1. Background of 5G Smart Terminal Cooling Requirements

1. 5G technology features lead to intensified heat issues

• 5G networks operate at higher frequencies and offer faster data transmission rates compared to 4G. The transmission of high-frequency signals increases the workload of core components like chips, as they need to process more complex signals and consume more power in the 5G communication process. According to the law of conservation of energy, much of this additional power is converted into heat. For example, 5G smartphones experience a significant increase in chip power consumption when performing high-speed data downloads or uploads, potentially generating 30% - 50% more heat than in 4G states.

• 5G smart terminals need to integrate more radio frequency (RF) components to support multi-antenna technology. These RF components also generate heat when working, and they influence each other in the narrow internal space of the terminal, which makes it easy for heat to accumulate.

2. Performance boost vs. heat generation

• 5G smart terminals, in order to provide a better user experience, are often equipped with high-performance components such as more powerful processors and high-resolution displays. The improvement in processor performance means higher clock speeds and moretransistorsintegrated, which can lead to increased power consumption and thus more heat generation. For example, some high-end 5G smartphones use high-performanceSnapdragon or Kirin processors, which may quickly rise to 40 - 50 degrees Celsius in temperature when running large games or multitasking.

2. Types and characteristics of thermal conductivity materials

1. GraphiteHeat sink

• Principle: Graphite heat sinks mainly use the high thermal conductivity of graphite to achieve heat dissipation. Graphite has a layered structure, within the layerscarbon atomsare connected throughcovalent bonds, and electrons can move freely, allowing heat to be rapidly conducted within the layers. Its thermal conductivity can reach 1000 - 1500 W/(m・K).

• Advantages: It is very light and thin, and can be well attached to the heat-generating components inside the smart terminal, such as chips and batteries, etc. For example, in many lightweight and thin 5G mobile phones, the graphite heat sink can be placed on the back of the mainboard, effectively conducting the heat generated by the chip out, and it will not occupy too much space, and will not have a great impact on the lightweight and thin design of the terminal. At the same time, it has good flexibility, and can be bent and attached according to the complex shape inside the terminal.

• Limitations: The thermal conductivity of graphite heat sinks is relatively weak in the direction perpendicular to the graphite layers, so for some cases where heat needs to be diffused in multiple directions, the use of graphite heat sinks alone may not meet the requirements.

2. Thermal Conductive Gel

• Principle: Thermal grease is a filler material, the main components of which arehigh molecularpolymers and high thermal conductivity fillers. It reduces thermal resistance by filling the tiny gaps between the heat-generating components and the heat-dissipating components, achieving effective heat transfer. Its thermal conductivity is generally in the range of 1 - 10W/(m・K).

• Advantages: It has good flexibility and plasticity, which can adapt to different shapes of contact surfaces, ensuring a close fit between the heat source and the heat sink. For example, in the chip packaging process of 5G smart terminals, the thermal grease can fill the gaps between the chip and the heat sink, effectively improving the efficiency of heat transfer from the chip to the heat sink. Moreover, it has a certain shock-absorbing buffer effect, which can protect precision components such as chips from the influence of external vibrations.

• Limitations: The thermal conductivity of thermal grease is relatively low, and for some components with high heat generation density, it may not be able to quickly conduct heat away, and in the long term, issues such as drying and aging may arise, affecting the heat dissipation performance.

3. Heat pipe

• Principle: A heat pipe is an efficient heat dissipation device that utilizes the processes of vaporization and liquefaction. It contains a capillary structure and a working liquid. When the evaporating end of the heat pipe is heated, the liquid vaporizes, and the steam flows through the hollow channel inside the heat pipe to the condensing end. At the condensing end, the steam cools and liquefies, and then it returns to the evaporating end through capillary action, thus completing the cycle. This process quickly transfers heat from the heat source to the dissipation end. Its thermal conductivity can reach 1000 - 5000 W/(m・K).

• Advantages: The heat pipe has a very high heat dissipation efficiency, which can transfer a large amount of heat from one place to another in a short period of time. In 5G smart terminals, it is often used to dissipate heat from components such as high-heat-generating processors and 5G chips. For example, in some gaming phones, the heat pipe can quickly conduct the heat generated by the processor to the edges of the phone or to the heat sink on the back cover for heat dissipation, effectively reducing the temperature of the processor and ensuring the stable operation of the game.

• Limitations: The structure of the heat pipe is relatively complex, costly, and requires a certain amount of installation space. In the miniaturization of 5G smart terminals, its layout may be limited, and the performance of the heat pipe can be affected by factors such as the installation angle.

Three, specific solutions for heat-conducting and heat-dissipating materials in 5G smart terminals

1. Multi-layer heat dissipation structure design

• Scheme Description: The method of using a combination of multi-layer different thermal conductivity materials is adopted. For example, in a 5G mobile phone, the graphite heat sink is placed on the *** layer close to the chip and other heat-generating components, using its good plane thermal conductivity to preliminarily diffuse the heat; then, thermal grease is filled between the graphite heat sink and the heat sink of the mobile phone back cover or frame to further reduce the thermal resistance and transfer the heat to the external heat sink; for components with high heat generation, such as 5G chips and processors, heat pipes can be installed under or next to them to quickly transfer the heat to positions with better heat dissipation, such as the edge of the mobile phone.

• Advantages: Through this multi-layer structure, the advantages of different thermal conductivity materials can be fully brought into play, forming an efficient heat dissipation system. It can effectively meet the heat dissipation needs of different heating components inside 5G smart terminals, reduce the overall temperature, and improve the stability and service life of the equipment. For example, after the optimization of the multi-layer heat dissipation structure, the 5G mobile phone can control the temperature within a reasonable range during long-term 5G data transmission or running large applications, avoiding performance degradation or equipment damage due to overheating.

2. Customized cooling solution

• Design Description: Customized cooling solutions are designed based on the different types of 5G smart terminals (such as smartphones, 5G tablets, 5G smart watches, etc.) and different application scenarios (such as gaming, office work, video calls, etc.). For gaming-oriented 5G smartphones, since the processor and graphics processing unit (GPU) will generate a lot of heat when running games, it is necessary to focus on strengthening the cooling around these components. A combination of thicker graphite heat sinks, high-performance heat pipes, and high thermal conductivity coefficient thermal grease can be used, and the layout of the heat pipes can be optimized to quickly transfer heat from the processor and GPU. As for 5G smart watches, since the internal space is smaller, it is necessary to choose lighter and more efficient thermal conductivity materials, such as ultra-thin graphite heat sink film and micro heat pipes, and arrange the cooling path reasonably to conduct heat from the chips and batteries and other heat-generating components in the watch to the straps or cases of the watch, which are the cooling parts.

• Advantages: Customized heat dissipation solutions can better meet the heat dissipation needs of different 5G smart terminals, improving heat dissipation efficiency without significantly increasing the volume and weight of the terminal. This can provide a better user experience under the premise of ensuring device performance, such as maintaining the fluency of the game in the game scenario, and not affecting the comfort of wearing in the process of using the smart watch due to overheating.