Simulation, Experimental Evaluation, and Characterization of a Novel Grid Line Design for TOPCon Solar Cells With Reduced Silver Consumption

Silver paste accounts for a substantial portion of the nonsilicon cost of tunnel oxide polysilicon contact solar cells. Silver consumption is as well a major concern for material sustainability of global PV manufacturing. It is necessary to propose innovative grid line designs to reduce the amount of silver paste. Partially interrupting the metal fingers (also known as "Finger Break") between the bus bars in areas where the fingers carry a relatively small current is a good method for reducing silver consumption in industrial production. Under the assumption of uniform generated current density (ISO-current), this article discusses the impact of the width of finger interruption on the cell efficiency under two different scenarios. Through simulations, experiments, and outdoor testing, it was found that one of the considered novel grid designs can save silver paste to a great extent, but suffers a rapid decline in power conversion efficiency, and also poses potential stability risks, while the other grid design not only saves silver, it does not severely affect the efficiency, and can be used outdoors while maintaining stability. Based on the different light intensities, the finger interruption width can be as high as 5 mm, resulting in a saving of 9.32 mg (∼1.61 mg/W) of silver paste on the front surface of 158.75 cm×158.75 cm solar cell, for a reduction of 12.97% of the original front silver consumption.