A thermoelectric-pyroelectric hybrid power generation device and preparation method thereof

Abstract

The present invention discloses a thermoelectric-pyroelectric hybrid power generation device and a preparation method thereof, which are composed of a coupling of a thermoelectric material and a photothermal pyroelectric power generation material. The thermoelectric-pyroelectric hybrid power generation device of the present invention can not only collect the temperature difference generated at the upper and lower ends of the device under sunlight irradiation for power supply, but also effectively collect the energy of the temperature fluctuation on its surface, so as to realize the full recovery and conversion of fluctuating energy. The thermoelectric-pyroelectric hybrid power generation device prepared by the present invention is an efficient, practical and intelligent heat energy recovery device, which realizes the full recovery and utilization of fluctuating heat energy. The design and preparation of the hybrid generator are simple and easy for industrial production and large-scale promotion.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy conversion functional devices, and particularly relates to a thermoelectric-pyroelectric hybrid power generation device and its application. Background Art

[0002] Fluctuating thermal energy is ubiquitous in life, such as the change of light heat generated by sunlight over time, the temperature fluctuation generated by air flow, the heat absorption or heat release process during the dissolution of chemical substances, etc. These fluctuating thermal energies can usually be recycled using pyroelectric technology. This technology can convert the energy of fluctuating temperature into useful electrical energy. However, its output power is small and the conversion efficiency is low. In order to obtain a higher output, additional mechanical devices are often required, which increases its cost, and a single pyroelectric generator cannot fully recover thermal energy, resulting in energy waste. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: In order to overcome the above deficiencies, there is an urgent need to develop a coupled thermal energy collection device that can collect different types of thermal energy and convert it into electrical energy, make full use of the wasted energy, and at the same time effectively improve the output of the thermal energy recovery device.

[0004] The technical solution of the present invention is: A thermoelectric-pyroelectric hybrid power generation device, including a thermoelectric device layer, a pyroelectric power generation material layer, and a photothermal material layer. The pyroelectric power generation material layer is fixed at the heating end of the thermoelectric device layer, and the photothermal material layer is fixed on the pyroelectric power generation material layer.

[0005] Further, the photothermal material layer is a composite material formed by mixing CNT and rGO-PEI, which exhibits better photothermal performance because the synergistic effect between the two reduces the interfacial thermal resistance and at the same time forms a more efficient thermal conduction network.

[0006] This composite material is prepared by the following method: CNT and rGO-PEI are ultrasonically dispersed in deionized aqueous solution, and then a layer of CNT-rGO-PEI layer is formed on the filter paper by suction filtration and dried at room temperature to obtain the CNT-rGO-PEI photothermal material layer.

[0007] Further, the mass ratio of CNT to rGO-PEI is 4:1, aiming at that the mixing ratio at this time will have the optimal photothermal performance, and its photothermal temperature can reach 61.3 °C, which is 5.6 and 5.3 °C higher than that of rGO-PEI and CNT respectively.

[0008] Further, the pyroelectric power generation material layer is a polarized aluminum-plated PVDF film. Preferably, the thickness of the polarized aluminum-plated PVDF film is 30 μm. The purpose of selecting a film with this thickness is that a thinner film will have better heat transfer performance and can effectively transfer heat to the surface of the thermoelectric device.

[0009] Further, it also includes a heat insulation sleeve wrapped around the heat generation end of the thermoelectric device layer.

[0010] The present invention also discloses a preparation method of a thermoelectric-pyroelectric hybrid generator, including the following steps:

[0011] (1) Ultrasonically disperse CNT and rGO-PEI in deionized aqueous solution, and then form a CNT-rGO-PEI layer on the filter paper by suction filtration and dry it at room temperature to obtain a CNT-rGO-PEI photothermal material layer;

[0012] (2) Transfer the photothermal material layer by transparent tape and connect it with the polarized aluminum-plated PVDF film to make a photothermal pyroelectric generator;

[0013] (3) Physically fix the photothermal pyroelectric generator on the heat generation end of the thermoelectric device by tape, and add a heat insulation sleeve on the surface of the thermoelectric device to obtain a thermoelectric-pyroelectric hybrid generator.

[0014] Further, the mass ratio of CNT to rGO-PEI in the photothermal material layer is 4:1. The purpose is that the mixing ratio at this time will have the optimal photothermal performance, and its photothermal temperature can reach 61.3 °C, which is 5.6 and 5.3 °C higher than that of rGO-PEI and CNT respectively.

[0015] Preferably, in step (1), 12.8 mg of CNT powder and 3.2 mg of rGO-PEI powder are respectively weighed and ultrasonically dispersed in 16 mL of deionized water. The mixed solution is evenly dropped on the surface of the filter paper and ensure that the surface mass content of the material is 1mg / cm 2 , carry out suction filtration, and dry at room temperature for 2h.

