Industrial solar cell tester: study and improvement of I-V curves and analysis of the measurement uncertainty

• Published in: Progress in photovoltaics 2016-01, Vol.24 (1), p.108-121
• Main Authors: López-Escalante, María Cruz, Fernandez, María Carmen, Sierras, Rafael, Ramos-Barrado, Jose Ramon
• Format: Article
• Language: English
• Subjects: Computer programs; contact bar; I-V curve; Irradiance; Photovoltaic cells; silicon solar cells; Software; Solar cells; temperature correction; Uncertainty; Volt-ampere characteristics
• ISSN: 1062-7995; 1099-159X
• DOI: 10.1002/pip.2634

Determination of solar cell parameters by illuminated I–V measurement is a standard characterisation technique in the photovoltaic industry. These measurements are carried out under standard conditions (STC: 25 °C, 1000 W/m2 AM1.5G spectrum). It can be considered as the most crucial in‐line test for solar cells as it provides the industry with the conversion efficiency, and it is also a reliable quality control test. Reference cells are mainly used in testing equipment to set irradiance and working conditions in the tester/sorter, the rest of the cells being measured and classified by comparison with that reference. An accurate calibration of the irradiance at STC in cell testers and high precision in determining the main parameters of the I–V curve are required; a suitable design of the mechanical components and an adequate selection of different programme options should be made (distribution of the points measured, temperature correction or classification method). Here, we have studied the accuracy of an industrial solar simulator whose mechanical, electrical, electronic and software components were analysed with an individual solar device and a production sample. An uncertainty analysis was carried out in order to determine the power uncertainty and which components to improve in order to reduce it. Copyright © 2015 John Wiley & Sons, Ltd. Contributions to the total uncertainty for different reference cell. We have established an appropriate procedure for determining the maximum output of manufactured photovoltaic cells and their range of uncertainty. We have studied the influence of the conditions acting on the measurement of the reference cell in the cell tester, the configuration of the tester and, more specifically, the influence of less standardised parameters such as the type of contact, the software used and the temperature during measurement.