CN111740637A - Omnidirectional sliding energy harvesting device, flexible direct power supply microsystem and electronic equipment - Google Patents

Abstract

The invention discloses an omnidirectional sliding energy acquisition device, a flexible direct power supply micro system and electronic equipment, and relates to the technical field of micro energy, wherein the technical scheme is as follows: the omnidirectional energy acquisition unit comprises a sliding block and fixed blocks distributed in an array manner, and the sliding block and the fixed blocks form an independent sliding type friction nano generator; the sliding block and the fixed block are of grid-shaped structures, the fixed block comprises a first comb-shaped grid and a second comb-shaped grid which are symmetrical, the first comb-shaped grid and the second comb-shaped grid are formed by odd-numbered grids and even-numbered grids which are alternately arranged, and the odd-numbered grids and the even-numbered grids are respectively connected with a positive electrode and a negative electrode; when the sliding block slides along the X-axis direction, the odd-numbered grids and the even-numbered grids form electrodes of the friction nano generator; when the sliding block slides along the Y-axis direction, the first comb-shaped grid and the second comb-shaped grid form an electrode of the friction nano generator, and the problems that the existing friction nano generator is weak in charge transfer capacity and low in mechanical energy collection efficiency are solved.

Description

Omnidirectional sliding energy harvesting device, flexible direct power supply microsystem and electronic equipment

technical field

The invention relates to the technical field of micro-energy sources, and more particularly, to an omnidirectional sliding energy collection device, a flexible direct power supply micro-system and electronic equipment.

Background technique

As a newly developed field, the Internet of Things is developing very rapidly. The Internet of Things involves all aspects of our lives. Its huge network has brought new challenges to our current electronic industry. The energy demand of entering electronic devices is very urgent, and batteries and capacitors are usually used to power these devices. Due to their limited capacity and large size, they must be frequently charged or replaced, thus becoming impractical and disadvantageous. Harvesting energy from the mechanical energy of the surrounding environment or the biomechanical energy of human motion for sustainable work is one of the most promising strategies to address such problems. In the past few years, triboelectric nanogenerators (TENGs) are emerging as a promising energy harvesting method, which has the advantages of high performance, light weight, simple structure, low cost, and high efficiency.

The existing triboelectric nanogenerators can be mainly divided into four types according to the working mode: contact separation type, relative sliding type, independent sliding type, single-electrode type. The sliding type triboelectric nanogenerator has a larger energy density and a higher output. High, the traditional relative sliding type and independent sliding type both use a monolithic material as the friction layer, and there is no good separation process, so that the charge transfer cannot be completely transferred. In addition, the traditional sliding mode is to harvest mechanical energy only by reciprocating sliding in one direction, while in real life, it is often irregular sliding friction, resulting in low mechanical energy harvesting efficiency of triboelectric nanogenerators.

SUMMARY OF THE INVENTION

In order to solve the problems of weak charge transfer capability and low mechanical energy collection efficiency of the existing triboelectric nanogenerator, the present invention provides an omnidirectional sliding energy collection device, a flexible direct power supply microsystem and an electronic device.

The above-mentioned technical purpose of the present invention is achieved through the following technical solutions:

In a first aspect, an omnidirectional sliding energy harvesting device is provided, including:

at least one omnidirectional energy harvesting unit;

The omnidirectional energy harvesting unit includes a slider and at least two fixed blocks distributed in an array, and the slider and any one of the fixed blocks form an independent sliding friction nanogenerator;

The slider and the fixed block are both grid-shaped structures, and the fixed block includes a symmetrical first comb-tooth-shaped grid and a second comb-tooth-shaped grid, and the first comb-tooth-shaped grid and the second comb-tooth-shaped grid are both symmetrical. It is composed of alternately arranged odd-digit grids and even-digit grids, and the odd-digit grids and even-digit grids are respectively connected to the positive and negative electrodes;

When the slider slides along the X-axis direction, the odd-numbered grids and the even-numbered grids constitute the electrodes of the triboelectric nanogenerator;

When the slider slides along the Y-axis direction, the first comb-tooth-shaped grid and the second comb-tooth-shaped grid constitute electrodes of the triboelectric nanogenerator.

Preferably, the fixing block is provided with two first electrodes and two second electrodes;

The two first electrodes are located at opposite edges of the first comb-tooth-shaped grid and the second comb-tooth-shaped grid, and are connected to the corresponding odd-numbered bit grids;

The two second electrodes are located at the back edges of the first comb-tooth-shaped grid and the second comb-tooth-shaped grid, and are connected to the corresponding even-numbered bit grids.

