Active equalization based on capacity during charging and discharging. Capacity-based equalization strategies take C C during charging and C R during discharging as equalization variables to determine whether a battery pack is consistent or not, and then equalize based on capacity.
The concept of using battery pack capacity as the equalization objective is that all cells are theoretically fully charged or discharged at the same time. Thereby it can avoid reaching cell cut-off voltages and make the battery stop charging or discharging even when the capacity or SOC is not zero , thus maximizing capacity utilization.
After a thorough literature survey, it was found that there are many battery pack equalization strategies developed, but the systematic review and classification are missing. Some studies simply classify the equalization strategies based on the equalization variable, such as voltage, SOC, and capacity.
C. Lin et al. introduced a novel battery equalization method that shuttles capacity among cells. It calculates the DSM automatically to determine equalization charge under conditions of interference and inconsistency. It has the capability of equalizing individual cells in noisy conditions with large inconsistencies.
Measuring and estimating battery pack equalization variables have many problems, such as accuracy and computational complexity. It is difficult to ensure the accuracy and reliability of battery voltage, temperature, and current measurements due to multi-physical field interference in the operating environments of EMSs.
The new voltage equalisation circuit uses two sets of switch arrays to connect the cells in the battery pack to the input side and output side of the isolation flyback converter, Cf in the two sets of flyover capacitor equalisation structures are replaced by the input and output ends of the isolation flyback converter, respectively.