Research On Active Equalization Technology Of Power Lithium Battery Pack

The equalization circuit is designed to avoid battery damage caused by overcharging and over-discharging of the battery in use.It is an important research aspect in the battery balance management system.The existence of the active equalization circuit is of great significance in improving battery inconsistency,optimizing the performance of the battery pack,extending the life of the battery,and improving the mileage.Therefore,how to make the battery equalization time shorter and the balance effect better,the active balancing technology of the lithium battery pack has theoretical research significance and practical application value.Firstly,the parameter characteristics test of lithium iron phosphate battery was carried out,and the influence of parameters such as capacity,internal resistance,charge and discharge rate on the inconsistency of lithium battery was explained by the test curve.It can be combined with battery component selection technology and equalization technology.Method to improve the consistency between the batteries.Secondly,the working principle and efficiency of the traditional Buck-Boost circuit and the flying capacitor circuit are analyzed and the calculation of related parameters is completed.It is concluded that Buck-Boost is used as the equalization circuit to equalize the efficiency of the two-cell battery pack.The flying capacitor balances the three-cell battery.The group or higher is more efficient.Combined with the Buck-Boost circuit and the flying capacitor circuit,a composite layered active equalization topology is designed.The layered analysis of the battery combination and structure of this scheme is carried out from the single-layer,multi-layer,dual-cell and three-cell topology diagrams.The equalization strategy with battery voltage as the equilibrium variable is adopted,and the flow chart of equalization strategy control is designed.The hardware circuit of the composite layered equalization system with STM32F103ZET6 as controller is designed,including the main control circuit and the unit acquisition circuit.Finally,the MATLAB is used to build the equalization circuit simulation model,and the single-layer dual-cell Buck-Boost,single-layer traditional Buck-Boost,doublelayer dual-cell Buck-Boost and composite layered circuits are simulated.The simulation results show that the composite stratified active equalization circuit is reduced by 14~156 times compared with other equalization topologies in this paper.After the equilibrium tends to be consistent,the composite stratified active equalization circuit is improved by 39.47% compared with the traditional topology voltage consistency.The voltage uniformity is increased by 253% compared to the double-layer dual-cell circuit.The data shows that compared with other topologies in this paper,the scheme has the fastest equalization speed,the battery voltage is equalized,the voltage difference between the batteries is smaller,the consistency is better,and the equalization effect is more ideal.This solution is effective and feasible.Figure [57] Table [9] References [60]...