Research on parameter identification and state of charge estimation of improved equivalent circuit model of Li‐ion battery based on temperature effects for battery thermal management
“…The behavior of the battery changes considerably at low temperatures [2] and to account for that, model parameters are adjusted for different temperatures. Huo et al [3] developed a temperature dependent 2 nd order ECM and used it to improve SoC estimation using an EKF. Guo et al [4] combined a temperature adjusted 2 nd order ECM with a dual extended Kalman filter and showed that their method greatly improves SoC estimation compared to an EKF without temperature compensation.…”
Section: A Motivation and Technical Challengesmentioning
Lithium-ion battery State of Charge (SoC) estimation for Electric Vehicle (EV) applications must be robust and as accurate as possible to maximize battery utilization and ensure safe operation over a wide range of operating conditions. SoC estimation commonly utilizes filters such as the Extended Kalman Filter (EKF) which rely on battery models, usually in the form of Equivalent Circuit Models (ECM). At low temperatures the battery response to current draw becomes increasingly non-linear, resulting in amplified SoC estimation errors. In this study, current dependent SoC estimation at low temperature is proposed using an Interacting Multiple Model (IMM) filter with three ECMs covering a range of C-rates. The IMM is combined with the Smooth Variable Structure Filter (SVSF) to obtain robust SoC estimates within a SoC estimation error of 2%.
“…The behavior of the battery changes considerably at low temperatures [2] and to account for that, model parameters are adjusted for different temperatures. Huo et al [3] developed a temperature dependent 2 nd order ECM and used it to improve SoC estimation using an EKF. Guo et al [4] combined a temperature adjusted 2 nd order ECM with a dual extended Kalman filter and showed that their method greatly improves SoC estimation compared to an EKF without temperature compensation.…”
Section: A Motivation and Technical Challengesmentioning
Lithium-ion battery State of Charge (SoC) estimation for Electric Vehicle (EV) applications must be robust and as accurate as possible to maximize battery utilization and ensure safe operation over a wide range of operating conditions. SoC estimation commonly utilizes filters such as the Extended Kalman Filter (EKF) which rely on battery models, usually in the form of Equivalent Circuit Models (ECM). At low temperatures the battery response to current draw becomes increasingly non-linear, resulting in amplified SoC estimation errors. In this study, current dependent SoC estimation at low temperature is proposed using an Interacting Multiple Model (IMM) filter with three ECMs covering a range of C-rates. The IMM is combined with the Smooth Variable Structure Filter (SVSF) to obtain robust SoC estimates within a SoC estimation error of 2%.
“…For parameters identification of the battery ECM (R 0 , R 1 , C 1 , R 2 , C 2 ), the HPPC test was implemented on the cell with SOC of 90% to 10% with SOC interval of 10; and SOC is calculated by Coulomb counting technique. Once the charge and discharge pulses are applied to the cell, the abrupt change in the terminal voltage is used for R 0 calculation, while other parameters (R 1 , C 1 , R 2 , C 2 ) are estimated by the remaining dynamic voltage change 41 . The identified model parameters of a fresh LIB cell in various temperatures and SOCs conditions are plotted in Figure 5.…”
Summary
Reliable operation and control of battery packs can lead to increasing applications of batteries as energy sources for mobile power systems such as electric/hybrid electric aircraft. If the operation of a battery pack is controlled and monitored thoroughly, the safety in the battery system of an electrified aircraft can be guaranteed. The battery model has many applications in battery management systems such as battery performance analysis and fault detection. To achieve an accurate fault diagnosis for electric aircraft, an intelligent fault detection scheme within an accurate battery cell model is required. In this study, an adaptive lithium‐ion battery model is proposed in which models' parameters are estimated by a supervised machine learning paradigm. This adaptive battery model is developed based on a second order equivalent circuit model, which has a good representation of lithium‐ion batteries dynamics. Comparative verification experiments show good accuracy and robustness of the machine learning‐based parameter estimator lead to an accurate battery model with an average error less than 0.4%. Moreover, to see the effectiveness of this machine learning‐based model in fault detection applications, a model‐based fault diagnosis scheme is developed. Finally, the analysis of fault diagnosis tests under different test conditions proves that the proposed adaptive battery model can significantly improve the fault diagnosis accuracy of batteries.
“…And the parameters used to describe the model can be identified offline by current profile test conveniently. 22,23 In engineering application, ECMs are often used for lithium battery system in combination with some filter-based methods, such as Kalman filter (KF), extended Kalman filter (EKF), 24 unscented Kalman filter (UKF), 25,26 Particle Filter (PF) 27 , and moving horizon estimation (MHE) 28 and its variation. 29 Huo et al, put forward a novel approach based on an improved ECM that considers the influence of ambient temperatures and battery surface temperature (BST) on battery parameters.…”
Section: Introductionmentioning
confidence: 99%
“…29 Huo et al, put forward a novel approach based on an improved ECM that considers the influence of ambient temperatures and battery surface temperature (BST) on battery parameters. 23 Combining the UKF and least support vector machines (LSVM), Meng et al, constructed a new SOC estimation concept, which can deal with the observation noise and system noise naturally and automatically. 25 However, the application of EKF is not very friendly in the estimation of batteries characterized by strong coupling and nonlinearity as the higher-order terms are ignored when Taylor expansion is performed on the nonlinear ECM.…”
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