Freudenberg Sealing Technologies Thermal Interface Material (TIM) used in series-production EV charging port

Freudenberg Sealing Applied sciences has provided its Thermal Interface Materials (TIM) elastomer to be used in high-quantity collection manufacturing of a EV charging port for a well known automobile producer. The elastomer, which is warmth conductive and electrically insulating on the identical time, was first introduced in 2020 with a watch towards purposes for charging sockets, management models and batteries in electrical automobiles.

Behind the charging port cowl, the car shows a typical multi-pin connector for the charging cable, embedded in a plain plastic entrance. What stays invisible is the high-tech space proper behind it. Listed here are a number of parts the interplay of which is crucial for the thermal administration of the charging course of: a circuit board with temperature sensors and measurement and management electronics for charging administration, all secured inside a housing in regards to the measurement of a hand.

The Thermal Interface Materials (TIM) ensures the very best thermal conductivity between the housing and the sensors: It picks up the warmth stream via the copper wires linked to the battery and passes it on to the temperature sensors, thus selling the speedy build-up of charging management, together with the continual thermal administration of the car battery.


The 2-component plastic housing has a posh three-dimensional geometry, for the reason that charging plug’s connection poles go via it. It reliably retains the simply bent board in place and facilitates the meeting; the electronics unit is clipped in with snap connections.

The elastomer helps exact contact whereas its electrical insulation functionality shields the delicate electronics from the charging voltage of as much as 800 volts. Freudenberg Sealing Applied sciences manufactures the housing with injected elastomer and supplies it to an automotive provider, which in flip produces the module prepared for set up by the automaker. The latter installs it in massive numbers in series-produced autos.

This mission was proper up our alley, as a result of our materials is predestined for a variety of complicated electrical purposes. With its quite a few qualities, it supplies the suitable solutions. An essential benefit for environment friendly collection processes: The elastomer materials could be processed via injection molding. This additionally makes its use very versatile, since practically all three-dimensional geometries are potential and, because of its the fabric properties, at all times adhere optimally to the substrate—whether or not plastic or metallic. It may be sprayed on straight and doesn’t want primer.

—Armin Striefler, Product and Course of Developer at Freudenberg Sealing Applied sciences

Like all plastics, silicone is inherently thermally insulating. For the brand new materials, it’s blended with inorganic fillers that make it thermally conductive. These fillers are particular non-conductive metallic compounds.

Thermal conductivity for the revolutionary thermal interface materials is 1.7 to 2 watts per meter Kelvin. For comparability, the thermal conductivity of air is 0.026. The manufacturing course of makes thin-walled parts potential. In keeping with the warmth equation from Fourier equation, that is good for thermal conductivity.

Within the above-mentioned mission, the elastomer under the temperature sensor has a thickness of solely 0.8 millimeters.

Now we have had superb experiences with thicknesses between 0.8 and three millimeters. For bodily causes, warmth switch decreases when the partitions are thicker.

—Armin Striefler

The fabric achieves a CTI (Comparative Monitoring Index) worth of 600, inserting it in the very best safety class for monitoring resistance. The dielectric energy is greater than 10 kilovolts per millimeter. Because of this the frequent take a look at voltages of two.4 to 4 kilovolts gained’t pose any explicit challenges for the fabric. Its hardness is round 35 Shore A.

Having the ability to use an injection molding processes is a particular plus. The particular manufacturing course of prevents trapped air each within the elastomer and on the contact surfaces with different supplies. This would possibly in any other case result in electrical issues, akin to voltage breakdowns. The fabric is fire-resistant in accordance with UL94 with classification V0, which places it on the highest potential security degree.

Efficient warmth dissipation is a prerequisite for environment friendly processes in quite a few electrical purposes, wherever appreciable computing energy is required or excessive currents are flowing. Presently, typical purposes are within the discipline of electromobility, not least due to the numerous necessities when the charging voltage is 800 volts, which is more and more frequent in electrical autos. Cooled busbars in traction batteries are one instance. Particularly throughout quick charging or excessive energy output, these warmth up with comparatively excessive depth.

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