Ion-doped thermoelectric thin film, preparation method thereof and application of ion-doped thermoelectric thin film in temperature sensor

Abstract

The invention provides an ion-doped thermoelectric thin film, a preparation method thereof and application of the ion-doped thermoelectric thin film in a temperature sensor, and belongs to the technical field of temperature sensors. The preparation method comprises the following steps: mixing and stirring N-methyl pyrrolidone and a polyvinylidene fluoride-hexafluoropropylene copolymer to obtain a solution A; mixing and stirring the solution A, 1-butyl-1-methyl pyrrolidinium bis (sulfonyl fluoride) imine, 1-methyl-1-propyl piperidinium bis (sulfonyl fluoride) imine and lithium tetrafluoroborate to obtain a solution B; placing the solution B on a mold, and carrying out vacuum drying to obtain the ion-doped thermoelectric thin film; by doping the lithium salt, the organic polymer is subjected to amorphous transition, the sensing stability is improved, the sensing response time is shortened, and the performance of the sensor is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensor devices, and in particular relates to an ion-doped thermoelectric film and a preparation method thereof and an application in a temperature sensor. Background Art

[0002] Accurate detection of heat flow and temperature is required in both industrial and daily life fields. Thermoelectric devices based on the Seebeck effect can detect heat flow and temperature accurately under certain temperature differences. Δ Thermal voltage generated by carrier diffusion at T Δ V( Δ V=V hot -Vc old ), providing a feasible and direct solution for directly converting heat into electricity. It also has temperature sensing capabilities.

[0003] The Seebeck coefficient (or thermal power, = -ΔV / □T) of electronic high-performance thermoelectric materials ranges from tens to hundreds of microvolts per Kelvin. The microvolt-level Seebeck coefficient of electronic thermoelectric materials greatly limits their thermal sensitivity. In thermopile configurations such as thermoelectric temperature sensors, a large number of units must be integrated in order to amplify the signal output, which usually leads to complex manufacturing and high costs. At the same time, insulators with high Seebeck coefficients have low conductivity, resulting in large measurement noise. It is a challenge to significantly increase the Seebeck coefficient without sacrificing other important thermoelectric properties (such as conductivity).

[0004] Therefore, ionic thermoelectric materials came into being. In the reports in the past five years, ionic thermoelectric materials have a Seebeck coefficient, i.e., thermal power, in the millivolt range. Compared with electronic thermoelectric materials, greatly enhanced thermal power and reasonable ionic conductivity can achieve more sensitive temperature monitoring, especially for small temperature difference occasions, such as human body thermal monitoring and battery temperature measurement. Unlike traditional electronic thermoelectric materials, which are rigid bulk metals or semiconductors, ionic thermoelectric materials have the advantages of flexibility and easy manufacturing. Ionic thermoelectric materials are good candidates in the fields of healthcare and wearable thermal sensors.

[0005] Therefore, there is an urgent need for a thin film material for temperature sensors that has stable thermovoltage, high corresponding sensitivity, and resistance to environmental interference. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide an ion-doped thermoelectric film, a preparation method thereof and an application in a temperature sensor. The sensor prepared with the film has a thermovoltage response at the millivolt level. The thermovoltage of the ion thermoelectric film material is stable and has the ability to recover after environmental interference under a fixed temperature difference, thereby achieving stable and timely temperature monitoring.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] In a first aspect, the present invention provides a method for preparing an ion-doped thermoelectric film, comprising the following steps:

[0009] 1) mixing N-methylpyrrolidone and polyvinylidene fluoride-hexafluoropropylene copolymer and stirring to obtain solution A;

[0010] 2) mixing solution A, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide and lithium tetrafluoroborate and stirring to obtain solution B;

[0011] 3) Placing solution B on a mold and vacuum drying it to obtain an ion-doped thermoelectric film.

[0012] Preferably, in step 1), the mass ratio of N-methylpyrrolidone to polyvinylidene fluoride-hexafluoropropylene copolymer is 5-47:1-3.

[0013] Preferably, the mixing and stirring in step 1) is carried out at a temperature of 60-80° C. and for a time of 8-12 hours.

