The solar LED lighting system consists of intelligent controllers, solar modules, energy storage components, LED circuits and LED light sources (see Figure 1). The working principle is: when there is sunlight in the day, part of the electricity generated by the solar battery. For LED use, the other part is stored by the battery through the intelligent controller. When it is night or rainy, the LED light source is powered by the battery. Therefore, the solar module must be installed in the direction of the sun and kept as clean as possible to ensure the transmittance of sunlight. Solar LED lighting systems are favored for their energy, environmental protection and sustainability, with extensive market space and development potential.
1 Features of solar LED lighting system
As we all know, the current solar photovoltaic power generation has the characteristics of clean and pollution-free, geographically unrestricted, and short time to obtain energy. LED light source has become the ideal illumination source for the future due to its environmental protection and energy saving, and the solar LED lighting system will be the two. The advantages of the people are further perfectly combined, thus having more advantages and development potential. Specifically in the following aspects.
1.1 Environmental protection is more obvious
The energy of the solar LED lighting system is provided by the solar cell module, which converts the solar energy into electrical energy through the photovoltaic effect and then supplies it to the LED. Compared with solar system photovoltaic power generation, there is no pollution to the environment and LED light source does not have mercury pollution. The solar LED lighting system effectively combines the environmental advantages of the two, neither threatening the environment nor material pollution. Puzzle.
1.2 Energy saving is more prominent
The system uses solar cells to generate electricity, without fuel, and uses LED as the light source. At the same lighting brightness, the power consumption is only 1/8 of that of incandescent lamps and 1/2 of fluorescent tubes. In China, even if only 1/3 of the incandescent lamps are replaced by LEDs, the annual electricity consumption can be saved by 1011 degrees, which is equivalent to the annual power generation of a Three Gorges project. Today, with the increasingly tight supply of natural gas, coal and other energy sources, the huge energy-saving value of solar LED lighting systems undoubtedly provides a bright future for its development.
1. 3 higher energy efficiency
The solar cell module directly converts the solar energy into direct current electric energy, and obtains the voltage required by the LED by re-matching the corresponding battery by parallel connection or series connection. Compared with traditional power supply, it does not require AC/DC conversion, and does not require complicated and expensive pipeline layout, which can achieve higher energy efficiency, and is more safe and economical.
1. 4 Installation is more convenient
Each solar LED luminaire is an independent power supply, no need for power design, power capacity expansion and manual power control, etc., as long as you plant a hole like a tree, bury a rod, you can place it at will, install and use it. More convenient.
2 obstacles in the development of solar LED lighting systems
At present, there are many places where solar LED lighting systems need to be improved and perfected, which affects the full play and utilization of the functions of the system to some extent. Expressed in the following points.
2.1 Solar cell power generation efficiency
Low-impact solar LED efficiency LED driving power in solar LED lighting system is mainly provided by solar cell modules. At present, the solar cell's power generation efficiency is generally low, and the single-crystal silicon solar cell with the highest conversion efficiency among all kinds has a photoelectric conversion efficiency of 15 About %, although the highest is up to 24%, but its production cost is too large. Polycrystalline silicon solar cells and single crystal silicon solar cells are similar in production process and low in cost, but their photoelectric conversion efficiency is only about 12%. Amorphous silicon solar cells can also generate electricity under low light conditions, but their conversion rate is only about 10%, and their conversion rate decays with time. In summary, the conversion efficiency of solar cell modules is low, which is one of the main reasons that seriously affect the efficiency of solar LED lighting systems. 2.2 LED luminous efficiency limits the luminous performance of solar LED lighting systems.
LED as a light source of solar LED lighting system, its luminescence performance directly affects the luminescence performance of the entire system. The luminous efficiency of LEDs is determined by factors such as internal quantum efficiency and external quantum efficiency. At present, the spontaneous polarization and piezoelectric effect generated by a large number of non-radiative defects inside the LED cause the luminous efficiency to decrease, that is, the Droop phenomenon. In addition, the increase in junction temperature caused by the inability to dissipate heat in the LED is also the main reason for the decrease in LED luminous efficiency. Improving LED performance and improving luminous efficiency have become one of the key issues in solar LED lighting systems, which has constrained the development of solar LED lighting systems.
2.3 High cost is the main obstacle to popularizing solar LED lighting systems
Due to the rising price of silicon materials and supply bottlenecks, solar LED lighting systems have higher electricity costs. According to statistics, the cost of a solar cell module is five yuan, which is 10 times the cost of traditional thermal power generation. Another reason for the high cost of solar LED lighting systems is that the cost of the light source LEDs in the system is also very high, for example, to generate luminous flux of 1000 lumens, the cost of using incandescent lamps is less than 1 US dollar, and the cost of using compact fluorescent lamps is less than 2 US dollars. The cost of using ten high-power LEDs exceeds $20, and it is difficult to offset the price difference of the light source without the cost of the cable and later saving the electricity bill. In summary, due to the high cost of solar power generation and LED light source, the price of solar LED lighting system is high, which has become a major obstacle affecting its wide application.