A Novel Room-Temperature Flexible Phase Change Material for Solar Energy Photothermal Conversion and Battery Thermal Management

In recognition of their excellent capacity for regulating thermal energy storage and release, phase change materials (PCMs) have been rediscovered and received growing significance in advanced solar energy storage and battery thermal management (BTM). Nevertheless, their insufficient thermal conductivity, poor shape stabilization, and high rigidity hinder their application in BTM systems. Herein, we reported a novel stable ordinary temperature flexible phase change material (FPCM) basis of paraffin wax (PW), polyolefin elastomer (POE), and expanded graphite (EG), which efficiently solves the aforementioned problem. And then, through flexibility, the FPCM was smartly mounted on the power batteries by overfilling, making the components compact and efficient. Thermal contact resistance (TCR) while operating the battery pack could be decreased by the flexible wrapping of the FPCM. Results show that the above BTM assembly effectively reduced the TCR to 0.28 °C/W. This FPCM-based reactive cooling BTM ensures that the temperature of the battery pack is kept under a safe temperature (55 °C) at all times. With the effect of EG, the prepared FPCM exhibits a substantial improvement in thermal conductivity, achieving 1.929 W/mK, as well as a prominent photothermal efficiency of conversion (91.2%). Notably, its ultraflexibility, high thermal conductivity, and excellent latent heat provide a convenient way for the thermal management packaging of complex and multimodel electronic devices.