Comparison of New Thermal Management Design Solutions for Mainstream Mobile Phones

Especially in the era of 5G, a mobile phone cooling system is essential. Installing a cooling system is not only to meet the hardware needs of mobile phones, but also has a decisive impact on the user experience and sales level of mobile phones. After all, no one wants to hold a 'warm baby' when summer comes. At present, there are solutions for the cooling system of mobile phones. It can be roughly divided into two approaches: module heat dissipation scheme design and thermal conductivity material selection scheme.

01

Graphite heat dissipation

(Huawei Honor 20 PRO)

At present, Huawei Honor 20 PRO is a typical representative of using graphene heat dissipation solution. Due to its high thermal conductivity and diffusion of heat, graphite can provide users with a better user experience by reducing the thermal density of the heating area. In addition, it has the advantage of lightweight, soft material texture, and no additional interference with electromagnetic waves. The combination of metal backplate and graphite heat dissipation once seemed to be a standard configuration for flagship phones of major brands. However, with the thinning of the body and the gradual narrowing of the available convection space, this type of cooling system design is no longer the preferred choice for flagship models. At present, the simple graphite heat dissipation mode seems to only meet basic functional needs such as watching videos, browsing web pages, and communicating and chatting.

(Metal backplate combined with graphite heat dissipation)

02

Heat dissipation of gel

With the development of thermal conductive materials, the thermal conductive gel heat dissipation scheme appeared in the later period. Its principle is similar to that of thermal conductive silicone grease, which can transmit the heat of the core to the radiator or convection port faster through lower thermal resistance, and achieve the purpose of rapid heat dissipation. But thermal conductive gel and thermal conductive silicone grease are completely different types of thermal conductive materials. The thermal conductive gel is semi-solid and does not flow. It can be evenly applied around the heat source in the form of quantitative dispensing by a large-scale machine, so as to achieve rapid heat transfer, heat dissipation and other purposes. And compared to silicone grease, it has characteristics such as never curing, higher thermal conductivity, and lower thermal resistance.

(Huawei Honor V30 PRO)

At present, the mainstream mobile phone model in the market that uses gel for heat dissipation is Huawei Glory V30 PRO. With the use of thermal conductive gel, when the mobile phone runs large games or software for a long time, even if the special effects are fully turned on, there is basically no jam, and there is no obvious sign of burning on the hands. Therefore, thermal conductive gel has been applied to the heat dissipation scheme of high-end mobile phones, and has become one of the consideration schemes of major mobile phone manufacturers.

(Heat conduction gel heat dissipation application)

(Thermal conductive gel with copper foil heat dissipation application)

03

liquid cooling

Heat pipe technology has also been utilized by mobile phone manufacturers by covering the top of a liquid filled thermal conductive copper tube on the mobile phone processor. When the processor generates heat during operation, the liquid in the heat pipe absorbs the heat and vaporizes. These gases will pass through the heat pipe to the top of the phone's heat dissipation area, cool down and condense, and then return to the processor part, repeating the process to effectively dissipate heat. This heat dissipation solution is commonly used in gaming phones.

(Xiaomi Black Shark 2)

In order to solve the heating problem caused by high-frequency operation of mobile phones, Xiaomi Black Shark 2 series phones have adopted a comprehensive liquid cooling technology called Liquid Cooling 3.0. Through detailed disassembly and analysis of its mobile phone, it can be observed that this heat dissipation scheme not only upgrades the heat dissipation materials, but also improves the heat transfer efficiency through the optimization of the module multi-layer heat dissipation structure.

The thermal management plan first transfers heat quickly to the liquid cooling plate through liquid cooling pipes, and then evenly discharges the heat from around the body through the horizontal surface of the liquid cooling plate. This solution can not only effectively cover the heating parts of the body, but also achieve independent thermal control.