Experimental research on the performance of ultracapacitor in EVs's application

Ultracapacitor is widely used in EVs for its high performance such as high power density, long cycle life and wide working temperature. However, the frequent use and variation of the operating temperature will affect the performance parameters of ultracapacitor and the variation trend of the ultracapacitor's performance in this situation is always different from it is in normal operate situation. Meanwhile, the variation rules of the ultracapacitor's performance directly affect the accurate estimate of the state of energy storage and the safety of energy storage system. Research on the variation rules of ultracapacitor's performance parameters based on the practical application of EV is presented in this paper. According to the classic equivalent circuit, four different test methods are experimented. Then, the identification of these experimental parameters are carried out with each adapted tests and the variation rules of the performance parameters are also discussed. Finally, the general variation rules of the performance parameters are obtained.