Self-heating kneecap utilizing human body movement mechanical energy

Abstract

The invention discloses a self-heating kneecap utilizing human body movement mechanical energy, and belongs to the technical field of kneecap health care. The knee pad comprises a protection pad, a hook-and-loop fastener, an electric heating layer, a nanometer generator, a wire and an energy management unit. The whole knee pad is divided into a knee area, a knee bending area and a connecting area. A nano generator and an energy management unit are arranged in the protection pad of the knee bending area, the nano generator is composed of a composite layer electrode, a composite material layer and a metal friction layer, and the composite layer electrode and the metal friction layer are connected with the energy management unit through wires; the energy management unit stabilizes and filters the current, stores the current, and transmits the current to the electric heating layer after subsequent voltage transformation; an electric heating layer is arranged in a knee area of the knee pad, is composed of resistance heating materials and fibers and is connected with the energy management unit through a wire. The position of the whole kneecap is fixed and the tightness degree is adjusted through the Velcro. Mechanical energy generated by human knee joint movement is collected and converted into electric energy for heating the knee area, and the advantages of energy conservation and environmental protection are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of kneepad health care, and relates to a self-heating kneepad which utilizes a nanogenerator to collect mechanical energy of human body movement for powering the kneepad. Background Art

[0002] The mechanical energy generated by human movement is not affected by the weather and other environmental factors, is continuous, green, pollution-free, and low-cost. The emergence of nanogenerators makes it possible to collect energy from human movement. It uses frictional electrification or piezoelectric polarization of materials to collect and store various forms of mechanical energy from the environment to provide energy for wearable devices.

[0003] Wearing knee pads is an effective measure to protect the knee joint. For patients with knee injuries or serious lesions, using knee pads can enhance joint stability and prevent joint pain symptoms from worsening. If the knee pads can also generate heat, they can maintain the temperature of the knee joints in cold external environments, and improve blood circulation and relieve muscle fatigue. Current self-heating knee pads mostly use the exothermic reaction of materials to generate heat. If nanogenerator technology is used to convert the mechanical energy generated by walking into electrical energy, it will provide a new way to obtain green and sustainable energy for self-heating knee pads. Summary of the invention

[0004] The purpose of the present invention is to provide a self-heating knee pad that utilizes the mechanical energy of human movement. It is a self-heating knee pad based on the principle of a nanogenerator that couples piezoelectricity and friction power generation. The self-heating knee pad drives the nanogenerator through the movement of the knee joint, collects the mechanical energy generated by human movement, converts it into electrical energy, and inputs it into an electrothermal material to achieve self-heating of the knee pad.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] The invention discloses a self-heating kneepad that utilizes the mechanical energy of human motion, comprising a pad, a hook and loop fastener, an electric heating layer, a nanogenerator, a wire, and an energy management unit. The nanogenerator is mainly composed of a composite layer electrode, a composite material layer, and a metal friction layer. The entire self-heating kneepad is divided into a knee area, a knee bend area, and a connection area.

[0007] The knee area is composed of a pad, Velcro, an electric heating layer and wires. The wires transmit electrical energy from the energy management unit to the electric heating layer to generate heat.

[0008] The knee area consists of a pad, a nanogenerator, wires and an energy management unit.

[0009] The connection area is mainly composed of pads and Velcro.

[0010] The protective pad is made of insulating and heat-conductive material, and preferably, nylon is selected.

[0011] The Velcro is used to fix the position of the kneepad, and the tightness of the kneepad can be adjusted by adjusting its bonding position.

[0012] The nanogenerator is composed of a composite layer electrode, a composite material layer, and a metal friction layer. The composite layer electrode and the metal friction layer are both metal films. The metal films are made of silver, copper or aluminum. The composite material layer is made of electronic materials with piezoelectric effect, such as polydimethylsiloxane (PDMS) containing barium titanate (BaTiO3) nanoparticles or polyvinyl fluoride (PVC) containing barium titanate (BaTiO3) nanoparticles.

[0013] The cross section of the composite material layer facing the metal friction layer is an outwardly convex arch, and the composite material layer can come into contact with the metal friction layer after being compressed.

