KR20200005297A - Wrist-wearable type energy harvester and fabricating method thereof - Google Patents

Abstract

Disclosed are a wrist-wearable type energy harvester and a manufacturing method thereof. According to an embodiment of the present invention, the wrist-wearable type energy harvester comprises: a main body forming at least a part of a hollow curved tube; a magnet moving in the curved tube; a metal electrode formed outside the main body and charged in accordance with movements of the magnet in the main body; a coil formed outside the metal electrode or formed outside the main body by being spaced apart from the metal electrode and inducing current in accordance with the movements of the magnet; and a housing coupled with the main body and forming the curved tube. A triboelectricity generator is formed of the main body, the magnet, and the metal electrode. An electromagnetism generator is formed of the main body, the magnet, and the coil.

Description

Wrist wearable energy harvester and its manufacturing method {Wrist-wearable type energy harvester and fabricating method

The present invention relates to energy harvester technology.

Smart wearable devices are expanding the reach of the IoT industry, and smart bands and watches that can be worn on the wrist are the most common examples of IoT devices that monitor the body or health. However, all these smart devices need replaceable or rechargeable batteries. The use of such a battery has disadvantages such as limited life of the battery, inconvenience of replacement, environmental hazards, size of the battery, and cost of maintenance.

Therefore, in order to reduce the battery dependency of the wearable electronic device, a practically useful and efficient wearable energy harvester for power supply of an IoT device or a healthcare monitoring sensor is essential.

According to an embodiment of the present disclosure, the electronic device may be powered by an electronic device through a self-driving device that is light, inexpensive, and easy to operate, and converts the body's biomechanical energy into electrical energy through a natural swinging motion of the human body. We propose a wrist wearable energy harvester and a method of manufacturing the same.

Wrist-worn energy harvester according to an embodiment, the main body constituting at least a portion of the hollow curved tube, a magnet moving in the interior of the curved tube, and formed on the outside of the main body is charged in accordance with the movement of the magnet in the body A metal electrode, a coil formed on the outside of the metal electrode or spaced apart from the metal electrode, and formed on the outside of the main body and inducing current according to the movement of the magnet in the main body, and a housing constituting the curved tube in combination with the main body; The main body, the magnet and the metal electrode constitute a triboelectric generator, and the main body, the magnet and the coil constitute an electromagnetic generator.

Wrist-worn energy harvesters can convert low-frequency biomechanical energy into electrical energy by swinging a person's arm while moving.

The magnet is a spherical magnetic ball that freely rolls in a curved tube, the triboelectric generator generates triboelectric energy based on the contact charging and electrostatic induction of the metal electrode by the rolling of the magnet in the body, and the electromagnetic generator generates the magnet in the body Electromagnetic energy may be generated based on electromagnetic induction of the coil by rolling of.

The body may be composed of a triboelectric charge material. The main body may have a polymer thin film composed of a triboelectric charge material inserted into the main body to form a composite triboelectric charge layer composed of the triboelectric charge material of the main body and the polymer thin film inserted therein. The polymer thin film may have a nanostructure on the surface of the polymer thin film to increase the effective contact area between the magnet and the body. The body may be manufactured through any one of a 3D printing method, an injection method, and an extrusion method.

The metal electrode may have a multi-ring shape in which a plurality of metal electrodes are formed in pairs in the shape of the outer surface of the main body. The coil may be located at both ends of the body open from the housing. The wrist worn energy harvester may further include a ferrite thin film formed between the coil and the body to focus the magnetic flux.

According to another embodiment of the present invention, a method for manufacturing a wrist-worn energy harvester includes: constructing a main body constituting at least a portion of a hollow curved tube, inserting a magnet into the main body, and forming a metal electrode outside the main body. And forming a coil outside the metal electrode or spaced apart from the metal electrode, and assembling a curved tube by combining the body and the housing.

The step of configuring the main body can be configured through a 3D printing method. The wrist wearable energy harvester manufacturing method may further include inserting a polymer thin film made of a triboelectric charge material into the body. In this case, the method may further include forming a nanostructure on the surface of the polymer thin film to increase the effective contact area between the magnet and the main body.

