A Linear Interpolation Method to Extract the Solar Cell Series Resistance and the Quality Factor

We propose a linear interpolation method to determine the solar cell series resistance and the quality factor from the plot of an interpolated straight line. We approximate the implicit current-voltage relationship using a polynomial of degree 6 in voltage V. The computational program that we present here uses a selected threshold test to identify the quality of the cell (high or low) and to execute one of the two corresponding subprograms by plotting the experimental scatter of points and the interpolated straight line of the considered cell. From this study, a remarkable property appeared: the lumped nature of R-s in the case of high quality cells and its distributed nature in the case of low quality cells.