[0014] The composite material layer is a material with piezoelectric effect. When the knee joint bends, it generates piezoelectric energy due to its own deformation. It also serves as the negative friction layer of the friction nanogenerator. When the human body moves, it contacts and separates from the metal friction layer to generate frictional energy. The metal friction layer also serves as the positive electrode of the nanogenerator, and the composite layer electrode is the negative electrode of the nanogenerator. The two transmit the current generated by the nanogenerator to the energy management unit through a wire.

[0015] The energy management unit performs voltage stabilization and filtering on the collected current, and transmits it to the electric heating layer through wires after storage and voltage transformation.

[0016] The electric heating layer is composed of flexible resistive heating material and fibers and is fixed between the pads in the knee area.

[0017] When the nanogenerator is working, the amount of electrical energy generated by the deformed composite material layer is calculated by the piezoelectric energy storage formula shown in formula (1).

[0018]

[0019] Where: F max ——Peak load of a single cycle of the triboelectric nanogenerator;

[0020] d——piezoelectric coefficient;

[0021] h——piezoelectric unit thickness;

[0022] ε0——vacuum dielectric constant;

[0023] ε r ——The dielectric constant of the piezoelectric material;

[0024] A——Cross-sectional area of ​​piezoelectric unit.

[0025] When the composite material layer and the metal friction layer come into contact, due to contact electrification, equal amounts of electrostatic charges with opposite polarities will be generated on the surfaces of the two materials. When their surface size is much larger than the friction layer thickness and separation distance, the maximum amount of electrical energy generated by the friction layer contact and separation is:

[0026]

[0027] Where: S——contact area of ​​two friction layers;

[0028] d0——The sum of the thickness of the dielectric material between the electrodes and the ratio of its relative dielectric constant;

[0029] x max ——The maximum separation distance between two friction layers;

[0030] V OC ,max——maximum open circuit voltage.

[0031] Beneficial effects:

[0032] 1. The present invention discloses a self-heating kneepad that utilizes the mechanical energy of human movement. The cross-section of the composite material layer facing the metal friction layer is an outwardly convex arch, and the composite material layer can come into contact with the metal friction layer after being compressed. The composite material layer is a material with piezoelectric effect, and generates piezoelectric energy due to its own deformation when the knee joint is bent. It also serves as a negative friction layer of a friction nanogenerator, and comes into contact and separates with the metal friction layer when the human body moves to generate frictional energy. The electric heating layer is composed of flexible resistive heating material and fiber, and is fixed between the pads in the knee area. On this basis, the present invention can achieve human functional self-heating that conforms to the shape of the kneepad.

[0033] 2. The present invention discloses a self-heating knee pad that utilizes the mechanical energy of human movement. The metal friction layer also serves as the positive electrode of the nanogenerator, and the composite layer electrode is the negative electrode of the nanogenerator. The two transmit the current generated by the nanogenerator to the energy management unit through a wire. The energy management unit stabilizes and filters the collected current, and transmits it to the electric heating layer through a wire after storage and voltage transformation. A piezoelectric energy storage formula is constructed to calculate the amount of electric energy generated by the deformed composite material layer, and a maximum electric energy formula is constructed to quantitatively predict the maximum electric energy generated by the friction layer contacting and separating once. The piezoelectric energy storage formula and the maximum electric energy formula are used for quantitative prediction and regulation of the self-heating energy of the energy management unit to improve the energy storage and heating effect of the self-heating knee pad.

[0034] 3. The present invention discloses a self-heating kneepad that utilizes the mechanical energy of human motion. The movement of the knee joint drives the nanogenerator to work. Based on coupled piezoelectricity and frictional power generation, the mechanical energy generated by human motion is collected and converted into electrical energy, and then input into the electrothermal material to achieve self-heating of the kneepad. The present invention improves the efficiency of collecting mechanical energy of human motion based on coupled piezoelectricity and frictional power generation.

