Influence of non-uniform fine lines in silicon solar cell front metal grid design

摘要

While it is well known that the typical printed silver fingers on a silicon solar cell have profile striations, bottle-necks, and line breaks, the impact of these imperfections have not been assessed in calculations of front grid related power losses. This study uses detailed finite element modeling to show that when the realistic effects of non-uniform line conductance is accounted for; the simulated cell efficiency can be significantly lower than under the assumption of uniform lines, becoming closer to measured trends. The study also explores the incorporation of additional interconnecting fingers to the parallel grid finger in the H pattern, concluding that they are typically of no benefit to improving the cell efficiency. As an auxiliary observation, it was found that the efficiency calculated by simple ohmic power loss formulae is typically underestimated by 0.1-0.2% absolute, a margin that should be accounted for in cell optimization and analysis. Copyright (C) 2015 John Wiley & Sons, Ltd.