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Operational factors (e.g., current rate, external temperature) influence the electrochemical reaction rate and heat generation in a lithium-ion battery. Standalone electrochemical models (EM) limit the estimation accuracy by considering only fixed electrochemical parameters.

Thus, an EM coupled with a thermal model (P2D-T) is proposed to understand battery behavior accurately. In the coupled model, the heat generation rate from the P2D model is introduced to the thermal model where the temperature-dependent electrochemical parameters (e.g., rate constant, diffusion coefficient, ionic diffusivity) are updated using Arrhenius expression and returned to the P2D model. The P2D-T is employed for a cylindrical type LiFePO4/Graphite battery design, simulated at different current rates (1C to 5C).

This study aims to demonstrate the relationship (e.g., the sources) between non-linear heat generation terms inside the batteries (e.g., reaction, entropic, ohmic). These relationships help to quantify heat generation term, evaluate thermal sensitivity based on different charge rates. This study provides an understanding the intrinsic battery behavior and thermal sensitivity will help the researchers to design robust safeguards against thermal runaways.