A piezoelectric triboelectric rotational energy harvester

Abstract

The present invention discloses a piezoelectric triboelectric rotary energy harvester, comprising a housing, a central shaft, and a power generation assembly. The central shaft is disposed within the housing and fixed relative to the circumference of the housing. The power generation assembly comprises an arched piezoelectric sheet, a sliding shaft, a first electrode layer, a first thin film layer, a second electrode layer, and a second thin film layer. Multiple arched piezoelectric sheets are circumferentially disposed on the outer circumference of the central shaft. Multiple sliding shafts corresponding to the arched piezoelectric sheets are radially slidably disposed within the housing. A first electrode layer and a first thin film layer are sequentially disposed on the end surface of each sliding shaft away from the central shaft. Multiple second electrode layers corresponding to the first electrode layers are disposed on the inner circumference of the housing. A second thin film layer is disposed on the inner side surface of each second electrode layer. The overall radial length of the sliding shaft, the first electrode layer at one end thereof, and the first thin film layer is less than the radial spacing between the corresponding arched piezoelectric sheet and the second thin film layer. The present invention can achieve small-scale, continuous power supply for micro-sized devices.

Description

Technical Field

[0001] The present invention relates to the technical field of triboelectric nano-power generation and piezoelectric power generation, and in particular to a piezoelectric triboelectric rotary energy collector. Background Art

[0002] In recent years, the Internet of Things (IoT) has experienced unprecedented growth. Almost every object now uses electricity, and with the increasing use of electricity, powering these devices has become a pressing challenge. Currently, most energy-supplying devices on the market are unable to achieve small-scale, sustainable power supply. With the introduction of triboelectric nanogenerators (FNGMs), micro-scale, sustainable energy supply has become a reality. FNGMs are environmentally friendly, sustainable, and low-cost generators with excellent application prospects. Furthermore, most objects in our daily lives experience motion, and rotation, as a typical example of motion, has numerous applications. Combining FNGMs with rotational motion offers numerous possibilities for continuously powering micro-devices. To this end, we propose a piezoelectric triboelectric rotational energy harvester that can continuously power micro-devices. Summary of the Invention

[0003] The purpose of the present invention is to provide a piezoelectric triboelectric rotational energy harvester to solve the problems existing in the above-mentioned prior art. It can utilize the coupling of contact electrification and electrostatic induction as well as the piezoelectric effect to collect rotational energy to achieve small-scale and continuous power supply for micro-devices.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a piezoelectric triboelectric rotary energy collector, comprising a shell, a central shaft and a power generation component, wherein the central shaft is arranged in the shell and fixed relative to the circumference of the shell, the power generation component comprises an arched piezoelectric sheet, a sliding shaft, a first electrode layer, a first thin film layer, a second electrode layer and a second thin film layer, a plurality of the arched piezoelectric sheets are arranged circumferentially on the outer circumference of the central shaft, and the arched opening of each arched piezoelectric sheet is arranged inward, a plurality of sliding shafts corresponding to each arched piezoelectric sheet are arranged radially in the shell, the first electrode layer and the first thin film layer are sequentially arranged on the end surface of each sliding shaft away from the central shaft, and a plurality of sliding shafts are arranged on the inner circumference of the shell. A plurality of second electrode layers respectively correspond to the first electrode layers, and the second thin film layer is arranged on the inner side of each second electrode layer. Each second thin film layer is respectively arranged corresponding to each first thin film layer. The overall radial length of the sliding shaft and the first electrode layer at one end thereof and the first thin film layer is smaller than the radial spacing between the corresponding arched piezoelectric piece and the second thin film layer. When the housing rotates, the sliding shaft moves back and forth in the radial direction to impact the arched piezoelectric piece and the second thin film layer respectively. The arched piezoelectric piece generates voltage due to the piezoelectric effect, and the first thin film layer and the second thin film layer achieve periodic contact and separation, and generate current due to the frictional electrification effect.

