EXPERIMENTAL ANALYSIS OF FAST-CHARGING EFFECTS ON ELECTRIC VEHICLE BATTERY LIFE

Abstract

It is necessary to achieve fast charging to achieve the practicality and acceptance of EV use, but frequent rapid charging can lead to battery degradation and thermal stress and lower energy efficiency over time. This study experiments and analyses the different impact parameters affecting performance and battery life of lithium-ion batteries in electric vehicle (EV) applications when subjected to various charging conditions. The charging rates of 0.5C to 3.0C were tested for 500 charge–discharge cycles. The battery performance was examined through battery capacity retention, peak cell temperature, internal resistance of the battery, charging time, round-trip energy efficiency, degradation rate, and battery lifetime- equivalent energy throughput. It was found that the charging rate has a significant effect on the charging time, but with severe thermal and electrochemical penalties. The capacity retention after 500 cycles went down from 94.3% at 0.5C to 79.2% at 3.0C, while the maximum temperature of the cells rose from 31.8ºC at 0.5C to 61.8ºC at 3.0C. This rise in internal resistance between 3.0C and 0.5C was also significant, rising from 31.1 mΩ to 47.9 mΩ. The 3.0C version shortened charging time from 10%-80% to 25 minutes, but it decreased round-trip energy efficiency to 88.7% and the capacity loss to 20.8%. The correlation between peak temperature and capacity degradation was used to conclude that thermal exposure has been important for the accelerated aging. Overall, the charging rates in the range of 1.5C to 2.0C proved to be the best balance between charging speed, charging efficiency, thermal stability, and battery durability. The results highlight the importance of making charging control and effective thermal management more adaptive to extend the EV battery life.