Research On The Method Of Estimating The State Of Charge Of Lithium-ion Battery In Electric Vehicle

The lithium iron phosphate battery is widely used in electric vehicle power battery for its high efficiency,safety and low cost.It is a prerequisite for the rational use of SOC(state of charge)and the battery management system with good performance.But at the same time,it is also a key issue to be solved in the development of electric vehicles.This paper studies the modeling and state estimation of electric vehicle lithium ion batteries under the support of the graduate scientific research and innovation fund of China Three Gorges University(SDYC2016044).First,it discusses the basis and significance of the topic,and summarizes the progress of relevant literature at home and abroad,especially for the development of power battery and the state of the battery charge.An overview of the estimates.Then,the performance characteristics of lithium iron phosphate battery are studied,and the linear relationship and performance characteristics are summarized,which will provide a good basis for the follow-up research.Then,the existing RC model of lithium ion battery is studied,especially its equivalent circuit model is improved.An improved time integral SOC estimation algorithm based on the modified RC model is proposed based on the modified SOC estimation method.Under different conditions,the SOC estimation method is verified by comparing the modified ampere integral method based on RC modified model with the standard method.The results show that the improved time integral SOC estimation algorithm based on the modified RC model proposed in this paper has better precision and efficiency,more perfect function and more secure and reliable.