Wireless transmission of internal hazard signals in Li-ion batteries

High-capacity lithium-ion batteries (LIBs) play a critical role as power sources across diverse applications, including portable electronics, electric vehicles (EVs) and renewable-energy-storage systems1. However, there is growing concern about the safety of integrated LIB systems, with reports of up to 9,486 incidents between 2020 and 2024 (ref. 2). To ensure the safe application of commercial LIBs, it is essential to capture internal signals that enable early failure diagnosis and warning. Monitoring non-uniform temperature and strain distributions within the jelly-roll structures of the battery provides a promising approach to achieving this goal3,4. Here we propose a miniaturized and low-power-consumption system capable of accurate sensing and wireless transmission of internal temperature and strain signals inside LIBs, with negligible influence on its performance. The acquisition of internal temperature signals and the area ratio between initial internal-short-circuited regions and battery electrodes enables quantitative analysis of thermal fusing and thermal runaway phenomena, leading to the evaluation of the intensity of battery thermal runaway and recognition of thermal abuse behaviours. This work provides a foundation for designing next-generation smart LIBs with safety warning and failure positioning capabilities.