Thermal Management in Electronics

March 2, 2020 By
CMC Klebetechnik GmbH

A well-known rule of thumb in electronics states that reducing the temperature by 10°C doubles the service life of a component.

This shows that thermal management is an important topic for LED applications, solar converters and, for example, power electronics such as IGBT units. In other words, wherever heat is generated in confined spaces and can lead to overheating.

Thermally conductive insulation foils, silicone foil, metal foils

CMC Klebetechnik offers high-performance products (e.g. Kapton® MT) for "heat dissipation". So that the heat can be dissipated as quickly as possible from the point of origin.

A rough distinction is made between thermally conductive materials that are also electrically conductive and products that conduct heat but have an insulating effect. In addition to the Kapton® variants described here, you can also obtain thermally conductive silicone films and gap fillers from CMC. All of these solutions are of interest not only to device manufacturers, but also to EMS service providers.

The thermally conductive films and gap fillers can be used as galvanic separation from the heat sink or heat spreader, to compensate for unevenness on the circuit board or, if required, are also very thin and space-saving: CMC Klebetechnik offers the right material for your heat conduction path - in electronics production, transformer construction, for electric drives, electric heaters in dryers, air heaters, oil heaters, for power LED lighting, pipe trace heating or in other thermal engineering applications: Heat management on demand.

Kapton® polyimide films offer high dielectric strength, extreme temperature resistance, low shrinkage and cannot break. They are therefore particularly popular films in the electronics industry for flexible printed circuits, insulation and heat conduction. Kapton® MT films can also be used as a replacement for aluminum oxide ceramic discs (flexible, break-resistant). Due to their low thickness, they have a low thermal resistance.

Compensation of heat transfer resistances

For thermal management in electrical engineering and electronics, CMC Klebetechnik offers variants with different coatings based on the thermally conductive Kapton® MT films. These coatings even out surface roughness and thus significantly reduce the contact resistance that forms. Kapton® MT films significantly complement all products offered by CMC for heat management in electronics.

Other options for improving heat transfer resistance are, for example, soft silicone foils or heat-conducting pastes (more information on https://www.cmc.de)/

If no insulation function is required or is guaranteed by a mechanically defined distance, heat-conducting pastes can also be used for thermal bonding. These offer optimum surface wetting and excellent thermal conductivity with thin layers. They are available in silicone-containing and silicone-free versions. The ageing behavior (pumping out, squeezing out, flowability, heat resistance, etc.) is important here.

Other applications for thermally conductive TIM products include Industrial, street, ship, façade and parking lot lighting, stadium and stage lighting as well as vehicle headlights, on-board chargers, power converters, rectifiers DC/AC, converters DC/DC in e-mobiles (powertrain), servo converters as well as high-voltage electronics and in medical technology. Also for power grids, battery technology, dU/dT filters, interference suppression filters in general, high-performance capacitors, super caps and automotive applications (HEV, OBC, DC/DC converters).

Important: Considerations regarding the use of TIM products in the context of the life cycle

  • Behavior of TIM materials under surface pressure (pump-out)

  • Behavior of various TIM materials in the power circle (degradation)

  • Changes in thermal resistance in the presence of vibrations

  • What mechanical stress is transferred to the component by the TIM

  • Resilience (e.g. for Powercircle with CTE pumps) of TIMs (e.g. silicone foils)

  • Behavior with temperature cycles and shock load of interface materials

  • Compensation behavior of TIMs with higher order deformations (concave, convex, wavy)

  • Chemical resistance and behavior within electrical insulation systems

  • Fire behavior of TIMs

  • Change in tensile strength due to ageing or deformation (thickness reduction)

  • Settling behavior of gap fillers and thermally conductive joints under mechanical load

  • Installation "control" to select the correct TIM for the correct load (e.g. constant pressure or constant gap dimension)

  • General service life behavior of TIMs

Need for heat conduction in various applications and industries

Thermally conductive products from CMC are manufactured to customer specifications for the following applications

