Preparation method and application of wireless passive temperature sensor

Abstract

The invention relates to the technical field of temperature sensors, in particular to a preparation method and application of a wireless passive temperature sensor. The preparation method comprises the following steps: (1) preparing three kinds of 3D printing resin, wherein the first kind of printing resin is prepared by mixing BAPO and PEGDA; the second printing resin is prepared by adding TPO into a mixed solution of EA and PUA; the third printing material is prepared by mixing di (methacryloyloxyethyl) hydrogen phosphate and the second printing resin; (2) printing in a 3D printer; and (3) adsorbing a conductive material on the surface of the resonant ring, and pasting a copper foil adhesive tape on the bottom of the substrate to obtain the wireless passive temperature sensor. The preparation method provided by the invention is simple and low in cost, the prepared sensor has relatively high sensitivity, the temperature of the liner of the hydrogen storage cylinder is reflected according to the deviation condition of the resonant frequency of the sensor, and the potential safety hazard existing in a traditional wired detection mode is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature sensors, and in particular to a preparation method and application of a wireless passive temperature sensor. Background Art

[0002] Hydrogen energy is a recognized clean energy source with its abundant reserves, wide sources, zero greenhouse gas and pollutant emissions, high combustion calorific value, high power generation efficiency, convenient storage and transportation, and recyclability. Hydrogen storage and transportation are the bridge between hydrogen production and use. Low hydrogen storage density and high hydrogen transportation costs are key factors restricting the scale of development of the hydrogen energy industry. Type IV large-capacity tube bundle gas cylinders can greatly increase the hydrogen storage density of container transportation and reduce transportation costs due to their low body mass.

[0003] Type IV large-capacity tube bundle gas cylinder is a non-metallic carbon fiber reinforced composite gas cylinder, that is, the non-metallic gas cylinder liner is used as the base, the metal BOSS structure is wedged, and then the carbon fiber winding process is used for composite molding. Its maximum working pressure can reach 90MPa. It is very important to detect the temperature of the hydrogen storage bottle liner. The abnormal increase in the temperature of the hydrogen storage bottle liner may cause the hydrogen pressure to increase, which will increase the risk of explosion. By monitoring the temperature of the hydrogen storage bottle liner, problems can be discovered in time and measures can be taken to avoid potential dangers. At the same time, high temperature may cause aging and damage to the material of the hydrogen storage bottle liner, thereby reducing the service life of the hydrogen storage bottle. By monitoring the temperature of the liner, temperature abnormalities can be discovered in time, measures can be taken to reduce the aging rate of the material, and the service life of the hydrogen storage bottle can be extended. Monitoring the temperature of the hydrogen storage bottle liner is an important measure to ensure the safety of hydrogen storage and the quality of hydrogen. Regularly monitor the temperature of the hydrogen storage bottle liner to prevent potential dangers and maintain the normal operation of the hydrogen storage bottle.

[0004] At present, most methods for detecting the temperature inside hydrogen cylinders use wired detection. For example, the patent document with publication number CN201488828U proposes a vehicle-mounted hydrogen cylinder temperature test device, which can achieve multi-point simultaneous measurement to avoid measurement errors caused by the uneven temperature inside the cylinder. However, when calibrating the resistance sensor, the sensor needs to be removed from the cylinder valve, which will cause air to enter the hydrogen cylinder. Once air is filled into the hydrogen cylinder during use, an airtightness test and a nitrogen replacement test are required.

[0005] The patent document with publication number CN201828358U proposes a non-disassembly calibration device for a resistance-type temperature sensor for hydrogen cylinders. However, as a wired sensor, the connecting wire needs to be inserted into the cylinder. During the storage and transportation of the cylinder, it may be damaged due to squeezing, wear or other reasons, thereby causing electrical problems or short circuits. This undoubtedly poses a potential risk to the safety of the hydrogen cylinder, such as causing fire or explosion. Therefore, for the detection of the temperature inside the hydrogen cylinder, it is necessary to invent a wireless passive temperature sensor with high efficiency, low cost and excellent performance. Summary of the invention

[0006] The first object of the present invention is to provide a method for preparing a wireless passive temperature sensor, which is simple and easy to operate, has low production cost, and the prepared sensor has high sensitivity. The second object of the present invention is to provide an application of a wireless passive temperature sensor in measuring the temperature of the inner liner of a type IV hydrogen storage cylinder.

