Modeling Of Capacity Decline And Research Of Performance Prediction Of Lithium-ion Battery Pack

Based on the lithium manganese battery pack, researches are conducted on modelingof capacity decline and performance simulation, as followings:Firstly, through charging and discharging experiments of lithium manganese batterypack under the condition of varying temperature and varying charging and discharging rate,it is carefully studied how temperature and charging and discharging rate and other factorshave an influence on the decline of battery pack capacity, and it is also carefully analyzedhow these factors may have an impact on battery pack performance, which providestheoretical support for modeling of capacity decline and performance simulation oflithium-ion battery pack.Secondly, through accelerated-life experiments of whole battery pack, quantitativeresearches are conducted on the influence of the two factors of temperature and dischargingrate on the capacity decline of the whole battery pack, and model of capacity decline andmodel of life prediction are established based on only one factor or both two factorsmentioned above, laying a foundation for modeling of performance prediction of batterypack.Thirdly, researches are conducted on cell-voltage inconsistency inside battery pack,providing evaluating indicators of cell-voltage inconsistency, and analysis is conducted onboth the relation between cell-voltage inconsistency at initial stage and two factors of bothtemperature and discharging rate and the relation between cell-voltage-declineinconsistency in the discharging process and two factors of both temperature anddischarging rate, and then model of performance prediction of battery pack is establishedbased on the evolution of cell-voltage inconsistency inside battery pack.Finally, the performance parameters of the second order battery model are calculatedbased on charging and discharging experiments using composite pulse, and the performancemodel of battery pack is established, and the results of performance model are comparedwith results of experiments in order to verify the accuracy of this performance model. Amethod of parameter estimation of different battery modules is proposed, which is testedagainst the results of experiments. A performance simulation of both35Ah/750V batterymodule and70Ah/900V battery module is conducted, figuring out how the performance ofbattery module change when the capacity declines.