A sustainable self-powered system for energy harvesting and storage based on carbon felt

Abstract

The application discloses a sustainable self-powered system based on carbon felt energy collection and storage, comprising CTENG responsible for energy collection and CSSC responsible for energy storage and supply; the output end of the CTENG is connected with the input end of a power management circuit, the first output end of the power management circuit is connected with the input end of the CSSC, the output end of the CSSC is connected with a load, and the second output end of the power management circuit is connected with the load. The stator of the CTENG is prepared from carbon felt material, which can buffer the friction layer while transmitting induced charges, reduce friction loss, simplify the structure of the device, and improve stability and durability. Meanwhile, the active carbon felt is prepared, the CSSC is made of the active carbon felt, has good capacitor characteristics, and serves as a stable energy storage device to continuously supply power to the load.

Description

Technical Field

[0001] This invention relates to the field of generator technology, and in particular to a sustainable self-powered system based on carbon felt energy harvesting and storage. Background Technology

[0002] The rapid development of technology has presented new challenges and requirements for distributed energy supply. Collecting and storing wind energy in the environment is a necessary technology for realizing the Internet of Things. This includes two parts: energy harvesting equipment that converts wind energy into electricity and energy storage equipment that stores the electricity. Currently, wind energy harvesting is mainly based on wind turbines.

[0003] Energy is a core issue in the development of human civilization. Over the past three centuries, the extensive use of coal, oil, and natural gas has led to increasingly severe global warming. Widely used thermal power plants not only generate substantial carbon emissions but also, due to their ordered, point-to-point energy transmission characteristics, struggle to meet the demands of the next generation of interconnected devices. Therefore, a possible solution is to harvest high-entropy energy from the environment to create self-powered devices, thereby addressing the energy supply needs of distributed, disordered, and wireless small devices.

[0004] For example, based on the coupling effect of contact charging and electrostatic induction, triboelectric nanogenerators (TENGs) can convert irregular, scattered, and wasteful mechanical energy into electrical energy. Currently, there are many reports on the harvesting and utilization of high-entropy energy in the environment, such as using TENGs to harvest wind, wave, and mechanical energy to power some commonly used electronic devices, achieving self-powered operation. However, some aspects still require further optimization and improvement. For instance, TENGs can convert environmental energy such as wind and waves into electrical energy to drive electronic devices. However, relative energy conversion must be maintained at all times to ensure the continuous operation of the entire self-powered system. When the environment is static, stopping the input of external energy to the system will cause the self-powered system to suspend operation due to insufficient energy conversion.

[0005] To address the aforementioned issues, existing technologies have taken several steps, such as adding additional energy storage devices (e.g., capacitors) to the system, but the following problems still exist:

[0006] 1) Traditional energy storage devices have complex structures and short lifespans due to frequent charging and discharging, leading to maintenance difficulties. They also pose risks of fire and explosion, potentially damaging equipment or even causing fires when applied to the Internet of Things. Meanwhile, traditional wind turbines are also complex in structure, being large and heavy. These shortcomings of traditional energy storage and harvesting methods make it difficult for them to meet the needs of small-scale, distributed, sustainable self-powered electricity generation.

[0007] 2) Triboelectric nanogenerators have advantages such as small size, light weight, low cost, and easy maintenance, which are significant compared to traditional wind turbines. In particular, rotary triboelectric nanogenerators have good charge output efficiency and stable power output. However, poor contact between the friction layers can easily lead to tip discharge, thus reducing output. At the same time, solid-state contact between the two friction materials can also cause considerable frictional loss.

