Abstract: This paper aims to solve the problem of high fuel consumption and large charge/discharge depth of lithium battery in charge sustain stage for the range-extended electric bus with single point on/off energy management strategy. Firstly the single-point on/off strategy and the equivalent fuel consumption minimum strategy (ECMS) are optimized and verified by simulation. Then a verification test is carried out on a semi-physical platform. The results show that in charge sustain stage, after single-point on/off strategy is optimized, the fuel consumption per 100km reduces from original 39.1L to 36.23L and the cycle charging factor of lithium battery reduces from 19.8/100km to 13.2/100km, decreasing by 7.3% and 33.3% respectively; and with optimized ECMS, the fuel consumption per 100km reduces again to 35.22L and cycle charging factor further reduces to 9.9/100km, lowering by 9.9% and 50% respectively compared with the original single point on/off strategy

Key words: range-extender, on/off control strategy, ECMS, lithium battery cycle life, fuel consumption