A Weakness Breakdown Model of BOPP Film Based on Blister Growth Under Cyclic Pulsed Voltage

The investigation into the failure mechanisms of thin-film materials has consistently been a critical aspect of ensuring the reliability of energy storage devices. In this study, full-lifecycle pulsed electrical aging tests were conducted on biaxially oriented polypropylene (BOPP) films. Experimental results reveal that the blisters formed on the surface of electrically aged BOPP films are cavity-structured bubbles, which essentially represent a distinct form of "latent electrical weakness" arising from irreversible material degradation under multi-field electro-thermo-mechanical coupling. Furthermore, a physical model and equivalent impedance were established for these bubbles, providing additional evidence that the blisters play a decisive role in the degradation of the breakdown performance of BOPP films.