[0006] Preferably, the outer shell comprises two symmetrically arranged half shells, and each of the half shells is respectively provided with a plurality of the power generation components uniformly distributed along the circumferential direction.

[0007] Preferably, the two opposite inner side surfaces of the two half shells are provided with first semicircular grooves corresponding to the respective sliding shafts, and a positioning block is provided in the middle of the two half shells. The positioning block is fixedly connected to the two half shells in the circumferential direction, and the two side surfaces of the positioning block are provided with second semicircular grooves corresponding to the respective first semicircular grooves and forming circular slides, and each of the circular slides is slidably connected to one of the sliding shafts.

[0008] Preferably, the outer sides of the two half-shells are respectively provided with a first end cover and a second end cover, and the first end cover and the second end cover are both provided with a plurality of limiting protrusions, and the side surfaces of the two half-shells are provided with limiting grooves corresponding to the limiting protrusions, and the limiting protrusions are inserted into the limiting grooves corresponding to them, one end of the central shaft extends into the outer shell and passes through the positioning block, and the other end is fixedly connected to the first end cover, and a bolt hole is provided on the end face of the central shaft extending into the outer shell, and a fastening bolt passes through the through hole on the second end cover and is threadedly connected to the bolt hole, so that the first end cover, the two half-shells, the positioning block and the second end cover are pressed and fixedly connected.

[0009] Preferably, the first film layer is a polyimide film, and the second film layer is a PMMA film.

[0010] Preferably, a plurality of mounting grooves are provided on the outer peripheral surface of the central shaft along the circumferential direction, and the two ends of the arched piezoelectric piece are respectively installed in two adjacent mounting grooves and fixed by industrial glue.

[0011] Preferably, a plurality of evenly distributed circular protrusions are provided on the inner circumferential surface of the housing, each second electrode layer is respectively bonded to the inner side surface of each circular protrusion, and each second film layer is respectively bonded to each second electrode layer.

[0012] Preferably, the first electrode layer is bonded to an end surface of the sliding shaft away from the central axis, and the first film layer is bonded to the first electrode layer.

[0013] Preferably, the surface of the first film layer is processed with a nanostructure or a microstructure.

[0014] Preferably, the positioning block is circumferentially fixedly connected to the two half-shells via cylindrical pins.

[0015] Compared with the prior art, the present invention has achieved the following technical effects:

[0016] The present invention provides a piezoelectric triboelectric rotary energy harvester. Utilizing the coupling effects of contact electrification and electrostatic induction, when two different materials rub against each other, their different electron-accepting capacities generate equal and opposite charges on their surfaces. As the telescopic shaft moves, a potential difference forms between the two electrode layers, which drives the induced charges within the electrode layers to move in a directional manner, thereby generating current. Utilizing the piezoelectric effect, when an arched piezoelectric plate located on the central axis is impacted by the sliding shaft, the dielectric within the arched piezoelectric plate is subjected to an external force in a certain direction, causing it to deform. Polarization occurs within the arched piezoelectric plate, and opposite positive and negative charges appear on two opposing surfaces of the arched piezoelectric plate, thereby generating a voltage. Based on the coupling effects of contact electrification and electrostatic induction, as well as the piezoelectric effect, the present invention absorbs the mechanical energy generated by rotation and converts it into electrical energy for subsequent use in micro-sized devices, thereby achieving the goal of providing power to micro-sized devices on a small scale and continuously. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] Figure 1A schematic diagram of the three-dimensional structure of the piezoelectric triboelectric rotational energy harvester provided by the present invention;

[0019] Figure 2 A front view of the piezoelectric triboelectric rotary energy harvester provided by the present invention;

[0020] Figure 3 A right side view of the piezoelectric triboelectric rotary energy harvester provided by the present invention;

[0021] Figure 4 An exploded view of the piezoelectric triboelectric rotary energy harvester provided by the present invention;

