Coupling system of thermoelectric module and heat pipe collector based on ethyl ion thermoelectric material

Abstract

The present invention provides a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials, belonging to the field of thermoelectric conversion technology. It includes an ethyl ion thermoelectric module and a heat pipe collector coupled with the ethyl ion thermoelectric module; the ethyl ion thermoelectric module includes PVDF-HFP / EMIM:DCA thermoelectric gel, copper electrodes and a packaging structure; the copper electrodes are respectively arranged at both ends of the thermoelectric gel, and the packaging structure is a vacuum plastic bag for packaging the assembled thermoelectric gel and copper electrodes. The present invention realizes stable thermoelectric conversion using the temperature difference formed by solar radiation by preparing a thermoelectric module based on ethyl ion thermoelectric materials and coupling it with a heat pipe collector. The module can stably output power and has reversible thermoelectric response characteristics. The voltage response of the coupling system is closely related to the solar radiation intensity and temperature difference, and can adapt to changes in solar radiation at different time periods, thereby realizing thermoelectric conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of thermoelectric conversion, and in particular to a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials. Background Art

[0002] With the growing global energy crisis and environmental issues, the development of clean and renewable energy technologies has become a key area of ​​scientific and technological development. As a clean energy source, the efficient utilization of solar energy has attracted widespread attention. Thermoelectric conversion technology, as a method of directly converting thermal energy into electrical energy, holds significant application prospects in the field of solar energy utilization.

[0003] Currently, thermoelectric conversion technologies are primarily categorized into electronic and ionic types. While traditional electronic thermoelectric materials, such as Bi2Te3 and PbTe, have achieved commercialization, their complex and costly preparation processes, combined with the inclusion of rare or toxic elements, have limited their widespread adoption. In recent years, ionic thermoelectric materials based on the Soret effect have become a research hotspot due to their environmental friendliness, low cost, and flexibility.

[0004] Ionic thermoelectric materials are typically composed of ionic conductors and carrier materials. CN113178515B discloses a hydrogel thermoelectric material based on ionic liquids. This material mixes inorganic salts, ionic liquids, and polymers to produce a low-cost, high-performance ionic thermoelectric gel material with a Seebeck coefficient of up to 131.2 mV / K. CN115141383A proposes an ionic thermoelectric gel material that uses surfactants as heat diffusers. Through the non-compensatory diffusion of anions and cations, it achieves a thermal conductivity of up to 43.1 mV·K. -1 Thermoelectric potential effect.

[0005] Solar thermal collection systems are a key area of ​​application for thermoelectric materials. CN2864500Y discloses a novel flat-plate solar heat pipe collector, comprising a water tank, a flat-plate heat pipe heat collection device, and a circulating heat collection device. This system utilizes water circulation to improve heating efficiency, fully utilizing solar energy and retaining heat. However, this system primarily focuses on heat collection rather than thermoelectric conversion.

[0006] To further improve the thermoelectric conversion efficiency, CN120051189A proposed an ion-electron coupled thermoelectric material, whose carriers are ions and electrons. The output voltage mainly comes from the voltage generated by ion thermal diffusion, and the output current mainly comes from the drift current in the electronic conductor caused by ion thermal diffusion, making the output power several orders of magnitude higher than that of existing ionic thermoelectric materials.

[0007] Although existing technologies have made certain progress in ionic thermoelectric materials and solar thermal collection systems, the following problems still exist: First, the thermoelectric conversion efficiency of existing ionic thermoelectric materials still needs to be improved, especially the insufficient stability and durability in actual application environments; second, the coupling between existing solar thermal collection systems and thermoelectric conversion devices is not tight enough, and there is a large loss in the heat energy transfer process, resulting in low overall system efficiency; third, existing ionic thermoelectric materials mostly use conventional ionic liquids, while there is little application research on ethyl ionic thermoelectric materials in the field of thermoelectric conversion, and their potential has not yet been fully explored; finally, the existing technology lacks an efficient integrated thermoelectric module and heat pipe collector coupling system, making it difficult to achieve efficient conversion of solar thermal energy to electrical energy.