IT technology: WLAN routers, servers, notebooks, VOIP telephones, memory modules, hard disks and printers

Power supply: Inverters, power converters, grid components (smart grid), uninterruptible power supplies, DC/DC inverters, solar inverters, motor control units, buck-boost DC/DC converters; high-performance resistors with aluminium housings/heat sinks, grid voltage stabilizers, systems for power factor correction, energy storage systems, active filters, heat dissipation on passive components such as capacitors, resistors, transformers, for chargers of electric vehicles, in high-voltage power supplies, for electronic transformers and heat management in converters for photovoltaics, traffic engineering and wind power. e.g. capacitors, resistors, transformers, for electric vehicle chargers, in high-voltage power supplies, for electronic transformers and thermal management in converters for photovoltaics, transportation technology and wind energy

Automotive technology: Daytime running lights, brake lights (LED strip), electronics for power steering, ABS brake modules, car electronics, power semiconductors, HV junction box, battery container, car control unit (CCU), HV air conditioning system, HV ACC, HV booster, battery storage systems, HV batteries

Possible applications of heat conducting materials in vehicles:

  • Thermal management for devices such as the On Board Charger (OBC), the Battery Junction Bock (BJB), the Cell Supervising Circuit (CSC), the Battery Management System (BMS), the Electric Drive Unit (EDU), the Power Inverter Module (PIM), High Power Distribution Module (HPDM), the Battery Coolant Heater and the Air Conditioning Compressor Module as well as the various DC/DC Inverters (Accessory Power Module) for voltages below the high-voltage battery level (e.g. 48VDC, 12 VDC and 5 VDC).e.g. 48VDC, 12 VDC and 5 VDC), step-up/step-down converter

  • Dissipation of heat loss within the battery (e.g. via the terminal lugs, battery housing, busbars)

  • Thermally conductive insulation for high-performance electronics (e.g. on-board charger, frequency converter for the drive motor)

  • Thermal management for the electric motor and the motor control unit

  • for the thermal connection of SuperCaps for a longer service life

  • Protection of power LEDs (e.g. headlights, LED strips) against overheating

Home and lighting technology: Power LED lamps, smart meters, audio devices, LCD televisions, smart meter gateway (SMGW), LED drivers, constant current sources

Cooling technology, enclosure air conditioning, cooling modules: Of course, cooling units, heat pumps and Peltier elements (thermoelectric cooling modules) can also be connected to heat sinks using TIM products

In WBG (wide bandgap) electronics (SiC, GaN) or silicone-based (IGBT, thyristor) with higher operating temperatures and power-intensive, densely packed applications, Kapton® guarantees long-term electrical insulation and thermal conduction thanks to its high temperature resistance.

For insulation and heat dissipation on passive components such as chokes, capacitors, filters on converters, power resistors, current transformers, thermistors, braking resistors, mains filters, transformers and in systems for power factor correction, discharge resistors for safe discharging of batteries or capacitors in e-mobility, for example

For insulation and heat dissipation in active components such as power modules, MOSFETs, thyristors, power diodes, rectifiers, power system in package (PSiP), IGBTs, heaters made of thick film resistors (thick film heating elements)

For connecting temperature sensors to the surface to be monitored, for improving thermal conduction in heat exchangers, heat sinks and fans

as well as in medical technology and in the construction of electric motors and generators.

Applications for thermal conductive Kapton® MT/MT+ are found in nearly all kind of industry, especially for these markets and applications:

  • Electrical Energy Storage

  • Transportation (trains, busses, etc)

  • UPS and Motor Drives

  • Silicon Carbide (SiC) Applications

  • EV and HEV automotive applications

  • Telecommunication

  • HV- Airheater and HVCH (High-Voltage Coolant Heater)

  • Alternative Energy such as Wind and Solar

  • (High voltage) Heat pump

  • Industrial Power Conversion