[0022] Figure 5 A cross-sectional view of the piezoelectric triboelectric rotary energy harvester provided by the present invention;

[0023] Figure 6 It is a structural schematic diagram of the power generation component in the present invention;

[0024] In the figure: 1-housing, 2-central axis, 3-power generation component, 4-arched piezoelectric sheet, 5-sliding shaft, 6-first electrode layer, 7-first thin film layer, 8-second electrode layer, 9-second thin film layer, 10-half shell, 11-first semicircular groove, 12-positioning block, 13-second semicircular groove, 14-first end cover, 15-second end cover, 16-limiting cam, 17-limiting groove, 18-fastening bolt, 19-mounting groove, 20-circular protrusion, 21-cylindrical pin. DETAILED DESCRIPTION

[0025] 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.

[0026] The purpose of the present invention is to provide a piezoelectric triboelectric rotational energy harvester to solve the problems existing in the prior art. It can utilize the coupling of contact electrification and electrostatic induction as well as the piezoelectric effect to collect rotational energy to achieve small-scale and continuous power supply for micro-devices.

[0027] 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.

[0028] like Figures 1-6As shown, this embodiment provides a piezoelectric triboelectric rotary energy collector, including a shell 1, a central shaft 2 and a power generation component 3. The central shaft 2 is arranged in the shell 1 and is fixed relative to the shell 1 in the circumferential direction. The power generation component 3 includes an arched piezoelectric sheet 4, a sliding shaft 5, a first electrode layer 6, a first film layer 7, a second electrode layer 8 and a second film layer 9. A plurality of arched piezoelectric sheets 4 are arranged circumferentially on the outer circumference of the central shaft 2, and the arched opening of each arched piezoelectric sheet 4 is arranged inward. A plurality of sliding shafts 5 corresponding to each arched piezoelectric sheet 4 are radially slidably arranged in the shell 1, and a first electrode layer 6 and a first film layer 7 are sequentially arranged on the end surface of each sliding shaft 5 away from the central shaft 2. A plurality of second electrode layers 8 corresponding to the first electrode layers 6 are provided on the inner circumferential surface of the shell 1, and a second thin film layer 9 is provided on the inner side of each second electrode layer 8. Each second thin film layer 9 is provided corresponding to each first thin film layer 7. The overall radial length of the sliding shaft 5 and the first electrode layer 6 and the first thin film layer 7 at one end thereof is smaller than the radial spacing between the corresponding arched piezoelectric piece 4 and the second thin film layer 9. When the outer shell 1 rotates, the sliding shaft 5 moves back and forth in the radial direction to impact the arched piezoelectric piece 4 and the second thin film layer 9 respectively. The arched piezoelectric piece 4 generates voltage due to the piezoelectric effect, and the first thin film layer 7 and the second thin film layer 9 achieve periodic contact and separation, and generate current due to the frictional electrification effect.

[0029] The rotation of the central axis 2 drives the entire energy collector to rotate, and then the sliding shaft 5 inside the energy collector produces radial reciprocating motion due to gravity. When the sliding shaft 5 moves radially toward the center of the circle, the impact force causes the arched piezoelectric plate 4 to vibrate. The dielectric inside the arched piezoelectric plate 4 is deformed in a certain direction by the external force, causing polarization inside the arched piezoelectric plate 4. At the same time, opposite positive and negative charges appear on the two opposing surfaces of the arched piezoelectric plate 4, thereby generating a voltage. At the same time, the reciprocating motion of the sliding shaft 5 causes the first thin film layer 7 located on the sliding shaft 5 to periodically contact and separate from the second thin film layer 9 located on the outer shell 1. When the first thin film layer 7 and the second thin film layer 9 separate, the distance between the two layers gradually increases, forming a potential difference between the two electrodes. The potential difference drives electrons from the first electrode layer 6 to the second electrode layer 8, generating a positive current. When the distance between the first thin film layer 7 and the second thin film layer 9 begins to decrease, the potential of the first electrode layer 6 becomes higher than that of the second electrode layer 8, causing electrons to flow from the second electrode layer 8 back to the first electrode layer 6, generating a negative current. This energy harvester, based on the coupling of contact electrification and electrostatic induction, as well as the piezoelectric effect, absorbs the mechanical energy generated by rotation and converts it into electrical energy for subsequent use in the micro-device, thereby achieving the goal of providing small-scale, continuous power to micro-devices.

