SOC Estimation of Lithium-Ion Battery Packs Based on Thevenin Model

2013 ◽  
Vol 299 ◽  
pp. 211-215 ◽  
Author(s):  
Yuan Qi Fang ◽  
Xi Ming Cheng ◽  
Yi Lin Yin
Keyword(s):  
Lithium Ion Battery ◽  
Equivalent Circuit ◽  
Equivalent Circuit Model ◽  
Lithium Ion ◽  
Test System ◽  
Experimental Result ◽  
Current Collection ◽  
Soc Estimation ◽  
Test Platform ◽  
Battery Packs

Due to the immeasurability of SOC in battery and inevitability of error in current collection, SOC estimation of Lithium-ion battery has become a focus of EV research. With Thevenin equivalent circuit model, this paper employs EKF algorithm to estimate SOC, which takes into consideration both precision requirement of the estimation and amount of computation involved in online estimation. Based on above-mentioned objectives and principles, a test platform composed of Digatron battery test system and thermostat was built. Experimental result has confirmed that the combination of EKF algorithm with Thevenin model can improve precision and reduce amount of computation.

scholarly journals An Adaptive Estimation Scheme for Open-Circuit Voltage of Power Lithium-Ion Battery

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Yun Zhang ◽  
Chenghui Zhang ◽  
Naxin Cui
Keyword(s):  
Lithium Ion Battery ◽  
Equivalent Circuit ◽  
Open Circuit Voltage ◽  
Adaptive Estimation ◽  
Equivalent Circuit Model ◽  
Lithium Ion ◽  
Open Circuit ◽  
Adaptive Scheme ◽  
Power Battery ◽  
Estimation Scheme

Open-circuit voltage (OCV) is one of the most important parameters in determining state of charge (SoC) of power battery. The direct measurement of it is costly and time consuming. This paper describes an adaptive scheme that can be used to derive OCV of the power battery. The scheme only uses the measurable input (terminal current) and the measurable output (terminal voltage) signals of the battery system and is simple enough to enable online implement. Firstly an equivalent circuit model is employed to describe the polarization characteristic and the dynamic behavior of the lithium-ion battery; the state-space representation of the electrical performance for the battery is obtained based on the equivalent circuit model. Then the implementation procedure of the adaptive scheme is given; also the asymptotic convergence of the observer error and the boundedness of all the parameter estimates are proven. Finally, experiments are carried out, and the effectiveness of the adaptive estimation scheme is validated by the experimental results.

A Novel Method for Estimating State of Charge of Lithium Ion Battery Packs

2010 ◽  
Vol 152-153 ◽  
pp. 428-435 ◽  
Author(s):  
Yuan Liao ◽  
Ju Hua Huang ◽  
Qun Zeng
Keyword(s):  
Lithium Ion Battery ◽  
Estimation Method ◽  
Lithium Ion ◽  
State Of Charge ◽  
Estimation Methods ◽  
Counting Method ◽  
Soc Estimation ◽  
Battery Packs ◽  
Novel Method ◽  
Road Data

In this paper a novel method for estimating state of charge (SOC) of lithium ion battery packs in battery electric vehicle (BEV), based on state of health (SOH) determination is presented. SOH provides information on aging of battery packs and it declines with repeated charging and discharging cycles of battery packs, so SOC estimation depends considerably on the value of SOH. Previously used SOC estimation methods are not satisfactory as they haven’t given enough attention to the decline of SOH. Therefore a novel SOC estimation method based on SOH determination is introduced in this paper; trying to compensate the deficiency for lack of attention to SOH. Real time road data are used to compare the performance of the conventionally often used Ah counting method which doesn’t give any consideration to SOH with the performance of the proposed SOC estimation method, and better results are obtained by the proposed method in comparison with the conventional method.

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