[0035] 4. The present invention discloses a self-heating kneepad that utilizes the mechanical energy of human movement. A nanogenerator is used to collect the mechanical energy of human movement as energy input for the heating layer of the kneepad, thereby realizing green and sustainable energy input. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a schematic diagram of the structure of the self-heating knee pad in contact with the knee skin;

[0037] Figure 2 It is a schematic diagram of the structure of the outer surface of the self-heating knee pad;

[0038] Figure 3 It is a cross-sectional view of the knee bend area;

[0039] Figure 4 It is a cross-sectional view of the knee area;

[0040] Figure 5 This is a schematic diagram of how to wear a knee pad;

[0041] Among them, 1-pad, 2-velcro, 3-electric heating layer, 4-composite layer electrode, 5-composite material layer, 6-metal friction layer, 7-conductor, 8-energy management unit. DETAILED DESCRIPTION

[0042] like Figure 1 , 2 As shown in , 3 and 4, the present embodiment discloses a self-heating knee pad based on the principle of a nanogenerator, comprising a pad 1, a velcro 2, an electric heating layer 3, a composite layer electrode 4, a composite material layer 5, a metal friction layer 6, a wire 7 and an energy management unit 8.

[0043] like Figure 1 , 2 As shown, the kneepad is divided into a knee area, a knee bend area and a connection area, and the pad 1 is made of insulating material, wherein a Velcro 2 is provided for fixing the position of the kneepad.

[0044] like Figure 3 As shown, the knee area is composed of a protective pad 1, a Velcro 2, an electric heating layer 3 and a wire 7. The wire 7 transmits the electrical energy in the energy management unit 8 to the electric heating layer 3 to generate heat.

[0045] like Figure 4As shown, the knee bend area is composed of a pad 1, a nanogenerator (including a composite layer electrode 4, a composite material layer 5, and a metal friction layer 6), a wire 7, and an energy management unit 8; the cross-section of the composite layer facing the metal friction layer is an outwardly convex arch, and the other side is a plane, on which the composite layer electrode 4 is bonded. When the leg is bent, the composite layer 5 will generate electric energy due to the piezoelectric effect, and it will also generate electric energy when it contacts and separates from the metal friction layer 6; the main function of the composite layer 5 is triboelectric charging and piezoelectric effect, so polydimethylsiloxane (PDMS) containing barium titanate (BaTiO3) nanoparticles, polyvinyl fluoride (PVC) and other materials are used; the metal friction layer 6 is the positive friction layer of the nanogenerator, and is also the positive electrode, and it and the composite layer electrode 4 can be made of metal materials such as silver, copper, and aluminum.

[0046] When the nanogenerator is working, the amount of electric energy generated by the deformed composite material layer 5 is approximately calculated using the piezoelectric energy storage formula, as shown in formula (1).

[0047]

[0048] Where: F max ——Peak load of a single cycle of the triboelectric nanogenerator;

[0049] d——piezoelectric coefficient;

[0050] h——piezoelectric unit thickness;

[0051] ε0——vacuum dielectric constant;

[0052] ε r ——The dielectric constant of the piezoelectric material;

[0053] A——Cross-sectional area of ​​piezoelectric unit.

[0054] When the composite material layer 5 and the metal friction layer 6 come into contact, equal amounts of electrostatic charges with opposite polarities will be generated on the surfaces of the two materials due to contact electrification. When their surface size is much larger than the friction layer thickness and separation distance, the maximum value of the electrical energy generated by the friction layer contact and separation is:

[0055]

[0056] Where: S——contact area of ​​two friction layers;

[0057] d0——The sum of the thickness of the dielectric material between the electrodes and the ratio of its relative dielectric constant;

[0058] x max ——The maximum separation distance between two friction layers;

[0059] V OC ,max——maximum open circuit voltage.

[0060] The above-mentioned knee pad converts the mechanical energy generated by human movement into electrical energy through the composite material layer 5 and the metal friction layer 6, and transmits the collected electrical energy to the energy management unit 8 through the wire 7 connected to the composite layer electrode 4 and the metal friction layer 6; the electrical energy is stabilized, filtered, stored, transformed, and output to the electric heating layer 3 through the energy management unit 8; the electric heating layer 3 generates heat to keep the knee warm.

