This study employs the isothermal battery calorimetry (IBC) measurement method and computational fluid dynamics (CFD) simulation to develop a multi-domain thermal modeling framework for battery systems, spanning from individual cells to modules, clusters, and ultimately the. This study employs the isothermal battery calorimetry (IBC) measurement method and computational fluid dynamics (CFD) simulation to develop a multi-domain thermal modeling framework for battery systems, spanning from individual cells to modules, clusters, and ultimately the. Computational Fluid Dynamics (CFD), a powerful numerical tool, is extensively used to optimize the design and performance of these enclosures. As the global shift towards renewable energy sources intensifies, a pressing need for battery storage facilities arises. These facilities provide a means to. Computational Fluid Dynamics (CFD) simulation has become a key engineering tool for analyzing, predicting, and optimizing thermal performance within battery enclosures. By modeling airflow, heat transfer, and material conduction, CFD allows engineers to validate and refine designs virtually. This is where BESS shines, by storing renewable energy when supply exceeds demand, and restoring that energy to the grid when needed; the BESS provides the much-needed flexibility and resiliency to the grid. Unlike conventional top–bottom flow systems, this tank operates with two inlets and two outlets that switch between top–bottom.