[0008] Therefore, there is an urgent need to develop a thermoelectric module and heat pipe collector coupling system based on high-performance ethyl ion thermoelectric materials to improve the solar thermoelectric conversion efficiency. Summary of the Invention

[0009] In order to overcome the shortcomings of the existing technology, the purpose of the present invention is to provide a thermoelectric module based on ethyl ion thermoelectric materials and a heat pipe collector coupling system. By preparing a thermoelectric module based on ethyl ion thermoelectric materials and coupling it with a heat pipe collector, stable thermoelectric conversion is achieved by utilizing the temperature difference formed by solar radiation. The module can output power stably and has reversible thermoelectric response characteristics. The voltage response of the coupling system is closely related to the solar radiation intensity and temperature difference, and can adapt to changes in solar radiation at different time periods, thereby achieving thermoelectric conversion.

[0010] To achieve the above object, the present invention provides the following solutions:

[0011] A thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric material, comprising an ethyl ion thermoelectric module and a heat pipe collector coupled to the ethyl ion thermoelectric module;

[0012] The ethyl ion thermoelectric module includes PVDF-HFP / EMIM:DCA thermoelectric gel, copper electrodes and a packaging structure. The PVDF-HFP / EMIM:DCA thermoelectric gel is formed by a PVDF-HFP matrix and an ionic liquid composite system. The ionic liquid composite system contains 1-ethyl-3-methylimidazole dicyanamide salt and sodium dicyanamide; the copper electrodes are respectively arranged at both ends of the PVDF-HFP / EMIM:DCA thermoelectric gel, and the packaging structure is a vacuum plastic bag for packaging the assembled thermoelectric gel and copper electrodes.

[0013] Preferably, the preparation steps of the PVDF-HFP / EMIM:DCA thermoelectric gel include:

[0014] S1, dissolving PVDF-HFP in acetone and stirring at room temperature until no solid remains to obtain an acetone solution of PVDF-HFP;

[0015] S2, 1-ethyl-3-methylimidazolium dicyanamide salt and sodium dicyanamide are mixed to obtain a mixed solution, wherein the mass of 1-ethyl-3-methylimidazolium dicyanamide salt is 80% of the total mass of the mixed solution;

[0016] S3, mixing the mixed solution with the PVDF-HFP acetone solution to obtain a thermoelectric gel precursor solution;

[0017] S4. Spin-coat the thermoelectric gel precursor solution on a glass substrate treated with deionized water, isopropyl alcohol, and ultraviolet ozone at a spin-coating speed of 1000 r / min for 60 seconds, and then dry in an oven at 60° C. for 3 hours to obtain the PVDF-HFP / EMIM:DCA thermoelectric gel.

[0018] Preferably, in S4, the size of the glass substrate is 25×75 mm 2 The thickness of the PVDF-HFP / EMIM:DCA thermoelectric gel was controlled by micrometer measurement.

[0019] Preferably, in the ethyl ion thermoelectric module, the copper electrode and the two ends of the PVDF-HFP / EMIM:DCA thermoelectric gel form a conductive path, and when there is a temperature gradient between the two electrodes, the ethyl ion thermoelectric module can generate thermoelectric potential.

[0020] Preferably, the heat pipe collector includes a solar heat pipe vacuum collector tube, a header and a cold source component. The hot end of the solar heat pipe vacuum collector tube is attached to one end of the ethyl ion thermoelectric module through a copper tube. The cold source component is a water pipe through which water flows. The water pipe is in contact with the other end of the ethyl ion thermoelectric module to form a temperature gradient.

[0021] Preferably, the solar heat pipe vacuum collector tube of the heat pipe collector is fixed on a bracket with an inclination angle of 22.8° to the ground, and the junction box connects the solar heat pipe vacuum collector tube and the cold source component. The cold source component also includes a water pump, a flow meter and a valve for controlling the water flow rate to 1L / min.

[0022] Preferably, the coupling method of the ethyl ion thermoelectric module and the heat pipe collector is: the hot end of the solar heat pipe vacuum collector is attached to one end of the thermoelectric module through a copper tube, and the flowing water in the water pipe contacts the other end of the thermoelectric module, forming a temperature gradient that drives thermoelectric conversion.

