Status quo and future prospects for metallized polypropylene energy storage capacitors

The most important polymer film used in commercial capacitors is biaxially oriented polypropylene. Other materials such as polyester or paper are also used for selfhealing metallized capacitors, depending on the application. Capacitors manufactured with polypropylene have the big advantage of being less expensive than other materials, and have a very low equivalent series resistance (ESR), due to the propylene-repeating group, which results in a regular polymer chain. Electrical breakdown behavior will be analyzed in order to improve the electric field stress. Performance versus energy density will be investigated as well. We will give an overview of new proposals in the field of films, considering their reported better dielectric and mechanical performance.