Electric vehicles (EVs) are getting more popular in the field of automobiles due to environmental factors and others. Since electric vehicles manage their power from the rechargeable battery so it's essential to have a reliable, efficient, and economical battery charger that can provide stable required output for the specified EV's battery. In this paper, a DC-DC converter with a modified PI controller has been presented which helps to achieve the required output voltage and high current density with negligible overshoot for the specified lithium-ion battery system to minimize the charging time. Apart from minimizing the power loss of the active switches, the proposed system minimizes the junction temperature which eventually improves the life cycle of the converter. The analysis of the proposed converter is performed both in ideal and non-ideal conditions. The power loss of the active switches and the junction temperature have also been analyzed. An economical and effective dc and ac side inductor has been designed and perform the total power loss and the temperature rise. The analysis results show that the proposed converter can maintain a power factor of more than 90% and a total harmonic distortion of less than 0.46%, which is ideal for the high-density load current. The reliability of the dc-dc converter is also evaluated. A hardware prototype has also been implemented to confirm its viability for EV battery charging applications.INDEX TERMS Buck, Lithium-ion battery charger, Electric vehicle battery charger, AC-DC converter, Isolated ac-dc converter, Power factor correction, MOSFET power loss estimation, MOSFET thermal analysis, Modified PI controller, State-space representation of converter.