[0008] To address this issue, researchers have proposed adding a soft felt layer beneath the friction layer as a buffer to increase the contact area and reduce frictional losses. However, this approach complicates the already simple TENG device and reduces the structural stability of the material. Using a propeller to adjust the frictional losses between the friction layers provides good output at lower wind speeds, while separating the stator and rotor at higher wind speeds avoids frictional losses at high speeds. However, this device only operates at lower speeds, and its output at high speeds is not ideal. Furthermore, limited by the capacitance of traditional capacitors and the limited output performance of TENGs, the long-term driving performance under external loads remains unsatisfactory. Summary of the Invention

[0009] To address the technical problem of short autonomous driving time of existing TENGs (Tribometric Nanogenerators) under external load, this invention proposes a sustainable self-powered system based on carbon felt for energy harvesting and storage. Carbon felt is used as the buffer layer, sensing layer, and current collector of the CTENG (Carbon Felt Triboelectric Nanogenerator), which is responsible for energy harvesting. This simplifies the device structure and improves stability and durability. A CSSC (Carbon Felt Solid-State Supercapacitor) assembled from treated activated carbon felt is connected to the CTENG via an energy management circuit, enabling the system to harvest wind energy and achieve integrated energy harvesting and storage, thus increasing the autonomous driving time.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A sustainable self-powered system based on carbon felt energy harvesting and storage includes a CTENG (Chemical Coupling Engine) responsible for energy harvesting and a CSSC (Chemical Storage and Supply Engine) responsible for energy storage and supply. The output of the CTENG is connected to the input of a power management circuit, the first output of the power management circuit is connected to the input of the CSSC, the output of the CSSC is connected to the load, and the second output of the power management circuit is connected to the load.

[0012] Preferably, the CTENG includes a rotor and a stator; the stator includes a first substrate, a first substrate groove, a first sensing layer and a first friction layer; the first substrate groove is disposed on the upper surface of the first substrate, the first sensing layer is fixed inside the first substrate groove, and the first friction layer is fixed on the surface of the first sensing layer.

[0013] Preferably, the stator manufacturing steps include:

[0014] (v) Cut a 4mm thick acrylic sheet into a disc with an outer diameter of 230mm and an inner diameter of 10mm as the first substrate.

[0015] (vi) Cut a 2mm thick acrylic sheet into a disc of the same size as the first substrate. Use a laser cutting machine to manufacture a total of 32 fan-shaped units with an outer diameter of 220mm and an inner diameter of 100mm on the disc. Each fan-shaped unit is pasted on the first substrate with a spacing of 3mm to serve as the first substrate groove.

[0016] (vii) Print carbon felt into carbon felt sheets that are the same shape and size as the fan-shaped units of the first substrate groove, and fix them in the fan-shaped units of the first substrate groove as the first sensing layer.

[0017] (viii) A nylon film is attached to the surface of the first sensing layer as the first friction layer, and the first sensing layer under the nylon film is divided into two groups at intervals, and wires are connected to each group as output terminals.

[0018] Preferably, the rotor includes a second substrate and a second friction layer, with the second friction layer fixed to the surface of the second substrate.

[0019] Preferably, the manufacturing steps of the rotor include:

[0020] (i) Cut the acrylic sheet into a disc with an outer diameter of 230 mm and an inner diameter of 10 mm as the second substrate;

[0021] (ii) Cut the FEP film into FEP units that are the same shape and size as the carbon felt on the stator, and fix them alternately on the surface of the second substrate with a spacing of 6 mm as the second friction layer.

[0022] Preferably, the first friction layer of the stator and the second friction layer of the rotor are in close contact.

[0023] Preferably, the steps for creating the CSSC include:

[0024] The carbon felt was subjected to a first high-temperature treatment under an argon atmosphere, then removed and immersed in a potassium hydroxide solution; after freeze-drying, it was subjected to a second high-temperature treatment under a medium argon atmosphere, then removed and immersed in a hydrochloric acid solution, and finally removed, cleaned and dried to obtain activated carbon felt.

[0025] PVA-KOH solid electrolyte is dropped onto the surface of activated carbon felt, and then the activated carbon felt is attached to both ends of the electrolyte film to form two active electrodes. The active electrodes and the electrolyte film are then sealed together with tape. The two active electrodes are connected externally with wires as positive and negative electrodes.

[0026] Preferably, the charge-discharge time ratio of the sustainable self-powered system is 9.6:1.

