Anomalous Discharge Current in Polyethylene (PE), Ethylene-Vinylacetate Copolymer (EVA) and PE-EVA Laminated Films

Conduction currents and discharge currents were measured in polyethylene (PE), ethylene-vinylacetate copolymer (EVA) and PE-EVA laminated films. Anomalous discharge currents (ADC) flowing in the same direction as the charging current were observed at 10-45°C in EVA, at 25-50°C in +PE-EVA-, of which PE side was applied to positive voltage, and at 25-60°C in PE and -PE-EVA+ with evaporated silver electrodes after application of a field of strength 2.0× 10⁸ V/m. The electrode material affects the ADC peak in EVA. The results are discussed on the basis of the previous reported analytic conclusions; the ADC is caused by two types of injected charges (electrons and holes).