The Fabrication And Thermal Management Application Of Flexible Carbon-based Nanomaterials

In recent years,with the fast development of wearable devices,the need of a higher performance of wearable devices also grows.But,in the meanwhile,with the failure of Dennard's law,the power density of multi-core processors is also growing very fast;on the other hand,the temperature threshold of wearable devices is greatly limited;last,due to the increasing core number of wearable devices' chips,the hotspot generated by the uneven distribution of active cores are inevitable.All these factors not only make the heat dissipation of wearable devices very challenging,but also greatly limit the potential growth of the wearable devices' performance.For this demand,we propose to use new flexible material to assist the heat dissipation of wearable devices by conduction heat from chip to flexible heat sink composed of such material.We research on the fabrication of flexible heat dissipation material based on the carbon-based nanomaterials and the structure of flexible heat sink,we also design thermal management algorithm for such design,both of them can greatly improve the performance of wearable devices with the same temperature threshold,which is verified by experiments.In this paper,the fabrication of the composite heat dissipation material based on the doping of carbon-based nanomaterial and the thermal conductivity and mechanical properties of the material in different doping ratio are tested and analyzed,the experiments results show: the modification of KH570 on doping materials can effectively improve the dispersion of the materials,therefore improving the thermal conductivity and mechanical properties of the composite material.By using the synergistic effect of CNT and graphene,the thermal conductivity of composite material can be greatly improved.The test results show,the improvement of thermal conductivity of mixed doping materials on composite materials is maximum at the ratio of 2:3 for CNT and graphene;as the doping concentration improves,the elongation at break for composite material peaks and then gradually goes down;the composite material reaches the best thermal conductivity and elongation at break when the doping concentration is 8wt%,the thermal conductivity of composite material is 3.35W/m K,the elongation at break is 118%.Then,the flexible heat sink based on such flexible heat dissipation material is made by simulating on different heat sink structures and experiments.The simulation results of flexible heat sink show that,at a height a 1.25 mm,the pillar-structure heat sink with a twisted distribution has the best heat dissipation capability,compared to traditional watch band made of fluoro-rubber,our flexible heat sink can increase the power budget of the chip of the smart watch by 11%.Finally,a thermal management algorithm based on greedy strategy is designed and tested.The thermal management algorithm of this paper shows that,compared to the case of tradition wearable devices,the flexible heat sink along with the greedy strategy based thermal management can improve the performance of the devices by 20% in the same thermal threshold.