Thermal runaway (TR) is considered a significant safety hazard for lithium batteries, and thermal protection materials are crucial in mitigating this risk. However, current thermal protection materials generally suffer from poor mechanical properties, flammability, leakage, and rigid crystallization, and they struggle to continuously block excess heat transfer and propagation once thermal saturation occurs. This study proposes a novel type of thermal protection material: an aerogel coupled composite phase change material (CPCM). The composite material consists of gelatin/sodium alginate (Ge/SA) composite biomass aerogel as an insulating component and a thermally induced flexible CPCM made from thermoplastic polyester elastomer as a heat-absorbing component. Inspired by power bank, we coupled the aerogel with CPCM through the binder, so that CPCM can continue to 'charge and store energy' for the aerogel, effectively absorbing heat, delaying the heat saturation phenomenon, and maximizing the duration of thermal insulation. The results demonstrate that the Ge/SA aerogel exhibits excellent thermal insulation (with a temperature difference of approximately 120 °C across a 1 cm thickness) and flame retardancy (achieving a V-0 flame retardant rating). The CPCM exhibits high heat storage density (811.9 J g