Efficient thermal management is essential for maintaining the performance and safety of large-capacity battery packs. To overcome the limitations of traditional standalone air or liquid cooling methods, which often result in inadequate cooling and uneven temperature distribution, a hybrid air-liquid cooling structure was designed. A three-dimensional model was developed, and heat transfer and fluid flow characteristics were analyzed using computational fluid dynamics (CFD) simulations. Experimental validation was carried out through discharge temperature rise tests on individual battery cells and flow resistance tests on the liquid cooling plate. The thermal performance of the hybrid system was compared to that of standalone cooling methods under various discharge rates. The results indicated that the hybrid system significantly enhanced cooling performance, reducing the maximum temperature difference by 5.54°C and 3.37°C, and the peak temperature by 11.66°C and 4.5°C, compared to air and liquid cooling, respectively, at a 0.8C discharge rate. The effects of key parameters, such as coolant flow rate, fan speed, channel width, and channel depth, on cooling performance were investigated. A turbulence-inducing structure was proposed to further improve cooling efficiency. The optimized system maintained peak temperatures and temperature differences below 35°C and 5°C, respectively, at a 0.5C discharge rate, with a reduction in pressure drop by 14.50 kPa. This study proposes an effective hybrid air-liquid cooling solution, providing valuable insights for the thermal management design of battery packs.