Effect of Low Temperature on Energy Storage Performance of Polypropylene Film

In this paper, the dielectric and energy storage properties of biaxially oriented polypropylene (BOPP) films at low temperature are reported. The experimental results show that the highest direct current (DC) breakdown strength of BOPP films as high as 906.7 kV/mm is obtained at ‐40 °C, signifying a substantial 23.4% enhancement compared to the performance observed at 20 °C. Furthermore, the maximum discharge energy density attains 7.61 J/cm3, achieving a commendable efficiency level of 90.77%. Carriers are subjected to a degree of freezing at low temperatures, inhibiting injection and migration, which diminishes the conductivity current. In addition, the vitreous molecular chain structure can have higher intermolecular forces to protect the molecular chain from being destroyed. This paper provides a new direction and insight for the development of film capacitors with high energy density and low loss.