CN103532253A - Laser wireless energy transmission system - Google Patents

Abstract

A laser wireless energy transmission system, comprising: a laser; a light homogenizer, which is located on the output light path of the laser; a collimator, which is located on the output light path of the light homogenizer; a laser energy receiver, which is located on the collimator The output optical path of the straightener; a monitor whose input end is connected with the output end of the laser energy receiver. The invention can realize long-distance wireless transmission of energy, and has the advantages of simple structure and low cost.

Description

Laser wireless energy transmission system

technical field

The invention relates to the field of energy, in particular to a laser wireless energy transmission system.

Background technique

There are many forms of power transmission, the most common one is wired transportation, that is, metal wires are used to transport electric energy from A to B; it can also be carried by batteries, charged at A and discharged at B; wireless can also be used in the form of energy transfer. There are two forms of wireless energy transmission, one is microwave energy transmission, and the other is laser energy transmission. Both forms convert electrical energy into wave energy, and the wave is transmitted in the air. for the process of electrical energy. Relatively speaking, the energy transmission density of the laser system is 100 times that of the microwave system; secondly, the directionality is good and the intensity is not limited, but it cannot work in the foggy and cloudy weather in the atmosphere. On the contrary, the microwave energy transmission system can supply energy in bad weather in the atmosphere, but the microwave divergence is strong, so the size of the receiving antenna of the system is too large, and its strength is limited by the interference of the atmospheric ionosphere. It can be seen that as long as you avoid rainy weather, or above the clouds, laser energy delivery is the best choice.

Laser energy transmission is often used in special occasions, such as between two places that cannot be wired, cannot be transported, and require long-term power supply. So its market is small but important.

references:

[1] Hong Yanji, Jin Xing, Li Xiaojiang, Dou Zhiguo, Li Qian, etc., "Approaching Space Vehicle Technology", an academic monograph of the School of Equipment, National Defense Industry Press, first edition in January 2012.

[2] Xiong Shaozhen, Zhu Meifang, "Basics and Applications of Solar Cells", Chapter 5: Silicon-based Thin Film Solar Cells, Science Press, first edition, October 2009.

The first is the uniformity of light intensity in the spot. Usually the best lasers are single-mode, with a Gaussian distribution of light intensity, that is, the light intensity decreases with radius. Due to the difference in light intensity, the receiving efficiency of the receiver will be greatly affected. If the batteries are connected in series, the current of the entire receiver will be the minimum value based on the weakest light intensity. And if the batteries are connected in parallel, although the current can be superimposed, the voltage of the entire receiver is only 0.5V, the current is very large, and it is difficult to boost the voltage.

The second is the collimation of the laser beam. As the transmission distance of the laser increases, the conventional laser has a divergence angle of 5 milliradians. After a certain distance, the spot will become larger and the light intensity will decrease. For example, after the laser travels 1000 meters, the laser spot will become a large circular spot with a radius of 5 meters. Therefore, the laser divergence angle should be controlled within 0.5 milliarc.

The third is the problem of photoelectric conversion under high light intensity. At present, photovoltaic cells are designed with shallow junction (<0.5μm) and wide grid (>1mm) structures based on the standard of one solar light intensity (0.1W/cm ² ). But when the laser light intensity rises to 100 times (10W/cm ² ) or 1000 times the sun light intensity (100W/cm ² ), the photogenerated carriers will increase by hundreds or thousands of times, and they will gather on the surface of the battery, and their recombination will also occur. increases substantially, and therefore, its efficiency will decrease. Usually the efficiency of solar cells begins to drop at 3 times the concentration. Therefore, in order to overcome this difficulty, the battery structure must be redesigned.

Contents of the invention

The purpose of the present invention is to provide a laser wireless energy transmission system, which can realize long-distance wireless transmission of energy, and has the advantages of simple structure and low cost.

The present invention provides a laser wireless energy transmission system, including:

a laser;

A homogenizer, which is located on the output light path of the laser;

A collimator, which is located on the output light path of the homogenizer;

a laser energy receiver, which is located on the output light path of the collimator;

A monitor whose input is connected to the output of the laser energy receiver.