[0014] Preferably, in step 2), the mass ratio of solution A, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide, and lithium tetrafluoroborate is (20-80):(5-80):(5-80):(5-50).

[0015] Preferably, the mixing and stirring temperature in step 2) is 20-30° C. and the time is 6-12 h.

[0016] Preferably, the vacuum drying in step 3) is carried out at a temperature of 50-80°C and for a time of 8-16 hours.

[0017] In a second aspect, the present invention provides an ion-doped thermoelectric film prepared by the above-mentioned preparation method.

[0018] In a third aspect, the present invention provides application of the above-mentioned ion-doped thermoelectric film in a temperature sensor.

[0019] In a fourth aspect, the present invention provides a temperature sensor comprising the above-mentioned ion-doped thermoelectric film, a fixed electrode, and a temperature measuring electrode; the ion-doped thermoelectric film is an intermediate layer, and the fixed electrode and the temperature measuring electrode form a sandwich structure on both sides of the ion-doped thermoelectric film.

[0020] Preferably, the electrode material is copper, silver or graphite.

[0021] Contains at least the following beneficial technical effects:

[0022] (1) The ion-doped thermoelectric film obtained by the present invention has a thermovoltage at the millivolt level;

[0023] (2) The voltage curve of the ion-doped thermoelectric film obtained by the present invention in response to temperature difference is stable and gentle, and there will be no phenomenon such as inclined rise or fall and fluctuation.

[0024] (3) The ion-doped thermoelectric thin film material obtained by the present invention is very flexible and thin, and does not take up too much space when collecting temperature differences.

[0025] (4) The ion-doped thermoelectric thin film material obtained by the present invention has a certain anti-freezing ability and can still work at minus 30 degrees Celsius. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the SEM image of the thermoelectric film prepared in Example 1.

[0027] Figure 2 This is the SEM image of the thermoelectric film prepared in Comparative Example 1.

[0028] Figure 3 This is a graph showing the change in thermal voltage of the thermoelectric film prepared in Example 1 with temperature.

[0029] Figure 4 This is a graph showing the change in thermal voltage of the thermoelectric film prepared in Comparative Example 1 with temperature.

[0030] Figure 5 Concept diagram for sensor array layout.

[0031] Figure 6 Temperature distribution diagram of the sensor array. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0033] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0034] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the main idea or essential features of the present invention. Therefore, from all points of view, the embodiments should be regarded as exemplary and non-restrictive, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention, and any reference numerals in the claims should not be regarded as limiting the claims involved.

[0035] In addition, it should be understood that although this specification is described according to the implementation modes, not every implementation mode includes only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. These other implementation modes are also covered within the protection scope of the present invention.

[0036] It should also be understood that the specific embodiments described above are only used to explain the present invention, and the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the protection scope of the present invention / invention.

[0037] Example 1

[0038] This embodiment provides an ion-doped thermoelectric film, and the preparation method is as follows:

[0039] 1) N-methylpyrrolidone and polyvinylidene fluoride-hexafluoropropylene copolymer were mixed in a mass ratio of 9:1 and stirred at 60° C. for 12 hours to prepare solution A.

[0040] 2) Solution A, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide, and lithium tetrafluoroborate were mixed and stirred to obtain solution B in a mass ratio of 27.3:31.8:31.8:9.1, and then stirred at 25° C. for 8 h to prepare solution B.

[0041] 3) Solution B is dripped onto the mold with a dropper, and the mold filled with solution B is moved to a vacuum drying oven and vacuum dried at 60° C. for 12 h. After drying, the obtained film is removed from the mold and cut into a certain shape to obtain a thermoelectric film.

[0042] Example 2

[0043] This embodiment provides an ion-doped thermoelectric film, and the preparation method is as follows:

[0044] 1) N-methylpyrrolidone and polyvinylidene fluoride-hexafluoropropylene copolymer were mixed in a mass ratio of 5:1 and stirred at 80° C. for 8 h to prepare solution A.

