Improved heat and flame resistance in EV batteries: WACKER introduces ceramifying silicone
Last update on Jun 17, 2026
Managing heat, preventing electrical failure, and maintaining structural integrity under fire conditions remain central engineering challenges in battery electric vehicle (BEV) design. WACKER presented innovative solutions for battery electric vehicle safety at the Battery Show in Stuttgart, Germany. One of the main areas of focus at the company’s booth was a ceramifying silicone that significantly improves the heat and flame resistance of thermal barriers.
The company also showcased thermally conductive potting compounds for effective temperature control of power electronics components. Because they exhibit little or no sedimentation, such products can be processed even after prolonged storage without involving any complex pretreatment.
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Potting compounds for thermal management
Another booth highlight was potting compounds for the thermal management of power electronics components: ELASTOSIL® RT 7616 TC and ELASTOSIL® RT 7624 TC. They are filled addition-curing silicone elastomer formulations that cure at room temperature. According to the company, this enables energy-saving processing of large and heavy components. ELASTOSIL® RT 7616 TC has a thermal conductivity of 1.6 W/mK, while that of ELASTOSIL® RT 7624 TC is 2.4 W/mK.
The most important requirements for thermally conductive potting compounds are on-spec thermal conductivity and low viscosity. The latter may cause the particulate fillers in such compounds to sediment after prolonged storage. In that case, the fillers accumulate near the base of the container, where they may also cake together. Redispersing the fillers is time consuming and may even require the use of special mixing equipment.
The company reports that these issues are solved by ELASTOSIL® RT 7616 TC and ELASTOSIL® RT 7624 TC potting compounds. The rheological properties of both products have been optimized so that sedimentation and agglomeration effects are no longer relevant to customers. If fillers still settle after unfavorable transport and storage conditions, they can be easily redispersed using standard mixing equipment.
ELASTOSIL® RT 7616 TC and ELASTOSIL® RT 7624 TC have a comparatively low viscosity of 5,500 and 8,000 mPa•s (as per DIN 53019), respectively. This means that these products can be used to fill gaps as small as a few hundred micrometers quickly, reliably and bubble-free. They cure at room temperature, which makes oven-free processing of components of any size possible. ELASTOSIL® RT 7616 TC and ELASTOSIL® RT 7624 TC are heat-resistant and low-emission formulations. They are mainly used in battery chargers in the field of electromobility, in DC/DC converters or in inverters for thermal management of discrete electronic components such as coils or inductors.
Solutions for electromobility
With its ELASTOSIL®, SEMICOSIL®, SILRES®, and WACKER Silgel® brands, WACKER offers a wide range of products and solutions for electromobility. At the Battery Show in Stuttgart, the Group featured the following products:
SILRES® MK is a condensation-curing methyl silicone resin that is readily soluble in various organic solvents. The product can be used as a binder or impregnating agent for mechanical and thermal barriers. Silicone-resin-bound laminates based on mica, glass fiber or mineral fiber withstand extreme temperatures over the long term. They retain their electrical and water-repellent properties, as well as their high mechanical strength.
ELASTOSIL® CM 18x potting compounds were developed specifically for the side potting of cells and the top potting of pressure-relief vents. These compounds cure at room temperature to form an elastomer of medium hardness. Self-adhesive grades are available too. In top potting applications, the potting compounds act as a protective layer without impairing the function of the vents. Side potting insulates the cells electrically and thermally. The potting compounds also provide mechanical support and protection. As a result, vibrations, impacts and thermal expansion within the cells can be compensated, without introducing mechanical stress into the cell assembly. As the silicone elastomer acts as a thermal insulator as well, heat transfer via the cell’s lateral walls is suppressed too.
ELASTOSIL® R 531/60 is a ceramifying silicone rubber for the insulation of busbars in high-voltage batteries. It can be extruded, which makes it possible to provide cost-effective insulation for such components. What is more, this silicone rubber also improves the safety of electric vehicles in extreme situations. In the event of fire, the rubber ceramifies. The busbars thus remain encased in the ceramic layer and stay electrically insulated.
You can review 1300+ silicone rubber grades for 25+ markets and compare specifications directly in the Master Catalog of Plastics.
Image credits: WACKER