CN105024007B - A kind of method prepared by thermoelectricity thick film - Google Patents

Abstract

The present invention relates to a kind of methods prepared by thermoelectricity thick film.The thermoelectricity thick film ink of the present invention is made of thermoelectric material particle, polymer and organic solvent, the polymer ratio that the present invention uses, it does not fall off voluntarily after only drying the thermoelectricity thick film ink being printed on flexible substrate, there is the one side of viscose glue closely to be covered using high-temperature resistant membrane after thermoelectricity thick film ink is fully dry, the thermoelectricity thick film of acquisition function admirable is handled by isostatic cool pressing.Since the ratio of Inventive polymers is only to make to be printed on the minimum ratio not fallen off voluntarily after the thermoelectricity thick film ink on flexible substrate is dried; attachment and molding of the thermoelectricity thick film on flexible substrate are handled by the high-temperature resistant membrane and isostatic cool pressing that closely cover to be obtained; thermoelectric granules are abundant and are closely contacted; the conductivity s close to bulk is not only obtained to improve its thermoelectricity capability; and due to the protection of high-temperature resistant membrane, even if thermoelectricity thick film works long hours in room temperature to 230^oC is not easy to aoxidize.

Description

A method for preparing thermoelectric thick film

technical field

The invention relates to the technical field of material preparation, and more specifically, to a method for preparing a thermoelectric thick film.

Background technique

The temperature difference is an important parameter to determine the efficiency of thermoelectric power generation. The length of traditional block thermoelectric arms is limited, and it is not easy to establish a large temperature difference. Therefore, the production of long film-shaped thermoelectric arms is a feasible method to improve the efficiency of thermoelectric power generation. The preparation method of the conductor thick film is flexible in design, small in investment, low in cost, and reliable in performance.

A good thermoelectric material must have a high thermoelectric coefficient S and electrical conductivity s, so as to ensure a more obvious thermoelectric effect, and at the same time make the generated Joule heat small.

The attachment and molding of the thermoelectric thick film on the substrate requires the use of a polymer binder. The existence of the polymer matrix has little effect on the thermoelectric coefficient S, but it reduces the mutual contact between the thermoelectric thick film particles, and the through-current conduction decreases. The conductivity s of the thermoelectric thick film is reduced by 2 to 3 orders of magnitude, and the thermoelectric performance is obviously reduced.

Contents of the invention

In order to overcome at least one of the defects described in the above prior art, the present invention provides a method for preparing a thermoelectric thick film, which can not only obtain the electrical conductivity s of the bulk material to improve its thermoelectric performance, but also provide a thermoelectric thick film even if it works for a long time It is not easily oxidized at room temperature to 230°C.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a method for preparing a thermoelectric thick film. The thermoelectric thick film slurry is composed of thermoelectric material particles, polymers and organic solvents. The polymer ratio used in the present invention is only The thermoelectric thick film paste printed on the flexible substrate does not fall off after drying. After the thermoelectric thick film paste is fully dried, it is tightly covered with the adhesive side of the high temperature resistant film, and the thermoelectric thick film with excellent performance is obtained after cold isostatic pressing. The film and the thermoelectric particles are fully and closely contacted to obtain the conductivity s of the bulk material and protect the thermoelectric thick film from oxidation at room temperature to 230°C for a long time.

The thermoelectric material particles are P-type or N-type Bi2Te3-based alloys and other thermoelectric material particles with good thermoelectric properties near room temperature; the polymer is a polymer such as polystyrene or ethyl cellulose; the organic solvent is organic solvents such as toluene, limonene, terpineol; the flexible substrate is a substrate such as mica sheet that can withstand isostatic pressing and has low thermal conductivity and high temperature resistance; the printing is mask printing, screen printing, etc. Printing, spraying, printing and other printing methods; the polymer ratio used in the present invention is the lowest polymer ratio that only makes the thermoelectric thick film paste printed on the flexible substrate dry and does not fall off by itself; the high temperature resistant The film is a Kapton film (polyimide film), etc., which can withstand isostatic pressure treatment and has a high-temperature resistant film with adhesive on one side; One side of the thermoelectric thick film is covered, and the high temperature resistant film has no obvious bubbles after covering; the cold isostatic pressing treatment is to fully dry and tightly cover the thermoelectric thick film of the high temperature resistant film at room temperature for more than 1 MPa and hold the pressure for 10 Seconds or more isostatic pressure treatment; the electrodes are silver electrodes printed on flexible substrates, or electrodes such as copper foils and silver foils that are attached to the adhesive side of the high-temperature resistant film and then covered with the thermoelectric thick film.

