How does thermal resistance affect the thermal conductivity of the thermal pad?

The more commonly used heat dissipation method is to conduct heat from the surface of the heat sink to the heat sink by contacting the heat sink with the heat source surface. However, there is a gap between the heat sink and the heat source surface, which increases the contact thermal resistance and reduces the thermal conductivity, and it needs to be filled with thermal pad. Between the two, the interface air is eliminated and the thermal conductivity is improved.

Thermal pad is a kind of gap-filling thermal pad made of silicone resin as the base material and added with temperature-resistant and thermally conductive materials. It has the characteristics of high thermal conductivity, low thermal resistance, insulation, compressibility, etc., because it is soft Its hardness makes it possible to realize a smaller thermal resistance under low pressure conditions, and at the same time eliminates the air between the contact surfaces and fully fills the rough surface between the contact surfaces, improving the heat conduction effect of the contact surfaces. Because of the good filling effect of the thermal conductive pad, it can effectively conduct the heat of the heat source to the shell, and the thermal conductive pad has good compressibility and elasticity, and can serve as a shock-absorbing pad.

What is thermal resistance? Scientific description: Thermal resistance refers to the ratio between the temperature difference between the two ends of the object and the power of the heat source when heat is transmitted on the object. Its unit is Kelvin per watt (K/W) or Celsius per watt ( ℃/W). When heat flows through the interface of two solids in contact, the interface itself presents a significant thermal resistance to the heat flow, which is called contact thermal resistance.

The thermal pad itself also has thermal resistance, which is like debris on the track. When heat is conducted from one end of the thermal pad to the other end, the transfer speed is reduced due to the debris, so the greater the thermal resistance, the greater the heat transfer in the thermal pad. The stronger the thermal conductivity, the worse the thermal conductivity, and there will be two types of thermal conductive pads with the same other parameters except for thermal resistance, and their thermal conductivity will be completely different.