Wrist wearable energy harvester according to an embodiment is light, inexpensive and easy to operate. Electric energy is generated by swinging a person's arm while moving on the wrist and converting the biomechanical energy collected through a person's natural motion into electrical energy. In addition, by having a hybrid structure in which energy generation methods such as electromagnetic and triboelectricity are mixed, more electric energy can be produced from one swing operation.

Furthermore, the electrical energy output through the wrist-worn energy harvester is proportional to the walking speed, which is excellent even at low frequencies such as walking at a normal speed. It can also collect energy from other arm movements, such as torsion, to provide sufficient power to drive the load.

The wrist wearable energy harvester according to an embodiment may manufacture a perfect wearable energy harvester using 3D printing technology because the 3D printing material is used as the energy harvesting material. In addition, since the energy harvester needs to be shaken with the wearer's wrist during exercise, lightweight and comfort are required to ensure that no external energy is required in the swinging arm except for the body's metabolism. Thus, the compact design and the ability of lightweight materials help to improve the feasibility of 3D printing energy harvesters. 3D printing technology can be a promising way to make a complete wearable energy harvester that is easy, time-saving, cost effective, low risk, and sustainable.

Furthermore, the wearable energy harvester may power electronic devices such as a wearable IoT device and a health monitoring sensor through self-driving. For example, a person's wrist's natural swing movement can be converted into electricity while walking and running to power commercially available electronics.

1 is a view showing the concept of a wrist worn energy harvester according to an embodiment of the present invention,
2 is a view illustrating an appearance of a wrist worn energy harvester according to a first embodiment of the present invention;
3 is a view illustrating an appearance of a wrist worn energy harvester according to a second embodiment of the present invention;
4 is a view for explaining a manufacturing process of the wrist-worn energy harvester according to the first embodiment of the present invention,
5 is a view showing a nanostructure of the triboelectric charge material attached to the inside of the main body according to an embodiment of the present invention,
6 is an exploded view of a wrist worn energy harvester according to a second embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them will be apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments of the present invention make the disclosure of the present invention complete and the general knowledge in the technical field to which the present invention belongs. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. Like reference numerals refer to like elements throughout.

In describing the embodiments of the present disclosure, when it is determined that a detailed description of a known function or configuration may unnecessarily obscure the subject matter of the present disclosure, the detailed description thereof will be omitted, and the following terms are used in the embodiments of the present disclosure. Terms are defined in consideration of the function of the may vary depending on the user or operator's intention or custom. Therefore, the definition should be made based on the contents throughout the specification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, embodiments of the present invention illustrated in the following may be modified in many different forms, the scope of the present invention is not limited to the embodiments described in the following. Embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art.

1 is a view showing the concept of a wrist-worn energy harvester (hereinafter, referred to as "energy harvester") according to an embodiment of the present invention.

Referring to FIG. 1, the energy harvester 1 according to an embodiment may be worn on a user's wrist. For example, as shown in Figure 1 is a bracelet in the form of a curved tube (curved tube) that can be worn on the wrist of the human body. At this time, the energy harvester 1 may obtain biomechanical energy through a swinging motion of the user shaking the wrist during movement, and may convert the obtained biomechanical energy into electrical energy. The energy harvester 1 may power the electronic devices such as a wearable IoT device and a health monitoring sensor through self-driving. Examples of wearable IoT devices include wearable smart bands and smart watches, and examples of health monitoring sensors include heart rate sensors. The energy harvester 1 may be worn on a wrist and applied to a smart band or a smart watch. As an energy source for operating the wearable energy harvester, the human body energy from the movement of the human body that is normally wasted is suitable. Therefore, we propose an energy harvester 1 that can convert biomechanical energy into usable electrical energy.

Significant energy is generated by the movement of the human body, but the method of harvesting energy in this manner is quite conductive because the device shape and size are a problem in actual application. Moreover, since natural human movements such as walking and running occur in the low frequency band below 5 Hz, energy harvesters also need to be able to produce output power in similar frequency bands. The energy harvester 1 according to an embodiment harvests energy through a hybrid method in which two or more technologies are combined to derive high power in an environment in which it is difficult to produce high power. For example, electromagnetic and triboelectric schemes are mixed. In this energy harvesting technique, electromagnetic and triboelectric methods have the advantages of simple structure and high performance. But hybrids are not limited to electromagnetic and triboelectric.

