The peak power of the battery (SOP) is an important parameter index for electric vehicle to improve the efficiency of battery utilization and ensure the safety of the system in the maximum limit. The estimation and prediction of SOP is based on a large number of test data at different temperature, different SOC and different time scales.
Based on the accurate voltage and SoC estimates, the peak power of battery pack is predicted for 20 s, generally between 1 s and 20 s in EVs ( Waag et al., 2013b ), using the multi-parameter limited method mentioned in Section 3. The design limits are listed in Table 6 according to battery manufacturer. Table 6. Design limits for the test cell.
If a battery pack is treated as “a big cell”, the predicted peak power may be inaccurate due to the neglect of the inconsistency among the in-pack cells and even cause some cells to be overcharged or over discharged. Therefore, the inconsistency problem should be paid enough attention about the peak power prediction of the battery pack.
The peak power capability is determined by combining terminal voltage prediction, SoC estimation, temperature limits and manufacturing power/current limits. This paper is structured as follows: In Section 2, the theoretical analysis of a general SoP estimation combining a battery model, SoC estimation and the temperature effect is given.
The peak power obtained by the most commonly used map method is more affected by SOC accuracy, temperature and aging, and the power in the table is measured after the battery is sufficiently static, and the actual polarization state is not considered.
Although there have been many studies on state estimation of lithium-ion batteries (LIBs), aging and temperature variation are seldom considered in peak power prediction during the whole life of the battery.