[0016] In step (2), the thickness of the polarized aluminum-plated PVDF film is 30 μm. The purpose of selecting a film with this thickness is that a thinner film will have better heat transfer performance and can effectively transfer heat to the surface of the thermoelectric device.

[0017] The photothermal pyroelectric generator is physically fixed on the heat generation end of the thermoelectric device by tape. The purpose is that the photothermal material on the surface of the photothermal pyroelectric generator can effectively absorb sunlight and convert it into heat energy, thereby making the upper and lower ends of the thermoelectric device have a greater temperature difference, thus improving its performance output.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The thermoelectric-pyroelectric hybrid generator device of the present invention can not only collect the temperature difference generated at the upper and lower ends of the device under sunlight irradiation for power supply, but also effectively collect the energy of the temperature fluctuations on its surface, thereby realizing the full recovery and conversion of fluctuating energy. Under one sunlight (0.1 W / cm 2 ), the open-circuit voltage and short-circuit current of the thermoelectric generator of this composite generator device can reach 0.15 V and 27 mA respectively, which are 68% and 67% higher than those of the pure thermoelectric device without coupling the pyroelectric generator in terms of current and voltage. In addition, the photothermal pyroelectric generator can capture the energy of the fluctuating temperature on the surface of the device, and its open-circuit voltage and short-circuit current can reach 30 V and 82 nA respectively, which are 50% and 37% higher than those of the pure photothermal pyroelectric device without coupling the thermoelectric device in terms of current and voltage. The output power of the prepared hybrid generator device is 269% higher than that of a single generator device. This hybrid thermal energy recovery generator device can also effectively collect other fluctuating energies, such as the heat released during the dissolution of sodium hydroxide. In addition, this functional device can also realize the function of self-sensing the surface temperature change of the thermoelectric material by detecting the change of the electric signal of the pyroelectric layer. The thermoelectric-pyroelectric hybrid generator device prepared by the present invention is an efficient, practical and intelligent thermal energy recovery device, which realizes the full recovery and utilization of fluctuating thermal energy. The design and preparation of this hybrid generator are simple and easy for industrial production and large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the thermoelectric-pyroelectric hybrid generator device prepared by the present invention;

[0021] Figure 2 Optimization process of the optimal mixing ratio of the photothermal material in the thermoelectric-pyroelectric hybrid generator device prepared by the present invention;

[0022] Figure 3 Optimization process of the optimal thickness of the pyroelectric material in the thermoelectric-pyroelectric hybrid generator device prepared by the present invention;

[0023] Figure 4 Power generation performance display of the thermoelectric device part of the thermoelectric-pyroelectric hybrid generator device prepared by the present invention;

[0024] Figure 5 Power generation performance display of the photothermal pyroelectric generator part of the thermoelectric-pyroelectric hybrid generator device prepared by the present invention;

[0025] Figure 6 Test situation where the device prepared by the present invention can be used for instant and effective charging of a capacitor;

[0026] Figure 7 Schematic diagram of the device prepared according to the present invention for collecting heat released by the dissolution of sodium hydroxide

[0027] Figure 8 Schematic diagram of the device prepared according to the present invention for temperature self-sensing Detailed implementation mode

[0028] Unless otherwise specified, the experimental methods in the following examples are all conventional methods. Unless otherwise specified, the test materials used in the following examples are all obtained by purchasing from commercial channels

[0029] Example 1 Preparation of a thermoelectric-pyroelectric hybrid generator

[0030] CNT (carbon nanotube) and rGO-PEI (reduced graphene oxide modified with polyethyleneimine) were ultrasonically dispersed in deionized aqueous solution, and then a layer of CNT-rGO-PEI layer was formed on the filter paper by suction filtration and dried at room temperature to obtain a CNT-rGO-PEI photothermal material layer

[0031] In the experiment, the mass ratios of CNT to rGO-PEI were set to 0:1, 1:1, 2:1, 3:1, 4:1, 5:1, and 1:0 respectively. The obtained photothermal material layer was monitored by an infrared camera for its photothermal temperature under sunlight (0.1W / cm 2 ) irradiation for 30 s to obtain the mixing ratio of CNT and rGO-PEI with the optimal photothermal performance, as Figure 2 shown; the best mixing ratio of CNT to rGO-PEI is 4:1, and its photothermal temperature can reach 61.3 °C