[0023] The present invention also provides a method for manufacturing the above-mentioned thermoelectric module based on ethyl ion thermoelectric material and heat pipe collector coupling system, comprising the following steps:

[0024] Preparation of PVDF-HFP / EMIM:DCA thermoelectric gel;

[0025] Copper electrodes were assembled at both ends of the PVDF-HFP / EMIM:DCA thermoelectric gel, and the assembled structure was encapsulated in a vacuum plastic bag to obtain an ethyl ion thermoelectric module;

[0026] The hot end of the solar heat pipe vacuum collector is connected to one end of the ethyl ion thermoelectric module through a copper tube, the water pipe of the cold source component is in contact with the other end of the ethyl ion thermoelectric module, and the header, water pump and flow meter are connected to form a coupling system.

[0027] Preferably, the copper tube and the ethyl ion thermoelectric module are bonded together by bonding them with thermally conductive silicone to achieve heat conduction.

[0028] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0029] (1) The ethyl ion thermoelectric module prepared by the present invention can achieve stable thermoelectric conversion by utilizing temperature gradient, has good output performance stability, can work continuously for a long time, and has been verified by cyclic charge and discharge tests to have reversible thermoelectric response characteristics. It is not a disposable power source and can meet the needs of continuous application.

[0030] (2) The system formed by coupling the ethyl ion thermoelectric module with the solar heat pipe collector of the present invention can effectively utilize solar energy as a heat source. A temperature gradient is formed at both ends of the module through the heat pipe collector and the water flow cold source, thereby realizing the conversion of solar energy into electrical energy. While the heat pipe collector performs the heat collection function, it can further convert the relevant thermal energy into electrical energy, thereby improving the comprehensive utilization efficiency of energy.

[0031] (3) The thermoelectric conversion performance of the coupling system provided by the present invention is closely related to the solar radiation intensity and temperature difference, and can respond to changes in solar radiation at different time periods. When the solar radiation conditions change, the voltage of the module will respond accordingly, showing sensitivity to changes in the external thermal environment, and can adapt to dynamic thermal environments for thermoelectric conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1This is a schematic structural diagram of a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to the present invention;

[0034] Figure 2 A graph showing the voltage radiation intensity variation over time at 10-11 a.m. for the coupling system provided in Example 1 of the present invention;

[0035] Figure 3 A graph showing changes in voltage and temperature difference over time for the coupling system provided in Example 1 of the present invention at 10:00-11:00 am;

[0036] Figure 4 A schematic diagram showing the variation of voltage radiation intensity over time at 1-2 noon for the coupling system provided in the first embodiment of the present invention;

[0037] Figure 5 This is a graph showing the voltage and temperature difference over time for the coupling system provided in Example 1 of the present invention at 1-2 noon;

[0038] Figure 6 A schematic diagram showing the change in voltage radiation intensity over time for the coupling system provided in Example 1 of the present invention at 3-4 pm;

[0039] Figure 7 A graph showing the voltage and temperature difference of the coupling system provided in Example 1 of the present invention changing with time at 3-4 pm;

[0040] Description of reference numerals:

[0041] 1. Ethyl ion thermoelectric module; 2. Solar heat pipe vacuum collector; 3. Junction box; 4. Thermometer; 5. Multimeter; 6. Valve; 7. Water tank; 8. Water pump; 9. Flow meter. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] like Figure 1 As shown, the present invention provides a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials, including an ethyl ion thermoelectric module 1 and a heat pipe collector, which are coupled to form a complete energy conversion system.

[0045] The ethyl ion thermoelectric module 1 consists of a PVDF-HFP / EMIM:DCA thermoelectric gel, copper electrodes, and a packaging structure. The PVDF-HFP / EMIM:DCA thermoelectric gel is a key component of the system, formed by a PVDF-HFP matrix and an ionic liquid composite system. The ionic liquid composite system contains two components: 1-ethyl-3-methylimidazole dicyanamide salt and sodium dicyanamide. Copper electrodes are respectively arranged at both ends of the PVDF-HFP / EMIM:DCA thermoelectric gel to collect the electricity generated by thermoelectric conversion. The packaging structure uses a vacuum plastic bag to completely encapsulate the assembled thermoelectric gel and copper electrodes to prevent the external environment from affecting the thermoelectric material.