The energy harvester 1 according to the embodiment is a curved wearable body and a hybrid wearable hybrid electromagnetic-friction-electron nano-curve in that it mixes two energy production methods, electromagnetic and triboelectric. shaped wearable hybridized electromagnetic-triboelectric nanogenerator (WHEM-TENG). The energy harvester 1 operates as a completely enclosed lightweight low frequency energy harvester driven by human body movement. For this purpose, the energy harvester 1 is in the form of a hollow curved tube, in which the magnet moves. The magnet may be a magnetic ball of spherical shape rolling freely in a curved tube. The energy harvester 1 incorporates the motion of swinging a person's arm during movement and the self-supporting rolling mode of the magnetic ball. The output electrical energy through the energy harvester 1 is proportional to the walking speed, and shows excellent performance even at low frequencies such as walking at a normal speed. It can also collect energy from other arm movements, such as torsion, to provide sufficient power to drive the load. Hereinafter, embodiments of the energy harvester 1 will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating an appearance of an energy harvester according to a first embodiment of the present invention.

Referring to FIG. 2, the energy harvester 1 is in the form of a curved tube comprising a body 10, a metal electrode 12, a coil 13, and a housing 14, and includes a magnet moving inside the curved tube. . As shown in FIG. 2, the energy harvester 1 according to an embodiment is assembled by assembling the main body 10 and the housing 14, which are formed by vertically cutting a curved tube, respectively. The main body 10, which is the half of the curved tube, is used for the energy harvester, and the other half of the curved tube is used as the housing 14. The half-shaped body 10 and the half-shaped housing 14 are assembled to form a horizontal coupling to complete the curved tube.

The body 10 constitutes at least a portion of a curved tube in the form of a hollow bent tube. The magnet moves freely inside the main body 10. The magnet may be a spherical magnetic ball or may be a permanent magnet including NdFeB. Hereinafter, the term may be used by mixing magnets and magnetic balls. The magnetic ball moves in a vibrating manner inside the body 10. At this time, the magnetic ball is rolled through the curved body 10 to minimize friction between the magnetic ball and the body 10.

The metal electrode 12 is formed outside the main body 10 and is charged in accordance with the movement of the magnet in the main body 10. The coil 13 is formed on the outside of the metal electrode 12 or is formed on the outside of the body 10 spaced apart from the metal electrode 12, the current is induced by the movement of the magnet in the body (10).

The energy harvester 1 according to an exemplary embodiment has a structure in which an electromagnetic generator (EMG, hereinafter referred to as "EMG") and a triboelectric nanogenerator (TENG, hereinafter referred to as "TENG") are mixed. The EMG is composed of a main body 10 constituting a part of a curved tube, a magnet moving inside the main body 10, and a coil 13 wound around the main body 10. Like the EMG, TENG includes a main body 10 constituting a part of the curved tube, a magnet existing inside the main body 10, and a metal electrode 12 formed outside the main body 10. At this time, the main body 10 is used as a frictional charging material. Therefore, the external material of the body 10 and the magnet may be made of a triboelectric charge material. In addition, the frictional charge material 11 for further increasing the output of the TENG in the main body 10 may be attached. The triboelectric charge material 11 is, for example, a polymer thin film such as polydimethylsiloxane (PDMS), polytetrafluoroethylene (PTFE), or the like. The triboelectric charge material 11 may have a nanostructure as shown in FIG. 5 to be described later.

The curved tube combining the body 10 and the housing 14 can be used as a triboelectric charge material for TENG. For example, the curved tube is an ABS tube made of acrylonitrile butadiene styrene (ABS). The main body 10 may be manufactured by a 3D printing method, an injection method, an extrusion method, or the like. In particular, 3D printing makes the manufacturing process faster, easier and more cost-effective than conventional methods. 3D printing materials can be used as triboelectric charging materials for TENG.

Since 3D printing materials are used as energy harvesting materials, 3D printing technology can produce a complete wearable energy harvester. In addition, since the energy harvester 1 needs to be shaken with the wearer's wrist during exercise, lightweight and comfort are required to ensure that no external energy is needed in the swinging arm except for metabolism of the body. Thus, the compact design and the ability of lightweight materials help to improve the feasibility of 3D printing energy harvesters. 3D printing technology can be a promising method for manufacturing a complete wearable energy harvester 1 that is easy, time saving, cost effective, low risk and sustainable.

