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 monitoring of battery surface temperature is widely recognized as essential for ensuring operational safety. By synergistically combining high‐resolution sensing‐interrogation systems, optimized DOFS deployment scheme, and intelligent reconstruction algorithms, this study achieves full‐range and high‐fidelity temperature field reconstruction with an error below 0.3 °C, offering critical guidance for the next‐generation battery design and thermal management systems optimization. Abstract 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. Real-time and accurate monitoring of battery surface temperature is widely recognized as essential for ensuring operational safety. By synergistically combining high-resolution sensing-interrogation systems, optimized DOFS deployment scheme, and intelligent reconstruction algorithms, this study achieves full-range and high-fidelity temperature field reconstruction with an error below 0.3 °C, offering critical guidance for the next-generation battery design and thermal management systems optimization. Abstract 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. Advanced Science, Volume 12, Issue 44, November 27, 2025.