material and diluent, wherein the diluent accounts for 10%-70% of the mass of the sealing solution.

[0007] The sealing technology is implemented using one or more sealing materials, which mainly depends on the wettability of the selected sealing material with the thermoelectric cooler material and the surface tension of the sealing material. It is necessary to select a material with good wettability to the material used in the thermoelectric cooler and relatively low surface tension. Preferably, the organic material includes organic small molecule materials, insulating varnish, paint, three-proof paint, and thermosetting plastic. The organic small molecule materials include PEI, PVP, PEIE, etc. Heating can polymerize organic small molecule materials into polymer materials. Insulating varnish, paint, three-proof paint, and thermosetting plastics are medium composite materials, which can be polymerized into monomers of polymers in the subsequent heating and drying process.

[0008] The diluent includes alcohol solvents and water, which make the organic material dissolve better in the diluent. The sedimentation solvent includes an oily solvent, which makes the organic material insoluble in the sedimentation solvent. The organic material can be dissolved in the diluent and then precipitated out by the sedimentation solvent with opposite properties.

[0009] Preferably, the immersion method is pressurized immersion or centrifugal immersion, the pressurized pressure is 2-10Mpa or the centrifugal speed is 500-2000 rpm.

[0010] By pressurizing or centrifuging, and repeating the above process several times, a sealing film is directly formed on the thermoelectric arm and the inner side of the substrate after immersion, and the film thickness reaches 15 to 30 microns, reducing the thickness of the packaging material. The reduction in the thickness of the packaging material reduces the heat transfer and heat convection between the substrates on the thermoelectric cooler, which can effectively reduce the loss of temperature difference, thereby improving the thermoelectric efficiency.

[0011] Preferably, the immersion time in the sealing solution or the precipitation solvent is 0.1-2 hours, respectively, and repeated 3-5 times to achieve the best encapsulation effect.

[0012] Preferably, the drying temperature is 80-300°C. The residual solvent on the coating is removed by heating, and the sealing coating is made of one or more monomers of high molecular polymers. Using the principle of polymer material polymerization, the surface of the thermoelectric cooler is first dip-coated with a layer of monomers of the polymer material, and then the monomers are precipitated on the surface of the thermoelectric cooler functional material by the principle that solvents of different properties are immiscible. Finally, the double bonds on the monomers are broken by high temperature and then reassembled. In this way, the polymer materials are polymerized together to form a stable coating, which isolates water and oxygen and ensures the airtightness of the working environment of the thermoelectric cooler.

[0013] The sealing method of the present application directly seals the surface of the N-type and P-type thermoelectric arms, the copper substrate and the welding point to isolate water and oxygen. By comparing the dT test before and after, the sealed thermoelectric cooler can increase the overall temperature difference of the thermoelectric cooler by 1K.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) A sealing film is directly formed on the inner side of the thermoelectric arm and the substrate. The film thickness is very thin, which reduces the thickness of the packaging material and can effectively reduce the additional heat leakage of the thermoelectric cooler, thereby indirectly improving the energy utilization rate. (2) The problem of heat leakage of the thermoelectric cooler caused by the packaging material is effectively solved. The method is simple and easy to operate, suitable for batch production, and saves a lot of manpower and material resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 FIG. 4 is a schematic diagram of the loss of dT of a thermoelectric cooler according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described in detail below by way of examples and drawings. The raw materials used in the examples are all commercially available or can be prepared by conventional methods.

[0018] Example 1

[0019] Protect the upper and lower substrates of the thermoelectric cooler with high-temperature resistant acrylic tape, and cut off the excess tape; then pour PVP and ethanol into a clean container, the height needs to be able to cover the thermoelectric cooler; ethanol accounts for 60wt%, and then slowly soak the protected thermoelectric cooler in the PVP solution for 150min. Seal the above container, and then pressurize it to 10Mpa to evacuate the air inside the thermoelectric cooler that cannot be removed due to the surface tension of the solution; then take out the product, drain it first, and then soak it in a container filled with ethyl acetate, a sedimentation solvent, for 150min. The same height needs to be able to cover the thermoelectric cooler. Seal the container, and then pressurize it to 10Mpa. Soak it repeatedly in the two solutions for 5 times, and then dry it at 250℃ to solidify the PVP, remove the residual solvent, and finally remove the protection of the upper and lower substrates.

[0020] Example 2

[0021] Protect the upper and lower substrates of the thermoelectric cooler with high-temperature resistant acrylic tape, and cut off the excess tape; then pour the insulating paint and insulating paint thinner into a clean container, the height needs to be able to cover the thermoelectric cooler; the thinner is 70wt%, and then slowly immerse the protected thermoelectric cooler in the insulating paint solution for 90 minutes. Seal the above container, and then centrifuge it at a speed of 200 rpm to empty the air inside the thermoelectric cooler that cannot be removed due to the surface tension of the solution; then take out the product, drain it first, and then soak it in a container containing the sedimentation solvent ethanol for 90 minutes. The same height needs to be able to cover the thermoelectric cooler. Seal the container, then centrifuge it at a speed of 200 rpm, and soak it repeatedly in the two solutions for 4 times, and then dry it at 200℃ to solidify the three-proof paint, remove the residual solvent, and finally remove the protection of the upper and lower substrates.

