Heat dissipation is the dissipation of heat generated by heat-generating components into the air. Its technical principles include heat conduction, heat convection and heat radiation. For example, the direct contact between the CPU heat sink base and the CPU takes away heat, which is heat conduction; the cooling fan drives the gas flow, that is, thermal convection; thermal radiation refers to the transfer of heat by radiation. Generally speaking, heat conduction and heat convection are the two main ways of heat dissipation system, where heat conduction is mainly related to the thermal conductivity and heat capacity of the radiator material, and heat convection is mainly related to the heat dissipation area of the radiator.
According to the different means of heat conduction and heat convection, radiator products can be divided into active and passive modes. Active heat dissipation involves the use of energy irrelevant to the heating element for forced heat dissipation, such as fans, water pumps in liquid cooling, and compressors in phase change refrigeration. It is characterized by high efficiency, but it also requires the assistance of other energy sources. Passive heat dissipation is to rely solely on the self-dispersion of the heating element or heat sink for cooling. Desktop computers and notebook computers use a combination of active and passive heat dissipation, while light and thin consumer electronics such as mobile terminals and tablet computers are affected by internal space structure restrictions, and passive cooling solutions are mostly used.
The current mainstream passive heat dissipation schemes include graphite sheets, graphene, metal backplanes, ice nest heat dissipation, thermal interface materials (TIM), heat pipes (HP), and heat distribution plates (Vapor Chamber, VC). Thermal conductivity is the core indicator for measuring heat dissipation schemes. The thermal conductivity of the above schemes is from low to high, in order of metal, graphite sheet, graphene, heat pipe and VC.
Although the thermal conductivity of the heat pipe and the soaking plate is higher, its function is only to speed up the transfer of heat from the mobile phone heating parts to the heat sink, and the final heat dissipation depends on the heat convection between the heat sink and the air The thermal characteristics of the film material have a non-negligible effect on the heat dissipation effect of the mobile phone. Therefore, the solution of heat sink + heat pipe / VC fusion is expected to become the mainstream of development, which will benefit the participating manufacturers of graphite sheet, TIM and heat pipe / VC industry chain.