For the purpose of investigating the air-cooling heat dissipation system of lithium-ion battery cabin,based on the simulation model of the actual battery cabin,the optimization scheme of air-cooling heat dissipation is designed. Due to the thermal characteristics of lithium-ion batteries,safety accidents like fire and explosion happen under extreme conditions. Effective thermal management can inhibit the accumulation and spread of battery heat. However,the existing battery cabin air cooling system is relatively simple and the heat dissipation efficiency is low. In order to optimize the heat dissipation system,deflectors are installed in the battery cabin to change the temperature field and flow field in the cabin. When the environment temperature is 25 ℃ and the wind speed is 4 m/s,the air-cooling heat dissipation system of 1 C charging battery cabin is conducted. The results show that by adding one deflector can reduce the average and the maximum temperature in the battery cabin by 2.9 ℃ and 4.5 ℃ respectively. Adding two deflectors can reduce the average and the maximum temperature in the battery cabin by 5.5 ℃ and 8.6 ℃ respectively. Reasonable deflector arrangement can optimize the air-cooling heat dissipation system,improving the heat dissipation efficiency and the safety of battery cabin operation.