Optimizing the Front Electrode of Silicon-Wafer-Based Solar Cells and Modules

Abstract

Front electrode optimization is one of the important design considerations that affects the efficiency of a silicon wafer solar cell. The optimization of the front electrode is usually done to maximize cell efficiency at standard test conditions (STC). However, with increasing prices in silver, optimization of the front electrode should be done by taking into account the cost of the silver paste. In this study, optimization of the front electrode is done at the cell level at STC (dollars per watt peak), module level at STC (dollars per watt peak), and under real-world module conditions (dollars per kilowatthour), taking into account the cost of the silver paste. For commercial screen-printed multicrystalline silicon wafer solar cells, it is found that to achieve the most cost-effective cell design at the outdoor module level (dollars per kilowatthour), the number of front metal fingers can be strongly reduced (by more than 20) compared with a conventional cell design, which is maximized for STC cell efficiency. For silver price of $1286/kg, optimization at the cell and module level for lowest cost will yield up to 1% cost savings compared with optimization for maximum efficiency. Optimization for the lowest levelized cost of electricity (LCOE) will yield on average 0.6% lower LCOE compared with optimization for maximum annual energy output.