[0027] In summary, by adopting the above technical solution, the present invention has at least the following beneficial effects compared with the prior art:

[0028] In this invention, the first induction layer of the stator in the generator is made of carbon felt material, which can transmit induced charge and also serve as a buffer for the friction layer, reducing friction loss, simplifying the structure of the device, and improving stability and durability.

[0029] Simultaneously, activated carbon felt is prepared, and CSSC is made using activated carbon felt. It has good capacitance characteristics and can serve as a stable energy storage device to continuously power the load. Attached image description:

[0030] Figure 1 This is a schematic diagram of a sustainable self-powered system based on carbon felt for energy harvesting and storage, according to an exemplary embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the stator in the CTENG according to an exemplary embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the rotor in the CTENG according to an exemplary embodiment of the present invention.

[0033] Figure 4 This is a schematic diagram illustrating the working principle of CTENG according to an exemplary embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of CTENG performance testing according to an exemplary embodiment of the present invention.

[0035] Figure 6 This is a schematic diagram illustrating the performance test of activated carbon felt according to an exemplary embodiment of the present invention.

[0036] Figure 7 This is a schematic diagram of the electrochemical testing of the activated carbon felt in a three-electrode system according to an exemplary embodiment of the present invention.

[0037] Figure 8 This is a schematic diagram of CSSC performance testing according to an exemplary embodiment of the present invention.

[0038] Figure 9 This is a schematic diagram of the voltage-time curve of a sustainable self-powered system based on carbon felt energy harvesting and storage, according to an exemplary embodiment of the present invention. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to embodiments and specific implementation methods. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0040] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] like Figure 1 As shown, this invention provides a sustainable self-powered system based on carbon felt energy harvesting and storage, including a CTENG (carbon felt-based triboelectric nanogenerator) responsible for energy harvesting and a CSSC (carbon felt-based solid-state supercapacitor) responsible for energy storage and supply; the CTENG is connected to the CSSC through a power management circuit, that is, the output terminal of the CTENG is connected to the input terminal of the power management circuit, the first output terminal of the power management circuit is connected to the input terminal of the CSSC, the output terminal of the CSSC is connected to the load, and the second output terminal of the power management circuit is directly connected to the load.

[0042] In this embodiment, the CTENG includes a rotor and a stator. The mover moves relative to the stator, or the mover can be fixed so that the stator moves relative to the mover. During the relative motion between the mover and the stator, electric charge will be generated.

[0043] In this embodiment, as Figure 2 As shown, the stator includes a first substrate, a first substrate groove, a first sensing layer, and a first friction layer. The first substrate groove is disposed on the upper surface of the first substrate, the first sensing layer is fixed inside the first substrate groove, and the first friction layer is fixed on the surface of the first sensing layer.

[0044] For example, the manufacturing process of the stator is as follows:

[0045] (ix) Cut a 4mm thick acrylic sheet into a disc with an outer diameter of 230mm and an inner diameter of 10mm (the inner hole is used to fix the rotating shaft) as the first substrate.

[0046] (x) A 2mm thick acrylic sheet was cut into a disc of the same size as the first substrate. A total of 32 sector-shaped units with an outer diameter of 220mm and an inner diameter of 100mm were manufactured on the disc using a laser cutting machine. Each sector-shaped unit was pasted on the first substrate with a spacing of 3mm to serve as the first substrate groove of the stator. Each sector-shaped unit was chamfered to prevent electrostatic breakdown.

[0047] (xi) Print carbon felt into carbon felt sheets (32 in total) that are the same shape and size as the fan-shaped units of the first substrate groove, and fix them in the fan-shaped units of the first substrate groove as the first sensing layer, and may also be a buffer layer and a current collection layer.

[0048] (iv) A nylon film is attached to the surface of the first sensing layer as the first friction layer. The first sensing layer (carbon felt) under the nylon film is then connected to the back of the acrylic plate in two groups according to the spaced units by conductive tape, and each group is connected with a wire as the two poles of the output terminal.

[0049] In this embodiment, as Figure 3 As shown, the rotor includes a second substrate and a second friction layer, with the second friction layer fixed to the surface of the second substrate.

