Recent Advances in Phase Change Materials for Thermal Management of Lithium-Ion and Emerging X-Ion Batteries: A Review

The rapid global transition toward electric vehicles (EVs) demands lithium-ion battery (LIB) systems that ensure both extreme performance and uncompromising safety. However, the inherent thermal asymmetry within battery packs—driven by non-uniform heat generation and localized hotspots—remains a critical bottleneck, accelerating degradation and triggering thermal runaway. Phase change materials (PCMs) have emerged as pivotal thermal buffers due to their high latent heat capacity and ability to maintain passive thermal symmetry. This review provides a comprehensive analysis of recent advancements in PCM-based battery thermal management systems (BTMSs), transitioning from material-level nanostructural enhancements to system-level hybrid architectures. Unlike traditional reviews, we critically evaluate how the integration of multidimensional conductive fillers and advanced encapsulation technologies resolves the trade-offs between energy density and thermal response rates. Furthermore, the synergistic coordination between PCMs and active cooling strategies (liquid, air, and heat pipes) is synthesized to provide a roadmap for achieving global thermal equilibrium under extreme fast-charging (XFC) conditions.