Year: 2014
Type: dissertation
Abstract: The growing interest in the use of electric vehicles worldwide has resulted in awareness of the\nimportance of ensuring the safety of these vehicles for users. The safety of electric vehicles\nis greatly determined by the state of the insulation between the high voltage system and the\nground. In this thesis, the behaviour of the insulation in a high voltage traction battery used\nin a hybrid vehicle has been studied and evaluated under different operational conditions. The\nobjective of this thesis was to assess how much the insulation resistance of the battery system is\naffected by the battery geometry and its environment of operation. The international standards\napplicable to insulation in electric vehicles have been studied to determine the requirements that\nthe battery insulation system must adhere to and to determine which tests are recommended\nfor testing the battery insulation system.\nIn this work the results from the insulation resistance tests, partial discharge tests and environmental\ntests performed on a battery system are presented. The results from insulation\nresistance tests combined with environmental tests under varying temperature and humidity\nconditions show that the presence of moisture on the insulating surfaces of the battery greatly\ndecreases the insulation resistance of the battery. The partial discharge tests show that grounding\nof the conducting non-current carrying parts of the battery through a path of low resistance\nis important to minimize discharges. At operational voltages, the weakest areas of the battery\nsystem insulation have been located inside the battery module on the edges of the cells.
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2104842105