聚合物纳米复合电介质电热耦合分子断裂击穿特性与机理研究  

Characteristics and mechanism of electrothermally coupled molecular fracture breakdown of polymer nanocomposite dielectrics

作　　者：杨玲钰 闵道敏[1] 武庆周[2] 于是乎 李盛涛[1] YANG LingYu;MIN DaoMin;WU QingZhou;YU ShiHu;LI ShengTao(State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China;Institute of Fluid Physics,China Academy of Engineering Physics,Mianyang 621900,China;Electric Power Research Institute of Guangdong Power Grid Corporation,Guangzhou 510080,China)

机构地区：[1]西安交通大学电力设备电气绝缘国家重点实验室,西安710049 [2]中国工程物理研究院流体物理研究所,绵阳621900 [3]广东电网有限责任公司电力科学研究院,广州510080

出　　处：《中国科学：技术科学》2024年第4期625-635,共11页Scientia Sinica(Technologica)

基　　金：国家自然科学基金面上项目(批准号:52077162);国家自然科学基金委员会与中国工程物理研究院联合基金项目(批准号:U1830131)资助。

摘　　要：薄膜介电电容器是电力系统、新能源汽车及电磁能装备中广泛使用的高功率储能设备.但面对越来越高的工作温度,电介质的击穿强度急剧下降,导致电容器的储能密度大幅减小.为了明确电介质击穿特性和温度间的定量关系,本文制备了聚丙烯/氧化铝和聚醚酰亚胺/氧化铝纳米复合电介质,研究其击穿强度的温度依赖性.结果表明,电介质的击穿场强随温度升高下降幅度增大,两者间为凸函数关系.但传统击穿模型均得到击穿强度与温度的变化为凹函数关系,与实验结果不符.本文建立了电热耦合分子断裂击穿模型,模型解析值与实验数据的最大误差仅为3.57%;从分子定向运动导致局部分子链相互作用强度下降的角度揭示了聚合物的击穿机理;纳米填料掺杂会导致复合电介质中的分子链受到束缚,界面区分子链间相互作用增强,并减少弱束缚分子链段,提升电介质的击穿场强及其温度稳定性.该研究为开发耐高温储能电容器提供了理论模型支持.Film dielectric capacitors are high-power energy storage devices widely used in power systems,new energy vehicles,and electromagnetic energy equipment.However,with increasing operating temperatures,the breakdown strength of dielectrics considerably decreases,resulting in a considerable energy storage density decrease of the capacitor.To elucidate the quantitative relation between dielectric breakdown characteristics and temperature,polypropylene/alumina and polyetherimide/alumina nanocomposite dielectrics were prepared,and temperature dependence of their breakdown strength was investigated in this study.The results revealed that the breakdown strength of the dielectrics decreased with increasing temperature,and the relation between the two dielectrics was a convex function.However,all the traditional breakdown models obtained the relation between breakdown strength and temperature as a concave function,which contradicted the experimental results.Herein,an electrothermally coupled molecular fracture breakdown model with a maximum error of only 3.57%between the analytical value of the model and the experimental data was established.The breakdown mechanism of polymers was revealed from the fact that the directional movement of the molecules decreases the contact strength of the local molecular chains.The doping of nanofillers will bind the molecular chains in the composite dielectrics,improving the interaction between the molecular chains in the interface region,reducing weakly bound molecular chain segments,and improving the breakdown strength and temperature stability of the dielectric.This study provides theoretical model support for the development of high-temperature-resistant energy storage capacitors.

关 键 词：纳米复合电介质 击穿模型 温度依赖性 分子断裂 

分 类 号：TM53[电气工程—电器] TB332[一般工业技术—材料科学与工程]