The metal electrode 12 according to an exemplary embodiment has a multi-ring shape in which a plurality of metal electrodes 12 are formed in pairs at predetermined intervals in an interdigitated form on the outside of the main body 10. For example, as shown in Fig. 2, it consists of two pairs (four in total) in the shape of a pod. The metal used as the metal electrode 12 may be aluminum (Al), gold (Au), or the like, but is not limited thereto.

As shown in FIG. 2, the coil 13 is connected in series to both ends of the body 10 of the energy harvester 1. The coil 13 may be made of copper (Cu). As shown in FIG. 2, experiments can produce an optimum output when the number of coils 13 is two, and the positions of the coils 13 are formed at both ends of the body 10. It is possible to maximize the speed of the magnet by the swing speed and acceleration of the arm due to gravity. To this end, the two coils 13 are connected in series and wrapped at both ends of the body 10 opened from the housing 14.

Referring to FIG. 2, the EMG includes a main body 10 constituting a part of a hollow curved tube and a spherical magnetic ball moving in the main body 10, by connecting two coils 13 in series. Wrap at both ends of the body (10). Similarly, TENG consists of a body 10 as a triboelectric charge material, a magnetic ball and a metal ring 12 in the form of a multi-ring wrapped around the body 10. As the magnet rolls along the body 10, an alternating current is generated between the metal electrodes 12 in a continuous interdigitated form. At the same time, a current is induced when the magnetic ball traverses the coil 13 wound around the body 10. Since TENG is designed with a single-electrode-based structure, the moving magnetic balls do not require electrical contact and can wrap the metal electrode 12 around the body 10 at predetermined intervals, simplifying device design and fabrication.

3 is a view illustrating an appearance of an energy harvester according to a second embodiment of the present invention.

Referring to FIG. 3, the energy harvester 1 is composed of a curved tube-shaped body and a curved tube-shaped housing 14 accommodating the body, as compared with the energy harvester 1 of FIG. Is used for energy harvester. In FIG. 3, the upper part of the housing 14 is removed to show the main body inside the housing 14. The energy harvester 1 of FIG. 3 consists of two pairs of metal electrodes 12 and four coils 13.

4 is a view for explaining a manufacturing process of the energy harvester according to the first embodiment of the present invention.

2 and 4, the energy harvester 1 includes a main body 10, a triboelectric charge material 11 inside the main body 10, a metal electrode 12 attached to an outer portion of the main body 10, A coil 13 surrounding the outside of the metal electrode 12 or spaced apart from the metal electrode 12 and surrounding the outside of the body 10, and a curved housing 14 coupled to the body 10.

In order to manufacture the energy harvester 1, first, a main body 10 constituting a part of a hollow curved tube is configured (410). The body 10 may be manufactured with a triboelectric charge material, for example ABS. The main body 10 may be manufactured by 3D printing.

Subsequently, the triboelectric charge material 11 is inserted into the main body 10 (420). At this time, the triboelectric material 11 may be a PTFE polymer, in this case, the body 10 made of ABS is combined with the PTFE polymer to form a composite PTFE-ABS triboelectric layer (composite PTFE-ABS triboelectric layer). . To form a composite PTFE-ABS triboelectric layer, the ABS tube can be symmetrically cut in two parts along the axis and the etched PTFE film can be attached to the inner wall of the ABS tube using a double sided conductive tape.

The surface of the PTFE polymer may be composed of nanostructures. In this case, a thin PTFE thin film of nanostructure is attached to the inner wall of the ABS tube to form a composite PTFE-ABS triboelectric charge layer. The nanostructure enhances TENG's output power performance by increasing the electron affinity difference between the composite PTFE-ABS triboelectric layer and the magnet. To this end, the surface of the PTFE film is further processed into nanostructures. For example, a mask is deposited on a PTFE surface and inductively coupled plasma reactive ion etching (ICP-RIE) is performed to form nanostructures on the PTFE film surface. As the PTFE film is etched, a uniform distribution of the nanostructures can be obtained.

Next, a magnet is inserted into the composite PTFE-ABS triboelectric charge layer of the main body 10. The magnet may be a magnetic ball, and the outside of the magnetic ball may be coated with a triboelectric charge material. In operation 430, a metal electrode for harvesting power generated from TENG is disposed at an external portion of the main body 10. For example, as the four ring-shaped Al thin films are wound around the composite PTFE-ABS triboelectric charge layer at regular intervals, a metal electrode having a shape interdigitated on the outside of the main body 10 is formed.

