Due to its good electrochemical performance, lithium batteries have been highly applied in photovoltaic energy storage power stations, new energy vehicles, and other scenarios. Lithium batteries have different SOC ranges and discharge rates in different application scenarios. Appropriate use range and discharge rate can effectively slow down the aging of lithium batteries. Therefore, it is one of the key issues to figure out the influence of SOC and discharge rate on the aging of lithium batteries.

The experiment selects a 1.5Ah lithium cobalt oxide battery. It has low internal resistance and a high discharge rate and is suitable for aging research under different discharge rates. Set the experimental SOC interval to 15%~90% and divide it into three equal-width ranges with the same depth of discharge, that is 15%~40%, 40%~ 65%, and 65%~ 90%. It represents the low, medium, and high SOC during use. Set the discharge rate to 2C(3A), 6C(9A), and 10C(15A), which represent small, medium, and large rate discharges, respectively.

The results show that the cycle aging of lithium batteries is the slowest in the low SOC, followed by the medium SOC, and the fastest in the high SOC range. In the medium and high SOC range, the higher the discharge rate, the faster the aging. But the aging in the low SOC range is less affected by the discharge rate. And the greater the depth of discharge, the faster the aging speed. There are three ways can reduce battery aging. 1. Avoid lithium batteries in the high SOC range. 2. When a high rate discharge is required, select a lower SOC range. 3. Reduce the depth of discharge.

new energy electric vehicles
new energy electric vehicles