Investigation on Operating Characteristics of Individual Cells in a Lead-Acid Battery Pack

Similar to series-connected batteries, series-connected cells in a battery pack also suffer from the perplexity of unbalanced voltage while charging or discharging processes, especially for lead-acid batteries. This paper is to study the impact on capacity reduction under different operation conditions, such as different float-charging voltages, different cut-off discharging voltages and even discharging to negative voltages. The results reveal that the health of battery cells is more significantly affected by float-charging voltage than by the discharging cut-off voltage. However, discharging a cell into exceedingly negative voltage incurs a destructive consequence. A bypass protection circuit is proposed to mitigate the deterioration rate of battery cells. Experimental results show that the capacity reduction rate can be decreased distinctly.

[1]  T.L. Churchill.  Battery condition management an important way to protect a critical asset , 2000, Fifteenth Annual Battery Conference on Applications and Advances (Cat. No.00TH8490).

[2]  Phillip M. Hunter,et al.  VRLA battery rapid charging under stress management , 2003, IEEE Trans. Ind. Electron..

[3]  C.S. Moo,et al.  A Bi-directional Charge Equalization Circuit for Series-connected Batteries , 2005, 2005 International Conference on Power Electronics and Drives Systems.

[4]  J. C. Cheng,et al.  Dynamic charge equalization for series-connected batteries , 2002, 2002 IEEE International Conference on Industrial Technology, 2002. IEEE ICIT '02..

[5]  C. S. Moo,et al.  Dynamic charge equalisation for series-connected batteries , 2003 .

[6]  Kostas Kalaitzakis,et al.  Designing a new generalized battery management system , 2003, IEEE Trans. Ind. Electron..

[7]  Philip T. Krein,et al.  Equalization of valve-regulated lead-acid batteries: issues and life test results , 2000, INTELEC. Twenty-Second International Telecommunications Energy Conference (Cat. No.00CH37131).

[8]  P. T. Krein,et al.  Equalization requirements for series VRLA batteries , 2001, Sixteenth Annual Battery Conference on Applications and Advances. Proceedings of the Conference (Cat. No.01TH8533).