Increasing need for EMC and thermal management in automotive
The vehicles become connected and more and more digitalized and electrified. All the waste heat created in PCB housings, in the electric motor, and in the batteries also creates an ever increasing demand 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, and if both EMI shielding and environmental protection is needed you need two gaskets. One conductive on the inner side, and one protecting against water and dust on the outer side. The main advantages with a FIP gasket is that you can easily adjust the gasket to an advanced mechanical design, very thin housing walls and most often no need for a groove.
An extruded gasket may be both environmentally protective and conductive in the same product. It has then a thin outer layer of some of the gasket that is conductive, see for example picture below showing Compashield 2.0. Main advantages are strong environmental protection, easy when need for open / close solutions and no need for dispensing equipment.
Thermal interface material (TIM) solutions for automotive applications
TIM’s are needed everywhere 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.
TIM 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.
Most important to know, is that there is no global standard for testing TIM’s! Hence, it is impossible to design a complete thermal solution only based on data sheet information; it is also impossible 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.