Analysis of single-cell shading impact on polycrystalline PERC module under hot-dry conditions

Abstract

PV technologies may often perform differently under outdoor operating conditions compared with Standard Test Conditions, which are performed under a controlled setup inside a laboratory. Outdoor-installed PV modules are exposed to continuously varying factors, like solar radiation and temperature, which significantly impact their electrical and thermal behavior. Moreover, due to prolonged exposure to these dynamic conditions, outdoor-installed PV modules are subject to gradual degradation over time. One frequently occurring degradation is partial shading, which can lead to hotspot formation in shaded modules. To predict the formation of the hotspot, it is essential to understand the impact of partial shading in a PV module. In this investigation, indoor and outdoor partial shading stress experiments are conducted on a single cell in a PV module. This methodology accelerates the degradation, and the impact of single-cell shading on the performance of a PV module is analysed. The results are extracted using obtaining I-V and P-V curves for different shading conditions, and various performance parameters like output power and efficiency are recorded to analyse the electrical and thermal response of a shaded module. The experiments performed in outdoor conditions recorded power loss as high as 49 %, and efficiency dropped to 8.11 % from its initial unshaded conditions. Additionally, the results confirm the occurrence of hotspot due to shading. Though indoor experiments did not exhibit any visible temperature rise in the shaded cell, outdoor experiments showed a significant thermal response. The highest temperature of 92.3°C was recorded in the shaded cell under a 40 % single-cell shading condition, highlighting the pronounced impact of real shading and environmental conditions on thermal behavior of a PV module.