Enhancing Lithium-Ion Battery Cooling Efficiency: A Dual Approach of Internal Electrode Optimization and External Hybrid Battery Thermal Management System

Efficient thermal management is essential for improving the performance, safety, and longevity of lithium-ion batteries (LIB), particularly under high discharge conditions. This numerical study presents an advanced hybrid battery thermal management system (BTMS) that combines internal electrode modifications with external hybrid cooling strategies. Internally, the influence of non-uniform particle size distribution in the active material of both electrodes is analyzed, demonstrating that an optimized particle size gradient can lower the maximum cell temperature by 2.9 K. Externally, a hybrid cooling system incorporating composite phase change material (CPCM) and forced convection using a ternary hybrid nanofluid (Al₂O₃–Fe₃O₄–SiO₂-water) is implemented. The study further examines CPCM placement, revealing that wrapping CPCM around the battery periphery reduces module temperature by 3 K compared to side placement. Additionally, the integration of converging twisting channels in the cold plates significantly enhances convective heat transfer, leading to a 2.9 K reduction in peak temperature. Increasing nanofluid volume fraction (5%) and mass flow rate further optimizes cooling efficiency, achieving a 3.5 K temperature reduction. These findings highlight the potential of combining internal and external thermal management strategies to enhance LIB thermal stability under fast charging and high discharge conditions.