[0007] The present invention provides a method for preparing a wireless passive temperature sensor, comprising the following steps:

[0008] (1) preparing three 3D printing resins, wherein the first printing resin is prepared by mixing a photoinitiator with polyethylene glycol diacrylate; the second printing resin is prepared by adding a photoinitiator to a mixture of epoxy acrylate and aliphatic polyurethane acrylate; and the third printing material is prepared by mixing di(methacryloyloxyethyl) hydrogen phosphate with the second printing resin;

[0009] (2) using computer software to design a 3D graphic of the sensor, and importing the 3D graphic into a 3D printer, and sequentially pouring a first printing resin, a second printing resin, and a third printing resin into a material box of the printer for printing, wherein the portion printed by the first printing resin and the second printing resin is a base, and the portion printed by the third printing resin is a resonant ring;

[0010] (3) A conductive material is adsorbed on the surface of the resonant ring, and a copper foil tape is pasted on the bottom of the substrate to obtain a wireless passive temperature sensor.

[0011] Furthermore, the photoinitiator used in the first printing resin in step (1) is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; the amount of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide added is 1.8-2.2wt%, more preferably 2wt%. The absorption peak of the photoinitiator used is around 405nm, and has a high initiation efficiency in the system.

[0012] Furthermore, the preparation process of the second printing resin in step (1) is as follows: epoxy acrylate and aliphatic polyurethane acrylate are mixed in a mass ratio of 7:1-10:1 to obtain a mixed solution, and then 1.8-2.2wt% of a photoinitiator is added to the mixed solution and stirred evenly; more preferably, the mass ratio of epoxy acrylate to aliphatic polyurethane acrylate is 9:1, and the photoinitiator is added in an amount of 2wt%.

[0013] Furthermore, the photoinitiator is trimethylbenzoyl-diphenylphosphine oxide, the aliphatic polyurethane acrylate is EBECRYL 8413, and the epoxy acrylate is EBECRYL 113.

[0014] Furthermore, in the step (1), the mass ratio of di(methacryloyloxyethyl) hydrogen phosphate in the third printing resin to the second printing resin is 1:2-1:6; more preferably 1:4.

[0015] Furthermore, the shape of the substrate in step (2) is a rectangle, and the resonant ring is a four-opening resonant ring.

[0016] Furthermore, the conductive material in step (3) is silver nanosheets, carbon nanotubes, graphene or metal nanowires.

[0017] Furthermore, the conductive material in step (3) is silver nanosheets; the process of adsorbing the silver nanosheets on the surface of the resonance ring is as follows: pouring the silver nanosheets and hexadecyltrimethylammonium bromide into deionized water, obtaining a dispersion after ultrasonication, immersing the printed product in the dispersion to deposit the silver nanosheets on the surface of the resonance ring, then rinsing with deionized water, and finally drying with flowing air at room temperature.

[0018] Furthermore, the concentration of the silver nanosheets in the dispersion is 1.5-3.5 mg / mL, and the concentration of cetyltrimethylammonium bromide is 1.8-2.2 mg / mL; more preferably, the concentration of the silver nanosheets in the dispersion is 3 mg / mL, and the concentration of cetyltrimethylammonium bromide is 2 mg / mL.

[0019] The present invention also provides an application of the above-mentioned wireless passive temperature sensor in detecting the temperature of the inner liner of a hydrogen storage cylinder. When detecting the temperature of the inner liner of a hydrogen storage cylinder, the wireless passive temperature sensor is attached to the inner liner of the hydrogen storage cylinder, an interrogation antenna is placed outside the hydrogen storage cylinder, and the interrogation antenna is connected to a network analyzer to read the resonant frequency of the wireless passive temperature sensor, and reflect the temperature of the inner liner of the hydrogen storage cylinder according to the offset of the resonant frequency.