The preparation method of the conductor thick film is flexible in design, small in investment, low in cost, and reliable in performance. Conductor thick films are usually prepared by adding conductive fillers such as metal particles to the polymer matrix. Conduction is achieved through conductive fillers. The conductive mechanism can be explained by the flow-through theory and tunneling effect: the flow-through theory believes that when the conductive filler is filled After the amount reaches the through-flow threshold, the metal particles that were originally in an independently dispersed state begin to contact each other to form a continuous network structure, making the conductive thick film conductive; while the tunneling effect takes into account the insulation of the polymer, it is considered that the metal particles on the Covered with an insulating organic film, the particles can only pass through the insulating layer through the tunneling effect between particles to achieve the effect of conduction.

The polymer ratio used in the present invention is such that the thermoelectric thick film paste printed on the flexible substrate does not fall off after drying. After the thermoelectric thick film paste is fully dried, it is tightly covered with the adhesive side of the high temperature resistant film. The thermoelectric thick film with excellent performance is obtained by isostatic pressing. Under the dual effects of polymer ratio and cold isostatic pressing treatment, the thermoelectric particles are fully and closely contacted, which can greatly improve the conduction effect of through-flow, obtain the conductivity s of the block, and improve its thermoelectric performance. In addition, due to Protection of high temperature resistant film, thermoelectric thick film is not easy to oxidize even if it works for a long time at room temperature to 230°C.

The manufacture of long film-shaped thermoelectric arms is a feasible method to improve the efficiency of thermoelectric power generation, and the preparation method of conductor thick film is suitable for the preparation of thermoelectric thick film. The attachment and molding of the thermoelectric thick film on the substrate requires the use of a polymer binder. The existence of the polymer matrix has little effect on the thermoelectric coefficient S, but it will reduce the mutual contact between the thermoelectric thick film particles and make the through-current conduction Decrease, the conductivity s of the thermoelectric thick film decreases by 2 to 3 orders of magnitude, and the thermoelectric performance decreases obviously.

Compared with the prior art, the beneficial effect is: the polymer ratio used in the present invention only makes the thermoelectric thick film paste printed on the flexible substrate printed with electrodes not fall off after drying, and the thermoelectric thick film paste is fully dried. The adhesive side of the high-temperature resistant film is used for tight covering, and a thermoelectric thick film with excellent performance is obtained after cold isostatic pressing. Because the ratio of the polymer of the present invention is the lowest ratio that only makes the thermoelectric thick film paste printed on the flexible substrate dry and does not fall off automatically, the adhesion and molding of the thermoelectric thick film on the flexible substrate are determined by the tightly covered high temperature resistant film and cold It is obtained by isostatic pressing, and the thermoelectric particles are fully and closely contacted, which not only obtains the electrical conductivity s of the bulk material to improve its thermoelectric performance, but also because of the protection of the high temperature resistant film, the thermoelectric thick film is not easy to work even at room temperature to 230°C for a long time oxidation.

Description of drawings

Fig. 1 is a schematic diagram of the process flow of the present invention.

Fig. 2 is the test data curve of the pyroelectric coefficient S of the P-type Bi2Te3-based alloy strip sample at room temperature.

Fig. 3 is a test data curve of P-type Bi2Te3-based alloy thermoelectric thick-film pyroelectric coefficient S at room temperature.

Detailed ways

The accompanying drawings are for illustrative purposes only, and should not be construed as limitations on this patent; in order to better illustrate this embodiment, certain components in the accompanying drawings will be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art It is understandable that some well-known structures and descriptions thereof may be omitted in the drawings. The positional relationship described in the drawings is for illustrative purposes only, and should not be construed as a limitation on this patent.

As shown in FIG. 1 , it is a schematic diagram of the process flow of the present invention, including a flexible substrate 1 , an electrode 2 , a mask 3 , a thermoelectric thick film 4 , and a high temperature-resistant film 5 .

Grinding thermoelectric material particles, polymers and organic solvents into thermoelectric thick film slurry with suitable viscosity, wherein the proportion of polymer used is only to make the thermoelectric thick film printed on the flexible substrate 1 printed with electrodes 2 using mask 3 The film 4 does not fall off by itself after drying. After the thermoelectric thick film slurry is fully dried, it is tightly covered with the adhesive side of the high temperature resistant film 5. After cold isostatic pressing, a thermoelectric thick film with excellent performance is obtained, and the thermoelectric particles are fully and tightly packed. Contact, to obtain the conductivity s of the bulk material and to protect the thermoelectric thick film from oxidation at room temperature to 230°C for a long time.

Example 1

The ratio of the polymer of the present invention is the lowest ratio that only makes the thermoelectric thick film slurry printed on the flexible substrate dry and does not fall off by itself through experiments. The adhesion and molding of the thermoelectric thick film on the flexible substrate are closely covered The high temperature resistant film and cold isostatic pressing treatment are obtained to verify that the present invention not only obtains the electrical conductivity s of the bulk material, thereby improving its thermoelectric performance:

As shown in FIG. 1 , it is a schematic diagram of the process flow of the present invention, including a flexible substrate 1 , an electrode 2 , a mask 3 , a thermoelectric thick film 4 , and a high temperature-resistant film 5 .