[0030] In this embodiment, the housing 1 includes two symmetrically arranged half shells 10, each of which is provided with a plurality of circumferentially evenly distributed power generation components 3. By providing a plurality of power generation components 3, more power can be generated and power generation efficiency can be improved.

[0031] In this embodiment, the opposing inner sides of the two half-shells 10 are provided with first semicircular grooves 11, corresponding to the respective sliding shafts 5. A retaining block 12 is provided between the two half-shells 10. The retaining block 12 is circumferentially fixedly connected to the two half-shells 10. The retaining block 12 has second semicircular grooves 13 on both sides thereof, corresponding to the first semicircular grooves 11 and forming circular slideways. Each circular slideway is slidably connected to a sliding shaft 5. The circular slideways guide and limit the sliding shaft 5, facilitate installation, and enable radial reciprocating movement of the sliding shaft 5.

[0032] In this embodiment, the outer sides of the two half-shells 10 are respectively provided with a first end cap 14 and a second end cap 15. Each of the first and second end caps 14 and 15 is provided with a plurality of stopper protrusions 16. Stopper grooves 17 corresponding to each stopper protrusion 16 are provided on the sides of the two half-shells 10. Each stopper protrusion 16 is inserted into its corresponding stopper groove 17. One end of the central shaft 2 extends into the outer shell 1 and passes through the stopper block 12. The other end is fixedly connected to the first end cap 14. Bolt holes are provided on the end surface of the central shaft 2 extending into the outer shell 1. Fastening bolts 18 pass through through-holes in the second end cap 15 and are threadedly connected to the bolt holes, thereby pressing and securing the first end cap 14, the two half-shells 10, the stopper block 12, and the second end cap 15 together. The stopper protrusions 16 are evenly distributed along the circumference, ensuring a more stable connection between the first and second end caps 14, 15, and the half-shells 10. Four fastening bolts 18 are evenly distributed along the circumference to ensure a secure connection.

[0033] In this embodiment, the first film layer 7 is a polyimide film, and the second film layer 9 is a PMMA film.

[0034] In this embodiment, a plurality of mounting grooves 19 are provided along the circumferential direction on the outer peripheral surface of the central axis 2. The two ends of the arched piezoelectric piece 4 are respectively installed in two adjacent mounting grooves 19 and fixed by industrial glue. The arched piezoelectric piece 4 is installed and positioned by the mounting grooves 19 and fixed by industrial glue, and the installation is convenient and reliable.

[0035] In this embodiment, a plurality of evenly distributed circular protrusions 20 are provided on the inner circumference of the housing 1 , each second electrode layer 8 is bonded to the inner side surface of each circular protrusion 20 , and each second film layer 9 is bonded to each second electrode layer 8 .

[0036] In this embodiment, the first electrode layer 6 is bonded to an end surface of the sliding shaft 5 away from the central axis 2 , and the first film layer 7 is bonded to the first electrode layer 6 .

[0037] In this embodiment, the surface of the first film layer 7 is processed with nanostructures or microstructures, such as nanoparticles, nanogrooves, and microgrooves, to increase the contact area, thereby generating more friction charges on the surface and enhancing the output electrical energy.

[0038] In this embodiment, the positioning block 12 is fixedly connected to the two half-shells 10 in the circumferential direction via cylindrical pins 21 . A plurality of cylindrical pins 21 are provided and evenly distributed along the circumference to ensure the stability of the connection.

