Breakthrough in fine state monitoring of lithium-ion smart batteries towards module applications

With the continuous development of electric vehicle intelligence, traditional battery technology faces shortcomings in sensing data and monitoring methods at the cell, module, and system levels, limiting the further enhancement of lithium-ion battery intelligence and safety. Among the “three major components” of electric vehicles-motor, electronic control unit (ECU), and battery - the first two have been or can be easily intelligentized, while the progress of battery intelligence lags significantly, becoming a key shortcoming in electric vehicle intelligence. Multi-source parameter sensors are crucial “nerves” for lithium-ion batteries to finely perceive their operational and safety status. Here, we report a prototype of a smart battery at the cell and module levels, equipped with a mechanical-thermal-electrical multi-source parameter sensor composed of fiber Bragg gratings (FBG) and advanced electrical sensors, capable of real-time monitoring of battery expansion force-displacement, temperature, voltage, current, and internal resistance. More importantly, the smart battery can achieve real-time perception of material phase transitions, state of charge (SOC), and state of health (SOH). Through the joint analysis of dV/dQ, dF/dQ, and dR/dQ, the intrinsic relationship between active-material phase-transition characteristics and the battery's mechanical-electrical response is revealed. By combining multi-source sensing with a lightweight response surface model, an SOC estimation error below 1.02% and an internal-resistance prediction error below 0.5% are achieved, and real-time SOH estimation is realized through the deviation between the predicted and measured internal resistance. Additionally, the multi-parameter and finely detailed smart battery can be easily extended into modules, enabling intelligent monitoring of each cell within the group, which is challenging to achieve in traditional battery systems. At the module level, the smart battery framework further reveals thermal non-uniformity and hotspot migration characteristics among cells, demonstrating its scalability and practical value in refined battery management. The development of smart batteries can significantly improve the quality, reliability, and lifespan of individual cells, avoid the short-board effect on battery system performance, and achieve breakthrough advancements in lithium-ion battery technology.