It can be seen from the above technical solutions that the present invention has the following beneficial effects.

1. With the present invention, multi-mode lasers can be used for laser energy delivery, and multi-mode lasers can also be used for laser energy delivery, which greatly reduces the cost of energy delivery.

2. By using the present invention, the intensity of the laser spot can be made uniform, thereby improving the efficiency of laser energy delivery.

3. With the present invention, the laser light can be transported to a farther distance, and the laser spot changes little.

4. By using the present invention, the battery can withstand the irradiation of high-energy laser without reducing the photoelectric conversion efficiency of the laser energy receiver.

Description of drawings

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings, wherein:

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the structural representation of homogenizer among Fig. 1;

FIG. 3 is a schematic structural diagram of the collimator in FIG. 1 .

Detailed ways

Please refer to Fig. 1-Fig. 3, the present invention provides a laser wireless energy transmission system, including:

A laser 11, the wavelength of the laser 11 is in the visible and infrared bands, that is, from 0.5 microns to 12 microns;

A homogenizer 12, which is located on the output optical path of the laser 11;

A collimator 13, which is located on the output optical path of the homogenizer 12, the collimator 13 is a single-wavelength multi-lens combination, which controls the divergence angle of the beam, and controls the spot size of the laser at a distant destination. Straightener 13 comprises, a first lens 131, a second lens 132, and this first lens 131 and second lens 132 are located on the same optical path, and this second lens 132 is located on the stepper motor slide rail 133, to adjust and the distance of the first lens 131;

A laser energy receiver 14, which is located on the output optical path of the collimator 13, the laser energy receiver 14 is an integration of semiconductor photovoltaic cells and heat dissipation and packaging thereof, the material of the laser energy receiver 14 is silicon, indium gallium As, gallium antimonide, lead tin or germanium telluride, the band gap is between 1.1 and 0.1 eV, and the corresponding wavelength is between 1.1 and 10 microns. The laser energy receiver 14 is a pn Junction photovoltaic cells, the gate electrodes of photovoltaic cells are densely distributed, and the grid spacing is less than 1 mm to capture more photogenerated carriers; the junction depth of photovoltaic cells is greater than 0.5 microns to reduce the series resistance of the cells. The laser The energy receiver 14 is a back-junction battery, and its pn junction is on the back side of the battery, and the light-facing surface is not blocked, so that the light-receiving area is maximized. The laser energy receiver 14 is a vertical junction battery, and its pn junction is perpendicular to the light-facing surface , and the light-receiving surface is not blocked, so that the light-receiving area is maximized, and the laser energy receiver 14 is a series-parallel connection of a plurality of photovoltaic cells to cope with the inhomogeneity of the receiver boost and laser energy density;

A monitor 15 whose input is connected to the output of the laser energy receiver 14 .

Lasers, homogenizers, collimators, laser energy receivers and monitors are used to form a laser wireless energy transmission system. Utilizing the present invention, energy can be transmitted from A to B in a wireless manner, thereby forming wireless energy transmission.

The near-infrared band is used, that is, from 0.5 microns to 12 microns. In this band, the laser energy is less lost in space; while the laser with a wavelength longer than 12 microns does not.

A homogenizer is used to change the distribution of the laser light intensity with the radius, so that the light intensity reaching the laser energy receiver is uniform, thereby improving the receiving efficiency of the receiver.

The single-wavelength lens combination is used to control the beam divergence angle and the spot size of the laser at the distant destination.

Using a photovoltaic cell corresponding to the laser wavelength, the band gap width of the cell is slightly smaller than the photon energy corresponding to the wavelength, so as to maximize the receiving efficiency.

Silicon, indium gallium arsenide, gallium antimonide, lead tin and germanium telluride are used as materials for the laser energy receiver, the band gap of which is between 1.1 and 0.1 eV, and the corresponding wavelength is between 1.1 and 10 microns.

A pn junction photovoltaic cell that can withstand a certain power density is used. The grid electrodes of the photovoltaic cell are densely distributed, and the grid interval is less than 1mm to capture more photogenerated carriers; the junction depth of the photovoltaic cell is greater than 0.5 microns to reduce The series resistance of the battery.