[0039] The working principle of the present invention is as follows: when the central shaft 2 is subjected to force and starts to rotate, due to the matching relationship, it drives the outer shell 1, the positioning block 12, the sliding shaft 5, the arched piezoelectric sheet 4, the first end cover 14 and the second end cover 15 to start rotating. Since the rotation speeds of the outer shell 1, the sliding shaft 5 and the arched piezoelectric sheet 4 are the same, the relative positions of each sliding shaft 5 and the corresponding second electrode layer 8, the second film layer 9 (PMMA film) and the arched piezoelectric sheet 4 remain unchanged. When the energy collector rotates, due to the influence of gravity, the sliding shaft 5 will produce reciprocating linear motion along the circular slide formed by the combination of the outer shell 1 and the positioning block 12. When the sliding shaft 5 is below the center of the circle, the sliding shaft 5 will impact toward the outside of the outer shell 1 as a whole due to the action of gravity. When the sliding shaft 5 rotates to a position above the center of the circle, it will impact toward the center of the circle as a whole due to the action of gravity.

[0040] The impact force of the sliding shaft 5 causes the arched piezoelectric piece 4 to vibrate. The dielectric inside the arched piezoelectric piece 4 is deformed in a certain direction by the external force, and polarization occurs inside the arched piezoelectric piece 4. At the same time, opposite positive and negative charges appear on the two opposite surfaces of the arched piezoelectric piece 4, thereby generating voltage.

[0041] The impact of the sliding shaft 5 simultaneously causes the first electrode layer 6 and first film layer 7 (Kapton film) on the sliding shaft 5 to periodically contact and separate with the second film layer 9 and second electrode layer 8 on the housing 1. When the first film layer 7 and the second film layer 9 come into contact, a triboelectric effect causes charge transfer between the two materials. Electrons on the surface of the polymethyl methacrylate (PMMA) transfer to the surface of the polyimide (Kapton), resulting in a negative charge on the surface of the Kapton film and a positive charge on the surface of the PMMA film. It is noteworthy that polymers have excellent insulating properties, so the surface charge can persist for a long time, up to several hours or even days. Because these charges are confined to the surface, and the two equal and opposite charges are in the same plane, there is still no potential difference between the two electrodes. As the Kapton film and the PMMA film separate, the distance between the two layers gradually increases, forming a potential difference between the two electrodes. This potential difference drives electrons from the first electrode layer 6 to the second electrode layer 8, generating a forward current. When the distance between the Kapton film and the PMMA film begins to decrease, the potential of the first electrode layer 6 becomes higher than that of the second electrode layer 8. This causes electrons to flow from the second electrode layer 8 back to the first electrode layer 6, reducing the amount of induced charge on the electrodes and generating a negative current. When the Kapton film and the PMMA film come into contact again, all the induced charges are neutralized.

[0042] The present invention has certain adaptability. During the rotation of the central shaft, within a certain speed range (to ensure that the sliding shaft can generate reciprocating motion), the faster the rotation speed, the stronger the electromechanical conversion ability of friction power generation and piezoelectric power generation, and the more output electrical energy.

[0043] In the present invention, both friction power generation and piezoelectric power generation adopt a double-layer annular array method to achieve more sliding shafts generating reciprocating motion, more arched piezoelectric sheets generating vibration, and more friction power generation sheets generating contact and separation within a unit period under low rotation speed, thereby improving power generation efficiency.