[0061] The above are only preferred embodiments of the present application and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-heating kneepad utilizing the mechanical energy of human motion, characterized in that: The invention comprises a protective pad (1), a hook and loop fastener (2), an electric heating layer (3), a nanogenerator, a wire (7), and an energy management unit (8); the nanogenerator is mainly composed of a composite layer electrode (4), a composite material layer (5), and a metal friction layer (6); the entire self-heating kneepad is divided into a knee area, a knee bend area, and a connection area; The knee area is composed of a protective pad (1), a hook and loop fastener (2), an electric heating layer (3) and a wire (7), and the wire (7) transmits the electric energy in the energy management unit (8) to the electric heating layer (3) to generate heat; The knee bend area is composed of a pad (1), a nanogenerator, a conductor (7) and an energy management unit (8); The connection area is mainly composed of a protective pad (1) and a hook and loop fastener (2); The hook and loop fastener (2) is used to fix the position of the knee pad, and the tightness of the knee pad can be adjusted by adjusting its bonding position; The energy management unit (8) performs voltage stabilization and filtering processing on the collected current, and transmits the current to the electric heating layer (3) through the wire (7) after storage and voltage transformation.

2. A self-heating kneepad utilizing mechanical energy of human motion as claimed in claim 1, characterized in that: The nanogenerator is composed of a composite layer electrode (4), a composite material layer (5), and a metal friction layer (6); the composite layer electrode (4) and the metal friction layer (6) are both metal films, and the composite material layer (5) is made of an electronic material having a piezoelectric effect.

3. A self-heating kneepad utilizing mechanical energy of human motion as claimed in claim 2, characterized in that: The cross section of the composite material layer (5) facing the metal friction layer (6) is an outwardly convex arch, and the composite material layer (5) can come into contact with the metal friction layer (6) after being compressed.

4. A self-heating kneepad utilizing mechanical energy of human motion as claimed in claim 3, characterized in that: The composite material layer (5) is a material with piezoelectric effect. When the knee joint is bent, it generates piezoelectric energy due to its own deformation. It also serves as a negative friction layer of the friction nanogenerator. When the human body moves, it comes into contact with and separates from the metal friction layer (6) to generate frictional energy. The metal friction layer (6) also serves as the positive electrode of the nanogenerator. The composite layer electrode (4) is the negative electrode of the nanogenerator. The two transmit the current generated by the nanogenerator to the energy management unit (8) through a wire (7).

5. The self-heating kneepad utilizing the mechanical energy of human motion as claimed in claim 1, characterized in that: The electric heating layer (3) is composed of flexible resistive heating material and fibers and is fixed between the pads (1) in the knee area.

6. The self-heating kneepad utilizing the mechanical energy of human motion as claimed in claim 1, characterized in that: When the nanogenerator is working, the amount of electric energy generated by the deformed composite material layer (5) is calculated by the piezoelectric energy storage formula shown in formula (1); Where: F max ——Peak load of a single cycle of the triboelectric nanogenerator; d——piezoelectric coefficient; h——piezoelectric unit thickness; ε0——vacuum dielectric constant; ε r ——The dielectric constant of the piezoelectric material; A——Cross-sectional area of ​​piezoelectric unit.

7. The self-heating kneepad utilizing the mechanical energy of human motion as claimed in claim 1, characterized in that: When the composite material layer (5) and the metal friction layer (6) come into contact, the maximum value of the electric energy generated by the friction layer contacting and separating once is: Where: S——contact area of ​​two friction layers; d0——The sum of the thickness of the dielectric material between the electrodes and the ratio of its relative dielectric constant; x max ——The maximum separation distance between the two friction layers; V OC ,max——maximum open circuit voltage.

8. A self-heating kneepad utilizing mechanical energy of human motion as claimed in claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The material of the protective pad (1) is nylon.

9. A self-heating kneepad utilizing mechanical energy of human motion as claimed in claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The metal film is made of silver, copper or aluminum.

10. A self-heating kneepad utilizing mechanical energy of human motion as claimed in claim 1, 2, 3, 4, 5, 6 or 7, characterized in that: The composite material layer (5) is made of an electronic material having a piezoelectric effect, and is selected from polydimethylsiloxane containing barium titanate nanoparticles or polyvinyl fluoride containing barium titanate nanoparticles.

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