A biomimetic melting-evaporation cooling bilayer for efficient thermal management of ultrafast-cycling batteries

Ultrafast-cycling batteries is starving for efficient thermal management means. Passive battery thermal management system (BTMS) offers many advantages over the active one including energy saving, cost-effectiveness, less weight, and reduced space. However, the trade-off between thermal conductance and thermal capacity of passive cooling materials makes it difficult to achieve rapid thermal response and durable temperature control simultaneously. Herein, a hybrid BTMS inspired by body heat dissipation is reported by employing a melting-evaporation bilayer, which integrates the high thermal conductivity of graphite-based form-stable phase change composites with high enthalpy-change of moisture sorption materials. Experimental results show that the BTMS exhibits excellent cooling effect for Li-ion batteries at extremely high operation rates. The surface temperature of the ultrafast-cycling batteries is decreased by 35.6 °C under 15 C discharge by using the cooling bilayer and the maximum equivalent average cooling power could reach up to 2.49 kW m −2 . Consequently, the available capacity of the batteries is greatly increased by 244.43Ah for 318 ultrafast charge/discharge cycles. Moreover, the cooling bilayer shows commendable fire-resistant characteristics, significantly retarding the thermal runaway. This work provides an energy-saving and self-adaptive cooling solution for high heat-flux devices beyond the ultrafast-cycling battery.