Design Of Equilibrium And Activation System For Battery Pack

In actual applications, batteries are ofen used in serial pattern to achieve higher voltage level.Caused by the differences in producing process and working process,some batteries in serial battery pack may be over-charged or over-discharged, and the differences of the battery pack will be expanded.As a result of the above situation, battery capacity utilization will be limited,and battery life will be shorten.In order to avoid the bad affection caused by battery inconsistency, we can apply equilibrium operation to serial battery pack.Besides, activation operation is needed for old batteries to recover their capacity.Based on battery inconsistency, equilibrium and activation system was designed in this paper, using for rapid equilibrium of battry pack, offline battery maintenance and battery protecting in activation process.Through the analysis of battery characteristics and consistency, meaning and function of battery equilibrium were researched and a practical equilibrium scheme was presented. The system takes single cell external voltage as balanced judgement basis, charging the low voltage sinle cell, keeping the battery difference in a narrow range, improving the battery pack capacity utilization rate, and protecing the battery pack. System was built in master-slave structure, the PC machine controls a number of detecting boards, and each detecting board controls twelve charging power boards. Detecting boards takes MC9S12D64CPU and DS2438measuring IC as its core to complete the voltage measurement, control and other functions. Charging powers complete charging function by double transistor flyback convertor.Through series of experiments, it proved that the equilibrium and activation system can reduce battery inconsistency, and avoid over-charing and over-discharging.