Application of Graphene in Heat Conduction and Heat Dissipation

      Since its discovery, graphene has been known as the "king of new materials" because of its excellent performance, excellent application scenarios and unparalleled position in the industrial field. At present, the research and development direction of graphene industry is to continuously expand the application of emerging industries around the national demand for new generation of display devices, big health, environmental protection, high-end manufacturing and other strategic emerging industries, and its application in the field of heat conduction and heat dissipation is one of the leading directions.

      The heat management of electronic components is undoubtedly very important to the development of information and intelligent society. With the rapid development of information technology, chip power consumption has increased significantly, and heat management has become a key part. The speed of heat export determines whether the chip can operate normally. The heat dissipation film with high thermal conductivity is the key material in this field and an effective means to achieve high efficiency heat management. According to the statistics of authoritative market research institutions, the global market of thermal interface materials will reach US $1.343 billion in 2022. Therefore, the development of high-performance and low-cost heat dissipation film materials has become the key to many fields such as consumer electronics, information technology and artificial intelligence. Andre Heim said: "graphene has high conductivity and thermal conductivity, and its chemical structure is very stable. It is an ideal new material for heat conduction and heat dissipation."

1、 Heat dissipation of graphene mobile phone:

     The heat dissipation of mobile phone is a big problem that perplexes the development of mobile phone. Now, the mainstream way of heat dissipation in mobile phones is graphite. Graphite heat sink distributes the central temperature of mobile phone heating to a large area, so as to evenly heat. Part of the mobile phone with metal shell also increases the heat dissipation of metal back. But once the mobile phone temperature is higher than the normal standard, the mobile phone will be stuck, slow response and other problems. In the past, manufacturers used to control the mobile phone temperature through a large area of metal backplane, limiting the maximum temperature, and the effect is not satisfactory.

      Although the name of graphene heat dissipation technology is similar to that of graphite sheet, its actual performance is quite different. The thermal conductivity of graphene is 5300w / (m · K), which is the highest known thermal conductivity material. Its heat dissipation efficiency is much higher than the current commercial graphite heat sink. It can be said that graphene is the most ideal heat dissipation material for smart phones and other electronic products.

2、 Graphene LED heat dissipation:

      With the development of science and technology, light-emitting diode (LED) is popular all over the world because of its high brightness, low energy consumption, long life cycle and other advantages. It has rapidly replaced incandescent lamp and fluorescent lamp in many application fields. But led will not radiate heat spontaneously, LED will produce a lot of heat at the junction of semiconductor. After a long time of heat accumulation, the service life of LED will rapidly decline, even low-power LED will have this problem. With the demand of higher power for LED lamp and its lighting equipment, how to control the temperature of LED surface has become a big challenge for large-scale application of LED. Because the structure of LED filament lamp has no redundant heat dissipation structure, it can only rely on gas and shell heat dissipation. According to the three elements of heat conduction (conduction, convection and radiation), at present, the filament lamp has no conduction, only convection and radiation. But it is mainly convective heat dissipation, and the proportion of radiation is very small. If we import the technology of graphene into filament lamps and use the thermal radiation characteristics of graphene to increase the heat dissipation of filament lamps, we can extend the service life of filament lamps.

     In order to verify the thermal radiation performance of graphene, a comparative test was carried out on the same copper sheet coated with graphene and uncoated to test the radiation performance of blackbody. Through image observation, we can see that the area coated with graphene has very obvious thermal radiation characteristics, no area coated with graphene, no obvious thermal radiation characteristics. When graphene is coated on the surface of copper foil or aluminum foil, the results of thermal imaging experiments are consistent, so graphene has better thermal radiation characteristics. Based on the experimental results, graphene is used on the metal substrate at the back of the filament. The heat generated by LED heating is radiated out through graphene. At the same time, the conduction gas in the bubble shell is used to realize effective convection and reduce the temperature. According to the comparison between graphene coated graphene and graphene free products, it can be seen that the junction temperature of the graphene coated chip is 3~5 degrees lower than that of the non coated graphene, which can obviously reduce the junction temperature of the chip and prolong the life of the filament.

      At present, with the gradual maturity of LED market and the increasingly fierce competition, how to reduce the cost, improve the service life of LED, and then create a higher performance LED products has become the direction and goal of enterprises. Applying graphene to LED field, "graphene + led" will bring a new bright spot for the development of LED industry. At present, the new LED bulb based on graphene technology developed by the national graphene Research Institute of Manchester University in the UK has a longer service life and lower average price, which has played a pioneering role in the application of graphene in the LED field. The relevant graphene teams of Tsinghua University and Beijing Institute of Technology have also increased the research and development of graphene in the LED application field.

       Although graphene heat dissipation technology will subvert the traditional heat dissipation mode, to realize its application in industrial products, it needs to invest a lot of costs and manpower for research and development, so this technology is undoubtedly beyond the reach of enterprises with weak R & D strength. Therefore, it is particularly important to strengthen the cooperation among graphene research institutions, manufacturers and downstream manufacturers. Focus on the stone that can solve practical problems