State-of-Charge Determination in Lithium-Ion Battery Packs Based on Two-Point Measurements in Life

The state-of-charge (SOC) estimation is of extreme importance for the reliability and safety of battery operation. How to estimate SOC for an assembly of cells in a battery pack remains a subject of great interest. Here a viable method for SOC determination and tracking for multi-cell assemblies is proposed and validated. Using 3S1P (three in series and one in parallel) strings as an example, an inference of SOC is illustrated in a battery assembly based on a correct open pack voltage (OPV) versus SOC (i.e. OPV = ƒ(SOC)) function. The proposed method only requires the measurements of the rest cell voltages of the single cells at two distinct occasions. This accurate SOC estimation approach shall facilitate reliable battery control and management.

[1]  Matthieu Dubarry,et al.  Evaluation of commercial lithium-ion cells based on composite positive electrode for plug-in hybrid electric vehicle applications. Part II. Degradation mechanism under 2 C cycle aging , 2011 .

[2]  Matthieu Dubarry,et al.  Synthesize battery degradation modes via a diagnostic and prognostic model , 2012 .

[3]  Aaas News,et al.  Book Reviews , 1893, Buffalo Medical and Surgical Journal.

[4]  Matthieu Dubarry,et al.  Investigation of path dependence in commercial lithium-ion cells chosen for plug-in hybrid vehicle duty cycle protocols , 2011 .

[5]  Jianqiu Li,et al.  A review on the key issues for lithium-ion battery management in electric vehicles , 2013 .

[6]  Binggang Cao,et al.  Combined state of charge estimator for electric vehicle battery pack , 2007 .

[7]  Matthieu Dubarry,et al.  Evaluation of commercial lithium-ion cells based on composite positive electrode for plug-in hybrid electric vehicle applications. Part I: Initial characterizations , 2011 .

[8]  Fengchun Sun,et al.  A novel dual-scale cell state-of-charge estimation approach for series-connected battery pack used in electric vehicles , 2015 .

[9]  Matthieu Dubarry,et al.  Origins and accommodation of cell variations in Li‐ion battery pack modeling , 2010 .

[10]  Hongwen He,et al.  Online estimation of model parameters and state-of-charge of LiFePO4 batteries in electric vehicles , 2012 .

[11]  Weijun Gu,et al.  Online cell SOC estimation of Li-ion battery packs using a dual time-scale Kalman filtering for EV applications , 2012 .

[12]  Tahsin Koroglu,et al.  A comprehensive review on estimation strategies used in hybrid and battery electric vehicles , 2015 .

[13]  Sergiy V. Sazhin,et al.  Evaluation of Commercial Lithium-Ion Cells Based on Composite Positive Electrode for Plug-In Hybrid Electric Vehicle Applications III. Effect of Thermal Excursions without Prolonged Thermal Aging , 2013 .

[14]  Matthieu Dubarry,et al.  From single cell model to battery pack simulation for Li-ion batteries , 2009 .

[15]  C. Delacourt,et al.  Calendar aging of a graphite/LiFePO4 cell , 2012 .

[16]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[17]  M. Dubarry,et al.  Identifying battery aging mechanisms in large format Li ion cells , 2011 .

[18]  C. Delacourt,et al.  Postmortem analysis of calendar-aged graphite/LiFePO4 cells , 2013 .

[19]  Matthieu Dubarry,et al.  State-of-charge estimation and uncertainty for lithium-ion battery strings , 2014 .

[20]  J. Schmidt,et al.  Analysis and prediction of the open circuit potential of lithium-ion cells , 2013 .

[21]  Zonghai Chen,et al.  A method for the estimation of the battery pack state of charge based on in-pack cells uniformity analysis , 2014 .

[22]  Matthieu Dubarry,et al.  Identify capacity fading mechanism in a commercial LiFePO4 cell , 2009 .