Green energy harvesting methods for novel class of batteries and power supplies
View Patent ↗An energy harvesting device for powering electronic devices such as wireless sensors and IoT devices is described. The device relies on nature's fundamental forces to convert kinetic energy to electrical energy, acting as power source; while accounting for the Casimir force. Nanotechnology and MEMS are used to fabricate the device embedding a mechanical oscillator, electronic circuitry, energy harvester, and transducer integrated in the same packaging. The device supports mechanism to excite and ignite the oscillatory behavior via RF signal from a remote signal source that synthesizes the RF signal on a fix or mobile platform. Additionally, solar and RF signals may be added constructively to boost the output power of the device. The device scales from micron size to blades and racks formed from arrays of the connected devices to increase the output power of the aggregate system to any desired level for powering home appliances or computer networks.
1. An energy harvesting device, comprising:
a radio frequency (RF) energy harvesting layer comprising:
an RF antenna configured to receive RF signals; and
an RF to direct current (DC) rectifier configured to convert RF signals received from the antenna into electrical current;
a mechanical energy harvesting layer comprising:
first and second substantially parallel plates;
a plurality of nanotubes connected between the first and second plates along an axial direction of the nanotubes; and
a piezoelectric cantilever connected to the first plate;
a device packaging housing the RF energy harvesting layer and the mechanical energy harvesting layer, wherein the second plate is fixedly connected to the device packaging, wherein the first plate and the piezoelectric cantilever are free to move towards and away from the second plate, wherein the piezoelectric cantilever is configured to oscillate by being attracted towards the second plate in response to the Casimir force and by being repelled from the second plate by a spring action on the axial direction of the nanotubes, and wherein the oscillations of the piezoelectric cantilever convert to electrical current; and
a voltage adder comprising:
a first input for receiving a voltage from the piezoelectric cantilever;
a second input for receiving a voltage from the RF to DC rectifier; and
an output current for providing a sum of the voltages received at the first and second inputs.
2. The energy harvesting device of claim 1 further comprising:
a DC-DC charge pump configured to:
receive a DC voltage from the RF to DC rectifier; and
step-up the output voltage of the RF to DC rectifier.
3. The energy harvesting device of claim 1 further comprising:
an electrical switch comprising first and second connections, wherein the first connection is connected to the piezoelectric cantilever, and wherein the second connector is connected to RF energy harvesting layer; and
a capacitor;
wherein the RF energy harvesting layer is configured to charge the capacitor for delivering an electrical current to the piezoelectric cantilever through the electrical switch.
4. The energy harvesting device of claim 3 , wherein the device packaging houses and vacuum seals the electrical switch and the capacitor.
5. The energy harvesting device of claim 3 ,
wherein the energy harvesting device is configured to operate in an excitement mode and an operating mode,
wherein, in the excitement mode, the electrical switch is closed and the piezoelectric cantilever is configured to force the first plate to exert strain on the nanotubes, and
wherein, in the operating mode, the electrical switch is open and the oscillations of the piezoelectric cantilever convert into electrical current.
6. The energy harvesting device of claim 2 , wherein the radio frequency (RF) energy harvesting layer further comprises a voltage regulator configured to provide a constant voltage level at an output of the DC-DC charge pump.
7. The energy harvesting device of claim 1 , wherein the device packaging is vacuum sealed.
8. The energy harvesting device of claim 1 , wherein the nanotubes are carbon nanotubes.
9. The energy harvesting device of claim 1 , wherein the piezoelectric cantilever is a bimorph cantilever comprising first and second independently polarized piezoelectric layers, wherein the energy harvesting device further comprises first, second, and third electrodes, wherein the first piezoelectric layer is stacked between the first and second electrodes, wherein the second piezoelectric layer is stacked between the second and third electrodes, wherein the first and second electrodes are configured as ground electrodes, and wherein the third electrode is configured as a voltage source electrode.
10. The energy harvesting device of claim 1 , wherein the piezoelectric cantilever is a unimorph cantilever comprising one piezoelectric layer, wherein the energy harvesting device further comprises first and second electrodes, wherein the piezoelectric layer is stacked between the first and second electrodes, wherein the first electrode is configured as a ground electrode, and wherein the second electrode is configured as a voltage source electrode.
11. The energy harvesting device of claim 1 , wherein the first and second plates are fractal shape plates.
12. The energy harvesting device of claim 1 , wherein the first and second plates are solid plates.
13. The energy harvesting device of claim 1 , wherein a distance between the first and second plates is less than a micrometer.
14. The energy harvesting device of claim 1 , wherein the energy harvesting device is connected to an electronic device, wherein the output current of the energy harvesting drives the electronic device.
15. The energy harvesting device of claim 14 , wherein the electronic device is one of a sensor and an Internet of things (IoT) device.
16. The energy harvesting device of claim 1 , wherein the piezoelectric cantilever is a microelectromechanical system (MEMS) nano piezoelectric cantilever.
17. The energy harvesting device of claim 1 , wherein the piezoelectric cantilever is a first piezoelectric cantilever, the energy harvesting device further comprising a plurality of piezoelectric cantilevers connected to the first plate.
18. The energy harvesting device of claim 1 further comprising a transceiver for transmitting telemetry data collected from at least one of a temperature sensor, a gyro, a magnetometer, an accelerometer, a chemical sensor, an electrical sensor, a nuclear sensor, and an optical transducers within the device packaging.