Subsequently, the coil 13 for the EMG is disposed 440 in the outer portion of the main body 10. For example, two copper coils are wrapped around the composite PTFE-ABS triboelectric layer of the body 10 at fixed intervals. In this case, an insulating layer may be disposed between the metal electrode 12 and the coil 13. Subsequently, the curved tube is assembled by combining the body 10 and the housing 14 (450).

The operation mechanism of the energy harvester 1 manufactured by the above-described process is explained below. The rolling of the magnetic ball inside the body 10 induces a voltage in the coil 13 which is proportional to the speed of the ball. As the magnetic ball moves at a higher speed, the coil 13 bisects the magnetic field lines at a higher speed to increase the induced EMF. In addition, the action of the same rolling magnetic ball activates TENG, the principle of operation of which is based on rolling contact electrification and electrostatic induction, and consequently through the interdigitated metal electrode 12 Transfer charges.

The magnetic ball and the composite PTFE-ABS triboelectric layer show positive and negative charges, respectively, when both components are in contact at the initial position of the magnetic ball. Due to the large difference in triboelectric polarity between the composite PTFE-ABS triboelectric layer and the magnetic ball, the composite PTFE-ABS triboelectric layer attracts electrons from the magnetic ball and becomes negatively charged. Positively charged. Rolling of the positively charged magnetic balls on the composite PTFE-ABS triboelectric layer on the metal electrode 12 results in the flow of charge between the two consecutive metal electrodes 12 to maintain charge balance. As a result, rolling the magnetic ball over a number of interdigitated metal electrodes 12 produces alternating current as a triboelectric output to the external circuit.

5 is a view showing a nanostructure of the triboelectric charge material attached to the inside of the main body according to an embodiment of the present invention.

Referring to FIG. 5, the triboelectric charge material attached to the inside of the main body may have a nanostructure. The nanostructure may be a nano-wire structure. In terms of the output performance of energy harvesters, there are some limitations with current 3D printing techniques. For example, the voltage generated by a 3D printing energy harvester made of ABS is not very high, and materials that provide better triboelectric output performance, such as PTFE, are currently unavailable. To solve this problem, a thin PTFE thin film of nanowire structure is attached to the inner wall of ABS tube to form a composite PTFE-ABS triboelectric charge layer. This nanostructure improves the output power performance of the nanogenerator by increasing the electron affinity difference between the composite PTFE-ABS triboelectric charge layer and the magnet. To this end, as shown in FIG. 4, the surface of the PTFE film is further processed into nanostructures such as nanowires. The nanostructure increases the effective contact area between the magnet and the composite PTFE-ABS triboelectric layer, resulting in high triboelectric charge transfer.

6 is an exploded view illustrating an energy harvester according to a second embodiment of the present invention.

3 and 6, the energy harvester 1 has a curved tube-shaped body 10, a frictional charge material 11 inserted into the body 10, and a spherical shape coated with a frictional charge material outside. A magnet 15, a metal electrode 12 attached to a portion outside the main body 10, a ferrite thin film 16 attached to an outer portion of the main body 10, and wound around the outer side of the ferrite thin film 16. A true coil 13, comprising a housing 14 in the form of a curved tube for receiving the body 10. In FIG. 6, the upper portion of the main body 10 and the housing 14 in the form of a curved tube is removed and shown, respectively, to show the inside.

As shown in FIG. 6, the energy harvester 1 may use the entire portion of the curved tube for the energy harvester. The body 10 and the housing 14 may be manufactured with a triboelectric charge material, for example ABS. In this case, it may be manufactured by a 3D printing method. The frictional charging material 11 may be attached to the inside of the main body 10. The triboelectric charge material 11 may be a PTFE polymer. In this case, the body 10 made of ABS may be combined with the PTFE polymer to form a composite PTFE-ABS triboelectric charge layer. The surface of the PTFE polymer may be composed of nanostructures. In this case, a thin PTFE thin film of nanostructure is attached to the inner wall of the ABS tube to form a composite PTFE-ABS triboelectric charge layer. The nanostructure improves the output power performance of the nanogenerator by increasing the difference in electron affinity between the composite PTFE-ABS triboelectric layer and the magnet.

