Design and Experiment of FBG Sensors for Temperature Monitoring on External Electrode of Lithium-Ion Batteries

Lithium-ion (Li-ion) battery becomes a promising energy storage element in the power grid. Temperature monitoring is a key tool to guarantee the safe service and durable life of Li-ion batteries. In this study, an optical fiber sensor was proposed for the temperature monitoring of Li-ion batteries. The proposed sensor consists of a metal ring and a fiber Bragg grating (FBG), which is gloved on the external electrode of the cell. This installation is not only easy to assemble but also no interference to the circuit connection. The results of calibration test on proposed FBG sensors show good linearity (0.99) and high sensitivity (12 pm/°C). A comparison test illustrates the response of proposed FBG sensors has a good agreement with PT100 sensors. The FBG sensor can be fabricated as sensor arrays to monitor the temperature of multiple cells during charge/discharge cycles, simultaneously. The experimental results show that the FBG sensors have good repeatability during several cycles. FBG sensor arrays can be used to achieve distributed temperature measurement for multiple cells. It provides a solution to monitor the thermal behavior of each cell in battery packs and an available tool to improve the thermal management and safety of Li-ion batteries.