Optimization of guide plates and orifice plates on thermal management of battery energy storage system

•A combined duct with guide plate and orifice plate is proposed for battery system.•Optimize the structure of guide plate and the porosity of orifice plate.•After optimization, air supply uniformity coefficient is reduced to 6.29%.•After optimization, temperature uniformity of battery system is improved 74.94%. The performance, state of health and lifetime of the battery energy storage system (BESS) depend heavily on the temperature uniformity between batteries. The BESS is more prone to uneven temperature distribution due to the inclusion of more battery modules. Improving the air supply uniformity of each battery module is the key to ensure the temperature uniformity of the system. In order to solve the problem of uneven air supply in traditional duct, the present study proposes a composite duct structure with optimized L-type guide plates and orifice plates. Based on the orthogonal analysis method, the optimization of guide plate structures in the sub duct and the main duct is completed. Combined with power consumption analysis, the porosity of orifice plates in the ducts is determined. The results show that when guide plates and orifice plates are in the best design condition, compared with the initial scheme, the air supply uniformity coefficient of the BESS is reduced from 75.07 % to 6.29 %. The air supply uniformity of the system is increased by 91.62 %. The maximum temperature difference of the BESS is reduced from 17.36 K to 4.35 K. The temperature uniformity of the system is increased by 74.94 %. This study is helpful to the design and optimization of the duct for the thermal management system of BESS in the future.