What Is The Working Principle of Flexible Soft Thermal Pad?

The core principle of flexible soft thermal pad is to fill the silicone matrix with high thermal conductivity filler, and fill the micro gaps with its own flexibility, turning the "air insulation layer" into a "continuous thermal conductivity channel", achieving excellent heat transfer and buffering insulation.

1. Structural principle

It usually consists of two parts:

Substrate: Soft silicone (silicone rubber), responsible for softness, compressibility, insulation, and aging resistance

Fillers: high thermal conductivity powders such as alumina, aluminum nitride, graphite, ceramic powder, etc

Silicone itself has average thermal conductivity, but it is filled with a continuous network of thermal conductive particles, resulting in a significant increase in overall thermal conductivity.

2.Heat transfer principle

The heat transfer mainly relies on three paths, and the thermal pad occupies all of them:

Solid thermal conductivity

The internal thermal conductive fillers overlap with each other to form a pathway, allowing heat to quickly transfer from the high-temperature surface to the low-temperature surface.

Interface contact thermal conductivity

The surface of the chip and heat sink appears flat, but at the microscopic level, it is full of bumps and depressions.

The flexiblesoft thermal pad is deformed under pressure, filling all gaps and driving away air.

Air thermal conductivity is particularly poor, and after replacing it with a thermal pad, the interface thermal resistance directly decreases by an order of magnitude.

Minor radiative heat transfer

Infrared radiation from high temperature surface → pad → low temperature surface to assist in heat dissipation.

3. Mechanics and Installation Principles

Compressible by 30% to 70%, automatically compensates for height differences and flatness errors

No need to apply glue or polish during installation, just stick and press once

Simultaneously serving as a buffer, shock absorber, and anti damage chip

Most models come with insulation to prevent short circuits between the radiator and components

4. Simplify understanding

You can think of it as a 'soft, conductive sponge'

Sponge=soft, filling gaps

The thermal conductive filler inside=countless tiny heat pipes

Function=Smooth and complete transfer of chip heat to the heat sink

5.What are the application scenarios of flexible thermal pads?

Flexible thermal pads, due to their softness, compressibility, insulation, and ease of construction, almost cover all heating devices and scenarios that require buffering/insulation/gap filling. The following are the mainstream and practical application areas:

1）Consumer Electronics&Digital Products

Laptops and tablets: between CPU/GPU/motherboard chip and heat sink

Mobile phones, smartwatches: chip, battery, camera module heat dissipation

Monitor, TV: backlight driver board, power board, COF/COG chip

Router, switch, optical modem: motherboard chip, power IC heat dissipation

2）Power Supply and Industrial Control Power Equipment

Switching power supply, adapter, charging station power module

UPS、 Inverter, frequency converter: IGBT, MOS transistor, rectifier bridge

Industrial control motherboard PLC、 Servo Drive: Power Device Heat Dissipation

Photovoltaic inverter, energy storage BMS system

3）Automotive electronics (especially new energy)

Vehicle mounted central control, ADAS autonomous driving domain controller

BMS battery management system, OBC car charger

Motor controller, DC-DC module

Headlights (LED headlights drive heat dissipation)

4）LED Lighting and Display

LED street lights, mining lights, panel lights

Outdoor large screen, MiniLED/MicroLED display module

Aluminum substrate heat dissipation for car lights and landscape lights

5） Communication and base station equipment

5G base station, RRU, AAU RF unit

Server, switch, optical module

Communication power supply, power amplifier module

6)Security, Aerospace

Security camera, NVR, DVR motherboard

Aerospace electronics, radar, high-precision sensors

7) Summary of typical usage locations

Between the chip and the heat sink

Between power device and housing/aluminum substrate

Heating surfaces that are uneven, have tolerances, and require insulation

Electronic components that are afraid of crushing chips and require shock absorption and buffering

Production lines that are inconvenient to apply thermal conductive silicone grease and require cleanliness and easy assembly