In the entire field of solar photovoltaic lighting, the best economic benefits are solar lawn lights and small solar photovoltaic lighting devices. This conclusion is consistent with the application of the entire photovoltaic industry. Since the current solar photovoltaic market is still in economically developed European and American countries, all photovoltaic products that can be exported have a high probability of obtaining economic benefits. Solar lawn lights and small solar photovoltaic lighting devices have achieved more impressive results because of the large number of exports. Encouraging economic benefits.
Solar road lighting is a project developed under the support of the government. Although its economic benefits are not obvious, its social benefits are obvious to all, especially in the construction of a new socialist countryside in Beijing and the “Bright Project” in areas without power supply. “In, it plays a good role in improving the lives of the people and publicizing new energy policies.
- Tomorrow of solar cells
Since the beginning of the 21st century, my country’s solar photovoltaic has entered a period of rapid development, and the efficiency of solar cells is constantly improving. With the help of nanotechnology, the conversion rate of silicon materials in the future can reach 35%, which will become a “revolution in solar power technology.” Sexual breakthrough”.
The mainstream material of solar photovoltaic cells is silicon, so the conversion rate of silicon materials has always been an important factor restricting the further development of the entire industry. The classical theoretical limit of the conversion rate of silicon material is 29%. The record set in the laboratory is 25%, and this technology is being put into the industry. At present, the conversion rate of photovoltaic solar cell modules put into mass commercial production is about 16%.
The laboratory can already extract high-purity silicon directly from silica without converting it into metallic silicon and then extracting silicon from it. This can reduce intermediate links and improve efficiency.
Combining the third-generation nanotechnology with the existing technology can increase the conversion rate of silicon materials to more than 35%. If it is put into large-scale commercial production, it will greatly reduce the cost of solar power generation. The gratifying thing is that such a technology “has been completed in the laboratory and is waiting for the process of industrialization.”
For solar cells with a conversion rate of 35%, it means that the conversion rate of solar cells has doubled compared to the current one; that is, the power generation of solar cell modules of the same area will be doubled, according to the national standard “General Technical Specifications for Solar Photovoltaic Lighting Devices” (GB 24460-2009) Regarding the relationship between solar cell modules and light source power, the power of solar cell modules must be 4 to 5 times the power of the light source, and in the future, it will only need 2 to 2.5 times. In this way, solar street lights in the true sense used on secondary roads and even main roads can be born.
The high price of solar cells is also a problem that hinders the development of solar photovoltaic lighting. Fortunately, since 2009, the price of solar cells has dropped by half due to the substantial drop in the price of silicon materials. It is estimated that the price of solar cell modules will drop to US$1/Wp just around the corner. Many large solar cell manufacturers in the world regard this price as the direction of their efforts.
- Energy storage
The most important part of solar photovoltaic lighting that needs to be improved is energy storage. The main technical indicators of the ideal energy storage components for solar photovoltaic lighting are still quite vague. Many battery manufacturers claim that their products are special solar batteries. In fact, most of them have not done so yet. Know what are the main technical indicators of the energy storage components of solar photovoltaic lighting.
The basic requirements of solar photovoltaic lighting for energy storage components are:
(1) High watt-hour efficiency, that is, high charging and discharging efficiency;
(2) The charging and discharging curves should be as flat as possible to improve the efficiency of the solar cell, so that the solar cell can work as close as possible to its maximum power output point;
(3) Long service life;
(4) The temperature characteristic is good, can work normally under the condition of 20~70℃;
(5) High performance-price ratio;
(6) Does not pollute the environment.
Based on the above requirements, the most ideal solar photovoltaic lighting energy storage components in the future may be lithium iron phosphate batteries and flywheel batteries. The efficiency of the rose battery is divided into voltage efficiency, ampere-hour efficiency and watt-hour efficiency. People are most concerned about watt-hour efficiency. The watt-hour efficiency of ordinary lead-acid batteries varies with the time of use. The watt-hour efficiency of new lead-acid batteries can reach 90%, while the watt-hour efficiency of old batteries is only 60%~70%; furthermore, the watt-hour efficiency of batteries Efficiency refers to the efficiency at 25°C. When the ambient temperature is below zero or above 40°C, the actual efficiency will drop a lot. The efficiency of the battery is often not noticed by everyone. In fact, it is very important for solar photovoltaic lighting appliances.
Lithium iron phosphate battery is particularly recommended here, which may be the most ideal energy storage component for solar LED systems in the future.
Flywheel energy storage technology has a history of about 100 years. It is the advancement of today’s magnetic levitation and modern power electronics technology that has refreshed this ancient technology.
Modern flywheel energy storage technology is to suspend the flywheel in a vacuum cavity to store energy with almost no loss. This is an epoch-making progress in flywheel energy storage technology. Its energy storage efficiency can reach more than 90%, and its energy storage cost can be close to that of colloidal lead-acid batteries, with a service life of 20 years, and it can be “comparable with solar batteries. At present, the price of a flywheel battery that stores 1kW.h of energy is about 2,000 yuan, and it can store energy for a solar street lamp.