The length, width and thickness of P-type Bi2Te3-based alloy strip samples are 29.3mm, 3.5mm and 2.1mm respectively. At room temperature, using the four-terminal method, the sample is measured with a precision LCR automatic balancing bridge and an AC signal of 60Hz. The resistance of the sample is 0.116 ohms, and the calculated conductivity s is 343S/cm; at room temperature, one end of the strip sample is heated with a PTC heating sheet, and the potential difference DV at both ends of the sample is measured by a multi-channel inspection instrument. In the changing process, the slope is the thermoelectric coefficient S (as shown in Figure 2), which can be obtained from the data in Figure 2. The thermoelectric coefficient S is 382mV/K, and the calculated power factor S2s is 50mW/cm×K2.

The P-type Bi2Te3-based alloy strip sample is crushed and ground, passed through a 200-mesh sieve, mixed with ethyl cellulose and terpineol and ground into a thermoelectric thick-film slurry with a suitable viscosity, wherein ethyl cellulose and P-type Bi2Te3-based alloy The mass ratio of the powder is 0.52%. Using a film mask 3 with a thickness of 0.10 mm, the thermoelectric thick film paste is printed on the mica substrate 1 printed with silver electrodes 2. The thickness of the mica substrate is 0.20 mm. After the mask 3 is removed, the formed thermoelectric thick film 4 is obtained. After the thermoelectric thick film 4 is fully dried, it will not fall off automatically. Tightly cover, the thickness of Kapton (polyimide) film 5 is 0.055mm, then through the cold isostatic pressing treatment of 10MPa holding pressure 1 minute, obtain length, width, thickness (deduct mica substrate and Kapton film thickness) respectively 25.2mm, 4.0mm and 0.027mm P-type Bi2Te3-based alloy thermoelectric thick film. At room temperature, using the four-terminal method, the resistance of the sample was measured as 13.4 ohms with a precision LCR automatic balancing bridge with an AC signal of 60 Hz, and the calculated conductivity s was 174 S/cm. Due to the full and close contact of the thermoelectric particles, the electrical conductivity s of the thermoelectric thick film only drops by half compared with the P-type Bi2Te3-based alloy strip sample. At room temperature, one end of the thermoelectric thick film sample is heated with a PTC heating plate, and the multi-channel inspection instrument is used to measure the change process of the potential difference DV at both ends of the sample with the temperature difference DT between the two ends. The data curve is shown in Figure 3. The data can be obtained, and the thermoelectric coefficient S is 385mV/K. Compared with the P-type Bi2Te3-based alloy strip sample, the thermoelectric coefficient S of the thermoelectric thick film is almost unchanged, and the calculated power factor S2s is 26mW/cm×K2.

It can be seen from the above examples that the polymer ratio used in the present invention only prevents the thermoelectric thick film paste printed on the flexible substrate printed with electrodes from falling off after drying, and the thermoelectric thick film paste can be used after being fully dried. The side of the high-temperature film with adhesive is tightly covered, and a thermoelectric thick film with excellent performance is obtained after cold isostatic pressing. Under the dual effects of polymer ratio and cold isostatic pressing treatment, the thermoelectric particles are fully and closely contacted, the electrical conductivity s is 174S/cm, the thermoelectric coefficient S is 385mV/K, and the power factor S2s is 26mW/cm×K2, The thermoelectric thick film prepared by the invention obtains the electrical conductivity s of the bulk material, and has higher thermoelectric performance.

Apparently, the above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (3)

1. a kind of method prepared by thermoelectricity thick film, which is characterized in that thermoelectricity thick film ink is by thermoelectric material particle, polymer and has Solvent forms, and the mass ratio of the polymer and thermoelectric material that use is 0.52%, only makes to be printed on the flexible substrate for being printed on electrode On the drying of thermoelectricity thick film ink after do not fall off voluntarily, have viscose glue using high-temperature resistant membrane after thermoelectricity thick film ink is fully dry It is closely covered on one side, the thermoelectricity thick film for obtaining function admirable is handled by isostatic cool pressing, thermoelectric granules are fully and close Ground contacts, and obtains the conductivity s of bulk and thermoelectricity thick film is protected to work long hours in room temperature to 230 DEG C of not oxidizable effects.

2. method prepared by a kind of thermoelectricity thick film according to claim 1, it is characterised in that：The use high temperature resistant is thin Film has being covered towards thermoelectricity thick film when carrying out close covering to be high-temperature resistant membrane having viscose glue for viscose glue, and covers High-temperature resistant membrane is without apparent bubble after lid.

3. method prepared by a kind of thermoelectricity thick film according to claim 1, it is characterised in that：The isostatic cool pressing processing Be at room temperature to fully dry and closely covering high-temperature resistant membrane thermoelectricity thick film make 1MPa or more and pressurize 10 seconds or more etc. Static pressure processing；The electrode is the silver electrode being printed on flexible substrate or is sticked to high-temperature resistant membrane and has the one side of viscose glue, so Thermoelectric thick film is covered below copper foil, silver foil electrode.