Large format lithium-ion batteries are widely used for electric vehicles and battery energy storage applications. Detection of temperature distribution for prismatic cell format is critical for early detection of thermal runaway. This study presents a distributed temperature monitoring (DTM) framework for prismatic lithium-ion batteries, addressing critical limitations in conventional single-point thermal sensing. A Multiphysics model is developed to assess the thermal gradient during normal charge/discharge cycling and during thermal runaway. The model is validated with 72 Ah LiFePO4 cell experimental data 0.5 C – 2 C rate and oven test at 150 to 25 ͦC. The predictions were in good agreement with experimental thermocouple data, showing less than 5% deviation
The developed multiphysics model successfully captured the spatial temperature distribution across the prismatic 72 Ah LiFePO₄ cell under various C-rates and thermal abuse scenarios. During normal cycling (0.5C–2C). Under thermal abuse conditions (oven heating from 150°C to 250°C), the model accurately predicted the onset location and propagation pattern of thermal runaway, including a steep temperature rise beyond 210°C. The DTM framework demonstrated early detection capability—identifying critical thermal deviations before conventional point sensors registered hazardous temperatures. This highlights the effectiveness of spatially resolved temperature monitoring for enhancing battery safety.
