Analysis of the power loss and quantification of the energy distribution in PV module

Efficiency improvements of PV modules has come under heated discussions. The conversion efficiency is hindered by losses that occur in the whole physical process, which poses a great challenge to classify and quantify the energy distribution. Many researchers have analyzed specific loss processes in theory, while the real situation is more complicated than the models that have been provided. To analyze the power loss and quantify the energy distribution in the PV module, this paper discusses the loss mechanisms in detail, based on material characteristics (optical coefficient and cell bandgap), operation mechanisms (carriers' generation, transportation, and recombination mechanisms) and environmental factors (temperature and solar irradiance). A comprehensive energy distribution model under standard test condition is then developed, and the electrical characteristics and thermal performance of PV modules are investigated. Finally, the model is verified for both PV cells and modules. The results indicate that, for a PV module, about 57.25% of the total incident solar energy is lost in the carriers' generation, while the remaining 1.28%, 23.47% and 2.10% are lost in the carriers' transportation, recombination and cell to module process, respectively. As a result, approximately 72.16% of the incident energy is dissipated as heat, resulting in the increase of cell temperature, and almost 11.94% of solar energy finally leaves the module due to multilayer reflection. The study also demonstrates that when the module temperature rises, the decrease in power output mainly originates from the increase in recombination loss of the PV cell. Furthermore, some potential suggestions are provided to control energy conversion losses and improve cell performance.