[0046] In the above content, the preparation process of PVDF-HFP / EMIM:DCA thermoelectric gel includes the following steps:

[0047] S1: Dissolve PVDF-HFP in acetone and stir at room temperature until no solid residue is observed to obtain a transparent PVDF-HFP acetone solution;

[0048] S2: 1-ethyl-3-methylimidazolium dicyanamide salt and sodium dicyanamide are mixed in proportion to prepare a mixed solution, wherein the mass of 1-ethyl-3-methylimidazolium dicyanamide salt accounts for 80% of the total mass of the mixed solution;

[0049] S3: The mixed solution is thoroughly mixed with the PVDF-HFP acetone solution to form a thermoelectric gel precursor solution;

[0050] S4: The thermoelectric gel precursor solution was spin-coated on the pretreated glass substrate at a speed of 1000 r / min for 60 s. The coated substrate was then placed in a 60°C oven and dried for 3 hours to obtain the PVDF-HFP / EMIM:DCA thermoelectric gel.

[0051] During the preparation process, the size of the glass substrate was 25 × 75 mm 2 Before use, the substrate surface must be treated with deionized water, isopropyl alcohol, and UV ozone to ensure a clean surface. The thickness of the PVDF-HFP / EMIM:DCA thermoelectric gel is measured and controlled using a micrometer to ensure consistent thermoelectric performance.

[0052] In the ethyl ion thermoelectric module 1, the copper electrode is in close contact with both ends of the PVDF-HFP / EMIM:DCA thermoelectric gel, forming a complete conductive path. When a temperature gradient exists between the two electrodes, the ions in the thermoelectric gel will migrate in a directional manner, thereby generating a thermoelectric potential between the two electrodes and realizing the conversion of thermal energy into electrical energy. Specifically, in the initial state, Na + and DCA −Evenly dispersed in the ethyl ion thermoelectric module 1. The Soret effect refers to the ion migration phenomenon caused by thermal diffusion in the electrolyte. When there is a temperature gradient ΔT between the two electrodes, due to the influence of the Soret effect, Na + With a smaller Stokes radius and a higher diffusion coefficient, its mobility is significantly higher than that of DCN with a larger volume. - ions, leading to Na + Directed migration from the high temperature end to the low temperature end, while DCN - Due to the blocked migration, it is relatively enriched at the high temperature end. This selective ion migration process induces space charge separation: at the low temperature end, Na + The accumulation of local cations forms a local excess, and the high temperature end is due to DCN - The retention of anions is dominated by anionic concentration. The spatially non-uniform distribution of charge leads to the formation of a double-layer structure at the electrode-electrolyte interface, in which the metal electrode compensates the ionic charge on the electrolyte side through the electrostatic induction effect of the surface charge, thereby establishing a stable thermoelectric potential between the two electrodes.

[0053] The heat pipe collector is another key component of the system, consisting of a solar heat pipe vacuum collector tube 2, a header 3, and a heat sink assembly. The hot end of the solar heat pipe vacuum collector tube 2 is tightly attached to one end of the ethyl ion thermoelectric module 1 via a copper tube, providing a heat source. The heat sink assembly, a water pipe with flowing water, contacts the other end of the ethyl ion thermoelectric module 1, creating a temperature gradient. This structural design creates a stable temperature difference between the two ends of the thermoelectric module, thereby continuously generating thermoelectric potential.

[0054] The solar heat pipe vacuum heat collecting tube 2 of heat pipe collector is fixed on the support that becomes 22.8 ° of inclination angles with the ground, and this angle design can obtain best solar absorption efficiency in specific geographical location.Header box 3 connects solar heat pipe vacuum heat collecting tube 2 and cold source assembly, guarantees that each part of system works in coordination.Cold source assembly comprises water pump 8, flow meter 9 and valve 6, is used to control the water flow constant at 1L / min, guarantees the stability of cold end temperature.In addition in the present embodiment, by water tank 7, water flow is provided in system, thermometer 4 tests the temperature variation of ethyl ion thermoelectric module 1, and multimeter 5 tests the voltage value of ethyl ion thermoelectric module 1.

[0055] The ethyl ion thermoelectric module 1 is coupled to the heat pipe collector in this way: the hot end of the solar heat pipe vacuum collector tube 2 is tightly attached to one end of the ethyl ion thermoelectric module 1 via a copper tube, while the flowing water in the water pipe directly contacts the other end of the ethyl ion thermoelectric module 1, creating a temperature gradient that drives thermoelectric conversion. This coupling method enables the system to effectively convert solar energy into electricity, achieving efficient utilization of clean energy.

