The Modeling And Simulation Of The Lithium-ion Battery

With the constant development of new energy industry,application of battery energy storage has become a research hotspot.Lithium batteries have been widely used for large energy,light weight,low self-discharge rate,non-pollution and so on.In order to research the battery system more conveniently,it is necessary to study the model of lithium battery.This paper firstly introduces the research background,significance and the development process of lithium-ion batteries.Secondly,the working principle,performance index and charging mode of lithium-ion batteries are introduced in detail.Several main lithium battery models are summarized in this paper.By reference to the theoretical knowledge of lithium battery,an equivalent circuit model which is improved and easy to use for lithium batteries is proposed.According to the proposed model,the simulation model is built in PSIM.The lithium battery model in the paper is constructed in standard condition,but the discharge of lithium battery is affected by temperature and discharge ratio,so the next is the study of the model of lithium batteries at different discharge rates.The different discharge rate of lithium battery is tested,and the calculation parameters are extracted from the battery data sheet.The obtained parameters are brought into the established simulation model for simulation,and the error rate is calculated by comparing the simulation figure with the experimental figure.The different temperature and dynamic performance of lithium battery are studied by the same method,and the model is established and verified.In addition,the lithium battery is tested under the mixed pulse discharge.The experiment and data show that the battery model can describe the state of the battery very well under the condition of the mixed pulse discharge.Finally,a square cell is used to verify the accuracy of the model.The parameters of the single cell model at different temperature and different discharge rate can be obtained through the above experiments and verification of the single cell.The series-parallel model of the battery is expected to be obtained by series-parallel connection of single cells which brings single cell parameters into the series-parallel model,gets simulation curve through simulation and gets the actual curve discharge experiment of series-parallel battery.In this paper,several different battery models are obtained:different discharge rate model,different temperature model,dynamic discharge model and series-parallel model.