Research on hot spot risk for high-efficiency solar module

Based on the working principles of solar cells, the photovoltaic module mismatch model was constructed to simulate the heat dissipated by one single cell with different shading percentage ranging from 10% to 100%. ANSYS simulation was utilized in this paper to explore the relationship of hot spot temperature and type of solar cell defects (for example point defect and planar defect) with the module output power. The simulation results showed that the module hot spot temperature is inversely correlated with the solar cell defective area, and positively correlated with module output power. Solar cells with different type of defects and solar modules with different output power were picked to conduct the hot spot experiments, in which the leakage currents for the defected solar cells and the high-efficiency module cells (normal cells) were less than 1.5 A and 0.1 A, respectively, for an applied negative bias of 12 V. The results showed that the temperature of the module with point defected solar cell and the high-efficiency module reached up to 200 and 170°C, respectively, which could lead to encapsulation failure. The experimental data was consistent with the simulation, demonstrating the accuracy of the simulation model and providing directives for solving the hot spot problem of the high-efficiency module.