Solar Module Fabrication

Abstract

One of the most important steps in the photovoltaic industry is the encapsulation of the solar cells. It consists to connect the cells in order to provide useful power for any application and also protect them from environmental damages which cause corrosion, and mechanical shocks. In this paper, we present the encapsulation process we have developed at Silicon Technology Unit (UDTS) for monocrystalline silicon solar cells. We will focus particularly on the thermal treatment, the most critical step in the process, which decides on the quality and the reliability of the module. This thermal treatment is conducted in two steps: the lamination and the polymerization. Several tests of EVA reticulation have been necessary for setting technological parameters such as the level of vacuum, the pressure, the temperature, and the time. The quality of our process has been confirmed by the tests conducted on our modules at the European Laboratory of Joint Research Centre (JRC) of ISPRA (Italy). The electrical characterization of the modules has showed that after the encapsulation the current has been improved by a factor of 4%to 6%and the power gain by a factor of 4%to 7%. This is mainly due to the fact of using a treated glass, which reduces the reflection of the light at a level as low as 8%.