[0020] In summary, compared with the prior art, the present invention has the following advantages:

[0021] The technical solution provided by the present invention adopts a 3D printing method, two types of printing resins are used in the base part, a material with a metamaterial structure is used in the resonant ring part, and a conductive material is adsorbed on the metamaterial to prepare a wireless passive temperature sensor. The preparation method is simple and easy to operate, low cost, easy to achieve large-scale production, and the prepared sensor has high sensitivity. When detecting the temperature of the inner liner of the hydrogen storage cylinder, the wireless passive temperature sensor is attached to the inner liner of the hydrogen storage cylinder, an interrogation antenna is placed outside the hydrogen storage cylinder, and the interrogation antenna is connected to a network analyzer to read the resonant frequency of the wireless passive temperature sensor, and the temperature of the inner liner of the hydrogen storage cylinder is reflected according to the offset of the resonant frequency, thereby solving the safety hazards existing in the traditional wired detection method. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 The present invention is a flow chart of the preparation of the wireless passive temperature sensor;

[0024] Figure 2 This is a physical picture of the wireless passive temperature sensor prepared by the present invention;

[0025] Figure 3 This is a test installation diagram of the wireless passive temperature sensor prepared by the present invention;

[0026] Figure 4 The frequency response of the sensor prepared by the present invention at different temperatures;

[0027] Figure 5 This is a sensitivity analysis diagram of the wireless passive temperature sensor prepared by the present invention.

[0028] Marking Description: Figure 2 1, 2, and 3 correspond to the parts printed by the first printing resin, the second printing resin, and the third printing resin, respectively. DETAILED DESCRIPTION

[0029] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0031] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] Example

[0033] A method for preparing a wireless passive temperature sensor, such as Figure 1 As shown, the specific process is as follows:

[0034] (1) First, three 3D printing resins were prepared at room temperature, wherein the first printing resin was prepared by adding 0.4 g of a photoinitiator, phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide (BAPO), into 19.6 g of polyethylene glycol diacrylate (PEGDA) and mixing them evenly;

[0035] The second printing resin is prepared by magnetically oscillating and mixing 17.28g of epoxy acrylate (EA) and 1.92g of aliphatic polyurethane acrylate (PUA) for 30 minutes to obtain a mixed solution, and then adding 0.4g of a photoinitiator trimethylbenzoyl-diphenylphosphine oxide (TPO) to the mixed solution and mixing evenly; the aliphatic polyurethane acrylate is EBECRYL8413 of Allnex, and the epoxy acrylate is EBECRYL 113 of Allnex;

[0036] The third printing resin is obtained by uniformly mixing 2 g of di(methacryloyloxyethyl) hydrogen phosphate and 8 g of the second printing resin.

[0037] (2) Use the software Solidworks to design the 3D graphics of the sensor, slice the drawn .stl format file, and then import it into the B9 Create software of B9 Creations. Then set the printing parameters in the DLP 3D printer (B9 Creations, B9 Core550), such as: the color of the material is white, and the exposure is 20. Pour the first printing resin, the second printing resin, and the third printing resin into the material box in turn, and print. The printed product is as follows Figure 2 As shown, the part printed by the first printing resin is located at the bottom, the part printed by the third printing resin is located at the top, the parts printed by the first printing resin and the second printing resin serve as the base, and the part printed by the third printing resin serves as the resonant ring. The size of the finished product printed in this embodiment is 26×26×4.2mm, wherein the thickness of 1 is 1mm, the thickness of 2 is 3mm, and the thickness of 3 is 0.2mm. The resonant ring in this embodiment is a four-open resonant ring, which is obtained by opening four openings in a square resonant ring and cutting off a small square at the four corners. The shape and size of the resonant ring can be changed so that the resonant frequency of the sensor is within the required frequency range.

