Composite power supply technology is an efficient way to solve the energy performance problem of EV, it makes battery with high energy density and super capacitor which has the advantage of high power combined with together. Using the super capacitor characteristics of instantaneous large current charge and discharge, when EV in starting, accelerating or climbing, provide the actuating motor for peak current; and when in braking, absorb the generator feedback current, so as to avoid the battery are damaged, prolong its service life, and realizes the braking energy efficient recovery. In this paper according to the characteristics of battery, super capacitor, and bidirectional DC/DC converter, use backward simulation model of electric vehicle to perform drive cycle. The results show that, the work efficiency of battery is enhanced by using the super capacitor, and to make the composite power supply obtain a higher braking energy recycling efficiency.
