Wang Fang, chief expert at my country's Automotive Technology Research Center, emphasized the need to fully understand battery safety zones and strive to address specific issues effectively.
Addressing the safety hazards of power lithium batteries requires targeted solutions.
Battery safety is a critical factor limiting the safety of electric vehicles. Wang Fang pointed out, "Batteries have both introverted and extroverted characteristics; we must find the points where the battery 'acts up.'" She suggested that companies conduct battery safety tests to fully understand the characteristics of the battery cells, determining whether they are introverted or extroverted. If extroverted, they should consider adding auxiliary limiting measures in certain usage stages, including during system integration, to keep the battery within a relatively regulated range, showcasing its superior safety qualities and reducing the risk of safety accidents due to its extroverted nature throughout the entire usage process.
Thermal runaway manifests in many ways, and the characteristics of each battery cell are not entirely the same. At different temperatures, the same battery cell will also exhibit different behaviors. Based on the different materials inside, including the separator, the same materials will react differently at certain temperature points, leading to different results.
The company should place greater emphasis on product design during development.
"When developing a battery, companies shouldn't just focus on passing safety tests, national regulations, and certifications, but rather on how to design a good product and make the battery cells safe," said Wang Fang. "To develop an evaluation system for battery thermal characteristics, we must first understand the battery's inherent thermal characteristics, the rate of temperature rise and heat generation during normal charging and discharging, the battery's safe operating range, and the triggering mechanisms and conditions for its 'explosive behavior'."
Product design should fully consider the necessary blocking and protection measures between each cell during thermal management to improve system safety. She emphasized that, firstly, the safety of each individual module must meet the standards; secondly, after understanding the safety characteristics of the battery, appropriate safety designs must be added, and the system integration must be done well to produce a truly reliable battery system.
The safety of batteries after three or four years of use deserves attention.
Extensive research has been conducted in my country regarding battery stability throughout its lifecycle. Tests show that batteries are prone to thermal runaway around 900 cycles. While batteries may still be usable after three to four years of normal use, with remaining capacity generally above 80%, their safety, along with safety oversight and hazard identification, warrants continued attention.