The magnet 15 is inserted into the composite PTFE-ABS triboelectric charge layer of the main body 10. Magnet 15 may be a magnetic ball rolling in the body 10, the outside may be coated with a triboelectric charge material. In addition, a metal electrode 12 for harvesting power generated in TENG is disposed at an external portion of the main body 10. For example, four Al electrodes are attached to the composite PTFE-ABS triboelectric charge layer of the main body 10 at regular intervals, thereby forming a metal electrode 12 having a clad shape.

The coil 13 for the EMG is disposed at an outer portion of the main body 10. For example, four copper coils are wrapped around the composite PTFE-ABS triboelectric layer of the body 10 at fixed intervals. In this case, an insulating layer may be disposed between the metal electrode 12 and the coil 13. A ferrite thin film 16 may be present between the coil 13 and the main body 10 to concentrate magnetic flux. Concentrating the flux can improve the power of the EMG.

So far, the present invention has been described with reference to the embodiments. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

Claims (14)

A body constituting at least a portion of the hollow curved tube;
A magnet moving inside the curved tube;
A metal electrode formed outside the main body and charged as the magnet moves in the main body;
A coil formed on the outside of the metal electrode or spaced apart from the metal electrode, the coil being induced in accordance with the movement of the magnet in the body; And
A housing coupled to the main body to form a curved tube; Including,
A triboelectric generator comprising a body, a magnet and a metal electrode, and an electromagnetic generator comprising the body, a magnet and a coil. The method of claim 1, wherein the wrist wearable energy harvester
Wrist-worn energy harvester, characterized by converting low-frequency biomechanical energy into electrical energy by swinging a human arm while moving. The method of claim 1,
The magnet is a spherical magnetic ball that freely rolls in a curved tube,
The triboelectric generator generates triboelectric energy based on contact charging and electrostatic induction of the metal electrode by rolling of the magnet in the body,
The electromagnetic generator is a wrist worn energy harvester, characterized in that for generating electromagnetic energy based on the electromagnetic induction of the coil by the rolling of the magnet in the body. The method of claim 1, wherein the body is
Wrist wearable energy harvester, characterized in that consisting of a triboelectric charge material. The method of claim 4, wherein the body is
A wrist wearable energy harvester, characterized in that a polymer thin film composed of a triboelectric charge material is inserted into a body to form a composite triboelectric charge layer composed of a triboelectric charge material of a body and a polymer thin film inserted therein. The method of claim 5, wherein the polymer thin film
Wrist wearable energy harvester, characterized in that the nano-structure on the surface of the polymer thin film to increase the effective contact area between the magnet and the body. The method of claim 1 wherein the body is
Wrist wearable energy harvester, characterized in that produced by any one of 3D printing method, injection method, extrusion method. The method of claim 1, wherein the metal electrode
Wrist-worn energy harvester, characterized in that it has a multi-ring form that is formed in pairs in the form of a pod on the outside of the main body. The coil of claim 1 wherein the coil is
Wrist-worn energy harvester, characterized in that located at both ends of the body opened from the housing. 2. The wrist wearable energy harvester of claim 1,
A ferrite thin film formed between the coil and the main body to concentrate the magnetic flux;
Wrist wearable energy harvester, characterized in that it further comprises. Constructing a body constituting at least a portion of the hollow curved tube;
Inserting a magnet into the body;
Forming a metal electrode on the outside of the main body;
Forming a coil outside of the metal electrode or outside of the body at a distance from the metal electrode; And
Assembling the curved tube by combining the body and the housing;
Wrist wearable energy harvester manufacturing method comprising a. 12. The method of claim 11, wherein constructing the body
Wrist wearable energy harvester manufacturing method characterized in that configured through the 3D printing method. The method of claim 11, wherein the wrist wearable energy harvester manufacturing method
Inserting a polymer thin film made of a triboelectric charge material into the body;
Wrist wearable energy harvester manufacturing method characterized in that it further comprises. The method of claim 13, wherein the wrist wearable energy harvester manufacturing method
Forming a nanostructure on the surface of the polymer thin film to increase the effective contact area between the magnet and the body;
Wrist wearable energy harvester manufacturing method characterized in that it further comprises.

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