ACTIVE EQUALIZATION CIRCUIT ANALYSIS.pptx
- 1. ACTIVE EQUALIZATION CIRCUIT TOPOLOGY OF LITHIUM-ION BATTERY PACK: A REVIEW Presented At Hybrid International Conference of the Department of Mechatronic Engineering, University of Nigeria, Nsukka.
- 2. Introduction • The global energy crisis has increased the focus on sustainable energy solutions. • Lithium-ion batteries (LIBs) are crucial in electric vehicles (EVs) and energy storage systems. • Their advantages include high energy density, low cost, and rechargeability. • Inconsistencies in the internal and exterior environments of lithium-ion cells once they are connected as a battery pack can significantly limit the pack's capacity
- 4. Overview of Active Equalization Circuits •Various active equalization methods: ◦Cell-to-Cell Energy Transfer ◦Cell-to-Pack Energy Transfer ◦Pack-to-Cell Energy Transfer •Uses DC/DC converters and selection switches.
- 5. Cell-to-cell energy flow technique • Uses a DC/DC converter with an array of selection switches. • Advantage: Faster balancing speed compared to other methods. • Challenge: Requires many switching elements, leading to low equalizing efficiency. • Optimization efforts focus on improving efficiency and reducing complexity.
- 6. Cell to pack energy flow technique • Uses a single DC/DC converter to transfer energy from an overcharged cell to the entire battery pack. • Advantage: High equalization speed due to significant voltage difference. • Challenge: Low balancing efficiency caused by transformer losses. • Research focuses on improving efficiency while maintaining high speed.
- 7. Pack to cell energy flow technique • Transfers charge from the battery pack to an undercharged cell. • The DC/DC converter connects the pack to the identified cell. • Similar to the cell-to-pack technique, but in reverse direction. • Focus on optimizing efficiency and minimizing energy losses.
- 8. Switched Capacitor Topology Title: Switched Capacitor (Flying Capacitor) Content: •Principle: Uses capacitors to transfer energy between adjacent cells. •Advantages: Simple design, low cost. •Disadvantages: Slow balancing, limited to adjacent cells. •Visual: Circuit diagram of a switched capacitor topology.
- 9. Inductive Topology Title: Inductive (Transformer-Based) Content: •Principle: Uses inductors or transformers to transfer energy. •Advantages: High efficiency, fast balancing. •Disadvantages: Complex design, higher cost. •Visual: Circuit diagram of an inductive topology.
- 10. DC-DC Converter Topology Title: DC-DC Converter (Buck-Boost) Content: •Principle: Uses bidirectional DC-DC converters to transfer energy. •Advantages: High flexibility, fast and efficient balancing. •Disadvantages: Complex control circuitry, higher cost. •Visual: Circuit diagram of a DC-DC converter topology.
- 11. Multi-Winding Transformer Topology Title: Multi-Winding Transformer Content: •Principle: Uses a single transformer with multiple windings. •Advantages: High efficiency, simultaneous balancing. •Disadvantages: Complex design, large transformer size. •Visual: Circuit diagram of a multi-winding transformer topology.
- 12. Modular Multilevel Converter Topology Title: Modular Multilevel Converter (MMC) Content: •Principle: Uses a modular approach with multiple sub- converters. •Advantages: Scalable for large packs, high efficiency. •Disadvantages: High cost and complexity. •Visual: Circuit diagram of an MMC topology.
- 13. Conclusion • Battery equalization is vital for LIB efficiency and longevity. • Active equalization offers superior performance over passive methods. • Ongoing research aims to optimize equalization topologies for improved energy management.