Accurate series resistance measurement & Sliver cell characterization
Kean Chern, Fong (ANU)
SOLAR SEMINAR SERIESDATE: 2011-04-07
TIME: 15:00:00 - 16:00:00
LOCATION: Ian Ross Seminar Room
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ABSTRACT:
The series resistance (Rs) of a solar cell is commonly represented as a constant value. However, due to distributed effect of resistance in the device, the effective Rs is a function of its operating condition such as the illumination intensity and current density. The assumption of a constant Rs value is sufficient as a means to roughly indicate the level of series resistance in a device. However, a constant Rs value is insufficient for accurate analysis of the solar cell J-V curve.
The purpose of presentation is to present a review of common methods of Rs measurement, and to demonstrate the Multi Light Method which can accurately measure Rs as a function of current Rs(J). This method is an extension of the double-light method, and improves upon it by using an additional main J-V curve, and measuring Rs across the entire current range at very small increments of I"J. The underlying principle behind the measurement is discussed, followed a discussion regarding practical implementation of the method in order to obtain accurate and repeatable results. The results were verified against the Jsc-Voc method and shows very good agreement between the two methods.
Applications of the Rs(J) is then demonstrated with the values applied to the main J-V curve to attain the Rs-corrected J-V curve and Rs-dark. Finally, a modification to the standard double-exponential model of a solar cell is discussed, which allows accurate modelling and parameter extraction of solar cells. Sliver cells were used as the test device for the work presented. Therefore the series resistance and modelling of Sliver cells are presented and discussed.
