Approaches to improving energy yield from PV modules

PV modules were fabricated that incorporated various methods to increase the amount of light which is ultimately transmitted to the solar cell in order to improve energy yield. The techniques employed included diffuse scattering and reflection to minimize shading losses, as well as using structured glass to increase the probability of incident light capture. In the first technology, a laser is used to create a scattering pattern on the front-side glass of the module. This pattern directed light away from the bus bars and grid fingers, resulting in an increase in short circuit current (ISC) of up to 3.3%. In the second technology, the bus wires were coated with a diffuse reflective coating. A part of the incident sunlight is reflected from this coating at such angles that internal reflection at the front surface of the front-side glass occurs. The light is reflected back to the active area of the solar cell and contributes to the generated photocurrent resulting in an av erage increase of 0.9% in ISC. Finally, four different types of commercially available structured glass were investigated: grooves, pyramids, inverted pyramids, and a very lightly textured glass with only 5% increased surface area. Results showed an increase in ISC of up to 3.2% for pyramid structures using normally incident light, with the effect increasing at higher angles of incidence. The results demonstrated the possibility of improving PV module energy yield by taking advantage of basic optical principles and straightforward processing methods