[0032] The CNT-rGO-PEI photothermal material layer was transferred by transparent tape and connected to a polarized aluminized PVDF film to make a photothermal pyroelectric generator. The photothermal pyroelectric generator was physically fixed at the heating end of the thermoelectric device by tape, and a heat-insulating sleeve was sleeved on the end of the thermoelectric device facing the sun. The heat-insulating sleeve can be but is not limited to being made of plastic foam and both ends are open. A thermoelectric-pyroelectric hybrid generator was obtained

[0033] The structure is as Figure 1 shown. The whole device includes a thermoelectric device layer 1, a pyroelectric power generation material layer 2, and a photothermal material layer 3. The pyroelectric power generation material layer 2 is fixed at the heating end of the thermoelectric device layer 1, the photothermal material layer 3 is fixed on the pyroelectric power generation material layer 2, and the heat-insulating sleeve 4 is sleeved on the end of the hot device facing the sun

[0034] In the experiment, polarized aluminized PVDF films with different thicknesses were set up to study their influence on the open-circuit voltage. A series of polarized aluminized PVDF films with thicknesses of 20μm, 30μm, 50μm, 100μm, and 200μm were physically fixed to the thermoelectric device and placed under illumination at 50mHz (0.1 W / cm 2 ) The pyroelectric performance output was monitored at the switching frequency. Specifically, the thermoelectric device was connected to a Keithley 2450 digital source meter with wires, and the digital source meter was connected to a computer through a USB interface to collect the real-time open-circuit voltage output for 300 s, thereby obtaining the thickness of the polarized aluminized PVDF film with the best performance output. The results are as Figure 3 shown. The thickness of the polarized aluminized PVDF film with the best performance output is 30μm, and the maximum open-circuit voltage can reach 47V.

[0035] The thermoelectric device refers to a solar thermoelectric device that converts light energy into heat energy through sunlight irradiation and then converts thermoelectricity into electrical energy.

[0036] Example 2 Preparation of a thermoelectric-pyroelectric hybrid generator

[0037] (1) Weigh 12.8 mg of CNT powder and 3.2 mg of rGO-PEI powder respectively and ultrasonically disperse them in 16 mL of deionized water. The mixed solution was evenly dropped on the surface of the filter paper to ensure that the surface mass content of the material was 1 mg / cm 2 , and then perform suction filtration and dry at room temperature for 2 h to obtain a CNT-rGO-PEI photothermal material layer.

[0038] (2) Transfer the photothermal material layer with transparent tape and connect it to a polarized aluminized PVDF film with a thickness of 30μm to make a photothermal pyroelectric generator.

[0039] (3) The photothermal pyroelectric generator was physically fixed to the heating end of the thermoelectric device with tape, and a heat-insulating sleeve was added to the surface of the thermoelectric device to obtain a thermoelectric-pyroelectric hybrid generator.

[0040] Application Example The thermoelectric-pyroelectric hybrid generator prepared in Example 2 was subjected to various performance and application tests

[0041] Application Example 1

[0042] Place the thermoelectric-pyroelectric hybrid generator under illumination at 500mHz (0.1 W / cm 2 ) At the switching frequency, connect the thermoelectric device to the digital source meter with wires, and the digital source meter is connected to the computer through a USB interface to collect the real-time open-circuit voltage and short-circuit current output for 700 s; the pure thermoelectric device without a coupled photothermal pyroelectric generator is under stable illumination (0.1 W / cm2 ) Monitor its open - circuit voltage and short - circuit current under the following conditions, and the test method is the same as above. During the light switching process, the thermoelectric generator can still maintain a stable output. Its open - circuit voltage and short - circuit current can reach 0.15 V and 27 mA respectively, as shown in Figure 4 (a) and (b) below; compared with the current - voltage of the pure thermoelectric device without the coupled photo - thermal pyroelectric generator, they are 68% and 67% higher respectively, as shown in Figure 4 (c) and (d) below. The prepared hybrid power generation device can fully collect the fluctuating temperature and improve the output of the thermoelectric device.

[0043] Application Example 2

[0044] During the light switching process, the open - circuit voltage and short - circuit current output of the photo - thermal pyroelectric generator are monitored by a Keithley 2450 digital source meter. The specific method is to connect the generator to the digital source meter with wires, and the digital source meter is connected to the computer through a USB interface. Its open - circuit voltage and short - circuit current can reach 30 V and 82 nA respectively, as shown in Figure 5 (a) and (b) below; compared with the current - voltage of the pure photo - thermal pyroelectric device without the coupled thermoelectric device, they are 50% and 37% higher respectively, Figure 5 (c) and (d) below. In the prepared hybrid power generation device, the photo - thermal pyroelectric generator can not only effectively collect the fluctuating temperature, but after coupling with the thermoelectric device, when there is no light, it can quickly cool down through the cold end of the thermoelectric device. Therefore, its temperature oscillation rate is increased, thereby improving its output.

