Effects of Cross-Linking Density on the Breakdown Characteristics of Silicone Gels for Power Device Encapsulation

Silicone gels are widely used as a high-performance polymer insulating material in the packaging of high-voltage, high-power devices. However, under long-term thermal stress conditions, silicone gels undergo cross-linking reactions, and the degree of cross-linking increases with the aging degree. In order to study the potential relationship between the aging degree and the crosslink density, this paper builds the AC and DC withstand voltage test platform, by changing the ratio of the specimen preparation, to obtain the silicone gel specimens with different crosslink density, and carries out the negative polarity under the role of the rod-plate electrode DC breakdown test, and draws the Weibull distribution diagram. The study shows that the increase of cross-linking density leads to the decrease of the breakdown voltage of the organosilicon gel, and the change of the cross-linking density of the organosilicon gel due to thermal aging is an important means by which it affects the breakdown voltage of the organosilicon gel.