Solar cells, also known as solar photovoltaic panels, are devices that convert light energy into electricity. They are commonly used in various applications such as photovoltaic power stations, solar street lights, garden lighting, outdoor monitoring systems, and more.
The main materials used in the production of solar panels are monocrystalline silicon and polycrystalline silicon wafers. Monocrystalline silicon wafers have a higher photoelectric conversion rate compared to polycrystalline silicon wafers, but they are also more expensive.
Silicon solar cells are made from silicon semiconductor material, which consists of a large area PN junction composed of series and parallel connections. Metal grid lines are made on the N-type material layer as contact electrodes, and metal films are also used on the backside as contact electrodes, forming the solar panel.
To minimize light emission loss, the surface of the solar panel is usually covered with an anti-reflection film. The main types of solar cells include monocrystalline silicon, polycrystalline silicon, and amorphous silicon.
Monocrystalline silicon solar cells have the highest conversion efficiency, with an experimental maximum conversion efficiency of 25% and an actual use conversion efficiency of about 18%. They have a service life of 15 to 25 years but come at a higher cost. They are widely used in large-scale applications and industrial production.
Polycrystalline silicon solar cells have a slightly lower conversion efficiency, with an experimental maximum conversion efficiency of 20% and an actual use conversion efficiency of about 15%. They have a lower service life compared to monocrystalline silicon, but they are more cost-effective.
Currently, many photovoltaic manufacturers mass-produce polycrystalline silicon solar cells.
Amorphous silicon solar cells are low in cost and have good performance in low-light conditions. However, they have a low conversion efficiency, less than 10%, and a shorter service life. The materials used in amorphous silicon solar cells are less stable and can lead to a decline in photoelectric efficiency over time, affecting their practical use.
In addition to the solar cell itself, a standard solar panel includes a glass enclosure at the front to enhance durability and protect the silicon photovoltaic material. Underneath the glass enclosure, the panel has a shell for insulation and a protective backsheet, which helps to limit heat dissipation and moisture within the panel. Proper insulation is crucial as increased temperatures can decrease the efficiency of the solar panel, thereby reducing its energy output.
The service life of solar panels is determined by the materials used. Silicon solar panels generally have a service life of 15 to 25 years. However, over time, environmental factors can cause the solar panel material to age. Typically, the power output of solar panels will decay by around 30% in 20 years and 70% in 25 years.
It is important to note that solar panels are only capable of converting light energy into electricity and cannot store electricity themselves. When exposed to strong light, solar panels can produce a high electric potential.
Conversely, when exposed to weak light, they can only generate a low electric potential. The output voltage of solar panels is highly unstable and not suitable for directly powering electrical devices.
To overcome this limitation, a voltage conversion module is used to convert the unstable voltage generated by the solar panel into a suitable voltage for charging batteries. The batteries then provide a relatively stable supply voltage to power-consuming equipment, ensuring a consistent and reliable energy supply.