[0045] Application Example 3

[0046] The prepared thermoelectric - pyroelectric hybrid power generation device can instantaneously and effectively charge a capacitor. Its schematic diagram is as shown in Figure 6 (a) below. The charging process of the thermoelectric device is as shown in Figure 6 (b) below; for the photo - thermal pyroelectric device, a rectifier is needed to rectify the alternating current generated by the power generation device, and its charging process is as shown in Figure 6 (c) below. The charging process is monitored by a Keithley 2450 digital source meter. The specific method is to connect the power generation device to the digital source meter with wires, and the digital source meter is connected to the computer through a USB interface. It is concluded that the thermoelectric device and the photo - thermal pyroelectric device can charge a 4.7 μF capacitor to 0.2 V and 4 V respectively within 3 minutes, and the stored electrical energy can supply power to electronic products such as watches and hand - held fans.

[0047] Application Example 4

[0048] The prepared thermoelectric-pyroelectric hybrid generator can collect the thermal energy of exothermic reactions, such as the heat released during the dissolution of sodium hydroxide. The schematic diagram of the collection process is shown in Figure 7 Figure (a). The output of the thermoelectric device part is monitored by a digital source meter. The specific steps are to connect the thermoelectric device to the digital source meter with wires. The digital source meter is connected to a computer through a USB interface, and its output is shown in Figure 7 Figure (b). The photothermal pyroelectric generator part is monitored by a Keithley 2450 digital source meter. The specific method is to connect the generator to the digital source meter with wires. The digital source meter is connected to a computer through a USB interface. Its output is shown in Figure 7 Figure (c). It can be seen that by repeating the exothermic experiment of sodium hydroxide dissolution three times, the outputs of the thermoelectric device and the photothermal pyroelectric device can both remain stable, indicating that the prepared hybrid generator can effectively collect the heat released during the dissolution of sodium hydroxide, and this generator has practical application significance.

[0049] Application Example 5

[0050] The prepared thermoelectric-pyroelectric hybrid generator can also realize the function of self-sensing the surface temperature change of thermoelectric materials by detecting the change of the electric signal of the pyroelectric layer. Its electric signal output is shown in Figure 8 Figure. The output of its open-circuit voltage is monitored by a Keithley 2450 digital source meter. The specific method is to connect the generator to the digital source meter with wires. The digital source meter is connected to a computer through a USB interface. It can be seen that when the temperature on the surface of the generator changes, its open-circuit voltage also changes accordingly, and the change is obvious, sensitive and easy to detect. This is because the spontaneous polarization intensity of the photothermal pyroelectric generator changes with temperature, thus generating corresponding induced charges. Therefore, when the temperature changes, its open-circuit voltage also changes accordingly. Therefore, by detecting the change of the electric signal of the pyroelectric layer, the self-sensing of the surface temperature change of thermoelectric materials can be realized.

Claims

1. A thermoelectric-pyroelectric hybrid power generation device, characterized in that It includes a thermoelectric material layer, a pyroelectric power generation material layer, and a photothermal material layer. The pyroelectric power generation material layer is fixed at the heating end of the thermoelectric material layer, and the photothermal material layer is fixed on the pyroelectric power generation material layer; The photothermal material layer is a composite material formed by mixing CNT and rGO-PEI. The mass ratio of CNT to rGO-PEI is 4:

1. This composite material is prepared by the following method: CNT and rGO-PEI are ultrasonically dispersed in deionized aqueous solution, and then a layer of CNT-rGO-PEI layer is formed on the filter paper by suction filtration and dried at room temperature to obtain the CNT-rGO-PEI photothermal material layer; The pyroelectric power generation material layer is a polarized aluminized PVDF film with a thickness of 30 μm; It also includes a heat insulation sleeve wrapped around the heating end of the thermoelectric material layer.

2. A preparation method of a thermoelectric-pyroelectric hybrid power generation device, characterized in that It includes the following steps: (1) Ultrasonically disperse CNT and rGO-PEI in an aqueous deionized solution at a mass ratio of 4:1, and then form a layer of CNT-rGO-PEI on the filter paper by suction filtration and dry it at room temperature to obtain a CNT-rGO-PEI photothermal material layer. The surface mass content of the CNT-rGO-PEI photothermal material layer is 1 mg / cm 2 ; (2) Transfer the photothermal material layer through transparent tape and connect it with a polarized aluminized PVDF film with a thickness of 30 μm to make a photothermal pyroelectric generator; (3) Physically fix the photothermal pyroelectric generator at the heating end of the thermoelectric device with tape, and add a heat insulation sleeve on the surface of the thermoelectric device to obtain a thermoelectric-pyroelectric hybrid power generation device.

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