Tokyo, Japan [RenewableEnergyWorld.com] Mitsubishi Electric Corporation has set two world records for photoelectric conversion efficiency in polycrystalline silicon photovoltaic (PV) cells, achieved by reducing resistive loss in the cells. The conversion efficiency rates have been confirmed by the National Institute of Advanced Industrial Science and Technology (AIST), in Japan.
One of the world records, which Mitsubishi Electric has now renewed for the third consecutive year, is a 19.3-percent efficiency rating for photoelectric conversion of a practically-sized polycrystalline silicon PV cell of 100 squared centimeters or larger, with the PV cell measuring approximately 15cm x 15cm x 200 micrometers. The rating is 0.2 points higher than the company’s previous record of 19.1 percent.
The second world record, achieved with the same technologies in an ultra-thin polycrystalline silicon PV cell measuring approximately 15cm x 15cm x 100 micrometers, is an efficiency rating of 18.1 percent, a 0.7-point improvement over the company’s previous record of 17.4 percent.
Photoelectric conversion efficiency is the rate at which sunlight energy is converted into electricity, with higher rates meaning more output. Mitsubishi Electric said that it plans to develop mass-production technology to deliver these high conversion rates in commercial PV modules.
Mitsubishi also announced that it has achieved a photoelectric conversion efficiency of 14.8% in a 5mm x 5mm thin-film silicon photovoltaic (PV) cell by using a triple-junction configuration in which the first layer absorbs short wavelengths and the third layer absorbs long wavelengths, thereby enabling the use of a wide solar spectrum from visible light to infrared rays..
Finally, the company said that it has developed the technology to maximize output power in PV systems by incorporating a new maximum power-point tracking (MPPT) system in PV inverters. The technology, which works with a single PV inverter, achieves the maximum power point even when part of a PV array is hidden by shadow or dust.
The technological breakthrough by Mitsubishi Electric allows the MPPT system to automatically measure the PV array’s output power characteristics and then control the array to operate at its maximum output-power point, thereby ensuring that the PV system receives maximum output power from the array. In some cases, this technology will be able to more than double the output power compared to a PV inverter equipped with a conventional MPPT system.