The relationship between partial discharge (PD) induced breakdown behaviour and the crystallinemorphology of PET films used in photovoltaic devices has been explored and discussed in this work for the first time. Biaxially orientated PET films with and without BaSO₄ filler were isothermally annealed at various temperatures before PD breakdown tests of the films to investigate the effect of crystalline morphology. Attenuated total reflectance - Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC) were used to study the changes of crystallinity and lamellar thickness of the samples. It was found that both PD resistances and PD lifetimes could be significantly improved when the samples were annealed at temperatures above 210 °C. On the other hand, improvements were much less in the annealing temperature region between 180 and 210 °C. This, we propose, is because the thinner and less perfect lamellae formed by annealing at the lower temperatures are less effective at resisting ion bombardment and electrical tree propagation. On the other hand, the formation of thickened and perfected lamellae produced at higher annealing temperatures can effectively increase the tortuosity of electrical tree propagation paths, thereby increasing the PD lifetimes.

在这项工作中，首次探索并讨论了局部放电（PD）引起的击穿行为与用于光伏器件的PET膜的结晶形态之间的关系。含和不含BaSO _4的双轴取向PET膜在薄膜的PD击穿测试之前，将填料在不同温度下等温退火，以研究晶体形态的影响。衰减全反射率-傅立叶变换红外光谱（ATR-FTIR）和差示扫描量热法（DSC）用于研究样品的结晶度和层状厚度的变化。发现当样品在高于210°C的温度下退火时，PD电阻和PD寿命都可以得到显着改善。另一方面，在180到210°C的退火温度范围内，改善程度要小得多。我们提出这是因为通过在较低温度下退火而形成的较薄且较不理想的薄片在抵抗离子轰击和电树传播方面不太有效。另一方面，