Multi-objective optimization design and experimental investigation for a parallel liquid cooling-based Lithium-ion battery module under fast charging

Abstract

• Parallel liquid cooling system is proposed for a battery module under fast charging. • Sensitivity analysis proves mini-channel depth as the most influential parameter. • Thermal control and energy cost can be enhanced by multi-objective optimization. • Volume energy density gets enhanced by 9.0% after optimization. • Accuracy of the numerical model and optimization is validated by experiments. Enhancing the charging rate capability is beneficial for the driving convenience of electric vehicles. However, high current rate charging causes inevitable severe heat generation, thermal inconsistency, and even thermal runaway. This study proposes a parallel liquid cooling system for a prismatic battery module to achieve the shortest charging interval and thermal safety under fast charging. Furthermore, a surrogate model with the objectives of the thermal performance and energy cost is constructed, the impact of some influential design parameters is explored through sensitivity analysis and response surface analysis. Moreover, a multi-objective optimization design is conducted for the optimal design selection. Finally, the optimal design is validated by experiments under 2.5C fast charging. Results demonstrate that mini-channel depth is the most influential design parameter on the cooling effect (70.8%), the temperature distribution uniformity (75.7%), and the energy cost (86.1%). Volume energy density, maximum temperature ( T max ), temperature standard deviation ( TSD ), and the energy cost ( W ) of the system are enhanced by 9.0%, 2.1%, 23.7% and 26.9%, respectively. Experimental validation proves that T max , TSD , and W of the battery module can be maintained within 33.1℃, 0.9℃, and 17.29 J, respectively. This study guides for the battery thermal management system design with enhanced efficiency and energy cost, especially during harsh operations.