| Work Detail |
Fujian Metrology Institute (FMI) and National Photovoltaic Industry Testing and Measurement Center (NPVM) have developed a metrological traceability system for silicon and perovskite solar cells. The calibration system consists of a monochromatic light system, a polarization light system, a temperature-controlled 3D motion measurement platform, and an electrical measurement system. Chinas Fujian Metrology Institute (FMI) and the National Photovoltaic Industry Testing and Measurement Center (NPVM) have created a metrological traceability system for solar cell technologies based on silicon or perovskite materials. The researchers explained that there are currently three methods for calibrating and tracing solar cells: the Physikalisch-Technische Bundesanstalt of Germany (PTB); the National Institute of Metrology of China (NIM); and the Industrial Technology Research Institute of Taiwan (ITRI). All three methods are based on differential spectral response (DSR), which is a standard method for measuring the spectral response of photovoltaic detectors at high irradiance level. “The PTB DSR calibration system currently has an uncertainty of 0.56% in measuring the short-circuit current of reference solar cells, and those of NIM and ITRI have uncertainties of 0.9% and 0.7%, respectively,” they specified. The Chinese team established the new system by taking as reference the IEC 60904-4 standard, which sets out the requirements for calibration procedures for the traceability of silicon solar cells, and the IEC 60904-2 standard, which sets out the requirements for the classification, selection, packaging, marking, calibration and care of reference photovoltaic devices. “We first developed a differential spectral response (DSR) calibration system and corresponding measurement method, and then used this system to perform calibration transfer from the standard detector to the World Photovoltaic Scale (WPVS) solar cell serving as the primary reference, thereby creating the measurement capability for the primary reference solar cells,” they further explained. The proposed DSR method can measure the absolute spectral response of a WPVS solar cell under 1000 W/m2 white bias light in the range of its effective response wavelength. It can then compare these values ??with those of the AM1.5 reference solar spectral distribution according to IEC 60904-3, which describes the basic measurement principles for determining the electrical power of photovoltaic devices, and calculate the calibration value of the WPVS solar cell. The entire procedure is carried out by maintaining the temperature of the reference solar cell and the standard detectors at 25 ºC, using a white bias light that is adjustable in the irradiance range of 0.01-1.2 sun, and using a uniform monochromatic light that is adjustable between 280 nm and 1200 nm. The group also created a device suitable for both silicon and perovskite cells and said the device enables the use of solar simulators to evaluate cell performance by transferring data from WPVS photovoltaic devices to reference secondary solar cells. The calibration system consists of a monochromatic light system, a polarization light system, a temperature-controlled 3D motional measurement platform, and an electrical measurement system. The monochromatic light system is equipped with a xenon lamp, a halogen lamp, two monochromators with 3 gratings, a chopper, a filter wheel and an optical lens module, while the polarization light system uses a set of halogen lamps and a programmable DC power supply. In addition, the measurement platform consists of a high-precision 3D automatic displacement platform, a temperature-controlled platform and a high-precision programmable temperature-controlled system. Finally, the electrical measurement system is based on two signal preamplifiers, two lock-in amplifiers, a high-precision digital multimeter with a multi-channel data acquisition device and data acquisition software. The developed calibration system has participated in international comparisons twice, demonstrating an uncertainty of 0.7% and achieving international equivalence, which is at the world level, the scientists said. The new system was presented in the study « The establishment of a metrological traceability system for solar cells», published in Measurements: Sensors . |