[0050] For example, the manufacturing process of a rotor is as follows:

[0051] (i) Use a laser cutting machine to cut an acrylic sheet into a disc with an outer diameter of 230 mm and an inner diameter of 10 mm as a second substrate. The inner control of the second substrate is fixed to the rotating shaft by a flange.

[0052] (ii) Cut the FEP film into FEP units (number of 16) that are the same shape and size as the carbon felt on the stator, and fix them alternately at equal intervals (spacing of 6 mm) on the surface of the second substrate as the second friction layer.

[0053] In this embodiment, when assembling the stator and rotor, the first friction layer of the stator and the second friction layer of the rotor are brought into close contact and connected by a rotating shaft.

[0054] In this embodiment, when the second friction layer of the rotor and the first friction layer on the stator rub against each other, the induced charge generated by the friction between the first friction layer of the stator and the second friction layer of the rotor is transferred to the external load through the carbon felt.

[0055] In this embodiment, the nylon material of the first friction layer has extremely high electropositivity, while the FEP of the second friction layer has relatively high electronegativity. The difference in electronegativity between the two materials will generate electron transfer when they come into contact, thereby effectively generating charge output. The first sensing layer (carbon felt) has good flexibility and conductivity, which allows the nylon material and FEP to have a closer contact.

[0056] like Figure 4 The diagram shown illustrates the working principle of CTENG.

[0057] When the rotor begins to rotate, relative friction occurs between the second friction layer (FEP) and the first friction layer (nylon film) that are in contact with each other. The difference in electronegativity between the materials in the two friction layers leads to the separation of positive and negative charges during friction, such as... Figure 4As shown in Figure i; when the FEP film begins to move, the positive charge accumulated in the first sensing layer (carbon felt, i.e., activated carbon felt) flows from one first electrode to the other through the external circuit, as shown in Figure i. Figure 4 As shown in ii; when moving to the next stage, as... Figure 4 As shown in Figure iii, the charge distribution between the two first electrodes is reversed from the initial state. Ultimately, as... Figure 4 As shown in Figure iv, continuous friction can drive the periodic transfer of electrons between the first sensing layers through an external load, thereby generating a periodic current in the external circuit.

[0058] In this embodiment, the output performance of CTENG was also tested. For example... Figure 5 As shown in Figure a, the voltage output at different speeds was evaluated. CTENG showed a peak current of about 10uA at 25r and increased to 130uA at 300r. It is worth noting that the CTENG output current is linearly related to the speed and does not decay significantly at high speeds, indicating that CTENG can have a stable rising current output as the speed increases. Figure 5 As shown in Figure b, the voltage output curve from 25r to 300r is displayed. The open-circuit voltage of CTENG stabilizes at around 2000V at speeds from 25r to 300r. Figure 5 As shown in Figure c, the short-circuit transfer charge at different rotational speeds is displayed. The maximum transfer charge generated at 25 r exceeds 750 nC, indicating that CTENG has excellent output performance. Therefore, as Figure 5 As shown in Figure d, the effects of matching impedance and load resistance on peak power were tested at 150r and 300r respectively. It can be seen that under the optimal matching load of 1.2×107Ω, the peak power can reach 91.5mW.

[0059] In this embodiment, the CSSC (carbon felt-based solid-state supercapacitor) responsible for energy storage and supply includes carbon felt as the active material and PVA-KOH solid electrolyte.

