Triboelectric Generators and Sensors

• US 20140338458A1
• Filed: 07/30/2014
• Published: 11/20/2014
• Est. Priority Date: 09/21/2012
• Status: Active Grant

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Wang, Zhong Lin, Wang, Sihong, Zhu, Guang, Zhou, Yusheng, Chen, Jun, Bai, Peng
• Granted Patent: US 9,790,928 B2
• Time in Patent Office: Days
• US Class Current: 73/658
• CPC Class Codes: F03G 5/06 other than of endless-walk type
• CPC Class Codes: G01H 11/06 by electric means
• CPC Class Codes: G01L 1/005 by electrical means and not provided for in G01L1/06 - G01L1/22
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: H02N 1/04 Friction generators

Abstract

A triboelectric power system includes a triboelectric generator, a rechargeable energy storage unit and a power management circuit. The rechargeable energy storage unit is associated to the triboelectric generator. The power management circuit is configured to receive an input current from the triboelectric generator and to deliver an output current corresponding to the input current to the rechargeable battery so that the output current has a current direction and a voltage that will recharge the rechargeable battery.

Claims

1. A triboelectric power system, comprising:

(a) a triboelectric generator;

(b) a rechargeable energy storage unit associated with the triboelectric generator; and

(c) a power management circuit configured to receive an input current from the triboelectric generator and to deliver an output current corresponding to the input current to the rechargeable battery so that the output current has a current direction and a voltage that will recharge the rechargeable battery.

2. The triboelectric power system of claim 1, wherein the triboelectric generator comprises:

(a) a first dielectric layer;

(b) a first conductive electrode layer affixed to the first dielectric layer, the first electrode layer having a first position on a triboelectric series;

(c) a second dielectric layer having a second position on the triboelectric series that is different from the first position, the second dielectric layer spaced apart from the first conductive electrode layer;

(d) a second conductive electrode layer affixed to the second dielectric layer on a side opposite from the first conductive electrode layer,

the first conductive electrode layer and the second dielectric layer configured to remain spaced apart when the triboelectric generator is in a resting state and to come into contact with each other when a predetermined force is applied to the triboelectric generator, thereby causing a charge imbalance when the triboelectric generator returns to the resting state after the predetermined force has been applied so as to cause current flow from the triboelectric generator to the power management circuit.

3. The triboelectric power system of claim 2, further comprising a separating mechanism configured to maintain the triboelectric generator in the resting state unless the predetermined force is applied thereto.

4. The triboelectric power system of claim 2, wherein at least a selected on of each first conductive electrode layer and each second dielectric layer includes a nano-scale texture applied thereto.

5. The triboelectric power system of claim 1, wherein the rechargeable energy storage unit comprises an energy storage unit selected from a group of energy storage units consisting of:

a rechargeable battery, a capacitor, a super capacitor, and combinations thereof.

6. The triboelectric power system of claim 1, wherein the rechargeable energy storage unit comprises a lithium ion battery that includes:

(a) an aluminum electrode layer;

(b) an LiFePO₄ layer disposed on the aluminum electrode layer;

(c) a separator layer;

(d) a carbon fiber cloth layer including a plurality of carbon fibers and a plurality of TiO₂ nanowires extending from the carbon fibers.

7. The triboelectric power system of claim 1, wherein the power management circuit comprises a power management circuit selected from a group consisting of:

a rectifier, an integrated power control circuit, a transformer, and combinations thereof.

8. A self-powered pressure sensor, comprising:

(a) a substrate;

(b) an array of spaced apart triboelectric generators disposed on the substrate, each triboelectric generator configured to generate a current when a force is applied and then released from the triboelectric generator;

(c) a plurality of sensing circuits, each electrically coupled to a different one of the triboelectric generators, each of the sensing circuits configured to generate a voltage when the current from its corresponding triboelectric generator passes therethrough, the voltage indicative of the force having been applied to the corresponding nanogenerator.

9. The pressure sensor of claim 8, wherein each triboelectric generator comprises:

(a) a first dielectric layer;

(b) a first conductive electrode layer affixed to the first dielectric layer, the first electrode layer having a first position on a triboelectric series;

(c) a second dielectric layer having a second position on the triboelectric series that is different from the first position, the second dielectric layer spaced apart from the first conductive electrode layer;

(d) a second conductive electrode layer affixed to the second dielectric layer on a side opposite from the first conductive electrode layer,

the first conductive electrode layer and the second dielectric layer configured to remain spaced apart when the triboelectric generator is in a resting state and to come into contact with each other when a predetermined force is applied to the triboelectric generator, thereby causing a charge imbalance when the triboelectric generator returns to the resting state after the predetermined force has been applied so as to cause current flow from the triboelectric generator to the power management circuit.

10. The pressure sensor of claim 9, further comprising a conductive layer disposed on the substrate and in electrical communication with the second conductive electrode layer of each triboelectric generator, wherein each sensing circuit is electrical communication with the conductive layer.

11. The pressure sensor of claim 9, wherein at least a selected on of each first conductive electrode layer and each second dielectric layer includes a nano-scale texture applied thereto.

