Electrically driven chip cooling device using hybrid coolants of liquid metal and aqueous solution

Heat dissipation of electronic devices keeps as a tough issue for decades. As the most classical coolant in a convective heat transfer process, water has been widely adopted which however inherits with limited thermal conductivity and relies heavily on mechanical pump. As an alternative, the room temperature liquid metal was increasingly emerging as an important coolant to realize much stronger enhanced heat transfer. However, its thermal capacity is somewhat lower than that of water, which may restrict the overall cooling performance. In addition, the high cost by taking too much amount of liquid metal into the device also turns out to be a big concern for practical purpose. Here, through combining the individual merits from both the liquid metal with high conductivity and water with large heat capacity, we proposed and demonstrated a new conceptual cooling device that integrated hybrid coolants, radiator and annular channel together for chip thermal management. Particularly, the electrically induced actuation effect of liquid metal was introduced as the only flow driving strategy, which significantly simplified the whole system design. This enables the liquid metal sphere and its surrounding aqueous solution to be quickly accelerated to a large speed under only a very low electric voltage. Further experiments demonstrated that the cooling device could effectively maintain the temperature of a hotpot (3.15 W/cm²) below 55ºC with an extremely small power consumption rate (0.8 W). Several situations to simulate the practical working of the device were experimentally explored and a theoretical thermal resistance model was established to evaluate its heat transfer performance. The present work suggests an important way to make highly compact chip cooling device, which can be flexibly extended into a wide variety of engineering areas.