Laser Power Transmission - Energy Supply Technology To The Future

Since the invention of electricity and widely pushed to the production of life applications, how to find a highly efficient transmission method, as far as possible to reduce the loss of long-distance transmission, is one of the focus of attention of the power sector and researchers. China's ultra-high voltage transmission technology is relatively leading in the world, however, there is still a loss rate of 2%-7% (depending on the distance) in the transmission process, which is a loss that should not be ignored.
The idea of wireless transmission of energy was first proposed by the Serbian scientist Nikola Tesla 100 years ago, and lasers have the ability to carry very high energy in a single direction, which theoretically meets the needs of long-distance transmission. Just as sunlight can charge a circuit board, laser as a means of long-distance transmission not only has a high output power, but also can be carried out at any time and any place without the constraints of charging cables, which has unparalleled advantages.
In 1992, the U.S. ABB company took the lead in laser power supply technology related research, the realization of high-voltage line circuit monitoring, and gradually replace the traditional CT take point current transformer. The U.S. Department of Defense and the National Aeronautics and Space Administration also realized that if the satellite and unmanned aircraft through the laser power supply, you can achieve a longer period of time to carry out more tasks, in other words, the laser in the military and aerospace has unprecedented possibilities, so a number of laser satellite function of the relevant technical research carried out in this way.
In 1997, Japan N. Kawashima and others carried out the use of laser energy transmission to the lunar volcano bottom probe robot (ROVER) energy supply experiment. Because there is no sunlight inside the volcano, only in the crater to receive sunlight into laser, transmitted to the bottom of the volcano to Rover energy supply. The transmission system laser output power of 60W, transmission distance of 1000m, successfully drive 10W robot operation, photoelectric conversion efficiency of about 20%.
In 2005, NASA Marshall Space Flight Center made a breakthrough, for the first time with a power of 500 W, wavelength of 940nm laser 15m away from the micro-vehicle to provide 6W of electricity, so that the vehicle operated for 15min. 2013, the U.S. Naval Laboratory successfully used 2kW laser to 40m away from the UAV remote power supply.
A complete laser energy delivery system consists of three modules, namely the laser transmitter module, the laser transmission module and the laser-to-electricity conversion module. Among them, the efficiency of laser and photovoltaic cell, is the core of the whole laser energy system, how to make laser energy through the conversion of electricity - light - electricity, as far as possible to minimize the atmospheric attenuation, photovoltaic conversion attenuation, is the key index of this system. China's National University of Defense Technology, Nanjing University of Aeronautics and Astronautics, Wuhan University, Shandong Institute of Aerospace Electronics Technology and other research institutes have also carried out relevant research to gallium arsenide, monocrystalline silicon and other photovoltaic cells to achieve different wavelengths and distances of the laser power supply.
In recent years, Japan, Russia and other countries are also focusing on laser power transmission related technology applications.
Russia focuses on the application of laser power transmission in space. 2021, Russia's "energy" rocket space company plans to use the laser for wireless power transmission experiments, for the future of energy transmission in space to provide feasibility testing. The space experiment, code-named "Pelican", refers to the use of lasers for power transmission between spacecraft, and the experiment has been included in the long-term scientific experiment program of the Russian section of the International Space Station. At present, the efficiency of photoelectric converters has reached 60%, so the use of lasers to transmit electricity from one spacecraft to another will be very effective. Russian scientists are optimistic about the use of laser wireless power transmission technology for charging satellites in space orbit.
Japan, on the other hand, is mainly casting its vision on its life applications. Tokyo Institute of Technology and other institutions are committed to the development of civilianization of the "light wireless charging" technology. The use of electrical energy to emit laser, laser irradiated objects and then through the power generation board will be converted into electrical energy, so that not only can save cell phones, home appliances configuration charging line trouble, but also to solve the new energy vehicles need to regularly stop on the way to find the charging pile charging problems.
Laser power transmission technology has many advantages, but also has some problems to be solved. For example, now used for power transmission of ultra-high voltage lines are not easy to contact with the human body, and ultra-high-power laser relying on air propagation, easy to be affected by a variety of reflections, once irradiated to the human body may bring serious danger. Another example, how to ensure that the laser in different climatic conditions to ensure stable and reliable transmission efficiency, reduce attenuation, while accurately transmitted to the need for equipment receivers, but also pending tracking and focusing technology breakthroughs. In conclusion, laser power transmission technology represents the future direction of energy supply development and has a broad application space.