12. A triboelectric generator, comprising:

(a) a first member, including;

(i) a first dielectric layer having a top side and an opposite bottom side;

(ii) a first electrode grid disposed on the top side of the first dielectric layer, the first electrode grid including a first plurality of spaced-apart rows of a conductive material that are electrically coupled to each other; and

(iii) a second electrode grid disposed on the bottom side of the first dielectric layer, the second electrode grid including a second plurality of spaced-apart rows of a conductive material that are electrically coupled to each other; and

(b) second member, including;

(i) a second dielectric layer having a top side and an opposite bottom side;

(ii) a third electrode grid disposed on the top side of the second dielectric layer, the third electrode grid including a third plurality of spaced-apart rows of a conductive material that are electrically coupled to each other; and

(iii) a fourth electrode grid disposed on the bottom side of the second dielectric layer, the fourth electrode grid including a second plurality of spaced-apart rows of a conductive material that are electrically coupled to each other,

the second member disposed under the first member so that the second electrode grid is in contact with the third electrode grid, wherein the first dielectric layer and the second dielectric layer each include a material having a first position on a triboelectric series and wherein the second electrode grid and the third electrode grid each include a material having a second position on the triboelectric series that is different from the first position on the triboelectric series, so that when the first member is slid laterally with respect to the second member, a charge imbalance forms between the first electrode layer and the second electrode layer and so that a charge imbalance forms between the fourth electrode layer and the third electrode layer.

13. The triboelectric generator of claim 12, wherein at least a selected one of the first dielectric layer and the second dielectric layer, the second electrode grid and the third electrode grid have a nanoscale texture applied thereto.

14. The triboelectric generator of claim 13, wherein the nanoscale texture results from PTFE nanoparticles applied to the first dielectric layer and to the second dielectric layer.

15. A displacement sensor, comprising:

(a) a top member, including;

(i) a first substrate;

(ii) a first micrograting base formed from a plurality of spaced-apart rows disposed on the first substrate separated by a corresponding plurality of spaced-apart troughs;

(iii) a first conductive layer disposed on the first micrograting base and the first substrate; and

(iv) a first dielectric layer disposed on the first conductive layer, the first dielectric layer having a first position on a triboelectric series; and

(b) a bottom member, including;

(i) a second substrate defining a second micrograting including a plurality of spaced-apart rows separated by a corresponding plurality of spaced-apart troughs;

(ii) a second conductive layer disposed on the second micrograting; and

(iii) a second dielectric layer disposed on the second conductive layer, the second dielectric layer having a second position on the triboelectric series that is different from the first position on the triboelectric series,

the bottom member disposed adjacent to the top member so that the first dielectric layer is in contact with the second dielectric layer and so that the rows of the first micrograting run parallel to the rows of the second micrograting so that a charge imbalance occurs between the second conductive layer and the first conductive layer when lateral movement occurs between the first micrograting and the second micrograting in a direction transverse to the rows, so that the charge imbalance is indicative of an amount of lateral movement.

16. The displacement sensor of claim 15, wherein the first substrate comprises a glass substrate;

wherein the first micrograting base comprises SU-8;

wherein the first conductive layer comprises ITO;

wherein the first dielectric layer comprises parylene;

wherein the second substrate comprises silicon;

wherein the second conductive layer comprises aluminum; and

wherein the second dielectric layer comprise SiO₂.

17. A generator for harvesting energy from a shoe having a sole, comprising:

(a) at least one first triboelectric member disposed in the sole and including a first electrode layer and a first material that has a first position on a triboelectric series;

(b) at least one second triboelectric member disposed in the sole, the at least one second triboelectric member including a second electrode layer and a second material that has a first position on a triboelectric series, the at least one second triboelectric member disposed so that the first material is opposite the second material; and

(c) a mechanism configured to maintain separation between the first triboelectric member and the second triboelectric member when the force is not applied therebetween.

18. The generator of claim 17, configured as parameter sensor for sensing forces applied to a shoe having a sole and further comprising a current sensor electrically coupled to the first electrode layer and the second electrode layer and configured to sense a current generated when a force is applied between the at least one first triboelectric member and the at least one second triboelectric member

19. The generator of claim 17, wherein the at least one first triboelectric member comprises:

(a) a first substrate; and

(b) an aluminum layer disposed on the first substrate.

20. The generator of claim 19, wherein the at least one second triboelectric member comprises:

(a) a second substrate;

(b) an PTFE layer disposed on the first substrate; and

(c) a copper electrode layer disposed between the second substrate and the PTFE layer.

21. A resonant frequency sensor, comprising:

(a) a first triboelectric generating member;

(b) a second triboelectric generating member spaced apart from the first triboelectric generating member and including a material that generates a charge imbalance after coming into contact with the first triboelectric generating member and then being separated therefrom; and

(c) a resonant separating member configured to maintain the first triboelectric generating member in a spaced apart relationship from the second triboelectric generating member when at rest, but to allow contact therebetween when a force is applied to a selected on of the first triboelectric generating member and the second triboelectric generating member, the resonant separating member having a resonant frequency so that when the force varies according to the resonant frequency, the a first triboelectric generating member and the second a triboelectric generating member will vibrate into and out of contact with each other, thereby generating a current that varies according to the resonant frequency.

22. The resonant frequency sensor of claim 21, wherein the resonant separating member comprises at least one spring tuned to the resonant frequency.