[0056] In practical applications, the solar heat pipe vacuum collector tubes 2 absorb solar radiation and convert it into heat. This heat is then transferred via copper tubes to the hot end of the ethyl ion thermoelectric module 1, while the cold end is kept cool by flowing water. Driven by this temperature gradient, the ions in the ethyl ion thermoelectric module 1 undergo directional migration, generating a potential difference between the two electrodes, thereby outputting electrical energy. This system features a simple structural design, no moving mechanical parts, high operational reliability, and low maintenance costs, making it an ideal solar thermoelectric conversion device.

[0057] This embodiment also provides a method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials, the method comprising the following steps:

[0058] Preparation of PVDF-HFP / EMIM:DCA thermoelectric gel:

[0059] The specific implementation of this step is the same as the above-mentioned PVDF-HFP / EMIM:DCA thermoelectric gel preparation process, including dissolving PVDF-HFP in acetone, preparing a mixed solution of 1-ethyl-3-methylimidazole dicyanamide salt and sodium dicyanamide, mixing the precursor solution and spin coating and drying.

[0060] Assemble copper electrodes and package:

[0061] Copper electrodes were assembled at both ends of the prepared PVDF-HFP / EMIM:DCA thermoelectric gel to form a conductive path. After assembly, the entire structure was encapsulated in a vacuum plastic bag to create an ethyl ion thermoelectric module. The packaging process ensured that the vacuum plastic bag was completely sealed to prevent the external environment from affecting the thermoelectric material's performance.

[0062] Coupling system assembly:

[0063] Connect the hot end of the solar heat pipe vacuum collector to one end of the ethyl ion thermoelectric module through a copper tube, and connect the water pipe of the cold source assembly to the other end of the ethyl ion thermoelectric module. At the same time, connect the header, water pump, and flow meter to form a complete coupling system.

[0064] The copper tube and the ethyl ion thermoelectric module are bonded together using thermally conductive silicone. This bonding method ensures efficient heat transfer, reduces heat loss, and improves the system's thermoelectric conversion efficiency. The thermally conductive silicone, with its excellent thermal conductivity and adhesion, fills the tiny gaps between the copper tube and the thermoelectric module, forming a continuous heat conduction path.

[0065] The coupling system in this embodiment is assembled in the same manner as described above. The solar heat pipe vacuum collector tube is fixed to a bracket with an inclination angle of 22.8° to the ground. The water flow rate of the cold source component is controlled at 1L / min, enabling the system to achieve optimal solar energy absorption efficiency in a specific geographical location while ensuring the stability of the cold end temperature.

[0066] In order to test the performance of the ethyl ion thermoelectric module on the heat pipe collector, this embodiment tests the performance of the thermoelectric module coupled with the heat pipe collector at different time periods of the day. Figure 2 The figure shows how the voltage and irradiation intensity of the ethyl ion thermoelectric module vary over time between 10:00 and 11:00 AM. The results show that as the experiment begins, the temperature difference between the two ends of the ethyl ion thermoelectric module gradually increases, and the voltage rises accordingly. The voltage peaks at approximately 0.95 mV around 700 seconds, then decreases slightly over time before reaching equilibrium, indicating that the thermoelectric effect has reached a certain equilibrium state. The decrease in solar irradiation intensity between 200 and 600 seconds is due to cloud cover, and the corresponding decrease in voltage is consistent with the experimental principle. After 700 seconds, the voltage shows a downward and fluctuating trend, but generally remains at a certain level, which is related to the pulsed irradiation intensity. Changes in irradiation intensity are the driving force behind the temperature changes in the thermoelectric material.

