Light-induced performance of SHJ solar modules under 2000 h illumination

Abstract

The light-induced degradation (LID) of solar module leads to severe loss in generated power due to the formation of recombination active defects. The silicon heterojunction (SHJ) solar cells based on n-type wafers are less affected by the LID test. In this paper, the glass/back sheet structure (GBS) modules with different encapsulant materials (TPO, POE, EVA) were laminated to evaluate their performance changes under 2000 h light soaking stress for the first time. The current-voltage (light I–V, dark I–V) parameters of the modules were measured, as well as the external quantum efficiency (EQE) and electroluminescence (EL), to verify the effect of light irradiation on SHJ solar modules. The SHJ modules with different encapsulant materials show excellent light-induced reliability. There is no degradation after 2000 h light irradiation, and even exhibits light-induced performance increase. The gain in output power (Pmax) is up to 1.41%, which is primarily due to an improved open-circuit Voltage (Voc) and fill factor (FF) as the result of a reduced density of recombination-active interface states. The front sheet/back sheet (FBS) modules also verified the accumulated light-induced stress could result in deteriorating interconnection between SHJ solar cell and ribbon, which suffers from significant output power degradation. The LID-free SHJ solar cells show great potential for lower levelized cost of energy (LCOE) of photovoltaic power generation.