Dielectric Strength Structure-Activity Relationship of BOPP Film for High Energy Density Pulse Capacitor

Abstract

Biaxially oriented polypropylene (BOPP) films are currently an indispensable material for pulse capacitor production. Research on the structure-activity relationship of BOPP films is an important way to optimize its manufacturing process and achieve high energy density. In this article, the influences of three key structural characteristic parameters (thickness, crystallinity, and tensile strength) on the electrical properties were investigated by testing and analyzing BOPP films manufactured by designed processes. The results show that when the thickness of films obtained with the same manufacturing process increases from 5.8 to $11.8~\mu \text{m}$ , the corresponding breakdown strength increases from 681 to 803 V/ $\mu \text{m}$ ; when the crystallinity of films increases from 71.66% to 75.93%, the corresponding breakdown strength increases from 728 to 756 V/ $\mu \text{m}$ ; and when the tensile strength of films increases from 22.3 to 29.1 MPa, the corresponding breakdown strength increases from 726 to 746 V/ $\mu \text{m}$ . It can be concluded further that increasing the thickness, crystallinity, and tensile strength of the BOPP film through a reasonable process will effectively increase its energy density.