[0060] The steps to create a CSSC are as follows:

[0061] The carbon felt was first subjected to a high-temperature treatment under an argon atmosphere (annealing at 800℃ for 2 hours followed by cooling). After the first high-temperature treatment, the carbon felt was removed and immersed in a 3 mol / L potassium hydroxide solution at room temperature for 12 hours. After freeze-drying, it underwent a second high-temperature treatment under an argon atmosphere (annealing at 800℃ for 2 hours). It was then removed and immersed in a 1 mol / L hydrochloric acid solution for 12 hours. After this period, it was removed, washed multiple times with deionized water and anhydrous ethanol, and then placed in an oven to dry at 80℃ for 12 hours to obtain activated carbon felt. The activated carbon felt was then cut into 1×2 cm pieces. 2To measure the size, take about 10 mL of 85℃ PVA-KOH solid electrolyte and drop it onto the surface of activated carbon felt. After being fully soaked for 2 hours, attach the activated carbon felt to both ends of the electrolyte film prepared from PVA-KOH solid electrolyte to form two active electrodes. Then, seal the active electrodes and electrolyte film as a whole with tape. Connect the two active electrodes externally with wires to serve as the positive and negative electrodes of the solid supercapacitor.

[0062] Preparation method of PVA-KOH solid electrolyte film:

[0063] Add 5 mL of 85℃ PVA-KOH solid electrolyte to a petri dish, freeze at -103℃ for 5 hours, then cool to room temperature. Repeat this process three times. Use a scriber to cut out an area of ​​1×2 cm². 2 Electrolyte membrane.

[0064] Two prepared CSSCs are connected in series as the energy storage component of a continuously self-powered device. The fabricated TENG and the solid-state supercapacitor are connected via a power management circuit.

[0065] In this embodiment, the activated carbon felt is subjected to performance tests, including XRD and BET tests. Figure 6 As shown in Figure a, the XRD diffraction peaks of the activated carbon felt are relatively flat on the 001 plane, while it has strong peaks on the 100 / 101 plane; as shown in Figure a. Figure 6 As shown in Figure b, the highest specific surface area reached 1124.4 m². 2 / g; such as Figure 6 As shown in Figure c, the activated carbon felt has a diameter of 0.9213 cm. 3 / g of high porosity.

[0066] In this embodiment, activated carbon felt was used as the active material of CSSC and electrochemical tests were performed using a three-electrode system. Figure 7 In the text, a and b represent linear sweep voltammetry curves; Figure 7 In the figure, 'c' represents the constant current discharge curve; Figure 7 In the figure, d represents the specific capacitance curve; Figure 7 In the figure, 'e' represents the cycle stability curve; Figure 7 In the figure, f represents the charge-discharge curve before and after cycling. From Figure 7 As can be seen from the three-electrode test, the activated carbon felt exhibits good capacitance characteristics in the alkaline electrolyte. The cyclic voltammetry curve is nearly rectangular and shows a series of redox peaks at a low scan rate. The discharge curve of the activated carbon station is basically linear, reaching a maximum specific capacitance of 402.4 F / g. After 20,000 cycles, it has an 89% capacitance retention rate. Moreover, the shape of the charge-discharge curve before and after 20,000 cycles does not change significantly.

[0067] In this embodiment, the prepared CSSC is subjected to performance testing. Figure 8 In this context, 'a' represents the cyclic voltammetry curve. Figure 8 In the figure, 'b' represents the charge / discharge curve. Figure 8 In the figure, 'c' represents the specific capacitance curve. From... Figure 8 As can be seen, CSSC still has ideal capacitance characteristics. The overall cyclic current-voltage curve presents a rectangular shape, and the charge-discharge curve presents an ideal isosceles triangle, with a maximum specific capacitance of about 101.8 F / g.

[0068] In this embodiment, the AC power generated by the CTENG is converted into DC power through a power management circuit (which can be an existing rectifier bridge circuit to convert AC power to DC power). Part of the DC power is supplied to the external load, and the excess is stored in the parallel-connected CSSC. When the CTENG stops working, the electrical energy stored in the CSSC can continue to supply power to the external load, enabling the external load to operate uninterruptedly throughout the entire process.

[0069] In this embodiment, to test the performance of the system, the system and a hygrometer are connected for testing. For example... Figure 9 As shown in Figure a, the system can charge the CSSC to 1.5V within 10 minutes under wind speeds of approximately 3 m / s. Figure 9 As shown in Figure b, when the airflow is stopped, the CSSC can power the hygrometer for more than 18 minutes. After 18 minutes, the hygrometer display dims, and the CSSC voltage drops to 1.1V. At a wind speed of 3m / s, the CTENG can recharge the CSSC from 1.1V to 1.5V within 2 minutes. It is worth noting that the hygrometer operates continuously throughout the entire process.

