This paper proposes a novel hybrid resonant PI controller for EV battery charger fed by an AC-DC-DC converter. Compared with a conventional EV battery charger, this method can effectively decrease the value of DC-link capacitor. This makes it possible to apply a much smaller value film capacitor such that the system will have more compact size and lower cost. Another advantage of this control method is that, it can suppress the ripple on the battery charging voltage and make no harm to the battery. Furthermore, this method does not involve any additional cost on hardware, only the control algorithm is applied. In this paper, we introduce the control method and analyze its principle. We conduct simulations, and verify the effectiveness of the proposed hybrid resonant PI control method, especially that the DC-link capacitance is reduced, and the output charging voltage is smooth.