In the fast-paced world of electric vehicles (EVs), lithium-ion batteries (LIBs) are the powerhouses driving the green revolution. However, as Peicheng Shi, a researcher at the School of Mechanical and Automotive Engineering, Anhui Polytechnic University, points out, “The increased energy density of lithium-ion batteries, while beneficial, has also exacerbated thermal runaway issues, posing significant challenges to large-scale applications.” This critical issue, where batteries experience rapid and uncontrollable temperature increases, can lead to fires and explosions, threatening both passengers and property.
Shi’s recent study, published in the World Electric Vehicle Journal, delves into the mechanisms behind thermal runaway and explores innovative solutions to enhance battery safety. The research highlights that thermal runaway can be triggered by various factors, including internal chemical reactions, overcharging, short circuits, physical damage, or high environmental temperatures. “The process typically begins with an initial temperature rise within the battery, potentially caused by internal resistance heating or improper battery management,” Shi explains. As the temperature exceeds 80°C, undesired exothermic side reactions are triggered, releasing additional heat and causing the temperature to soar.
The study systematically analyzes various thermal runaway early warning technologies, including temperature detection, gas detection, machine learning, and ultrasound methods. Each method has its pros and cons, but when combined, they offer a comprehensive approach to monitoring and preventing thermal runaway. For instance, temperature detection provides real-time monitoring of internal temperature changes, while gas detection is sensitive to gases from electrolyte decomposition, enhancing chemical reaction monitoring. Machine learning improves the accuracy and speed of warning systems by analyzing extensive data to identify potential fault patterns. Ultrasonic detection provides dynamic feedback on structural changes, offering comprehensive information for warning systems.
One of the most compelling aspects of Shi’s research is the exploration of novel fire extinguishing agents. Traditional firefighting techniques, such as water mist and sprinkling methods, have proven ineffective against lithium-ion battery fires due to reignition and the inability to prevent thermal runaway propagation between battery cells. However, new agents like hydrogels, perfluorohexanone, liquid nitrogen, dry powder, and aqueous vermiculite dispersion (AVD) show promise. These agents are designed to consider the unique characteristics of lithium-ion battery fires, which involve Class A, B, C, and D fires.
The study also highlights advancements in new fire-retardant coatings for batteries. These coatings provide deeper safety assurance by maintaining stability under high temperatures and enhancing mechanical performance. The integration of intelligent monitoring and response transforms these coatings into active safety systems, enabling quick response and emergency measures during early thermal runaway stages to reduce risk.
The implications of this research for the energy sector are profound. As the demand for EVs continues to rise, ensuring the safety and reliability of lithium-ion batteries is paramount. The development of effective thermal runaway warning and prevention technologies will not only enhance the safety of EVs but also boost consumer confidence in this emerging market. By focusing on the refinement and integration of these technologies, the industry can meet rising safety standards and market demands, elevating EV safety and supporting sustainable industry development.
Shi’s work underscores the importance of ongoing innovation and optimization in the field of lithium-ion battery technology. As the world moves towards a greener future, the safety and reliability of EVs will be crucial in driving the green transportation era forward. Through continued research and development, future EVs will be safer, more reliable, and will advance global low-carbon travel initiatives.