Dr. Chen-Wu Wu
Associate Professor, Institute of Mechanics, Chinese Academy of Sciences, China.

Speech title: Full-coupled model on the thermal effects in photovoltaic cell

Abstract: Efficiency of the light-electricity conversion of the solar cells is of critical meaning in solar energy utility. Actually, only a small part of the absorbed light energy changes into electricity in a solar cell. The large part of the absorbed light energy dissipates into heat, which would lead to temperature elevation as well as thermal stress within the solar cell. Both the temperature elevation and thermal stress influence the conversion efficiency of the solar cell, which in turn determines the fraction of the light energy changed into heat as well as the reliability of the solar power supply in applications. Therefore, this is an actually highly coupled problem in physics. Thermal effects in a typical multijunction photovoltaic cell are particularly discussed in a mathematical way. Temperature-dependent performance of the photovoltaic cell is reviewed and the physical mechanism demonstrated. Responses of the photovoltaic cell to the irradiation are theoretically investigated. A fully-coupled method was developed to describe the heat generation, heat diffusion and thermal strain in a multijunction photovoltaic subjected to monochromatic light. Temperature elevation and thermal stress developed in the photovoltaic cell accompanied with the light-electricity conversion was sketched by numerical simulation. The optimal designing concepts are discussed to improve the overall efficiency of the photovoltaic cells.