Research on the application of eutectic hydrated salt phase change microcapsules with excellent latent heat properties in battery thermal management

In the context of the widespread application of new energy vehicles, lithium-ion batteries have become a key factor restricting the development of new energy due to safety issues such as fire and explosion caused by high temperatures. This study proposes a novel phase change microcapsule (EG@DH-SC), which consists of expanded graphite (EG) encapsulating the eutectic hydrate salts Na2HPO4·12H2O (DHPD) and Na2CO3·10H2O (SCD), aimed at alleviating the thermal runaway phenomenon of batteries through a solid-liquid phase change mechanism. The EG@DH-SC demonstrates excellent leakage prevention performance, thermal conductivity (3.62 W/m·K), battery thermal management (BTM) compatibility (Th = 33.1 °C, ∆Hh = 178.5 J/g), and thermal cycling stability. Under simulated conditions of 4 C discharge at 20 °C, when the original battery temperature reaches 54.6 °C, the temperature of the phase change material (PCM) battery is only 51.2 °C. The efficient thermal regulation of EG@DH-SC maintains the battery temperature within a safe window, preventing and mitigating the risk of thermal runaway. In summary, the PCM designed in this study exhibits outstanding cycle stability, thermal conductivity, and latent heat characteristics, providing an innovative control strategy for BTM.