Читать книгу Materials for Solar Energy Conversion - Группа авторов - Страница 47

The single-crystalline PV cells are started to use in power production since 1970. It is also called first-generation photovoltaic cell, and this type of technology is more reliable, durable, and good for long time power generation.

Figure 2.2 displays schematic diagram of single-crystalline photovoltaic cells. PV solar manufacturing industry produces multi-crystalline photovoltaic solar cells from highly purified form of silicon. Chemical purification process has been employed for producing multi-crystalline solar cells, metallurgical silicon is used as raw material, and this type of process is also called as Siemens process. This process also involves refinement of unstable silicon compounds into stable silicon at higher temperature. It produces higher grade metallurgical silicon by using metallurgical technique as an alternative of chemical purification process. Multi-silicon contains less than one part of one billion impurities, which is known for less purity silicon grade. Multi-crystalline silicon comprises of small crystals, which gives materials in the form of wafer effects. The size of multi-crystalline solar PV cells is less than 1 mm. It is common type of PV cells, required nearly 5 tons of multi-crystalline silicon for producing 1-megawatt conventional solar unit. These multi-crystalline solar cells are different from single and amorphous crystals.

Figure 2.2 Single-crystalline PV cells.