Light management for reduction of bus bar and gridline shadowing in photovoltaic modules

摘要

Solar cells used in photovoltaic (PV) crystalline silicon modules commonly feature grid fingers and bus bars as front contacts. The grid fingers and bus bars partially block the sunlight from reaching the semiconductor layers of a solar cell and therefore reduce the efficiency of a solar module. In this paper, we present experimental results of different technologies to reduce the shadowing effect that bus bars and grid fingers impose. We focus on two technologies that can be easily integrated into standard PV module technology and help to increase the module's efficiency. In the first technology, a laser is used to create a scattering pattern on the front glass of the module. This pattern directs light away from the bus bars and grid fingers. In the second technology, the bus wires are coated with a diffuse reflective coating. The sunlight is diffusely reflected at this coating. A part of it is reflected at such angles that internal reflection at the front surface of the cover glass occurs. From there the light is reflected back to the solar cell and contributes to the generated photocurrent.