Simulation of second-order RC equivalent circuit model of lithium battery based on variable resistance and capacitance

2020 ◽  
Vol 27 (9) ◽  
pp. 2606-2613
Author(s):  
Yan-ju Ji ◽  
Shi-lin Qiu ◽  
Gang Li
Keyword(s):  
Equivalent Circuit ◽  
Lithium Battery ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Second Order ◽  
Variable Resistance

scholarly journals SOC Estimation with an Adaptive Unscented Kalman Filter Based on Model Parameter Optimization

2019 ◽  
Vol 9 (19) ◽  
pp. 4177
Author(s):  
Xiangwei Guo ◽  
Xiaozhuo Xu ◽  
Jiahao Geng ◽  
Xian Hua ◽  
Yan Gao ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Equivalent Circuit ◽  
Parameter Optimization ◽  
Unscented Kalman Filter ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Second Order ◽  
Model Parameters ◽  
Soc Estimation ◽  
Adaptive Unscented Kalman Filter

State of charge (SOC) estimation is generally acknowledged to be one of the most important functions of the battery management system (BMS) and is thus widely studied in academia and industry. Based on an accurate SOC estimation, the BMS can optimize energy efficiency and protect the battery from being over-charged or over-discharged. The accurate online estimation of the SOC is studied in this paper. First, it is proved that the second-order resistance capacitance (RC) model is the most suitable equivalent circuit model compared with the Thevenin and multi-order models. The second-order RC equivalent circuit model is established, and the model parameters are identified. Second, the reasonable optimization of model parameters is studied, and a reasonable optimization method is proposed to improve the accuracy of SOC estimation. Finally, the SOC is estimated online based on the adaptive unscented Kalman filter (AUKF) with optimized model parameters, and the results are compared with the results of an estimation based on pre-optimization model parameters. Simulation experiments show that, without affecting the convergence of the initial error of the AUKF, the model after parameter optimization has a higher online SOC estimation accuracy.

scholarly journals An Accurate Time Constant Parameter Determination Method for the Varying Condition Equivalent Circuit Model of Lithium Batteries

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2057 ◽  
Author(s):  
Liang Zhang ◽  
Shunli Wang ◽  
Daniel-Ioan Stroe ◽  
Chuanyun Zou ◽  
Carlos Fernandez ◽  
...  
Keyword(s):  
Equivalent Circuit ◽  
Time Constant ◽  
Lithium Battery ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Parameter Determination ◽  
Accurate Estimation ◽  
Model Parameters ◽  
Accurate Identification ◽  
Battery Model

An accurate estimation of the state of charge for lithium battery depends on an accurate identification of the battery model parameters. In order to identify the polarization resistance and polarization capacitance in a Thevenin equivalent circuit model of lithium battery, the discharge and shelved states of a Thevenin circuit model were analyzed in this paper, together with the basic reasons for the difference in the resistance capacitance time constant and the accurate characterization of the resistance capacitance time constant in detail. The exact mathematical expression of the working characteristics of the circuit in two states were deduced thereafter. Moreover, based on the data of various working conditions, the parameters of the Thevenin circuit model through hybrid pulse power characterization experiment was identified, the simulation model was built, and a performance analysis was carried out. The experiments showed that the accuracy of the Thevenin circuit model can become 99.14% higher under dynamic test conditions and the new identification method that is based on the resistance capacitance time constant. This verifies that this method is highly accurate in the parameter identification of a lithium battery model.

scholarly journals An Equivalent Circuit Model for Lithium Battery of Electric Vehicle considering Self-Healing Characteristic

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Zhaodi Pei ◽  
Xiaoxu Zhao ◽  
Huimei Yuan ◽  
Zhen Peng ◽  
Lifeng Wu
Keyword(s):  
Equivalent Circuit ◽  
Lithium Batteries ◽  
Mathematical Description ◽  
Lithium Battery ◽  
Healing Process ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
The Self ◽  
Self Healing ◽  
Experimental Platform

Considering the self-healing phenomenon of lithium batteries during intermittent discharge, a self-healing characteristic-based equivalent circuit model of lithium batteries is proposed. The mathematical description of the lithium battery in the self-healing process is obtained through the analysis of the equivalent circuit model. Based on experimental platform, an experiment considering self-healing characteristic was performed. Result shows that the self-healing characteristic-based lithium battery equivalent circuit model can describe the voltage of the lithium battery accurately during the self-healing process.

scholarly journals State of Charge Estimation for Lithium-Ion Batteries Based on Temperature-Dependent Second-Order RC Model

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1012 ◽  
Author(s):  
Yidan Xu ◽  
Minghui Hu ◽  
Chunyun Fu ◽  
Kaibin Cao ◽  
Zhong Su ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Equivalent Circuit ◽  
Equivalent Circuit Model ◽  
Lithium Ion ◽  
Circuit Model ◽  
Second Order ◽  
State Of Charge ◽  
Accurate Estimation ◽  
Temperature Dependent ◽  
Soc Estimation

Accurate estimation of battery state of charge (SOC) is of great significance for extending battery life, improving battery utilization, and ensuring battery safety. Aiming to improve the accuracy of SOC estimation, in this paper, a temperature-dependent second-order RC equivalent circuit model is established for lithium-ion batteries, based on the battery electrical characteristics at different ambient temperatures. Then, a dual Kalman filter algorithm is proposed to estimate the battery SOC, using the proposed equivalent circuit model. The SOC estimation results are compared with the SOC value obtained from experiments, and the estimation errors under different temperature conditions are found to be within ±0.4%. These results prove that the proposed SOC estimation algorithm, based on a temperature-dependent second-order RC equivalent circuit model, provides accurate SOC estimation performance with high temperature adaptability and robustness.

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