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Analysis of essential heat-conductive graphite sheets for smartphones!

With the development of the industry, smartphones are becoming more intelligent, with higher configurations and faster computing speeds. The CPU frequency will also continue to increase. For multi-functional and multi-tasking smartphones, such as those running large software or games for extended periods of time, the temperature of components like the CPU and LCM can rise, leading to a significant decrease in performance. Just like any electronic device, these components can function properly and durably only within an appropriate temperature range. Therefore, heat dissipation is important not only to prevent damage to these components but also to ensure their optimal performance. Additionally, communication components like WiFi generate a significant amount of heat due to signal transmission and reception. If the temperature becomes too high, the phone will activate its self-protection mechanism and automatically shut down, which also affects normal usage.

Now, imagine a scenario where a user is playing a game at its climax or watching an intense scene in a movie when suddenly the phone crashes. This would lead to frustration and a loss of trust in the phone brand. It is evident that in order to meet higher user demands, smartphones need to have efficient heat dissipation systems.

Heat Transfer Methods:

1. Conduction: Heat exchange through molecular collision between particles with lower and higher energy levels.

2. Convection: Heat transfer through the movement of matter. Forced convection can be achieved by adding fans to heat sinks.

3. Radiation: Direct dissipation of heat from a heat source in the form of electromagnetic waves.

These three heat dissipation methods are not isolated, as they all occur simultaneously and work together in daily heat transfer.

Common Heat Dissipation Methods:

1. Natural Heat Dissipation: Heat dissipates into the atmosphere through conduction and radiation under natural environmental conditions. Traditional phones we use today do not require special heat dissipation measures and rely on natural heat dissipation.

2. Heat Sink Heat Dissipation: Commonly used in computer CPUs and graphics cards.

3. Air Cooling: Also known as forced convection, it uses fans to force airflow and dissipate the heat from the heat source into the atmosphere.

4. Water Cooling: Heat is carried away by water or other liquids. This method is commonly used in internal combustion engine cooling systems.

5. Heat Pipe Cooling: Heat is transferred from one end of a heat pipe to the other, and then dissipated by a heat sink. Copper pipes are commonly used for CPU cooling in laptops.

6. Compression Cooling: This method is already familiar to us. Refrigerators, air conditioners, and other cooling devices use compression cooling in our daily lives.

Heat-Conductive Graphite Sheets:

Graphite thermal films, also known as heat-conductive graphite sheets, are a nano-advanced composite material that allows uniform heat conduction on any surface. They also provide EMI electromagnetic shielding effects.

The main chemical composition of graphite thermal sheets is carbon (C), a natural element and mineral obtained through chemical methods at high temperatures and pressures. Carbon, a non-metallic element, exhibits electrical and thermal conductivity similar to metal materials. It also possesses the plasticity of organic plastics, along with unique thermal properties, chemical stability, lubrication capabilities, and the ability to be applied to solid surfaces. Graphite thermal sheets exhibit ultrahigh thermal conductivity in the range of 150-1500 W/m-K within their plane.

Key features of graphite thermal sheets include: extremely high thermal conductivity, easy handling, low thermal resistance, and lightweight. These sheets are widely used in the heat dissipation applications of communication industries, medical equipment, SONY/DELL/Samsung laptops, smartphones, PC memory modules, LED substrates, and more.

By utilizing the plasticity of graphite, it can be made into thin sheets resembling stickers, which can be attached to the circuit board inside a phone. Specifically, graphite thermal sheets serve the purpose of conducting heat and evenly distributing it on the surface, indirectly achieving the goal of heat dissipation.

Features of heat-conductive graphite sheets:

(1) The surface can be combined with other materials such as metal, plastic, and adhesive to meet various design requirements and functions.

(2) Low thermal resistance: 40% lower thermal resistance compared to aluminum and 20% lower than copper.

(3) Lightweight: 25% lighter than aluminum and 75% lighter than copper.

(4) High thermal conductivity: Graphite thermal sheets can be smoothly attached to any flat or curved surface and can be cut into any desired shape according to customer requirements.

Comparison of Thermal Conductivity:

Thermal Conductivity (W/mK)    Electrical Conductivity (S/m)      Density (g/cm3)

Aluminum                                        200                                               3×107                        2.7

Copper                                             380                                               6×107                        8.96

Graphite                                         150-1500                                          0.7-2.1               Horizontal-2×105, Vertical-100

(Note: Units may slightly differ due to formatting limitations)



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