Abstract
Electric vehicle battery performance near end-of-life is limited by mismatched cell degradation, leading to an estimated 5-10% cell capacity variation across the pack. Active cell balancing hardware architectures incorporating a Low-Voltage (LV) bus supply have been introduced to unlock lost capacity due to cell imbalance at reduced cost, through elimination of the vehicle's 400-to-12V dc-dc converter. In this work, a hierarchical model-predictive control scheme is applied to a time-shared isolated converter active balancing architecture that incorporates LV bus supply. The proposed controller efficiently divides computation among the battery management system hardware components. The energy-buffering capability of the lead-acid battery, which is connected to the LV bus, is used to trade-off balancing and bus regulation objectives, reducing peak power and improving the system cost-effectiveness. Simultaneous state-of-charge balancing and LV bus regulation is verified in simulation and experiment using real-world drive and LV load data collected from a GM Bolt electric vehicle. Similar controller performance compared to a central scheme is achieved in simulation. The experimental setup includes a custom 12S2P, 3.9kWh, liquid-cooled Lithium Nickel Manganese Cobalt battery module with embedded battery management system. The controller performance is evaluated with an initial maximum state-of-charge imbalance of 6.8%.
Original language | English |
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Article number | 8928973 |
Pages (from-to) | 10464-10473 |
Number of pages | 10 |
Journal | IEEE Transactions on Industrial Electronics |
Volume | 67 |
Issue number | 12 |
DOIs | |
Publication status | Published - Dec 2020 |
Keywords
- Automotive electronics
- Batteries
- Computer architecture
- Electric vehicles
- Lead
- Microprocessors
- State of charge
- Temperature measurement
- battery management systems (BMS)
- control design
- electric vehicles (EVs)
- energy storage
- lithium batteries