The impact of current mismatch among individual cells on the performance of perovskite photovoltaic modules

Perovskite solar cells (PSCs) have emerged as a promising photovoltaic technology due to their high efficiency and low-temperature processing. However, scaling PSCs into perovskite solar modules (PSMs) faces significant challenges, particularly performance inconsistencies among individual cells, such as short-circuit current (I_SC) mismatches. These mismatches can result in localized heating and reduced power output. In this study, we systematically investigated the impact of current mismatch on the performance and reliability of PSMs operated by a central inverter, focusing on variations in I_SC across PSCs. Experimental results revealed that even minor I_SC mismatches (as low as 2%) can increase the temperature of underperforming cells by up to 8 °C. Theoretical analysis of a PSM with 200 series-connected PSCs showed that power losses correlate with the standard deviation of I_SC (σ_ISC). The losses caused by current-mismatch are negligible for a σ_ISC of below 2%, but increase to 12-17% at a σ_ISC of 10%. While bypass diodes can mitigate power losses by maintaining a higher operating current, they cannot fully prevent local heating arising from reverse bias. Alternatively, employing multiple inverters to optimize operating currents for non-uniform cells shows potential, but its economic feasibility remains unresolved. These findings highlight the importance of minimizing σ_ISC to enhance PSM performance and reliability for its commercialization.