Screening process of Li-Ion series battery pack for improved voltage/SOC balancing

In order to minimize few problems of voltage balancing, a new approach of screening process for Li-Ion series battery pack is proposed in this paper. Pulse type discharging/charging currents are applied for various state-of-charge (SOC) points to select the cells with similar voltage variance. This process matches open circuit voltage (OCV)-SOC relations, therefore SOC balancing can be achieved using the voltage balancing. A total of 20 Li-Ion 18650 type fresh cells (1.3Ah) are used for implementation of the proposed screening process.