Preferably, the fixing block and/or the slider is a flexible base polyimide film PI, and the friction surface of the fixing block is covered with a flexible polytetrafluoroethylene film PTFE.

Preferably, the surface of the grid structure is coated with a fibroin solution layer for humidity sensing and/or as a friction layer.

In a second aspect, a flexible direct power supply microsystem is provided, comprising cascaded micro energy harvesting devices and flexible energy management units, the micro energy harvesting devices and flexible energy management units are integrated in a flexible printed circuit board (FPCB) technology or screen printing technology. On the same flexible substrate, the micro energy harvesting device is the omnidirectional sliding energy harvesting device according to any one of claims 1-4.

Preferably, the flexible energy management unit includes a rectifier module, a peak detection module, a switch module, and a step-down module, and the switch module is connected in series between the rectifier module and the step-down module;

The rectifier module is used to convert the AC pulse voltage output by the micro-energy collection device into a DC pulse voltage and output it;

The peak detection module includes a voltage comparator, a logic circuit, and an RC differential circuit, which is used for pulse detection of the output DC pulse voltage, and sends a switch control signal to the switch module when the DC pulse voltage reaches a peak value;

The switch module is used to conduct the rectifier module and the step-down module after closing according to the switch control signal to realize the maximum transfer of energy;

The step-down module is used to step down and output the peak voltage output after the switch module is turned on.

Preferably, the bottom surface of the flexible substrate is covered with a PVDF piezoelectric film, and the PVDF piezoelectric film is cascaded with the flexible energy management unit.

Preferably, the flexible substrate is provided with a thermoelectric collection layer, and the thermoelectric collection layer is cascaded with the flexible energy management unit.

In a third aspect, an electronic device is provided, including at least one omnidirectional sliding energy harvesting device described in any one of the above.

In a fourth aspect, an electronic device is characterized in that it includes the flexible direct power supply microsystem described in any one of the above.

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

1. The system can collect sliding friction mechanical energy in any direction, solve the defect that traditional sliding friction nanogenerators can only slide in a certain direction, and improve the collection efficiency of mechanical energy;

2. The grid-like structure can realize rapid charge transfer and improve the energy collection capacity;

3. Convert triboelectricity into direct current and conduct step-down treatment to improve energy conversion efficiency;

4. By using flexible printed circuit board (FPCB) technology or screen printing technology, each module of the present invention is integrated on a flexible substrate polytetrafluoroethylene (PI) to become a flexible micro system that can be directly powered; the system integrates energy It integrates collection and energy management, and can be directly used as a power supply system to supply power to common electronic equipment;

5. The flexible energy management unit included in the present invention selects electronic components with small size and low power consumption, and the size of the energy management module is small, which can make it have better flexibility and bendability, which is compatible with friction nanogenerators and electronic equipment. It is easy to integrate and has broad application prospects for future technological development.

6. Compared with the traditional battery power supply, there is no flammable and explosive hazards and steps that need to be replaced regularly, which saves the earth's energy consumption and reduces pollution.

Description of drawings

The accompanying drawings described herein are used to provide further understanding of the embodiments of the present invention, and constitute a part of the present application, and do not constitute limitations to the embodiments of the present invention. In the attached image:

1 is a schematic diagram of the integration of a triboelectric nanogenerator and a flexible energy management unit of a single fixed block in an embodiment of the present invention;

Fig. 2 is the working principle diagram of the omnidirectional energy collection unit in the embodiment of the present invention;

3 is a schematic diagram of the integration of a triboelectric nanogenerator and a flexible energy management unit of multiple fixed blocks in an embodiment of the present invention;

4 is a functional block diagram of a flexible energy management unit in an embodiment of the present invention;

5 is a schematic circuit diagram of a flexible energy management unit in an embodiment of the present invention;

Fig. 6 is the equivalent circuit diagram of the opening and closing of the switch of the flexible energy management unit in the embodiment of the present invention;

Fig. 7 is the output voltage curve diagram of experimental verification of triboelectric nanogenerator in the embodiment of the present invention;

FIG. 8 is a graph showing a direct power supply from a flexible energy management unit to an energy storage capacitor in an embodiment of the present invention.

The marks in the attached drawings and the corresponding parts names:

101, rectifier module; 102, peak detection module; 103, switch module; 104, step-down module;

201, fixed block; 202, slider; 203, flexible polytetrafluoroethylene film PTFE; 204, flexible base polyimide film PI;

301, an odd bit grid; 302, an even bit grid; 303, a first electrode; 304, a second electrode; 305, a first comb-tooth grid; 306, a second comb-tooth grid.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to Embodiments 1-3 and accompanying drawings 1-8. The present invention is explained, but not limited to the present invention.

