Battery equalization improves efficiency, safety, and lifespan for powering electric vehicles

With the increasing demand for electric vehicle batteries, it’s now more important than ever to ensure they are optimized. One remaining challenge is equalizing the charge level of batteries in a pack, which invariably have different capacities. Equalizing the capacities is essential for improving usage, extending lifespan, and ensuring operational safety.

Qiang et al. developed a novel active method to mitigate these issues by using a dual-layer hybrid equalization topology. They used Cuk circuits and a flyback transformer to help equalize a series-connected battery pack separated into modules.

“Equalization operation emerges as a crucial method to effectively reduce the capacity inconsistency among batteries,” said author Hao Qiang. “However, the current practical applications mostly rely on passive equalization, which not only leads to energy waste but also carries the risk of fire.”

The authors tested the equalization strategy with theoretical analysis, simulations, and an experimental platform. The results showed the equalization control is continuously optimized and can be used in practical applications. The design was also able to equalize quickly and efficiently, which most existing active equalization methods are not able to do.

“This design can be integrated into the battery management system to manage battery charging, aiming to mitigate the inconsistency between batteries and enhance the lifespan of battery packs,” Qiang said.

The authors intend to continue working on introducing better algorithms into the equalization to further enhance speed and efficiency. They also plan to work on reducing the cost of equalization circuits.

Source: “Dual-layer active equalization control for series-connected batteries based on hybrid cuk-flyback topology,” by Hao Qiang, Zhengwen Mo, and Junhao Xie, AIP Advances (2023). The article can be accessed at https://doi.org/10.1063/5.0179197 .