Balancing Strategies for an Unbalanced LiFePO4 Battery Pack

Author(s):  
Zi-Yuan Chiou ◽  
Chih-Hao Lee ◽  
Chi Yao Wu
Keyword(s):  
2013 ◽  
Vol 226 ◽  
pp. 33-41 ◽  
Author(s):  
Yuejiu Zheng ◽  
Languang Lu ◽  
Xuebing Han ◽  
Jianqiu Li ◽  
Minggao Ouyang

Author(s):  
Peeyush Garg ◽  
Vishnu Goyal ◽  
Siddharth Bhattacharya ◽  
Deepika Bansal

Author(s):  
You Xu ◽  
Jiehao Li ◽  
Wei Xu ◽  
Jing Wu ◽  
Shuli Li ◽  
...  

Abstract The state of charge (SoC) is an important index of the energy output performance of power battery pack. But the SoC value is affected by various factors, namely, ambient temperature, working current, equilibrium potential, and the consistency between batteries in the pack. These factors might dampen the accuracy of the traditional SoC evaluation methods like current–voltage method and Kalman filter. The evaluation accuracy is also influenced by the data drift and rest time to equilibrium potential. Considering the multiple influencing factors of SoC, this paper analyzes the data drift and rest time to equilibrium potential, and builds an approximate model of overpotential for 32650 LiFePO4 battery, based on the time variation constant and the monotonicity of SoC trend. The proposed model was adopted to optimize the evaluation of SoC. To verify its effectiveness, the proposed method was compared with current–voltage method and Kalman filter through experiments. The results show that our method outperformed the contrastive methods in simplicity, relative error (<2.33%), compatibility, and state of health (SoH).


2014 ◽  
Vol 1044-1045 ◽  
pp. 545-548
Author(s):  
Xiang Wu Yan ◽  
Qi Guo ◽  
Heng Bo Xu

In order to estimate the state of health (SOH) of each cell in the battery pack, polarization resistance and ohmic resistance were analyzed in the aging process of the battery pack. Accelerating aging test for the battery was done, quantitative relationship between the ohmic resistance and the capacity aging was obtained, a method of relative state of health (RSOH) evaluation was proposed accordingly, Experiments on the LiFePO4 battery pack which is connected in series by 100 cells have been taken, the experimental results show that the evaluation method of RSOH can evaluate the cells SOH accurately and is not limited by the operating conditions.


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