Multi-Objective Optimization Design for Marine Battery Pack Immersion Cooling System

ObjectivesThis study optimizes the structure and thermal performance of an immersed liquid cooling system to enhance thermal management and temperature uniformity in large-capacity marine battery packs under high-rate discharge. MethodsA thermal model of a square LiFePO₄ battery was developed and validated experimentally. CFD simulations analyzed the effects of inlet/outlet layout, number of injection holes, battery spacing, flow velocity, and coolant type. Multi-objective optimization using the Kriging model and NSGA-Ⅱ algorithm was applied to minimize maximum temperature and temperature difference. ResultsA three-injection-hole configuration reduced the maximum temperature by 9.5% and the maximum temperature difference by 24.9%. A 10 mm lateral spacing decreased the maximum temperature difference by 52.0%. At 1.5 m/s flow velocity, the maximum temperature and temperature difference were reduced by 16.9% and 45.1%, respectively. Using ionic water instead of synthetic oil lowered the maximum temperature and temperature difference by 18.3% and 73.4%. The optimized system achieved a maximum temperature of 23.62°C and a maximum temperature difference of 3.33°C, with errors below 2.5%. ConclusionThe optimized immersed liquid cooling system significantly improves thermal safety and temperature uniformity, providing valuable insights for designing cooling systems for large-capacity battery packs.