IEC TS 63397:2022 defines additional testing requirements for modules deployed under applications or in environments where PV modules are likely to be exposed to the impact of hailstones leading to higher stress beyond the scope of the IEC 61 21 5 series.
The current safety standards of the IEC 61 730 series [4] and design qualification and type approval standards of the IEC 61 21 5 series specify tests for the ability of PV modules to withstand a defined hail impact. The requirements therein are the minimum for market entrance and are not written to propagate potential cell damage caused by the hail impact by subsequent mechanical and thermo-mechanical tests simulating the environmental stress that modules will potentially be exposed to after hailstorms. In this document modules are initially exposed to 200 h of damp heat to account for some level of humidity and heat before the first hail exposure. After that they are exposed to hail stresses and then to the selected thermo-mechanical stress tests of sequence C of IEC 61 21 5-1 :2021 , Figure 2.
The power loss from these modules is then compared to reference modules that have been through the same stress tests except the hail stress. Comparison of electroluminescence images and performance of both reference modules and modules exposed to hail stress provides additional insight regarding hail resistance and susceptibility. This document aims to assist in the selection of modules for deployment in specific regions that have a higher risk of hail damage and to provide tools for improving module design.
