Influence of electron beam irradiation on the dielectric strength of thin PEN films

Bi-axially oriented PEN film has superior performance in terms of dielectric strength, mechanical strength, heat resistance, anti-hydrolysis, etc. Thus, it has been widely used for energy storage applications, such as capacitors and batteries. In this paper, we attempted to increase the dielectric strength of PEN films by electron beam irradiation. PEN films of two different thickness, 6 µm and 12 µm, were exposed to an electron beam of 10 MeV energy. Improvement of breakdown strength was observed for both 6 µm and 12 µm PEN films. The largest increase was 13% for 12 µm PEN films with dosage of 100 kGy. The distribution of breakdown test results also improved upon irradiation as the increase of the shape parameter of Weilbull distribution. Post heat treatment slightly increased the dielectric strength for 12 µm but decreased the shape parameter of the breakdown test results for 6 µm.