High-Accuracy and Resolution Fluorescence Intensity Ratio Thermometer for Real-Time Temperature Monitoring in a Lithium-Ion Battery

ion codoping and used to construct a high-accuracy and resolution FIR thermometer for real-time temperature monitoring in LIBs. The temperature measurement accuracy and resolution are ±0.1 and 0.01 K, respectively. The thermal response time for a temperature difference of 100 K is 1.14 s. The as-built optical fiber sensing probe was implanted in the anode sheet of a 2000 mAh pouch LIB, and the internal temperature at different charging rates was determined. The maximum temperature rise was 25.30 K at a 5C charging rate. This work provides a new attempt from material design to device applications that is expected to lay the foundation for the practical utilization of ratiometric temperature sensors.