It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When an element is referred to as being "connected to" another element, it can be directly or indirectly connected to the other element.

It is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top" , "bottom", "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying the indicated device. Or elements must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. In the description of the present invention, "plurality" means two or more, unless otherwise expressly and specifically defined.

Embodiment 1: An omnidirectional sliding energy harvesting device, as shown in FIG. 1 and FIG. 3 , includes an omnidirectional energy harvesting unit. The omnidirectional energy harvesting unit includes a slider 202 and three fixed blocks 201 distributed in an array, namely S1, S2, and S3. The upper and lower spacing between adjacent fixed blocks 201 is 0.3 mm. The slider 202 is formed with any one of the fixed blocks 201. Independent sliding triboelectric nanogenerator. Among them, the fixed block 201 can be increased or decreased according to requirements.

As shown in FIG. 1 , the slider 202 and the fixing block 201 are both grid-shaped structures, and the fixing block 201 includes a symmetrical first comb-tooth-shaped grid 305 and a second comb-tooth-shaped grid 306 . The first comb-tooth-shaped grid The grid 305 and the second comb-shaped grid 306 are both composed of alternately arranged odd-digit grids 301 and even-digit grids 302, and the odd-digit grids 301 and even-digit grids 302 are respectively connected to positive and negative electrodes. It is defined that the first grid on the far left in the figure is an odd-numbered grid 301 , and the adjacent grids are an even-digit grid 302 . The grids are covered with copper, and each grid is 22mm long and 1.7mm wide.

As shown in FIG. 1 , the fixing block 201 is provided with two first electrodes 303 and two second electrodes 304 . The two first electrodes 303 are located at opposite edges of the first comb-tooth-shaped grid 305 and the second comb-tooth-shaped grid 306 , and are connected to the corresponding odd-numbered bit grids 301 . The two second electrodes 304 are located at the back edges of the first comb-tooth-shaped grid 305 and the second comb-tooth-shaped grid 306 , and are connected to the corresponding even-numbered bit grids 302 .

As shown in FIG. 2 , in this embodiment, the fixing block 201 and the sliding block 202 are flexible base polyimide films PI204. The friction surface of the fixed block 201 is covered with a flexible polytetrafluoroethylene film PTFE203 with a thickness of 0.01-0.1 mm.

In this embodiment, the surface of the grid structure is coated with a silk fibroin solution layer for realizing humidity sensing and as a friction layer.

The independent sliding triboelectric nanogenerator can realize the collection of mechanical energy sliding in any direction, as shown in Figure 1-3, and its basic working principle is as follows:

When the slider 202 slides along the X-axis direction, the adjacent odd-numbered grids 301 and even-numbered grids 302 form the two electrodes and the fixed friction layer of the triboelectric nanogenerator, and the odd-numbered grids 301 and the even-numbered grids 302 are each connected as the same electrode. When the free slider 202 slides in one direction, the slider 202 can realize fast switching between odd-numbered bits and even-numbered bits, and realize fast charge transfer of the triboelectric nanogenerator. The slider 202 adopts a grid structure, so that all the grids of the slider 202 can be in contact with all the odd-numbered grids 301 or even-numbered grids 302 of the fixed block 201 at the same time. When sliding in a certain direction, all the sliders 202 The grid is in contact with the odd bit grid 301 or the even bit grid 302 of the fixed block 201, the positive charge on the slider 202 remains unchanged, when the slider 202 slides on the fixed block 201, the fixed block 201 The electric charges on the electrodes of odd and even bits can be transferred quickly, and multiple adjacent grids can realize triboelectric power generation at the same time, which can improve the utilization rate and output capacity.

When the slider 202 slides along the Y-axis direction, all the first comb-tooth-shaped grids 305 and the second comb-tooth-shaped grids 306 form the friction layer and electrodes of the triboelectric nanogenerator of the independent slider 202 type. When the slider 202 slides from S1 to S2, the second comb-tooth grid 306 of S1 and the first comb-tooth grid 305 of S2 form the friction layer and electrodes of the triboelectric nanogenerator of the independent slider 202 type. When sliding along the Y-axis, the effective area of the friction layer is relatively large, and the output energy density is high. When the slider 202 slides irregularly, it can be decomposed into lateral and longitudinal sliding according to the vector property of the direction.