[0070] Calculations show that the charge-discharge time ratio is approximately 9.6:1. This means that in practical applications, if the actual working time of CTENG exceeds one-tenth of a day, it can achieve 24-hour continuous self-powered operation. This proves that by using CTENG and CSSC, uninterrupted self-powered operation can be achieved around the clock with only a short effective working time.

[0071] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A sustainable self-powered system based on carbon felt energy harvesting and storage, characterized in that... The system includes a carbon felt-based triboelectric nanogenerator (CTENG) responsible for energy harvesting and a carbon felt-based solid-state supercapacitor (CSSC) responsible for energy storage and supply. The output terminal of the CTENG is connected to the input terminal of a power management circuit. The first output terminal of the power management circuit is connected to the input terminal of the CSSC. The output terminal of the CSSC is connected to a load, and the second output terminal of the power management circuit is connected to the load. The carbon felt-based triboelectric nanogenerator (CTENG) includes a rotor and a stator; the stator includes a first substrate, a first substrate groove, a first sensing layer, and a first friction layer; the first substrate groove is disposed on the upper surface of the first substrate, the first sensing layer is fixed inside the first substrate groove, and the first friction layer is fixed on the surface of the first sensing layer; The stator manufacturing steps include: (i) Cut a 4mm thick acrylic sheet into a disc with an outer diameter of 230mm and an inner diameter of 10mm as the first substrate; (ii) Cut a 2mm thick acrylic sheet into a disc of the same size as the first substrate. Use a laser cutting machine to manufacture a total of 32 fan-shaped units with an outer diameter of 220mm and an inner diameter of 100mm on the disc. Each fan-shaped unit is pasted on the first substrate with a spacing of 3mm to serve as the first substrate groove. (iii) Print carbon felt into carbon felt sheets that are the same shape and size as the fan-shaped units of the first substrate groove, and fix them in the fan-shaped units of the first substrate groove as the first sensing layer. (iv) A nylon film is attached to the surface of the first sensing layer as a first friction layer, and the first sensing layer under the nylon film is divided into two groups at intervals, and wires are connected to each group as output terminals; The fabrication steps of the carbon felt-based solid-state supercapacitor (CSSC) include: The carbon felt was annealed at 800℃ under an argon atmosphere, then removed and immersed in a potassium hydroxide solution; after freeze-drying, it was annealed at 800℃ under a medium argon atmosphere, then removed and immersed in a hydrochloric acid solution, and finally removed, cleaned and dried to obtain activated carbon felt. PVA-KOH solid electrolyte is dropped onto the surface of activated carbon felt, and then the activated carbon felt is attached to both ends of the electrolyte film to form two active electrodes. The active electrodes and the electrolyte film are then sealed together with tape. The two active electrodes are connected externally with wires as positive and negative electrodes.

2. A sustainable self-powered system based on carbon felt energy harvesting and storage as described in claim 1, characterized in that... The rotor includes a second substrate and a second friction layer, with the second friction layer fixed to the surface of the second substrate.

3. A sustainable self-powered system based on carbon felt energy harvesting and storage as described in claim 2, characterized in that... The manufacturing steps of the rotor include: (i) Cut the acrylic sheet into a disc with an outer diameter of 230 mm and an inner diameter of 10 mm as the second substrate; (ii) Cut the FEP film into FEP units that are the same shape and size as the carbon felt on the stator, and fix them alternately on the surface of the second substrate at a spacing of 6 mm as the second friction layer.

4. A sustainable self-powered system based on carbon felt energy harvesting and storage as described in claim 1, characterized in that... This ensures that the first friction layer of the stator and the second friction layer of the rotor are in close contact.

5. A sustainable self-powered system based on carbon felt energy harvesting and storage as described in claim 1, characterized in that... The charge-discharge time ratio of the sustainable self-powered system is 9.6:1.

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