[0038] (3) Adsorbing a conductive material on the surface of the resonant ring. The conductive material in this embodiment is silver nanosheets. At room temperature, pour 0.06g of silver nanosheets (AgNSs) and 0.04g of hexadecyltrimethylammonium bromide (CTAB) into deionized water, and disperse the solution for 5 minutes under the power of 100w of the ultrasonic probe. Obtain a dispersion liquid, in which the concentration of AgNSs is 3mg / mL and the concentration of CTAB is 2mg / mL. Soak the printed product in the positively charged dispersion liquid for 10 minutes to achieve selective deposition of AgNSs on the surface of the resonant ring; then rinse with deionized water, dry with flowing air at room temperature for a few minutes, and after drying, stick copper foil tape on the bottom of the substrate to obtain a wireless passive temperature sensor. The deposition thickness of AgNSs can be changed by adjusting the immersion time in the dispersion liquid.

[0039] The wireless passive temperature sensor prepared in this embodiment is applied to the temperature measurement of the inner tank of a type IV large-capacity hydrogen storage cylinder. When detecting the temperature of the inner tank of the hydrogen storage cylinder, Figure 3 As shown, the wireless passive temperature sensor is attached to the inner liner of the hydrogen storage cylinder using copper foil tape, an interrogation antenna is placed 1 cm away from the outer surface of the hydrogen storage cylinder, and the interrogation antenna is connected to a network analyzer to read the resonant frequency of the wireless passive temperature sensor. The temperature of the inner liner of the hydrogen storage cylinder is reflected by the offset of the resonant frequency.

[0040] The working principle of the wireless passive temperature sensor prepared by the preparation method provided by the present invention is that the change of the dielectric constant of the substrate material at different temperatures causes the resonant frequency of the sensor to shift; since the dielectric constant of the substrate material changes significantly under temperature changes, the frequency shift is also obvious (such as Figure 4 As shown), the sensor has a higher sensitivity (as shown Figure 5 shown).

[0041] The sensitivity GF of the sensor is obtained by the following formula:

[0042]

[0043] where f Tem is the resonant frequency of the sensor at a certain temperature; f 0 is the resonant frequency of the sensor at 40°C; ΔT is the temperature difference between the test and the initial temperature.

[0044] Figure 4 The frequency here refers to the peak value of each line at different temperatures. Each line corresponds to a curve at a temperature. As the temperature rises, the curve will shift to the right. During the test phase, the network analyzer is connected to the interrogation antenna to transmit a 100M-8GHz sweep signal. The frequency indicates the feedback of the sensor signal at this frequency. S11 is regarded as a dimensionless parameter of electromagnetic waves and is used to nominally measure the signal strength of the sensor. Figure 4 It can be clearly seen that the feedback frequency is different at different temperatures.

[0045] Figure 5 for Figure 4 Derivatives of ● The curve is Figure 4 The feedback frequency at each temperature is extracted to form a curve. Because the change of the sensor is determined by the feedback frequency, the change of frequency is used as the sensitivity of the sensor; ▲The curve is Figure 4 The expression curve of the value extracted from the S11 peak; -0.610MHz / ℃ means the sensitivity of the sensor in terms of frequency.

[0046] In the range of 40℃ to 90℃, the frequency shift range of the sensor is 30.5MHz, and the sensitivity in this temperature range is -0.610MHz / ℃.

[0047] Most of the existing methods for detecting the temperature inside hydrogen storage cylinders use wired detection methods. During the storage and transportation of the cylinders, they may be damaged due to squeezing, wear or other reasons, thereby causing electrical problems or short circuits, posing potential risks to the safety of the hydrogen cylinders.

[0048] There is also a temperature measurement method in the prior art, which is to use an infrared thermometer to estimate the data inside the bottle by measuring the temperature externally. However, since the temperature gradients of the heterogeneous materials of the composite gas cylinder are different, the measurement error between the infrared temperature measurement and the true value is large, and energy will be generated, and it cannot be guaranteed to be safe when used in a hydrogen environment.

