Analytical Modeling of the Temperature Sensitivity of the Maximum Power Point of Solar Cells

Abstract

This article presents new analytical expressions for the temperature coefficients of the voltage, current, and power of a solar cell at its maximum power point (MPP). A new analytical expression of the temperature coefficient of the fill factor is also derived. The new expressions are written as functions of photovoltaic (PV) metrics that can be obtained from i-V measurements. Nonideal diode behavior is partially accounted for through a temperature dependent ideality factor. The recombination parameter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\gamma$</tex-math></inline-formula> , which has been shown to account for the thermal sensitivity of all mechanisms determining the open-circuit voltage, appears to play a role also for the temperature coefficient of the MPP. The expressions are tested against experimental data, which covers measurements from 18 multicrystalline silicon solar cells with different bulk resistivities and cell architectures. It is found that the new model captures the essence of the temperature variation shown by the investigated PV metrics.