| Lithium batteries in new energy are unique in new energy with high energy density,no memory effect,safety and pollution-However,due to the low voltage of lithium battery monomers,single cell batteries are usually used in parallel in groups in various fields.Groups of lithium batteries need to be equipped with battery management system to achieve balanced control,safety protection and other functions.Therefore,a good battery management system can maximize the performance of lithium batteries,this paper for the battery management system of battery balance technology research,the main research content is as follows:First of all,in order to accurately describe the characteristics of the power battery monomer and the battery pack,the second-order RC equivalent circuit model is determined as the analysis model of this paper,and the derivation verification battery pack can still be represented by the battery monomer model after paralleling,and the battery model can be verified by HPPC discharge test.From the battery inconsistency analysis of the causes and effects of inconsistency,comprehensive analysis of open-circuit voltage,operating voltage,SOC and other commonly used equilibrium variables,choose the working voltage as the criterion of battery pack inconsistency,and choose the voltage difference as the evaluation index of inconsistency.Then,the traditional capacitor inductor equalizer is simulated and compared,and the differences between the capacitor inductors and the equilibrium speed are analyzed.On the basis of inductive equilibrium,the inductive equilibrium circuit based on BUCK-Boost is chosen,and the equilibrium topology and equilibrium control strategy are designed to improve in intermittent working mode.Under the same number of components as the traditional inductive equilibrium circuit,and the corresponding equilibrium margin is set,the equilibrium simulation circuit is constructed and the feasibility of the topology is verified,and compared with the traditional equalizer.Finally,the STM32 is selected as the main control chip,the main control circuit,the voltage acquisition circuit,the driving circuit,the battery pack equilibrium experimental platform is built,the 4 thin-cell lithium battery pack is tested for charge-discharge equilibrium,and the feasibility of the equilibrium control is verified.Improved equalization control is applied in the battery management system,which can extend the life of the entire battery pack,reduce the inconsistency between the batteries,maximize the performance of lithium batteries,and improve the energy control of the battery management system. |
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