Optimizing Inlet/Outlet Configuration in a Forced-Convective Immersion-Cooled 1P52S Battery Module: A Numerical Study

The growing integration of renewable energy has intensified demand for advanced storage systems to stabilize grids and improve efficiency. Lithium-ion batteries, however, generate considerable heat during high-power cycling, which reduces performance and may trigger thermal runaway. Efficient thermal management is therefore essential for safety and reliability. This study numerically analyzes the thermal behavior of high-energy-density lithium iron phosphate batteries (1P52S module) under constant power discharge, comparing four immersion cooling layouts (top-in–bottom-out/bottom-in–top-out, middle/double-sided). Results show that under low-power (1P) discharge, the middle top-in–bottom-out design (Case 1) best suppresses maximum temperature, while the double-sided top-in–bottom-out layout (Case 2) performs better at high-power (2P), reducing peak temperature by 3.46 K. Although the middle bottom-in–top-out layout (Case 3) lowers pressure drop via gravity assistance, it produces local hot spots with large temperature differences. Moreover, at 30 L/min, the cooling benefit diminishes, while heat generation accelerates at the start and end of discharge. These findings highlight trade-offs between cooling effectiveness, flow resistance, and temperature uniformity, offering design guidance for optimizing immersion cooling channels and pump power to balance thermal control, efficiency, and economy.