[0067] Reference Figure 3 The data show the temporal variations of the voltage and temperature difference of the ethyl ion thermoelectric module from 10:00 AM to 11:00 AM. The results show that during the initial phase (0 to approximately 400 seconds), the voltage remained relatively stable and low, indicating that the temperature difference across the module was small or in an initial equilibrium state. During the rising phase (approximately 400 seconds to 800 seconds), the voltage exhibited significant fluctuations and an upward trend, reaching a distinct peak around 600 seconds. This phase reflects the response of the thermoelectric material to the external temperature difference. The voltage fluctuations may be due to the nonlinearity of the thermoelectric effect. Specifically, the Seebeck coefficient of thermoelectric materials is typically temperature-dependent, resulting in a non-linear relationship between voltage and temperature difference. During the falling phase (after 800 seconds), the voltage exhibited a fluctuating downward trend after reaching its peak, gradually approaching a relatively stable level. The temperature difference exhibited a distinct periodic pulse pattern, indicating that the heat pipe collector periodically heated the hot end of the ethyl ion thermoelectric module and the water flow within the tube periodically cooled the cold end. The overall voltage trend and fluctuations were driven by the periodic changes in the temperature difference. There is a certain delay in the change of voltage relative to the change of temperature difference. This is because the heat conduction process caused by the heat capacity and thermal resistance of the ethyl ion thermoelectric module takes a certain amount of time.

[0068] Reference Figure 4The data shows the dynamic relationship between the output voltage of an ethyl ion thermoelectric module and the intensity of solar radiation over time when exposed to solar radiation at 1-2 noon. During the period 0-200 seconds, the voltage rises rapidly from its initial value, exhibiting a clear positive slope. This indicates that the ethyl ion thermoelectric module's initial response to solar radiation is very rapid, with a temperature difference quickly established. From 200 to 1500 seconds, the voltage rise gradually slows, the slope of the curve decreases, and ultimately approaches a relatively stable level. After 1500 seconds, the voltage of the ethyl ion thermoelectric module remains almost unchanged, with the maximum voltage during this period being around 2.24 mV. Solar radiation intensity is not constant but fluctuates due to factors such as cloud cover and atmospheric disturbances. It can be seen that there is a slight delay in the change in voltage relative to the change in solar radiation intensity. This is primarily due to the time required for heat conduction due to the heat capacity of the thermoelectric material. The voltage fluctuations are correlated with the fluctuations in solar radiation and exhibit a direct positive correlation with solar radiation intensity: higher solar radiation intensity results in higher voltage generated by the thermoelectric module.

[0069] In addition, refer to Figure 5 , which shows the relationship between the voltage and temperature difference of the thermoelectric material between 1 and 2 noon. The data in the figure show a significant increase in the temperature difference in the early stages, especially at the beginning of the experiment, where it rises rapidly and remains high, before stabilizing. The periodic fluctuations in the temperature difference shown in the figure reflect the periodic heating of the ethyl ion thermoelectric module by the heat pipe collector during the experiment. The voltage curve shows a steady upward trend over time. In the early stages, the voltage increases rapidly, directly correlated with the increase in the temperature difference. This indicates that the voltage response of the thermoelectric material is more sensitive in the early stages of temperature changes, consistent with the fundamental principle of the thermoelectric effect: the greater the temperature difference, the higher the voltage. Over time, the voltage increase flattens, indicating that the material's voltage response is stabilizing, likely due to the temperature difference reaching a steady state. The voltage curve in the figure is not completely smooth but exhibits some fluctuations. These fluctuations may be caused by thermal response delays within the thermoelectric material, slight changes in the temperature difference, or external interference. The more obvious fluctuation range is concentrated in the process of temperature difference change, especially when the temperature difference is at a high level, which indicates that the material may show a large voltage fluctuation under high temperature difference conditions, reflecting the sensitivity of thermoelectric materials to temperature changes. Figure 5 The study revealed the voltage response characteristics of thermoelectric materials under different temperature differences. Both the voltage and temperature difference of the material show a certain regularity in their changes over time, and the change in voltage is closely related to the temperature difference.

