Direct and indirect cooling of Lithium-ion batteries with New manifold designs

• Novel baffled manifolds proposed for liquid-cooled Li-ion batteries. • Indirect cooling with an aluminum frame enhances temperature uniformity. • Maximum temperature reduced by 27.8 °C compared with base design. • Rectangular-cut manifold lowers pressure drop by 44 % compared to the simple one. Uneven temperature distribution and hot spots in lithium-ion batteries (LIBs) accelerate degradation and reduce safety. As electric vehicles (EVs) use increases, efficient thermal management is crucial for their reliable operation. This study introduces two manifold designs—a simple baffled manifold and a rectangular-cut baffled manifold—for liquid-cooled prismatic LIB modules. Three-dimensional numerical simulations are conducted for both direct cooling (DC) and indirect cooling (IDC) configurations under identical operating conditions, with discharge rates of 3C–5C and inlet mass flow rates of 0.005–0.007 kg·s −1 . The base case, a conventional manifold channel without baffles, shows significant thermal inefficiencies. In the DC setup, at the same mass flow rate, the rectangular-cut baffled manifold achieves a 27.8 °C reduction in the maximum battery temperature, while the simple baffled manifold lowers it by 25.5 °C. The rectangular-cut manifold also decreases the pressure drop by 44.3 % relative to the simple baffled case. In the IDC design, at 0.006 kg·s −1 and under a 5C discharge rate, it attains a maximum temperature of 43.8 °C and a temperature non-uniformity of 7.2 °C. The thermal performance index (PI) shows that the IDC–rectangular-cut design has the best heat transfer efficiency at all flow rates and provides a good balance between cooling performance and power use. These findings demonstrate that the inclusion of baffles enhances cooling performance, while temperature non-uniformity is significantly lower in the IDC design compared to the DC configuration. The proposed designs are compact, integrated, and practical for industrial-scale battery modules.