The telecom industry has an increasing need for EMI shielding, using EMC gaskets in between metal housing covers. This ensures no interference of the high frequency signals, and this need is now increasingly present also in the automotive sector.
The vehicles become connected and more and more digitalized and electrified. All creating electric heat waste in PCB housings, in the electric motor and in the batteries. This has an ever-more-demanding need also for efficient thermal management.
EMC solutions for automotive applications
Most of the EMI shielding in automotive is accomplished by an extruded or dispensed Formed-In-Place (FIP) conductive gasket. Examples of EMI shielding applications in a car:
- ECU module
- OTA module
- Radar module
- Camera system
- On-board charger
An FIP gasket is either conductive or non-conductive. If you need both EMI shielding and environmental protection, then you’ll need to purchase two gaskets. One will be conductive on the inner side, and one will protect against water and dust on the outer side. The main advantages with a FIP gasket is that you can easily adjust the gasket for an advanced mechanical design, very thin housing walls, and it won’t need a groove.
An extruded gasket may be both environmentally protective and conductive in the same product. It has a thin outer layer of some of the gasket that is conductive. Its main advantages include environmental protection, access for open / close solutions, and a lack of need to dispense equipment.
Thermal interface material (TIM) solutions for automotive applications
TIMs are necessary in automotive applications that waste heat needs to be removed from electronics – e.g. digital components, electric powertrains, etc. Depending on the situation and overall design, either thermal pads, filler materials, or pastes can be used to ensure good heat transfer by filling out the mechanical tolerances between e.g. components and enclosures.
TIMs are for example needed in the following automotive applications:
- LED lighting
- Power inverters
- Camera modules
- Battery cooling
- ECU modules
- Radar modules
- Infotainment systems
- Electronic instrument clusters
Thermally conductive silicone pads can be used where heat must be conducted between a component and a heat dissipating surface without adding undue stress. They bridge what would otherwise be insulating gaps between surfaces. Fillers have properties similar to pads, but are dispensed in liquid form in production instead of being assembled as discrete parts. There are both curing and non-curing fillers, where the curing fillers are more form stable and therefore generally better suited for the rough ambient conditions often found in the automotive industry.
Thermal pads and fillers are especially useful where there is a need, beyond the heat transfer itself, to also absorb relatively big mechanical tolerances in the surrounding design, mandating bondline gaps ranging from 0.2mm to 4-5mm. Where the bondline is thin (20-150µm), e.g. where the heat sink is attached directly against the heat source, a paste is recommended. The thinner the bondline, the more efficient the heat transfer between the heat source and the heat sink.
Remember: there is no global standard for testing TIMs! Thus, it is impossible to design a complete thermal solution only based on data sheet information or to compare different suppliers’ products from data sheets alone. Instead, you must always test the TIM performance in circumstances that emulate the real application as closely as possible – preferably in the actual application itself. That is the only way to ensure that the performance the material provides is sufficient to solve your requirement.
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