[0070] Finally, refer to Figure 6The figure shows the relationship between the voltage and radiation intensity of the ethyl ion thermoelectric module during the afternoon hours between 3 and 4 p.m. The voltage and radiation intensity in the figure fluctuate in a correlated manner, reflecting the voltage response of the thermoelectric material under varying radiation intensities. The radiation intensity decreases with time, indicating that solar radiation intensity decreases with increasing afternoon hours, consistent with the daily variation in solar radiation intensity. The voltage gradually increases over time, with a particularly significant increase during periods of high radiation intensity. This increase in voltage is consistent with the basic theory of the thermoelectric effect, which states that an increase in temperature differential generally leads to an increase in voltage. The gradual rise in the voltage curve reflects the voltage response of the ethyl ion thermoelectric module to increasing radiation intensity under the influence of a heat source. When the radiation intensity is low, the voltage increase is relatively slow, indicating that the voltage response of the ethyl ion thermoelectric module to radiation intensity is more pronounced. The voltage curve also exhibits some fluctuations, with the amplitude of the fluctuation increasing with increasing radiation intensity. This may be related to the increased thermal sensitivity of the ethyl ion thermoelectric module under high radiation intensity. The voltage fluctuation may be due to the response delay of the ethyl ion thermoelectric module under a changing temperature environment, or it may be caused by the thermoelectric characteristics inside the ethyl ion thermoelectric module.

[0071] also, Figure 6 The voltage response characteristics of the ethyl ion thermoelectric module under different radiation intensities are shown. The relationship between voltage and radiation intensity is close, and the periodic change of radiation intensity has a direct impact on the voltage, indicating that the voltage response of the ethyl ion thermoelectric module is closely related to the change of the heat source in the external environment. Figure 7The figure shows the relationship between the voltage and temperature difference of the ethyl ion thermoelectric module between 3:00 and 4:00 PM. The figure shows that the temperature difference exhibits periodic fluctuations over time: it gradually rises over a period of time, reaches a high level, then drops, then rises again, forming a distinct cyclical pattern. This fluctuation is due to the continuous heating of the ethyl ion thermoelectric module by the heat pipe collector, indicating that the ethyl ion thermoelectric module responds differently to varying temperature differences, driven by changes in the intensity of the heat source. The amplitude and frequency of the temperature difference fluctuations reflect variations in the heat source stability and temperature distribution, which may affect the thermoelectric performance of the ethyl ion thermoelectric module. The voltage curve shows a gradual upward trend over time, with a particularly significant increase in voltage as the temperature difference increases. This voltage increase is closely related to the change in temperature difference, consistent with the fundamental principle of the thermoelectric effect: the greater the temperature difference, the higher the voltage generated by the thermoelectric module. This trend is particularly pronounced when the temperature difference changes rapidly, with the voltage fluctuation being larger, reflecting the ethyl ion thermoelectric module's sensitive response to temperature changes. However, as time goes by, the voltage growth gradually tends to be flat, indicating that the voltage response of the ethyl ion thermoelectric module tends to be stable after the temperature difference reaches a certain stable value.

[0072] Furthermore, regarding voltage fluctuations, it can be observed that the voltage curve is not completely smooth, but rather exhibits significant fluctuations. These fluctuations are likely due to the hysteresis effect of the thermal response within the ethyl ion thermoelectric module, which is particularly pronounced when subjected to drastic temperature changes. The thermoelectric performance of the ethyl ion thermoelectric module is significantly affected by temperature changes, but the voltage response also fluctuates due to fluctuations in the frequency and amplitude of these temperature changes. This fluctuation reflects the response characteristics of the ethyl ion thermoelectric module in a dynamic thermal environment.

[0073] Therefore, based on Figures 2 to 7 Data from the study show a close correlation between the voltage and temperature difference of the ethyl ion thermoelectric module, and the voltage response of the ethyl ion thermoelectric module under different temperature differences exhibits a certain time lag and fluctuation. An increase in temperature difference promotes an increase in voltage, and the voltage response is particularly pronounced at high temperature differences. However, as the temperature difference stabilizes, the voltage change gradually slows, indicating that the ethyl ion thermoelectric module's response to temperature differences gradually approaches equilibrium.

[0074] Therefore, the above-mentioned thermoelectric module based on ethyl ion thermoelectric material and heat pipe collector coupling system is adopted. By preparing a thermoelectric module based on ethyl ion thermoelectric material and coupling it with a heat pipe collector, stable thermoelectric conversion is achieved by utilizing the temperature difference formed by solar radiation. The module can output power stably and has reversible thermoelectric response characteristics. The voltage response of the coupling system is closely related to the solar radiation intensity and temperature difference, and can adapt to changes in solar radiation in different time periods, thereby realizing thermoelectric conversion.

