Solar photovoltaic lighting device and its reliability analysis

Foreword

Humans invented solar cells soon after they were applied to lighting devices. In recent years, due to the improvement of people's awareness of environmental protection, solar photovoltaic lighting devices in China have been paid attention to and promoted, but many quality problems have also appeared. Especially the quality problems such as illumination and reliability are plaguing the development of solar photovoltaic lighting devices in China.

In response to the above problems, we conducted a systematic analysis of the effects of the reliability of the four major components of solar photovoltaic lighting devices, "solar battery", "light source", "battery" and "controller" on solar photovoltaic lighting devices. Based on our years of experience in solar cell application technology research, we have proposed a solution.

1 history of solar photovoltaic lighting installations

Due to the unique advantages of solar photovoltaic technology, solar cells have been used in the field of lighting soon after entering the practical stage. In China, solar cells were used on navigation lights as early as the early 1970s, when solar navigation lights were installed in Tianjin Port. Then, in order to solve the lighting problem in the power-free area, solar lighting has appeared more and more. In the south of China, solar tapping lamps and many other solar lights have appeared.

In recent years, due to the substantial increase in solar cell production and the improvement of national economic strength since the reform and opening up in China, solar lighting has begun to enter our lives; western bright projects, solar street lights, solar garden lights, solar lawn lights, solar landscape lights, Solar Craft Lights..., while beautifying our lives, it also brought unexpected surprises to people: the era of solar lighting is coming.

Solar traffic lights have also gained popularity in recent years. Now everyone knows what the solar yellow flashing lights are all about. Many people know solar cells through solar yellow flashing lights. At the crossroads of city or country roads, you can often see the solar yellow flashing lights flashing day and night, reminding passers-by to be alert to traffic. This kind of wire is not required to be laid (it is sometimes very difficult to lay wires at the intersection of highways). Traffic lights that do not need to provide power supply are developed and popularized in China's urban and rural areas in 4-5 years. It is very worthwhile. Our workers in the photovoltaic industry have pondered and summarized.

What I want to mention here is one of the most successful examples in this field - the solar lawn lamp. Its development is the only project in China that is completely in accordance with the laws of the market. It does not need to pay the taxpayer's money. The solar lawn lamp is the solar cell of China. An important part of the field of LED applications. In 2006, the export volume was nearly 200 million baht, accounting for more than 90% of the world's production. The solar cell consumption was about 30 MW, and the LED consumption was 2-3 billion. The semiconductor lighting system consisting of these solar cells and LEDs. Both solar lighting and LED lighting are currently the largest in China. The consumption of 1.2V small batteries will also exceed 200 million, which is definitely an exciting statistical data. Its production is mainly distributed in the coastal areas of Guangdong, Fujian, Zhejiang, Jiangsu, etc. It consists of 0.2-0.3W solar cells and 1-2 LEDs, which are connected by a control and boost circuit, the circuit mechanism Although relatively simple, it gives a lot of inspiration to solar photovoltaic lighting, and raises the problems that need to be solved in the system. Unfortunately, this largest solar photovoltaic lighting project has not been paid enough attention until now, in a disorderly competitive posture.

2 Classification of solar photovoltaic lighting devices

Since solar photovoltaic power generation is divided into two categories, namely: independent solar photovoltaic power generation system and grid-connected solar photovoltaic power generation system, the difference between them is that the independent solar photovoltaic power generation system is equipped with battery energy storage, and the grid-connected solar photovoltaic power generation system will directly The electricity from the solar cells is sent to the grid, so solar photovoltaic lighting is also divided into two major categories, as shown in Figure 1:

figure 1

The solar photovoltaic lighting devices we usually refer to are mainly independent systems, and its most obvious feature is the storage of batteries. It is this solar battery direct power supply that gives solar photovoltaic lighting devices unparalleled advantages: no need for power grids, no need to lay wires, flexible, portable, safe, energy-saving and environmentally friendly; in many cases has completely replaced Traditional lighting fixtures.

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