Research On The Equalization Charging Technology Of Polymer Lithium-Ion Battery Series

With the development of science and technology, the need for energy storagebattery are larger and larger, and the demand for voltage grade is higher and higher.Polymer lithium-ion battery has being widely used because of its prominent feature.In higher voltage grade systems, in order to raise voltage grade and capacity,lithium-ion battery connects by parallel series. While the scope of application limitedas the capacity of element cell differs, battery equalization circuit can eliminateimbalance problems of battery cell efficiently.This paper makes analyses from many aspects about equilibrium problems.The paper makes analyses of working principle，characteristics of polymerlithium-ion battery. Suitable charging method is selected considering battery’selectrical characteristics. With knowledge of the relationship between battery SOCand open-circuit voltage in a certain range, this paper estimates SOC of the battery byopen circuit voltage and builds simulation model of elementary cell.With summaries of lithium-ion battery equalization methods, equalizing circuitand relative parameters are discussed on the basis of Boost-Buck circuit. Signalcollection circuit, drive circuit and software program flow charts are designed with themain circuit.Equalizing circuit model is built, equalization simulation has been done accordingto the circuit used in this paper to test and verify the effectiveness of the circuit.Analysis has been made on the basis of the simulation result. This paper also gives anoutlook for application prospect.