Thermal management in high-power lithium-ion Batteries: Synergistic effects of phase change material thickness, graphene enhancers, and active cooling systems
S. Rahmanian, Hossein Rahmanian‐Koushkaki, Kh. Hosseinzadeh
Abstract
Effective thermal management is critical to mitigating thermal runaway risks, optimizing performance, and extending the operational lifespan of lithium-ion batteries (LIBs) in high-rate applications. This study systematically evaluates four thermal management strategies for a 14.6 Ah LIB under aggressive discharge currents (1C, 3C, 5C): (1) baseline (no thermal control), (2) phase change material (PCM) with thickness variations, (3) hybrid PCM-K-enhancer (copper foam, graphene, metal plates) systems, and (4) active cooling (heat pipes + forced air convection). High-fidelity 3D simulations in ANSYS Fluent V22 quantified temperature uniformity, peak temperature suppression, and transient phase change behavior. At 5C discharge, baseline tests revealed unsafe peak temperatures of 84.03 °C. PCM thickness optimization demonstrated a nonlinear cooling effect: 1 mm PCM reduced peak temperature to 66.91 °C, while 3 mm PCM achieved 55.38 °C, underscoring the role of latent heat capacity scaling. Graphene-based K-enhancers outperformed copper foam and metal plates, synergizing with PCM to limit temperatures to 47.82 °C through thermal bridging. Synergistic integration of optimized PCM thickness (2 mm), graphene-enhanced thermal bridges, and heat-pipe cooling achieved a 53.3 % temperature reduction vs. baseline (39.23 °C). The study introduces a hierarchical thermal management framework, demonstrating that hybrid systems integrating optimized PCM thickness, graphene-enhanced interfacial conductivity, and active cooling achieve superior thermal equilibrium. These findings advance the design of multi-scale thermal regulation strategies for high-power LIB packs in electric vehicles.