Embodiment 2: A flexible direct power supply microsystem, as shown in FIG. 2 and FIG. 3 , includes cascaded micro energy harvesting devices and a flexible energy management unit, and the flexible energy management unit has a small size. The micro energy harvesting device and the flexible energy management unit are integrated on the same flexible substrate through the flexible printed circuit board (FPCB) technology or screen printing technology, and the micro energy harvesting device is the omnidirectional sliding energy harvesting device described in Example 1.

As shown in FIG. 4 , the flexible energy management unit includes a rectifier module 101 , a peak detection module 102 , a switch module 103 , and a step-down module 104 . The switch module 103 is connected in series between the rectifier module 101 and the step-down module 104 .

The rectifier module 101 is used for converting the AC pulse voltage output by the micro-energy collection device into a DC pulse voltage and then outputting the voltage. The rectifier module 101 adopts a rectifier bridge with full-wave rectification, and is directly connected to different electrodes of the triboelectric nanogenerator.

As shown in FIG. 4 and FIG. 5 , the peak detection module 102 includes a voltage comparator, a logic circuit, and an RC differential circuit, which are used for pulse detection of the output DC pulse voltage, and send it to the switch module 103 when the DC pulse voltage reaches a peak value. switch control signal. The differential circuit includes a resistor R ₁ with a resistance value of 1-100 MΩ and a capacitor C ₁ with a capacitance value of 0.1-10 pF. The voltage comparator is a low-power zero-crossing comparator, which detects the peak value of the output voltage of the triboelectric nanogenerator. The logic circuit module includes two inverters, an AND gate And, a resistor R ₂ with a resistance value of 0.1-10 MΩ, and a capacitor C ₂ with a capacitance value of 1-10 pF.

As shown in Figure 5, the RC differential circuit can obtain the pulse slope. When the peak value is reached, the slope is 0. The voltage comparator outputs a low level, and goes through the first inverter Inv1 to a high level. The first inverter Inv1 The output goes through an RC delay circuit and the second inverter Inv2. The output of the two inverters is the AND gate And input, which can reduce the output pulse width of the comparator, and the pulse width is also the delay time of the delay circuit. This allows the switch to detect voltage peaks more accurately. The time constant of the differentiator (τ=C ₁ R ₁ ) must be much smaller than the duration of each peak of the TENG voltage (t _w ≥ 5τ). A delay unit consisting of an inverter, an AND gate and an RC delay circuit (C ₂ -R ₂ ) will generate a control time T when the comparator switches to the "high" state. T is mainly determined by the RC delay circuit, and its expression formula is T≈-R ₂ C ₂ ln((V _i -V _e )/V _e ). The logic circuit voltage is Vcc, so Vi=Vcc, Ve=0.3Vcc, so T≈0.36R ₂ C ₂ .

As shown in FIG. 5 , the switch module 103 is used to conduct the rectifier module 101 and the step-down module 104 to achieve maximum energy transfer after the switch control signal is closed, and the switch module 103 is a switch MOS transistor.

As shown in FIG. 5 and FIG. 6 , the step-down module 104 is used to step down and output the peak voltage output after the switch module 103 is turned on. The step-down module 104 is a Buck circuit composed of a diode _D , an inductance, and a capacitor C3. When the switch is closed, the inductance, the switch and the generator TENG form a loop. When the switch is turned off, the inductive current is generated due to the action of the inductance, which forms a loop with the diode _D and the capacitor C3, thereby realizing the charging _of the capacitor C3. The flexible energy management unit module of the single-inductance step-down circuit used in the present invention has the advantages of small size, soft substrate, etc., and is convenient to be integrated and wearable with electronic equipment. The inductor is a chip power inductor, the inductance value of the inductor is 10μH-10H, the diode D is a rectifier diode 1N4007, and the capacitance value of the capacitor C3 is 1μF _- 10F.

Embodiment 3: A flexible direct power supply microsystem. The difference between Embodiment 3 and Embodiment 2 is that the bottom surface of the flexible substrate is covered with a PVDF piezoelectric film, and the PVDF piezoelectric film is cascaded with the flexible energy management unit (not shown in the figure). show). The flexible substrate is provided with a thermoelectric collection layer, and the thermoelectric collection layer is cascaded with the flexible energy management unit (not shown in the figure). The piezoelectric and pyroelectric energy harvesters are integrated to realize multi-functional composite energy harvesting and humidity sensing.

Experimental verification and analysis:

Experiments were carried out on the output voltage value of the omnidirectional sliding energy harvesting device in Example 1 by sliding friction along the X-axis direction, the Y-axis direction and any direction. The experimental results are shown in FIG. 7 . Most of the mechanical motions in daily life are irregular, while the friction mode of most current triboelectric nanogenerators is regular. The frictional mechanical energy of sliding in any direction can be collected through the symmetrical grid structure of the array. The mechanical energy can also have a high efficiency collection capacity.

