Photovoltaic cells are semiconductors which have nonlinear dynamics. Therefore, the dynamic model instead of static must be used in order to study their dynamic behaviors. Main advantage of using dynamic model is able to analyses interactions accurately and effectively in grid-connected PV power system, etc. This paper gives an approach to use of Lyapunov exponents for the stability analysis of the dynamic behavior of PV cells. For this reason, firstly we created a dynamic model for the PV cell, then stability of the system was analyzed while load resistant and short-circuit current is changing in this model. A Lyapunov exponent for dynamic behavior of the PV cell was not computed before in any study. Under the condition such as shadowing, stability criterion of PV array connected with any platform can be obtained from results of this study.