[0049] The present invention uses DLP-3D printing to prepare a wireless passive temperature sensor. The wireless passive sensing method eliminates potential safety hazards, can be directly attached to the bottle body, does not have the adverse effect of judging the true value by infrared temperature, and does not affect the normal use of the hydrogen storage cylinder. In a hydrogen environment, its energy feedback is small, does not affect the normal use of hydrogen, and will not cause explosion accidents. At the same time, the 3D printing preparation method is relatively convenient, low cost, and can be mass-produced; and the prepared sensor has a high sensitivity. This wireless passive sensor based on a resonant ring has broad application prospects in the field of internal temperature detection of hydrogen cylinders.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a wireless passive temperature sensor, characterized in that: The following steps are involved: (1) preparing three 3D printing resins, wherein the first printing resin is prepared by mixing a photoinitiator with polyethylene glycol diacrylate; the second printing resin is prepared by adding a photoinitiator to a mixture of epoxy acrylate and aliphatic polyurethane acrylate; and the third printing material is prepared by mixing di(methacryloyloxyethyl) hydrogen phosphate with the second printing resin; (2) using computer software to design a 3D graphic of the sensor, and importing the 3D graphic into a 3D printer, and sequentially pouring a first printing resin, a second printing resin, and a third printing resin into a material box of the printer for printing, wherein the portion printed by the first printing resin and the second printing resin is a base, and the portion printed by the third printing resin is a resonant ring; (3) A conductive material is adsorbed on the surface of the resonant ring, and a copper foil tape is pasted on the bottom of the substrate to obtain a wireless passive temperature sensor.

2. The preparation method according to claim 1, characterized in that: The photoinitiator used in the first printing resin in step (1) is phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide; the addition amount of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide is 1.8-2.2wt%.

3. The preparation method according to claim 1, characterized in that: The preparation process of the second printing resin in step (1) is as follows: epoxy acrylate and aliphatic polyurethane acrylate are mixed in a mass ratio of 7:1-10:1 to obtain a mixed solution, and then 1.8-2.2wt% of a photoinitiator is added to the mixed solution and stirred evenly.

4. The preparation method according to claim 3, characterized in that: The photoinitiator is trimethylbenzoyl-diphenylphosphine oxide, the aliphatic polyurethane acrylate is EBECRYL 8413, and the epoxy acrylate is EBECRYL113.

5. The preparation method according to claim 1, characterized in that: In the step (1), the mass ratio of di(methacryloyloxyethyl) hydrogen phosphate in the third printing resin to the second printing resin is 1:2-1:

6.

6. The preparation method according to claim 1, characterized in that: The shape of the substrate in the step (2) is a rectangle, and the resonant ring is a four-opening resonant ring.

7. The preparation method according to claim 1, characterized in that: The conductive material in step (3) is silver nanosheets, carbon nanotubes, graphene or metal nanowires.

8. The preparation method according to claim 7, characterized in that: The conductive material in step (3) is silver nanosheets; the process of adsorbing the silver nanosheets on the surface of the resonance ring is as follows: pouring the silver nanosheets and hexadecyltrimethylammonium bromide into deionized water, obtaining a dispersion after ultrasonic treatment, immersing the printed product in the dispersion to deposit the silver nanosheets on the surface of the resonance ring, then rinsing with deionized water, and finally drying with flowing air at room temperature.

9. The preparation method according to claim 8, characterized in that: The concentration of the silver nanosheets in the dispersion is 1.5-3.5 mg / mL, and the concentration of hexadecyltrimethylammonium bromide is 1.8-2.2 mg / mL.

10. An application of a wireless passive temperature sensor prepared by the method according to any one of claims 1 to 9 in detecting the temperature of the inner tank of a hydrogen storage cylinder, characterized in that: When detecting the temperature of the inner liner of the hydrogen storage cylinder, the wireless passive temperature sensor is attached to the inner liner of the hydrogen storage cylinder, an interrogation antenna is placed outside the hydrogen storage cylinder, and the interrogation antenna is connected to a network analyzer to read the resonant frequency of the wireless passive temperature sensor, and reflect the temperature of the inner liner of the hydrogen storage cylinder according to the offset of the resonant frequency.

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