Thermally conductive silicone pads are a polymer composite made of silicone rubber and specially produced thermally conductive fillers. In addition to being soft, they have great heat conductivity, flexibility, and good insulation.
Essential Purposes and Uses of Thermally Conductive Silicone Pads
Thermally conductive silicone pads are primarily used for gap filling, heat transfer, shock absorption, and cushioning.
Closing the Gaps: Electronic components (such as chips and MOSFETs) and heat sinks or housings frequently have invisible air gaps between them. Heat transfer is greatly impeded by air, which is a poor heat conductor. Thermally conductive silicone pads' soft texture makes it possible for them to precisely fill in these uneven spaces and release air.
Heat Transfer: By forming an effective heat flow channel once gaps are filled, the thermally conductive silicone pad lowers core temperature by swiftly and uniformly moving heat from the heat source to the heat sink.
Shock Absorption: Its elastomeric qualities safeguard sensitive electronic components by absorbing and cushioning shock and vibration.
Electrical Insulation: Safe use is ensured by the silicone base material's inherent electrical insulation.
Main Application Areas:
LED Lighting: Heat conduction between LED lamp beads and aluminum substrates and heat sink fins.
Power Modules: In switching power supplies and inverters, these provide thermal insulation between the housing and power electronics.
Battery pack thermal management (BMS), motor controllers, and on-board chargers (OBCs) are components of new energy vehicles.
Chip cooling in computers, graphics cards, routers, and cellphones is an example of consumer electronics.
Communications Equipment: Cooling systems for servers, optical modules, and 5G base stations.
How Can the Best Thermal Silicone Pad Be Selected?
The following crucial factors should be taken into account when choosing a thermal silicone pad:
Conductivity of Heat
W/m·K is the unit. Greater thermal conductivity is indicated by a higher value. 1.0 W/m·K to more than 10.0 W/m·K are typical values.
Select based on the power consumption of the heat source and the required heat dissipation. A higher value is not necessarily better; cost-effectiveness should be considered. For general applications, 1.5-3.0 W/m·K is sufficient, while 6.0 W/m·K and above are recommended for high-power scenarios. Thickness
This is one of the most critical choices. The thickness must be greater than or equal to the assembly gap and perfectly fill the space after compression.
Measure the actual gap between the heating element and the heat sink and select a gasket that is 10%-15% thicker than the gap, relying on its compressibility to fill the gap.
Hardness
This is usually expressed in Shore C hardness. The lower the value, the softer the material and the easier it is to compress to conform to the surface.
For components with uneven surfaces or those that are susceptible to compression damage (such as chips), a softer gasket (such as Shore C 20-40) should be selected. A harder gasket (such as Shore C 50-80) is more durable but requires greater installation pressure.
Breakdown Voltage
This indicates the strength of the insulation capacity, measured in kV/mm. This parameter is crucial for applications requiring high-voltage insulation (such as power modules). Volume Resistivity (Volume Resistivity)
In addition to measuring insulation performance, the unit is Ω·cm; greater values suggest better insulation.
Safety Measures and Frequently Held Myths Regarding the Use of Thermal Silicone Pads
Make the Surface Clean: To prevent influencing thermal conductivity, make sure the surfaces of the heating element and heat sink are dry, clean, and free of debris and oil before applying.
Steer clear of excessive stretching: When handling and installation, use caution, as too much stretching could result in tears or deformation.
Compression Ratio: Thermal silicone pads that are compressed between 10% and 30% usually have the best thermal conductivity. To prevent harming the part or the pad itself, do not apply too much installation pressure.
Myth: It's better to have more thermal conductivity. Gaskets with medium to low heat conductivity are suitable for a wide range of applications. More thermal conductivity gaskets are frequently stiffer and require more installation pressure; thus, pursuing them mindlessly would just drive up expenses.
Myth: Better, thicker Heat dissipation is impacted by excessively thick gaskets because they increase thermal resistance. Select a thickness that corresponds to the gap. Silicone pads that conduct heat are a crucial part of electronic equipment's thermal management systems. Choosing and utilizing the right thermally conductive silicone pad can greatly increase a product's stability, dependability, and lifespan.
