Polycrystalline solar cells are a cheaper alternative to mono crystalline solar cells. Although, they are less efficient but their cost can counterbalance this loss in efficiency. Mono crystalline solar cells are expensive due to the costly processes involved in obtaining single crystal silicon.
Poly crystalline versus thin film solar cells
Polycrystalline solar cells are first generation silicon based solar cells. The thin film solar cells, previously used, are second generation solar cells. They are more expensive and more efficient than second generation thin film cells.
Polycrystalline versus mono crystalline solar cells
Cylindrical ingots of silicon are used in the formation of mono crystalline process. But a large number of processes are involved in converting it into the final desired form. In polycrystalline solar cells large square blocks of silicon are used.
Square shape has the advantage that it does not let the material waste. This shape allows the material to fill the entire shape of the standard solar cell.
- These blocks are first converted in to molten form.
- Then this molten liquid is cooled until it solidifies.
- Thin wafers are then cut out of this solidified silicon.
- Finally, the most important process that is doping is done. Doping is the process of adding additional impurities to pure silicon to make it electrically conductive. Doping produces free electrons and holes that move freely in order to conduct electricity.
Why are thin film solar cells more trending?
Thin film solar cells are cheaper. Both consumers and producers need a reduction in cost. There are different categories of consumers. Some of them demand the best efficiency and do not compromise over the efficiency even if it is expensive. These consumers are usually from industries, factories etc. on the other side, there are consumers who want to use the technology at a cheaper rate. If the producers only provide high efficiency expensive solar cells, the technology will become out of the access of many people and they will lose a number of their potential customers.
That is why they seek refuge in providing them with thin film solar cells which are less efficient but are available at a cheaper cost.
World record of Mitsubishi Electric Corporation 2009
In February of 2009, Mitsubishi Electric Corporation exclaimed to have achieved a world record by achieving an efficiency of 18.9% efficiency. The 150x150mm square converted 18.9% of the sunlight striking on it into electricity. This is a big achievement as compared to thin film solar cells. A rough estimate is that they convert around 11% of the sunlight into electric energy.
Warranty of polycrystalline solar panels
Polycrystalline solar panels are expensive but have a much longer life. Most of the manufacturers provide the warranty of 25 years. They work precisely like the best attainable efficiency conditions for these 25 years. But it does not mean that they will become completely useless after this time. They will still be able to provide 80% of the initial efficiency.