The back-junction battery is used as the laser energy receiver, and the pn junction is on the back of the battery, and the light-facing surface is not blocked, so that the light-receiving area is maximized.

The vertical junction cell is used as the laser energy receiver, and its pn junction is perpendicular to the light-receiving surface, and the light-receiving surface is not blocked, so that the light-receiving area is maximized.

Multiple photovoltaic cells are connected in series and in parallel to form a laser energy receiver. The series connection of photovoltaic cells is to increase the output voltage, while the parallel connection can resist the reduction of receiving efficiency caused by uneven laser energy density. The two are an organic combination.

4. Principle Description

1. Uniformity of light intensity in the spot

Using the optical diffraction characteristics of the laser output and the total reflection characteristics of the conical wall to the light, the optimal multi-junction conical structure for uniform light can be obtained through ray tracing simulation, so that the single-mode or multi-mode laser light intensity can be obtained by Uniform distribution after homogenizer, not Gaussian distribution.

2. Collimation of laser beam

Select two lenses for collimation combination. For the laser wavelength, an optical anti-reflection coating is evaporated on it, so that the transmittance of a single lens is greater than 95%, and the transmittance of a lens combination is greater than 90%. By fine-tuning the relative position of the two geometric lenses, the collimation is greatly improved, which can be lower than 0.5.

3. Photoelectric conversion under high light intensity

Parallel junction cell: increase the junction depth and encrypt the gate lines;

Back-junction battery: increase the area of the light-facing surface;

Vertical junction cell: reduce series resistance and increase output voltage.

The above embodiments are only to illustrate the technical ideas of the present invention, and cannot limit the protection scope of the present invention with this. Any changes made on the basis of the technical solutions according to the technical ideas proposed in the present invention all fall into the protection scope of the present invention. within range.

Claims (9)

1. A wireless laser energy transmission system, comprising: a laser; A homogenizer, which is located on the output light path of the laser; A collimator, which is located on the output light path of the homogenizer; a laser energy receiver, which is located on the output light path of the collimator; A monitor whose input is connected to the output of the laser energy receiver. 2. The wireless laser energy transmission system according to claim 1, wherein the wavelength of the laser is in the visible and infrared bands, that is, from 0.5 microns to 12 microns. 3. The laser wireless energy transmission system according to claim 1, wherein the collimator is a single-wavelength multi-lens combination, which controls the beam divergence angle and the spot size of the laser at a distant destination. 4. The wireless laser energy transmission system according to claim 3, wherein the collimator comprises a first lens and a second lens, the first lens and the second lens are located on the same optical path, and the second lens Located on the stepper motor slide to adjust the distance from the first lens. 5. The laser wireless energy transmission system according to claim 1, wherein the laser energy receiver is an integration of a semiconductor photovoltaic cell and its heat dissipation and packaging, and the material of the laser energy receiver is silicon, indium gallium arsenide, antimony Gallium, lead tin or germanium telluride have band gaps between 1.1 and 0.1 eV, corresponding to wavelengths between 1.1 and 10 microns. 6. The laser wireless energy transmission system according to claim 5, wherein the laser energy receiver is a pn junction photovoltaic cell that withstands a predetermined power density, and the grid electrodes of the photovoltaic cells are densely distributed, reaching a grid interval of less than 1mm, To capture more photo-generated carriers; the junction depth of the photovoltaic cell is greater than 0.5 microns to reduce the series resistance of the cell. 7. The laser wireless energy transmission system according to claim 6, wherein the laser energy receiver is a back-junction battery, its pn junction is on the back of the battery, and the light-facing surface is not blocked, so that the light-receiving area is maximized. 8. The wireless laser energy transmission system according to claim 7, wherein the laser energy receiver is a vertical junction cell, the pn junction of which is perpendicular to the light-receiving surface, and the light-receiving surface is not blocked, so as to maximize the light-receiving area. 9. The laser wireless energy transmission system according to claim 8, wherein the laser energy receiver is a series-parallel connection of a plurality of photovoltaic cells to deal with receiver boost and unevenness of laser energy density.

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