Researchers from China's Zhejiang University have developed a new thermal management system to prevent thermal runaway of Li-ion battery (LIB) cells, using hyperbolic graphene phase change composites. This addresses the safety concerns of LIB cells, mainly caused by thermal runaway. While phase change material systems already exist, the unresolved trade-off between high power and energy density greatly limits its practical applications.
The newly developed thermal management system relies on a composite material that consists of hyperbolic graphene framework and paraffin, and reportedly exhibits an impressive thermal conductivity of ∼30.75 W/mK at 12.5 wt% graphene loading and ultrahigh retention (90%) of latent heat, beyond that of most of the reported phase change composites.
The team describes the paraffin-graphene composite (PGC), that shows almost three-folds improvement of efficient energy density at high power density compared with commercial paraffin.
The temperature of a battery pack in series at 3.75 C rate capability is less than 60℃ with protection of PGC system, far below ∼120℃ of bare battery pack. The PGC system expands the usability and safety of Li-ion batteries and provides a reliable battery thermal management strategy towards extreme fast-charging goals.