In-situ monitoring of internal temperature and strain of solid-state battery based on optical fiber sensors

As an emerging battery, solid-state battery has broad development and application prospects. The safety and stability of the battery cannot be monitored in real-time during the work process. In this work, we fabricated solid electrolytes, assembled solid-state battery and proposed a method to monitor internal real-time temperature and strain information by embedding short fiber Bragg gratings in the battery. The experimental results show that the maximum temperature change is 0.42 °C and the maximum strain change is 11.5 με during the charging and discharging processes of the battery, and the formation of lithium dendrites is observed. This method enables real-time online in-situ monitoring of temperature and strain in solid-state battery and explains the causes of strain at the microscopic level, which is critical for the safe use of the battery. • Optical fiber sensors embedded in solid-battery for in-situ measurements. • Real-time monitoring of temperature and strain. • To explain the formation of strain at the microscopic level. • To optimise of battery designs and to promote solid-battery safety improvement.