Heat dissipation is becoming a critical factor in determining product performance and longevity in today's increasingly complex and power-hungry electronic equipment. Engineers and do-it-yourselfers now favor thermally conductive silicone pads over other heat dissipation materials due to their superior filling capacity and dependable insulating qualities.
A thermally conductive silicone pad is a sheet-like thermal interface material composed of thermally conductive fillers and silicone as the foundation material. It has a smooth texture and high surface affinity, elasticity, and compressibility.
One way to conceptualize its operation is as a "filling and bridging effect": There are numerous tiny, imperceptible spaces between heat sinks and electrical components (such as chips). Heat transport is substantially hampered by the poor heat conductivity of the air in these spaces. The thermally conductive silicone pad is slightly compressed under pressure, precisely filling these spaces, releasing the air, and creating an effective heat conduction channel between the heat source and the heat sink.
Key features and benefits of silicone pads that conduct heat: Elevated thermal conductivity. The "thermal conductivity coefficient," which is its primary indicator, quantifies its capacity to conduct heat. The thermal conductivity of common thermally conductive silicone pads ranges from 1.0 W/m·K to more than 10.0 W/m·K, satisfying a variety of heat dissipation needs.
Electrical Insulation: By successfully eliminating short circuits and guaranteeing safe equipment operation, the silicone substrate itself serves as an excellent electrical insulator.
Softness, Elasticity, and Low Contact Thermal Resistance: Reduces contact thermal resistance greatly by filling uneven surfaces with ease and achieving tight contact even at low pressure.
Natural Adhesion and Usability: The surface is easy to remove and replace, and its slight adhesiveness makes it easier to install and position without the need for extra adhesives.
High and Low Temperature Resistance and Weather Resistance: Stable performance, resistance to weathering and aging, and a broad operating temperature range (usually -40°C to 200°C).
Cushioning and Shock Absorption: Protects precise components by offering a certain level of shock absorption.
Where is it indispensable?
LED Lighting: Thermal conduction between LED chips and aluminum substrate/heat sink housing.
Power Modules: Thermal insulation between the housing and power MOSFETs, transformers, and other heat-producing parts.
Chip heat dissipation in base stations, routers, switches, and other communication equipment.
Automotive electronics in new energy cars include motor controllers, battery management systems (BMS), and on-board chargers (OBC).
Smart TVs, tablets, and smartphones all have localized heat dissipation.
Industrial Control: Power device heat dissipation in industrial control equipment, including servo motors and PLCs.
How to Choose the Right Thermal Pad?
Choosing the right thermal pad requires considering the following key parameters:
The most crucial indicator is thermal conductivity. Higher isn't necessarily better; the power consumption of the heat source and the need for heat dissipation must be balanced. In general, low-power scenarios can use 1.0–3.0 W/m·K, while high-power scenarios need 5.0 W/m·K or more.
The parameter that is most likely to be selected incorrectly is thickness. The idea is that the thermal pad's thickness should be either slightly larger than or equal to the real space between the heat source and the heat sink. If it is too thick, it will not be compressed, increasing thermal resistance; if it is too thin, it cannot fill the space. Typical thicknesses range from 0.5 to 5.0 mm.
Hardness: Usually expressed in Shore 00. A softer pad with less hardness is easier to compress and fill in small spaces. However, severe compression may cause harm to an excessively soft pad for wider gaps.
Breakdown Voltage: If the application requires electrical insulation, this characteristic must be considered to ensure the equipment meets the insulation class criteria.
Size and Shape: Sheets are available for purchase and can be die-cut, punched, or specially shaped as desired.
When placing thermally conductive silicone pads, what safety measures should be followed?
Make sure the surface is clear of dust and grease by cleaning it.
If necessary, remove the protective film before carefully attaching and aligning the pad.
To guarantee complete contact between the pad and the surface, apply the proper amount of pressure.
To avoid ripping, do not bend or stretch excessively.
As a highly effective, dependable, and user-friendly thermal interface material, temperature-conducting silicone pads are essential to the current electronics industry. Achieving the best heat dissipation design requires a thorough understanding of and careful selection of factors, including thermal conductivity, thickness, and hardness.