[0044] The present invention 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 piezoelectric triboelectric rotary energy harvester, characterized by: The invention comprises a shell, a central shaft and a power generation component, wherein the central shaft is arranged in the shell and fixed relative to the circumference of the shell, the power generation component comprises an arched piezoelectric sheet, a sliding shaft, a first electrode layer, a first film layer, a second electrode layer and a second film layer, a plurality of the arched piezoelectric sheets are arranged circumferentially on the outer circumference of the central shaft, a plurality of the sliding shafts corresponding to the arched piezoelectric sheets are arranged radially and slidingly in the shell, the first electrode layer and the first film layer are sequentially arranged on the end surface of each sliding shaft away from the central shaft, and a plurality of the second film layers corresponding to the first electrode layers are arranged on the inner circumference of the shell. electrode layer, the second thin film layer is arranged on the inner side of each second electrode layer, and each second thin film layer is arranged corresponding to each first thin film layer respectively. The overall radial length of the sliding shaft and the first electrode layer and the first thin film layer at one end thereof is less than the radial spacing between the corresponding arched piezoelectric piece and the second thin film layer. When the shell rotates, the sliding shaft moves back and forth in the radial direction to impact the arched piezoelectric piece and the second thin film layer respectively. The arched piezoelectric piece generates voltage due to the piezoelectric effect, and the first thin film layer and the second thin film layer achieve periodic contact and separation, and generate current due to the frictional electrification effect.

2. The piezoelectric triboelectric rotary energy harvester according to claim 1, characterized in that: The housing comprises two symmetrically arranged half shells, each of which is provided with a plurality of the power generation components evenly distributed along the circumferential direction; the arched opening of each arched piezoelectric sheet is arranged toward the axis of the central axis.

3. The piezoelectric triboelectric rotary energy harvester according to claim 2, characterized in that: The two opposite inner side surfaces of the two half shells are provided with first semicircular grooves corresponding to the respective sliding shafts, and a positioning block is provided in the middle of the two half shells. The positioning block is fixedly connected to the two half shells in the circumferential direction, and the two side surfaces of the positioning block are provided with second semicircular grooves corresponding to the respective first semicircular grooves and forming circular slides, and each of the circular slides is slidably connected to one of the sliding shafts.

4. The piezoelectric triboelectric rotary energy harvester according to claim 3, characterized in that: The outer sides of the two half shells are respectively provided with a first end cover and a second end cover, and the first end cover and the second end cover are both provided with a plurality of limiting protrusions, and the side surfaces of the two half shells are provided with limiting grooves corresponding to the limiting protrusions, and the limiting protrusions are inserted into the limiting grooves corresponding to them. One end of the central shaft extends into the outer shell and passes through the positioning block, and the other end is fixedly connected to the first end cover. A bolt hole is provided on the end surface of the central shaft extending into the outer shell, and a fastening bolt passes through the through hole on the second end cover and is threadedly connected to the bolt hole, so that the first end cover, the two half shells, the positioning block and the second end cover are pressed and fixedly connected.

5. The piezoelectric triboelectric rotary energy harvester according to claim 1, characterized in that: The first film layer is a polyimide film, and the second film layer is a PMMA film.

6. The piezoelectric triboelectric rotary energy harvester according to claim 1, characterized in that: A plurality of mounting grooves are arranged on the outer peripheral surface of the central shaft along the circumferential direction, and the two ends of the arched piezoelectric piece are respectively installed in two adjacent mounting grooves and fixed by industrial glue.

7. The piezoelectric triboelectric rotary energy harvester according to claim 1, characterized in that: A plurality of evenly distributed circular protrusions are provided on the inner circumferential surface of the shell, each second electrode layer is respectively bonded to the inner side surface of each circular protrusion, and each second film layer is respectively bonded to each second electrode layer.

8. The piezoelectric triboelectric rotary energy harvester according to claim 1, characterized in that: The first electrode layer is bonded to an end surface of the sliding shaft away from the central axis, and the first film layer is bonded to the first electrode layer.

9. The piezoelectric triboelectric rotary energy harvester according to claim 1, characterized in that: The surface of the first film layer is processed with a nanostructure or a microstructure.

10. The piezoelectric triboelectric rotational energy harvester according to claim 3, characterized in that: The positioning block is fixedly connected to the two half shells in the circumferential direction via a cylindrical pin.

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