New Coupled Model for Prediction of the Temperature Distribution in a PV Cell with a Hot Spot Induced by Partial Shading

Since the use of photovoltaics in the domestic and industrial sector is increasing, the reliability and safety of photovoltaic power generation systems is becoming more and more important. One of the crucial issues for safety is the formation of a hot spot, which can reach several hundred degrees Celsius in less than thirty minutes. For this reason, a fire may occur under prolonged exposure. However, a method for hot-spot detection during operation, based solely on current-voltage characteristics, has not yet been established because the detailed formation mechanism of these hot spots is different for every sample. As an initial step for the development of a suited detection method, we propose a new electro-thermal coupled model to predict the temperature distribution in a solar cell with a hot spot that is caused by a reverse bias voltage due to a local partial shade. The model is that couples electric model and thermal model, as temperature feedback is reflected in the electric model, it is implemented as a model including the temperature characteristics of the PV cell. We compare the results of the numerical simulations with experimental data and found that our coupled model can predict temperature distributions with an accuracy better than thirty degrees Celsius.