### An introduction to Electric Vehicle (EV) Technology

An introduction to
A Novel Cell Equalizer Topology for
Plug-In Hybrid Electric Vehicle
Energy Storage System
Kun Zhuge
[email protected]
Overview
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Significance of Cell Equalization
Battery Model
Novel Topology Analysis
Simulation Result
Conclusion
Significance of Cell Equalization
• A battery of a plug-in hybrid electric vehicle (PHEV)
consists of a long string of cells (typically 100 cells,
• Cost: 500\$/KW for a typical 16KWh battery, which can
provide about 80KM in urban area, surcharge of \$5000
• Cycle life and calendar life:
– 500 cycles of 80% the capacity
– Expecting 6000-7000 cycles for future PHEV
• Safety:
– Safety improvement of the system if there is continuously
monitoring the cell current, voltage and temperature
Battery Model
[1]. Accurate Electrical Battery Model Capable of Predicting
Runtime and I-V Performance, Min Chen, Student Member,
IEEE, and Gabriel A. Rinc´on-Mora, Senior Member, IEEE,
IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 21,
NO. 2, JUNE 2006
Cell Equalization Topology
• Current Ieq will flow in or out of the battery through the inductor
• “Control” of the system monitors the battery voltage and responses to
equalize the battery voltage by turning on or off the switches
Cell Equalization Topology
Optimal choice: One equalizer unit is limited to four to
five cells
• Low cost constraint
• Voltage margin to improve the reliability
Cell Equalization Formula
Cell Equalization Formula
Cell Equalization
Cell Equalization
VOC estimation
Ieq: equalizing current, active only at To and interrupted after T1
 0 : is one at To and zero thereafter
I batt : is the battery pack current
Ra / Rb : are the dynamic resistances
Ta / Ta
: are constants
Conclusion
• In summary, the feasibility of the novel
battery cell equalizer was explored
• Cell equalization does contribution to
battery cost, battery life and cycle, and
battery safety
Reference
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[1]. Accurate Electrical Battery Model Capable of Predicting Runtime and I-V
Performance, Min Chen, Student Member, IEEE, and Gabriel A. Rinc´on-Mora,
Senior Member, IEEE, IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL.
21, NO. 2, JUNE 2006
[2]. Feasibility Analysis of a Novel Cell Equalizer Topology for Plug-in Hybrid Electric
Vehicle Energy-Storage System, Pablo A. Cassani, Student Member, IEEE, and
Sheldon S. Williamson, Member, IEEE, IEEE TRANSACTIONS ON VEHICULAR
TECHNOLOGY, VOL. 58, NO. 8, OCTOBER 2009
[3]. Design, Testing, and Validation of a Simplified Control Scheme for a Novel Plug-In
Hybrid Electric Vehicle Battery Cell Equalizer, Pablo A. Cassani, Student Member,
IEEE, and Sheldon S. Williamson, Member, IEEE, IEEE TRANSACTIONS ON
INDUSTRIAL ELECTRONICS, VOL. 57, NO. 12, DECEMBER 2010
Thanks!
Q&A