리튬 이온 배터리 수명을 고려한 하이브리드 연료전지 자동차의 최적 에너지 관리 전략 분석

Abstract

This study analyzes an optimal energy management strategy for fuel cell hybrid electric vehicle (FCHEV) when lithium-ion battery lifetime is considered. First, a simplified FCHEV model is developed to describe power and energy flows throughout the powertrain and evaluate hydrogen consumption. Then, lifetime prediction model for lithium-ion is used to formulate an optimal control problem considering lithium-ion battery lifetime. In order to find the globally optimal energy management strategy of FCHEV over driving cycles, Dynamic Programming, a dynamic optimization method, is used, and their results are analyzed to find out how to operate the lithium-ion battery for improving the lifetime. The results show that the optimal energy management strategy considering lithium-ion battery lifetime tends to discharge the battery beforehand and also penalize the battery power at appropriate moderate magnitude. For this reason, the battery is operated in lower voltage and lower temperature. In conclusion, if the battery lifetime is more emphasized, the battery capacity fade is more reduced, on the other hand, hydrogen consumption is more increased.