This thesis presents a comprehensive study on the Immersive Cooling Battery Thermal Management System (BTMS), highlighting the critical role of supporting BTMS design with advanced Computational Fluid Dynamics (CFD) analysis. The primary objective is to define and experimentally validate a robust methodology for designing the hydraulic layout of such systems, ensuring optimal thermal management to maintain battery performance and safety. Extensive benchmarking has revealed that achieving a temperature gradient as ambitious as 3°C within the cell and the entire battery pack is currently unattainable. However, a thorough review of existing literature shows that a more widely accepted and achievable target is a maximum temperature difference of 5°C within individual cells and 10°C at the module level.