Development of Battery Parallel Operation for Improving Battery Service Life and Flexibility in Electric Vehicles

Abstract

This paper is a novel method for connecting in parallel old batteries, new batteries, batteries of various types, batteries with various voltages, batteries with different capacities and batteries with various States of Charge (SOC) to improve the flexibility of their use and their service life. The percentage load share for each battery is determined by its SOC, voltage and actual capacity. When the capacity of the battery in an electric vehicle is degraded so that it cannot function over the originally specified number of kilometers, the battery can be connected in parallel to another battery with a smaller capacity to extend its service life without the need to replace it. Experimental results reveal that the life of batteries can be improved by more than 50% in this way. 