[0045] 2) Solution A, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide, and lithium tetrafluoroborate were mixed and stirred to obtain solution B in a mass ratio of 20:5:5:5, and then stirred at 30° C. for 12 hours to prepare solution B.

[0046] 3) Solution B is dripped onto the mold with a dropper, and the mold filled with solution B is moved to a vacuum drying oven and vacuum dried at 80° C. for 16 h. After drying, the obtained film is removed from the mold and cut into a certain shape to obtain a thermoelectric film.

[0047] Example 3

[0048] This embodiment provides an ion-doped thermoelectric film, and the preparation method is as follows:

[0049] 1) N-methylpyrrolidone and polyvinylidene fluoride-hexafluoropropylene copolymer were mixed in a mass ratio of 47:3 and stirred at 70° C. for 10 hours to prepare solution A.

[0050] 2) Solution A, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide, and lithium tetrafluoroborate were mixed and stirred to obtain solution B in a mass ratio of 80:80:80:50, and then stirred at 20° C. for 6 hours to prepare solution B.

[0051] 3) Solution B is dripped onto the mold with a dropper, and the mold filled with solution B is moved to a vacuum drying oven and vacuum dried at 70° C. for 8 h. After drying, the obtained film is removed from the mold and cut into a certain shape to obtain a thermoelectric film.

[0052] Comparative Example 1

[0053] The preparation method of this comparative example is the same as that of Example 1, except that lithium tetrafluoroborate is not added in step 2).

[0054] Test Example 1

[0055] The surfaces of the thermoelectric films prepared in Example 1 and Comparative Example 1 were observed. The electron microscope scanning images of the thermoelectric films in Example 1 and Comparative Example 1 are as follows: Figure 1 , Figure 2 shown.

[0056] Experimental Example 2

[0057] The thermoelectric films prepared in Example 1 and Comparative Example 1 were tested for temperature difference and thermovoltage. Figure 3-Figure 4 It can be seen that compared with Comparative Example 1, the thermovoltage stability of Example 1 is significantly improved.

[0058] Experimental Example 3

[0059] The sensor is placed on the designed integrated circuit (16 units are integrated on the integrated circuit, and each unit is independent of each other), and the sensor is packaged by a vacuum sealer to successfully make the sensor. Figure 5 , Figure 6 .

[0060] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing an ion-doped thermoelectric thin film, characterized in that: The following steps are involved: 1) mixing N-methylpyrrolidone and polyvinylidene fluoride-hexafluoropropylene copolymer and stirring to obtain solution A; 2) mixing solution A, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide and lithium tetrafluoroborate and stirring to obtain solution B; 3) Placing solution B on a mold and vacuum drying it to obtain an ion-doped thermoelectric film.

2. The preparation method according to claim 1, characterized in that: In the step 1), the mass ratio of N-methylpyrrolidone to polyvinylidene fluoride-hexafluoropropylene copolymer is 5-47:1-3.

3. The preparation method according to claim 1, characterized in that: The mixing and stirring in step 1) is performed at a temperature of 60-80° C. and for a time of 8-12 hours.

4. The preparation method according to claim 1, characterized in that: In the step 2), the mass ratio of solution A, 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide, 1-methyl-1-propylpiperidinium bis(fluorosulfonyl)imide and lithium tetrafluoroborate is 20-80:5-80:5-80:5-50.

5. The preparation method according to claim 1, characterized in that: The mixing and stirring temperature in step 2) is 20-30° C. and the time is 6-12 hours.

6. The preparation method according to claim 1, characterized in that: The vacuum drying temperature in step 3) is 50-80°C and the time is 8-16h.

7. The ion-doped thermoelectric thin film prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the ion-doped thermoelectric film according to claim 7 in a temperature sensor.

9. A temperature sensor, characterized in that: It comprises the ion-doped thermoelectric film, fixed electrode and temperature measuring electrode as described in claim 7; the ion-doped thermoelectric film is the middle layer, and the fixed electrode and the temperature measuring electrode form a sandwich structure on both sides of the ion-doped thermoelectric film.

10. The temperature sensor according to claim 9, characterized in that The electrode materials are copper, silver and graphite.

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