[0075] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials, characterized in that: The following steps are involved: Preparation of PVDF-HFP / EMIM:DCA thermoelectric gel; The preparation steps of the PVDF-HFP / EMIM:DCA thermoelectric gel include: S1, dissolving PVDF-HFP in acetone and stirring at room temperature until no solid remains to obtain an acetone solution of PVDF-HFP; S2, 1-ethyl-3-methylimidazolium dicyanamide salt and sodium dicyanamide are mixed to obtain a mixed solution, wherein the mass of 1-ethyl-3-methylimidazolium dicyanamide salt is 80% of the total mass of the mixed solution; S3, mixing the mixed solution with the PVDF-HFP acetone solution to obtain a thermoelectric gel precursor solution; S4, spin-coating the thermoelectric gel precursor solution on a glass substrate treated with deionized water, isopropyl alcohol and ultraviolet ozone at a spin-coating speed of 1000 r / min for 60 seconds, and then drying in an oven at 60° C. for 3 hours to obtain the PVDF-HFP / EMIM:DCA thermoelectric gel; Copper electrodes were assembled at both ends of the PVDF-HFP / EMIM:DCA thermoelectric gel, and the assembled structure was encapsulated in a vacuum plastic bag to obtain an ethyl ion thermoelectric module; The hot end of the solar heat pipe vacuum collector is connected to one end of the ethyl ion thermoelectric module through a copper tube, the water pipe of the cold source component is in contact with the other end of the ethyl ion thermoelectric module, and the header, water pump and flow meter are connected to form a coupling system.

2. The method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to claim 1, characterized in that: The copper tube and the ethyl ion thermoelectric module are bonded together by bonding them with thermally conductive silicone to achieve heat conduction.

3. The method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to claim 1, characterized in that: In S4, the size of the glass substrate is 25×75 mm 2 The thickness of the PVDF-HFP / EMIM:DCA thermoelectric gel was controlled by micrometer measurement.

4. A method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to any one of claims 1 to 3, wherein the thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials is prepared, characterized in that: It includes an ethyl ion thermoelectric module and a heat pipe collector coupled to the ethyl ion thermoelectric module; The ethyl ion thermoelectric module includes PVDF-HFP / EMIM:DCA thermoelectric gel, copper electrodes and a packaging structure. The PVDF-HFP / EMIM:DCA thermoelectric gel is formed by a PVDF-HFP matrix and an ionic liquid composite system. The ionic liquid composite system contains 1-ethyl-3-methylimidazole dicyanamide salt and sodium dicyanamide; the copper electrodes are respectively arranged at both ends of the PVDF-HFP / EMIM:DCA thermoelectric gel, and the packaging structure is a vacuum plastic bag for packaging the assembled thermoelectric gel and copper electrodes.

5. The method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to claim 4 is characterized in that: In the ethyl ion thermoelectric module, the copper electrode and the two ends of the PVDF-HFP / EMIM:DCA thermoelectric gel form a conductive path. When a temperature gradient exists between the two electrodes, the ethyl ion thermoelectric module can generate thermoelectric potential.

6. The method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to claim 4 is characterized in that: The heat pipe collector includes a solar heat pipe vacuum collector tube, a header and a cold source component. The hot end of the solar heat pipe vacuum collector tube is attached to one end of the ethyl ion thermoelectric module through a copper tube. The cold source component is a water pipe for circulating water. The water pipe is in contact with the other end of the ethyl ion thermoelectric module to form a temperature gradient.

7. The method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to claim 6 is characterized in that: The solar heat pipe vacuum collector tube of the heat pipe collector is fixed on a bracket with an inclination angle of 22.8° to the ground. The junction box connects the solar heat pipe vacuum collector tube and the cold source component. The cold source component also includes a water pump, a flow meter and a valve for controlling the water flow rate to 1L / min.

8. The method for preparing a thermoelectric module and heat pipe collector coupling system based on ethyl ion thermoelectric materials according to claim 7 is characterized in that: The coupling method of the ethyl ion thermoelectric module and the heat pipe collector is as follows: the hot end of the solar heat pipe vacuum collector is attached to one end of the thermoelectric module through a copper tube, and the flowing water in the water pipe contacts the other end of the thermoelectric module, forming a temperature gradient that drives thermoelectric conversion.

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