Utilized Distributed Optical Fiber Sensor with Spiral‐Serpentine Deployment Enabling High‐Precision Full‐Field Temperature Reconstruction and Thermal Management for Pouch Lithium‐Ion Battery

Real-time and accurate temperature monitoring has been widely recognized in both academia and industry to ensure battery operation safety. Traditional techniques are generally limited to incomplete information caused by discrete sampling points. Hence, the spiral-serpentine distributed optical fiber sensor (DOFS) layout is presented to realize in-situ full-range temperature measurement. Unlike conventional contact-based sensors, DOFS offers high spatial resolution with 1.28 mm for comprehensive-accurate monitoring. The proposed deployment enables mapping across the entire surface, rather than being restricted to certain points or localized regions. Meanwhile, the locally adaptive radial basis function interpolation algorithm is developed to reconstruct temperature filed, which aims to ensure the global smoothness and local variability. Uncertainty quantification is incorporated to enhance the results reliability. Experimental studies are conducted on large-format pouch LIBs used in BYD electric vehicles under various currents. The results demonstrate that it can accurately and in real-time capture temperature variations. The developed reconstruction method precisely acquires the full-field temperature distribution with a max standard deviation below 0.3 ℃. Detailed comparison with other six measurement-reconstruction methods such as thermocouple (TC), infrared thermography (IT), Fiber Bragg Grating (FBG) and different-shaped DOFS further highlights the superiority. This work offers significantly valuable insights for optimizing battery thermal management systems.