[0022] Example 3

[0023] Protect the upper and lower substrates of the thermoelectric cooler with high-temperature resistant acrylic tape, and cut off the excess tape; then pour the three-proof paint and industrial alcohol into a clean container, the height needs to be able to cover the thermoelectric cooler; the industrial alcohol accounts for 70wt%, and then slowly immerse the protected thermoelectric cooler in the three-proof paint solution for 60 minutes. Seal the above container, and then pressurize it to 5Mpa to evacuate the air inside the thermoelectric cooler that cannot be removed due to the surface tension of the solution; then take out the product, drain it first, and then soak it in a container filled with sedimentation solvent octane for 60 minutes. The same height needs to be able to cover the thermoelectric cooler. Seal the container, and then pressurize it to 5Mpa. Repeat the immersion in the two solutions for 3 times, and then dry it at 130℃ to solidify the three-proof paint, remove the residual solvent, and finally remove the protection of the upper and lower substrates.

[0024] Example 4

[0025] Protect the upper and lower substrates of the thermoelectric cooler with high-temperature resistant acrylic tape, and cut off the excess tape; then pour PMMA and ethanol into a clean container, the height needs to be able to cover the thermoelectric cooler; among them, ethanol accounts for 70wt%, and then slowly immerse the protected thermoelectric cooler in the three-proof paint solution for 120 minutes. Seal the above container, and then centrifuge it at a speed of 200 rpm to empty the air inside the thermoelectric cooler that cannot be removed due to the surface tension of the solution; then take out the product of the step, drain it first, and then soak it in a container filled with sedimentation solvent ethyl acetate for 120 minutes. The same height needs to be able to cover the thermoelectric cooler, seal the container, and then centrifuge it at a speed of 200 rpm. Repeat the immersion in the two solutions for 5 times, and then dry it at 300℃ to solidify PMMA, remove the residual solvent, and finally remove the protection of the upper and lower substrates.

[0026] Comparative Example:

[0027] Using conventional technology, a layer of RTV glue is sealed around the thermoelectric cooler to isolate water and oxygen.

[0028] Test Case

[0029] Example 1-4 The loss of dT of the product after different insulating varnishes were used as the seal of the thermoelectric cooler is as follows Figure 1 As shown, it can be seen from the figure that the dT loss of the thermoelectric cooler in Example 1-2 is reduced by 0.6K, and it can be seen from the figure that the dT loss of the thermoelectric cooler in Example 3 is reduced by 0.5K. It can be seen from the figure that the dT loss of the thermoelectric cooler in Example 4 is reduced by 0.2K, while when conventional technology is used to seal thermoelectric materials, the dT loss is generally 1.5-2K.

[0030] Through testing, these materials are used as sealing materials, and the thickness left on the N and P type thermoelectric arms is about 30μm. Since the sealing technology involved is closely related to the logarithm of the thermoelectric cooler, especially for micro coolers, the dT loss of the present invention is relatively small, so it has greater advantages in the mechanized production process.

Claims

1. A sealing method for a thermoelectric cooler, characterized in that: The sealing method comprises the following steps: first immersing the protected thermoelectric cooler in a sealing solution, which includes an organic material and a diluent; then taking it out and immersing it in a sedimentation solvent, which includes an oily solvent so that the organic material does not dissolve in the sedimentation solvent; the organic material can be dissolved in the diluent, and then it is precipitated out by using a sedimentation solvent with opposite properties; repeating the process several times, and finally removing the protection of the thermoelectric cooler after heating and drying.

2. The sealing method of a thermoelectric cooler according to claim 1, characterized in that: The protection method of the thermoelectric cooler is: the upper and lower substrates of the thermoelectric cooler are protected by adhesive tape.

3. The sealing method of a thermoelectric cooler according to claim 2, characterized in that: The adhesive tape can be removed by wiping or soaking.

4. The sealing method of a thermoelectric cooler according to claim 1, characterized in that: in, The diluent is 10%-70% of the sealing solution mass.

5. The sealing material for a thermoelectric cooler according to claim 4, characterized in that: The organic materials include organic small molecule materials, insulating varnish, paint, conformal coating, and thermosetting plastics.

6. The sealing material for a thermoelectric cooler according to claim 4, characterized in that: Diluents include alcohol solvents and water.

7. The sealing method of a thermoelectric cooler according to claim 1, characterized in that: The soaking time is 0.1-2 hours respectively.

8. The sealing method of a thermoelectric cooler according to claim 1, characterized in that: The immersion method is pressurized immersion or centrifugal immersion, wherein the pressurized pressure is 2-10Mpa or the centrifugal speed is 500-2000 revolutions / min.

9. The sealing method of a thermoelectric cooler according to claim 1, characterized in that: The drying temperature is 80-300℃.

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