A 10 μF electrolytic capacitor is powered by a flexible direct power supply microsystem in Example 2, and the direct power supply curve is shown in FIG. 8 . In about 3.5s, the system directly charges the energy storage capacitor to 22V, which has high charging efficiency.

The specific embodiments described above further describe the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. Omnidirectional sliding energy collection device, characterized by includes:

at least one omnidirectional energy collection unit;

the omnidirectional energy acquisition unit comprises a sliding block (202) and at least two fixed blocks (201) distributed in an array, wherein the sliding block (202) and any one fixed block (201) form an independent sliding type friction nano generator;

the slider (202) and the fixed block (201) are both in a grid-shaped structure, the fixed block (201) comprises a first comb-tooth-shaped grid (305) and a second comb-tooth-shaped grid (306) which are symmetrical, the first comb-tooth-shaped grid (305) and the second comb-tooth-shaped grid (306) are both composed of an odd-numbered grid (301) and an even-numbered grid (302) which are alternately arranged, and the odd-numbered grid (301) and the even-numbered grid (302) are respectively connected with a positive electrode and a negative electrode;

when the sliding block (202) slides along the X-axis direction, the odd-numbered grids (301) and the even-numbered grids (302) form the electrode of the friction nano generator;

when the sliding block (202) slides along the Y-axis direction, the first comb-tooth-shaped grid (305) and the second comb-tooth-shaped grid (306) form the electrode of the friction nano-generator.

2. The omnidirectional sliding energy harvesting device according to claim 1, wherein said fixed block (201) is provided with two first electrodes (303), two second electrodes (304);

the two first electrodes (303) are positioned at the opposite edges of the first comb-tooth-shaped grid (305) and the second comb-tooth-shaped grid (306) and are connected with the corresponding odd-numbered grids (301);

the two second electrodes (304) are positioned at the back edges of the first comb-tooth-shaped grid (305) and the second comb-tooth-shaped grid (306) and are connected with the corresponding even-numbered grids (302).

3. The omni-directional sliding energy harvesting device according to claim 1, wherein the fixed block (201) and/or the sliding block (202) is a flexible substrate polyimide film PI (204), and the friction surface of the fixed block (201) is coated with a flexible polytetrafluoroethylene film PTFE (203).

4. The omni-directional sliding energy harvesting device according to claim 1, wherein the surface of the grating structure is coated with a fibroin solution layer for moisture sensing and/or as a friction layer.

5. A flexible direct power supply microsystem is characterized by comprising a micro energy acquisition device and a flexible energy management unit which are cascaded, wherein the micro energy acquisition device and the flexible energy management unit are integrated on the same flexible substrate through a Flexible Printed Circuit Board (FPCB) technology or a screen printing technology, and the micro energy acquisition device is the omnidirectional sliding energy acquisition device as claimed in any one of claims 1 to 4.

6. The flexible direct power supply microsystem as claimed in claim 5, wherein the flexible energy management unit comprises a rectification module (101), a peak detection module (102), a switch module (103) and a voltage reduction module (104), wherein the switch module (103) is connected in series between the rectification module (101) and the voltage reduction module (104);

the rectifying module (101) is used for converting the alternating current pulse voltage output by the micro energy collecting device into direct current pulse voltage and then outputting the direct current pulse voltage;

the peak value detection module (102) comprises a voltage comparator, a logic circuit and an RC differential circuit, and is used for carrying out pulse detection on the output direct current pulse voltage and sending a switch control signal to the switch module (103) when the direct current pulse voltage reaches a peak value;

the switch module (103) is used for conducting the rectifying module (101) and the voltage reduction module (104) after being closed according to the switch control signal so as to realize maximum energy transfer;

and the voltage reduction module (104) is used for reducing the peak voltage output after the switch module (103) is conducted and then outputting the reduced peak voltage.

7. The flexible direct power supply microsystem as claimed in claim 5, wherein the flexible substrate is coated with a PVDF piezoelectric film on the bottom surface, and the PVDF piezoelectric film is cascaded with the flexible energy management unit.

8. The flexible direct power microsystem as claimed in claim 5, wherein the flexible substrate is provided with a thermoelectric collection layer, the thermoelectric collection layer being cascaded with the flexible energy management unit.

9. An electronic device comprising at least one omni-directional sliding energy harvesting device as claimed in any of claims 1 to 4.

10. An electronic device comprising at least one flexible direct current powered microsystem as claimed in claim 5.

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